Aquaculture Notes 4z543f

01/23/2009

Preliminary /definitions:

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Capture fishery – harvesting of fish or other aquatic organisms that nature has largely produced – usually related to commercial fishing (fishing for profit)

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Sport fishery – harvesting of fish or other aquatic organisms for primarily recreational purposes.

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Culture fishery (a.k.a. aquaculture – a farmer harvests fish or other aquatic organism (including shellfish aquatic plants) – that he/she stocked into a pond, cage, indoor recirculation tank, raceway, etc and a varying degrees managed their growth and survival often to be sold for profit. But also subsistence or to sportfishing.

Some familiar examples of aquaculture

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Channel catfish reared in ponds to be sold as food fish.

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Atlantic salmon reared in nearshore marine net pens as food fish.

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Rainbow trout reared in raceways for stocking purposes re/ sportfisheries

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Golden shiners and fathead minnows reared in ponds to sell as bait dealers

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Largemouth bass or bluegill reared in ponds for stocking primate and recreational ponds / small impoundments

Some less familiar examples of aquaculture •

Rearing marine flatflish in anchored, offshore marine nets as food fish (“open-ocean aquaculture”)

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Culturing redear sunfish in ponds for snail control

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Paddlefish ranching in small to mid-size impoundments (KY, MO, Asia) for caviar / meat market

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Ultra-extensive “family ponds” in Nepal and other 3rd world countries for subsistence

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Integrated aquaculture systems with carps (agriculture wastes placed in pounds to stimulate fish production)

Complete vs. Incomplete Aquaculture Operations

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Complete: producer deals with all life stages / aspects of rearing a given culture species: spawning – egg hatching – larval stage – fingerlings – adult stage; may even produce own feeds (e.g., Kahr’s paddlefish culture operation)

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Incomplete: producer deals only with a few life stages of a species – e.g. Mo sunfish producers often purchase 1-2” fingerlings, pond rear to 3-6” (“grow-out”) then sell or e.g. producer deals only with fingerlings and sells to others for grow-out

Common expressions/subcategoies of aquaculture •

Mariculture – any type of aquatic animal/plant aquaculture in ocean

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Brakish water aquaculture – in coastal areas

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Fish culture – rearing finned fish

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Shellfish culture – oysters, clams, mussels

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Crustacean culture – crayfish, shrimp, lobsters, crabs

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Marine farming – in ocean

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Open-ocean aquaculture – offshore marine farming

Warmwater and Coldwater Aquaculture

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commonly used in U.S. aquaculture

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originate from the two main culture species (channel catfish and rainbow trout) which involve very distinct rearing methods.

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In general, warmwater aquaculture involves fish that grow best at 21-30C (70-86 F) vs. 7-16C) (45-61F_ for coldwater fish

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“warmwater facilities” involve largely pond rearing and may include some coldwater species (catfish, LMB, BG, / HSB, crappie, walleye, muskelluge, perch [lost valley]

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Extensive vs. Intensive Aquaculture

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Extensive: Rearing culture species under conditions close to the natural production capacity of the rearing environment (e.g. a pond) typically low-maintenance (natural fish density; no supplemental feed) ○ (Note: in pond settings, adding only fertilizer to stimulate primary production is still considered “extensive”) ○ Example:

 Raising fish in fertilized or unfertilized fonds at natural densities without adding prepared feeds  Rearing planktivorous fishes in netpens or impoundments  Traditional polyculture

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Intensive – rearing culture species under conditions where productivity is artificially boosted to well above what is natural; maintenance of such unnatural conditions must be carefully sustained to avoid catastrophic loss.

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○ Common characteristics – use of formulated feed; high stocking density; need for water quality control – O2 NH3, disease control, need for continuous monitoring ○ Examples: Catfish ponds (stocking 10,000 vs. 500 fingerlings per acre), formulated feed, aeration, careful monitoring of DO ○ Salmon in net pens (high density; feed medicants) vs. salmon ranching ○ Indoor water recirculation tanks – RASs; formulated feed only; high fish densities; management of water quality; temp, chemistry and solids removal; disease control

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History of Aquaculture (and species cultured world-wide)

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Indo-Pacific ○ China:  Earliest records of aquaculture  Chinese aquaculture closely associated with silk manufacturing (2700 BC)  Artificial hatching practiced ~2000 BC  Treatise on Common Carp (*Cyprinus carpio) culture written by Fan Lai 475 BC  1214 AD: records of carp fry being transported in baskets (nature of early aquaculture)  1639 AD: Heu wrote “A complete Book of Agriculture” (carp collected from rivers and reared in ponds)  Story of origin of Chinese polyculture:  Common carp pronounced “Lee” in China  During 6th Century, emperor’s name also pronounced “Lee”, causing embarrassment b/c “eating common carp” sounded like one was “eating the emperor”  Efforts put forth to rear other carp species

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 Collected multiple carp species from rivers to rear in ponds, but couldn’t effectively select out the common carp; i.e., didn’t solve the problem but led to rearing of mixed carp species together, polyculture ; for which China is now known for

What is polyculture?

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Involves rearing of more than one culture species together to achieve productive advantage (versus monoculture)

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Best known polyculture developed and perfected by Chinese – involves rearing up to six “Asian carp” species together in ponds

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Production increases come from two sources:

○ 1) taking advantage of multiple feeding niches in a pond ○ 2) “enrichment effects” – feeding by one species enhances food supply of another

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Up to six species involved:

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○ Common carp Cyprinus carpio – consumes benthic invertebrates (chironomids) and detritus (detritus is dead organic matter) ○ Silver carp Hypophthalmichtys molitrix feeds of the phytoplankton in midwater ○ Bighead carp Aristichtys nobilis feeds on zooplankton in midwater ○ Grass carp Ctenopharyngodon idellus consumes vegetation (nearshore) ○ Black carp Mylopharyngodon piceus has pharyngeal teeth and consumes snails (imported for snail control) ○ Mud carp Cirrhinus moliforella eats decaying vegetation, some benthic inverts and detritus on pond bottom

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○ Enrichment effects – e.g., mud and common carps both consume the feces of grass carp; bighead carp’s zooplankton consumption releases trapped phosphorous which stimulates bottom-up productivity; grass carp feces stimulate primary productivity in pond ○ Note: the six carp species are not obligate feeders – i.e., some diet flexibility

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Chinese Polyculture ○ Chinese have perfected stocking rates of the six carps (or subsets), pond fertilizing regimes, and/or additions of agricultural wates to maximize fish production via extensive pond culture according to local conditions ○ Production data from China has been hard to secure. Former Soviet Union study shows polyculture (extensive) increases pond production 400-600 kg/ha at mid latitudes; 600-1000 kg/ha at southern latitudes. Chinese may achieve more production gains.

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Duo-culture ○ Involves rearing of two aquatic species together ○ We have reared bulegill and yellow perch together in cages and RASs to enhance BG growth ○ How – the perch interfere with aggressive behaviors among the BG (shading) which normally leads to dominate hierarchies

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Asian Polyculture (cont.) ○ Current trends are towards intensive polyculture where prepared feeds are given to further enhance pond production ○ Maximum polyculture production levels of 7500 to 8000 kg/ha (wow ~ 7000 lbs / acre) have been documented in the Far East ○ Average Asian production levels for intensive polycultures are 3000 – 4000 kg/ha

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Side note: Asian carp in U.S. ○ At least five of six major Asian carp (all but mud carp) introduced into U.S.

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○ Common carp introduced over a century ago ○ Other Asian carps more recently introduced for aquaculturerelated purposes (food-fish; vegetation control; snail control)

 Black carp for snail control  U.S. consumers eat negligible amounts of carp  Asian enclaves (large U.S. cities, Toronto) represent a substantial demand for bighead and grass carp; other carps  Establishment of Asian carp populations in “natural waters” of the U.S. (MS drainage) has contributed to negative view of aquaculture as an “environmentallyunfriendly” industry  Bighead, silver carp, and grass carp populations in MS drainage appear to be growing/expanding rapidly  Concern over trophic competition with native species – zooplankton, phytoplankton (evidence of declining Wr of resident species in IL)

○ Silver carp – Illinois River

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 Fish reaching weights up to 60 pounds  Major effort being put forth to exclude from Great Lakes  Jumping tendency is likely a fright response – presents hazard for boaters

○ Grass carp  Well-known for vegetation control  Reach 100 lbs: valued as a food-fish by Asian enclaves  Also present a jumping hazard when seining production ponds

○ A Point re/ Asian Carps  Characteristics that cause Asian carps that cause them to be so widely reared (in aquaculture) and consumed: 

E.g., general “hardiness”. High tolerance to handling; feed low on food chains but, flexible feeders; tolerate wide temp. ranges; highly prolific; disease resistant fast growers ---

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Also make good “invaders”

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History •

Chinese emigrants believed to have brought aquaculture concepts to nearby countries: Taiwan, Thailand, Malaysia and Indonesia

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Many species historically cultured in these four countries; most common is the milk fish (*Chanos chanos) whose culturing is believed to have begun in Java in the 15th century

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Euryhaline, fast-growing, reared in brackish water ponds; feed low on the food chain; disease resistant; harvested well below maximum sizes

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Cambodia: Siluroid catfishes have long been reared in bamboo cages in flowing water and ponds

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Most important species is *Pangasius sutchi reaching 150 cm (60 in); tolerates poor water quality; voracious feeders; supplemental feeding needed; high stocking densities (also sold as aquarium fish – Iridescent shark)

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Thailand: Pangasius spp. Has long culture history; also Java tilapia (*Oreochromis mossambicus) reared since 1930s; tolerate warm water, low DO and variable salinity

India/Pakistan:

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Long history of aquaculture documented back to 300 BC

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Major culture species include Indian carps: “catla” (*Catla catla), “rohu” (*Labeo rohita), “Mrigal” (*Cirrhinus mrigala); “calbasu” (Labeo calbasu); often grown together in polyculture

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Also catfish Pangasius and * Clarias spp. (possess accessory breathing organ – “walking catfish”) and prawns; Asian carps

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Reared together in polyculture

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Hybrids have been formed with Chinese carps for hybrid vigor (growth) in ponds

Japan •

Substantial aquaculture activity dating to 745 AD (clam culture)

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Current major culture species: mullet (*Mugil spp.) brakish water ponds; yellowtail (*Seriola quinqueradiata) cage culture now including “OOA” (Hawaii); common carp; rainbow trout (*Oncorhynchus mykiss); shrimp (*Penaeus spp.); oyster (*Crassostrea gigas)

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Mullet (mugil spp_)

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○ Exist world-wide, in temperate to tropic zones; harvested in capture fisheries ○ Inhabit marine / brakish waters; benthic feeders; max size ~20 in. ○ Excellent flesh texture and taste ○ >100 species; many species called mullet are not mullet (mullet’s favorable reputation being “extended” to other species) (e.g., white sucker in Ithaca NY) ○ Culture characteristics:

 Euryhaline  Wide temperature tolerance  Reared in brackish-water coastal ponds  Accept supplemental feeds (rice bran, peanut meal) beyond natural diet  Cultured mainly as a food fish  Artificially spawned – gives control over seed availability; versus harvesting seed

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Yellowtail Seriola quinqueradiata (Carangidae)

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○ Pacific Ocean; pelagic species; fast swimmers ○ Culture: reared to 4-6 pounds (age 2); cage culture; cannibalistic in culture systems

Australia •

Oyster farming has longest hsitroy (1800s): rock oyster (Crassostrea commercialis); marron crayfish (*Cherax tenuimanus) and red claw (C. quadricarinatus); rainbow and brown trout (Salmo trutta); recently Southern bluefin tuna reared for Japan’s sashimi market

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Hawaii; Milkfish (Chanos chanos); freshwater prawn (Macrobrachium rosenbergii); mullet (Mugil spp.) in ponds

Southern Bluefin Tuna (Thunnus macoyii) •

Reared off southern Australia since 1991 (Port Lincoln)

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High prices paid by Japan fish market; One grow-out net-pen (pontoon) contains ~1700 fish; market value $1.7 million

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Individual fish (dressed, frozen) auctioned off in Japanese fish markets

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Loaded into transport pontoons and slowly (1 month) towed to coastal rearing area

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Currently fed baitfish (prepared diets being developed – less costly); 40,000 tons baitfish used annually in one operation! (bioconcern??)

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Fish reachmarket weight between 20-30kg (55 lbs) in 4-9 months

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Culturing the fish give desirable marble trait

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Overfishing and consequent low/declining densities of SBFT and also NBFT keep value of cultured BFT very night

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Entry into SBFT culture operation difficult; --must be former commercial fisher with quota-harvest share;

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Pontoons costly ($80-200k); feed costs high; must secure coastal area lease

Tasmania

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Trout farms; giant freshwater grayfish (*Astracopsis sp.) reaches 8 lbs, activity in Moberly, MO (“freshwater lobsters”)

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Atlantic salmon

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Aquaculture advantages in Australia and Tasmania; strong government leadership favorable for aquaculture; low population density; good environmental record; proximity to vast Asian markets

Trend shift in Indo-Pacific region: •

Post WW-II, aquaculture production focused on efficient protein production to feed growing human population high-yield/ lowinput species e.g., carps, tilapia and mollusks; environmentally favorable – little N, P, BOD

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Post 1980, emphasis shifted to production of “high-value” carniv. Species (shrimps/salmon), paralleled by shifts from extensive to more intensive rearing; commercial feeds, protein wasting, less environmentally friendly

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This was in response to growing demand for certain higher-levelfeeding species by the “sophisticated pallet” of developed countries like the U.S.

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E.g. Indonesia; milkfish to black tiger shrimp (*Penaeus monodon); China, the base of efficient carp production became #1 shrimp producer

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“Feeding up the food chain”; more protein required; more wastes / pollutants

Israel is only country in region with substantial history of aquaculture

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Main species cultured; common carp, tilapia, mullets, other Chinese carps in polyculture with common carp

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Inrael has water supply limitation – led to reduced total culturepond numbers as development has progressed:

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Post 1970s, # of ponds declined (79 to 59; 10,000 to 7,000 surface acres 30%)

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Yet, fish yields increased (3.5 + tons/acre) by shifting from monoto polyculture (intensive)

Egypt – some pond culture of Indian carps (Labeo, Cirrhina, Catla) plus eel (*Anguilla), Chineese silver carp (*Hypophalmichthys molitrix); common carp and Nile tilapia (Oreochromis niloticus) (major species)

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Iran – sturgeon (*Acipenser spp.)

Syria – African catfishes (*Clarias spp.)

Iraq – Barbus spp. (local herbivorous cyprinid; Tawes); common, grass and silver carps in pond culture; 1,893 fish farms; Fish Research Centre; Baghdad – aquaculture research; 100 of staff

Sudan – Heterotis niloticus (African Arowana, filter-feeder, omnivore / carnivore)

Saudi Arabia – tilapia, marine shrimp. Freshwater prawn, rabbitfish (Siganus spp., marine, herbivore); water limits

Europe

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Aquaculture quite widespread

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Earliest records from Rome 2000 years ago - - Oysters collected from Adriatic Sea and transferred to locations where they might grow better

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Central and Western Europe •

Fish culture developed in Middle Ages (11-1400)

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Common carp main species

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Carp bred and cultured in monasteries

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, Poland, Czech, Hungary, Yugoslav. And Romania cultured carp at significant levels

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14th Century – trout culture stimulated by French monks who developed artificial fert. Capacity

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15-16th Centuries – carp culture grows in prominence (450,000 ac of carp pronds in Bolivia, Moravia and Czech)

England •

Aquaculture established 14,00-1500 AD (carp focus)

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Current culture species: marine flatfishes: plaice (*Pleuronectes platessa), Dover sole (*Solea solea) and turbot (*Scophalmus maximus)

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Blue mussel Mytilus edulis (suspension culture)

Scotland

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Atlantic salmon (Salmo salar), brown trout (*Salmo trutta) in net pens; market values often plunge for salmon when large producers saturate the market; e.g., Nutrco (35% of total on world market)

Europe •

History of strong interest in crayfish culture in Scandinavia, Austria, Poland and Spain

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Native species (Actecus) decimated by fungal disease (the plague) 1960s-70s

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Crayfish imported from California: signal crayfish (*Pacificatus), and from Louisiana: red swamp crayfish (*Procambarus clarkii); high prices paid to U.S. producers

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Spain currently major aquaculture producer in Europe – current top species: blue mussel, rainbow trout, gilthead bream Sperus auratus (demersal species; reared in costal ponds; also cage culture) (demersal means near the bottom)

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Norway: long fishing history – major fish eaters

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Yet, fish farming began only in 1950s with 70-80 trout/salmon farms by 1970s

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Net-pen culture of salmonids prominent by late 1980s (82,000 tons/yr)

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Production jumped to 170,000 tons/yr by early 1990s; now among top producers of salmonids in world (esp. Atlantic salmon)

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Currently the largest aquaculture producer in Europe; Salmon, rainbow trout and blue mussel

Scandanavia •

Denmark ○ Mainly involved in trout culture: 90% rainbow trout (*Oncorhynchus mykiss) w/ 600 farms by 1972 ○ Brown trout cultured mainly by exporting eggs; much global demand for healthy BT eggs ○ Trout cultured in ponds and fed “trash fish” collected from seas (vs. pelleted feed_ due to high availability of prey fish.

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and Italy ○ Also significant European producers of trout. ○

 Top culture species now: Pacific cupped osyteer Crassostrea ariekensos, blue mussle and rainbow trout

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Russia •

Modest production of carp in major cities including Leningrad

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2500 ac of ponds in 1970s

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Sturgeon culture was prominent – mainly for caviar production

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In U.S. efforts to rear white and shortnose sturgeon are ongoing; artificial spawning and culture; high market value potential

Africa •

Despite food security issues, little development of aquaculture, particularly inland; northern nations – water limited; southern nations = abundant water but economically limited.

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U.S. AID s efforts to increase aquaculture

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Tilapia stocked at 1-2 fish/m2 agriculture byproducts fed; very extensive w/ little to no managmenet; Clarias garipinus

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High reproductive slows tilapia growth rates

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Despite producing few eggs, survival very high

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Stocking of Hemichromis fasiatus (predatory cichlid) often done to control tilapia reproduction

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Vs. use of mono-sex males (sex-reversal) as in more advanced tilapia culture operations

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Stocking of Hemichromis fasciatus (predatory cichlid “banded jewelfish”) often done to control tilapia reproduction

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Vs. use of mono-sex males (sex0reversal) as in more advanced tilapia culture operations

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Some trout production done in coastal Morocco

Central and South America •

Historically very little aquaculture activity but rapidly increasing – impacts on U.S.

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Mexico: pond culture of common carp began – 1964 w/ 31,000 acres of ponds, tilapia species introduced as well as grass carp (*Clenopharyngodon idella)

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Brazil: also involved in carp farming. Rearing parana and tilapia. Great potential for increase: large freshwater supply. Soybean production (good protein source for tilapia)

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Now major exporters of “fresh” tilapia (iced) into U.S.; flown into Miami to wholesalers

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China’s subst. exports of cheap, frozen tilapia to U.S. plus C/S American’s imports squeezes U.S. tilapia producers; few U.S. tilapia niches exist (live market?)

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Shrimp farming (*Penaeus spp. Whiteleg and blue shrimp) developed substantially

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Chile has emerged as major producer of Atlantic salmon (*Salmo salar) in nearshore net-pens

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Production comparable to Norway and Scotland, also coho salmon (O. kisutch), rainbow trout, seaweeds (uses: food, fertilizers, biofuels, cosmetics)

North America •

Aquaculture only about 150 years old in U.S.

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Oysters received earliest attention; initially harvested from public beds by hand; 1850s

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Yugoslavs settled in Louisiana brought knowledge of oyster farming, involved harvesting and translocating small oysters in favorable settings

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Theodatus Garlick – began artifical fertilization of brook trout (*Salvelinus fontinali) in 1853

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This is key development stimulated growth of trout and salmon culture in US and gov. fisheries

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Early culture efforts were aimed at producing fish to stock natural waters, enhance fishing activities and counter fish stock depletion

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Declines in U.S. capture fisheries reported as early as 1762 striped bass (*Morone saxatilis) and sturgeon eliminated from Exeter River in NH, dam building had prevented alewife from spawning in NW by 1790

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Privately owned hatcheries emerged 1864 Seth Green began rearing brook trout – originally planned to rear food fish but made more by selling eggs; hatchery building still used by NYDEC

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By 1870 fish cultures practiced in 19 of 37 states

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In addition to the prominenet brook trout state fish commissions cultured Atlantic salmon, American shad (Alosa sapidissima), lake trout (Salelinus namaycush), yellow perch (*Perca flavescens) largemouth bass (*Micropterus salmoides) and others

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Many species transported about the country – stocked well outside their native ranges (Larval fish often stocked due to inability to rear to later stages) (survival was assumed better in non-native environs)

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1870 a meeting of fish culturists in New York resulted in formation of the American Fish Culture Association which later became the American Fisheries Society

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Commerical wamrwater fish culture

○ Baitfish •

Commericail catfish farming (channel catfish, *Ictaluris punctatus) farming emerged in 1950s after failing efforts with buffalo and indications at Aurburn University that catfish could be reared profitably; fash growth, hardy species

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Substantial gov’t research funding was directed towards enhancing catfish rearing techniques in MS

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Crayfish farming began in 1940s in Lousiana – industry remains focused there today

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1969: 1,300 acres 1980s: 140,000 acres

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Major farmed species is red swamp crawfish (*Procarnbarus clarkii)

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Lesser involvement in: MO, TX, MS, NC, SC and AR

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Hint: know order oa appearance of catfish, crayfish, baitfish and brook trout production in U.S.

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○ Baitfish, crayfish, catfish Canada and Alaska •

Japanese Oyster (*Crassostrea gigas) culture practiced as early as 1912 in British Columbia with seed imported from Japan

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Freshwater trout farming began in 1950s

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Salmon culture emerged in 1970s. Pacific salmon; coho (*Oncorhynchus kisutch) Chinook (O. tshawytscha), rainbow trout (O. mykiss) and the Atlantic salmon (Salmo salar) are major species cultured

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1984 – 10 licensed salmon farms along B.C. coast – over 170 by late 80s

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Atlantic Salmon most prominent salmon species cultured on Pacific Coast

Basis for Aquaculture

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World human population growing exponentially:

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Population “doubling times”; 1700s (230 years); 1800s (100 years); since 1950 (37 years)!

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Population increased from 2.5 billion in 1950 to 6.1 billion by 2000Recently growing nearly 90 million annually (about like adding a new U.S. every 3 years)Despite slowing trends, population expected to continue rapid increase possibly reaching 10-12 billion before leveling off as 2050 its approached

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Global birth rate is 27/1000 people and death rate is 10/1000 per year

Trends in per Capita Consumption

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In addition to population size, per capita consumption also influences the strain placed on world’s essential resources (water, food, energy) by the human population

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Global demand for food is increasing to a large extent b/c of exponential human population growth, but also substantially b/c of increasing per capita demand.

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Grain does not for all sources of human food but its availability is a good, global-scale barometer of food availability for humans.

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Grain consumption

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Developing countries: 400# / person /yr. here grain is largely consumed directly

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Developed countries: 2000# / person, <10% being directly consumed, mostly eaten in form of animals that were fed grain.

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Associated efficiencies of grain to protein conversion; beef: 31%, pork 56%, poultry 71% (wasting protein)

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As countries develop and become more affluent, they include more animal products in their diet thus further increasing demand on world grain supply.

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Increased demand for grain contributes to higher prices and may negatively affect availability to poorer countries parallel situation with aquatic species consumed e.g. eating salmon vs. carp

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Only 30% of world’s land is suitable for food production (crop, rearing and grazing by food animals)

Increase land production? •

Increase land area farmed

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Increase yields on existing farm land by multi-cropping, fertilizing and imgating, use of pesticides

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Negative environmental impacts

○ Overuse of water supply ○ Loss of high quality farm land ○ Pollution impacts

Alternative food sources •

Single cell proteins from algae, yeasts and bacteria

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Fish Protein Concentrate

○ Contains high-density fish protein ○ Aimed at using underexploited fish stocks ○ Species used: hake, menhaden, herring, anchovy, alewife, ocean pout (oily; high fat) ○ Expt. Facility in MA produced 7.5 tons of FPC from 50 tons of fish per 24 h.

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Hydroponics •

Growing plants in nutrient solutions (water) as opposed to soil; minimal land requirement

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Liquid hydroponic systems have no medium for mechanical of plant; aggregate systems incorporate medium (sand, gravel, rockwool)

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Potential for high productivity, conservation of water, minimal land requirement and environmental impacts

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Systems that include fish as nutrient source for plants have received attention (fish feeds sometimes used)

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Hydroponics has had multiple upstarts since late 1800s; though believed to hold good potential, has not reached potential to date.

Consumption of Fish

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~20% of global protein consumption as fish

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Mean, global per capita fish consumption; 12 kg (27 lbs/person/yr)

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Highly variable by world region:

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○ Europeans and Asians consume fish regularly ○ Greatest fish consumers: Iceland (196 lbs/yr), Japan (164), Denmark (89) ○ Latin America variable: Brazil, Cuba, Mexico: low levels (<20 lbs); signif. Higher in Panama. ○ Middle East and Africa: generally low; higher in coastal areas

Consumption of Fish in U.S.

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Beef and pork historically most importantn animal protein in diet (100-150 lbs/person/yr)

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Poultry: 40-60 lbs (globally, has sured beef)

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Fish: distant 4th (10-15 lbs); tendency to focus on high-value species (salmon, shrimp); eaten more for taste than as a source of protein

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Low fish consumption in U.S. has impeded growth of U.S. aquaculture industry

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Fish protein content similar to beef and chicken (18%) and higher than pork (10%)

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Fish generally have low fat content similar to chicken (<5%); less than beef and pork (10-18%); beef and pork fats being reduced

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Fish have lower caloric density due to lower fat (2 cal/g for RBT) than beef (27) and pork (51); similar to chicken

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Fish, crustaceans, mollusks 90%-100% digestible due to high ratio of muscle protein: connective tissue, relative to mammals

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Fish low in cholesterol relative to beef and poultry; high in omega-3 PUFAs; believed to reduce arterial sclerosis; enhance brain function)

Some “shellfish” (lobster) higher cholesterol Fish vitamin rich: A,D (fish liver oil), B complex; also good sources of P, K, Fe, Ca, Mg and Cl, trace minerals

Four Compositional Groups of Fish

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Low fat / high protein (<5%/>15%): channel catfish, lobster, shrimp, RBT, tuna

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Medium fat (5-15%) / high protein: Pacific and Atlantic salmon

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High fat / low protein (>15%/<15%): lake trout, herring, mackerel, sardine

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Low fat / low protein: Oysters and clams

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Very high energy fish: eel (17% fat)

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High protein fish: yellowfin tuna (34%)

Situation with Capture Fisheries

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Oceans cover 70% of world’s surface; freshwater lakes and streams cover only 0.4%

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Common view as recently as ~1950s was that overuse/depletion of marine fishery resources was unlikely to impossible

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In fact, open ocean areas (90% of total) are low in productivity due to low nutrient supply; levels of photosynthesis (algae production) – the base of fish production are generally low here

01/23/2009

Situation with Capture Fisheries •

Nearshore marine areas e.g., estuaries, shallow continental shelf zones, certain upwelling areas where nutrients vertically transported to upper, warmer waters are the most productive areas (10% of ocean surface)

•

Estimates of instantaneous total available fishery products from all oceans: 220-275 mmt

•

However, much less than this amount is available in a sustainable way

Situation with Capture Fisheries

•

Estimates of sustainable yield of fishery products from all oceans (more meaningful) range from 75-150 mmt/year

•

Higher sustainable yields have been thought possible, if lower-foodchain marine organism were targeted also (e.g., krill in Antarctic – bad idea!)

•

Implication from harvest curve is that we’re extracting all that we can from world’s capture fisheries

01/23/2009

•

Likely we are harvesting above sustainable levels b/c despite increasing fishing effort harvest is showing indications of decline

•

In reality, to maintain harvest of about ~90 mmt/yr we are “fishing-down” many populations to “economic extinction” then jumping to the next most available population (“fishing up”)

•

Economic extinction: costs can not be recouped on fishing population

•

also targeting smaller and smaller fish

Fishing pressure •

Harvest increases, stimulates fish production

•

Increase slows, approaching max sustainable level

•

MSY = max sustainable yield (anything past is, called overfishing)

•

Harvest downturns, harvesting beyond replacement capacity

•

Drops rapidly increase

•

“Fishing down” the population

Situation with capture fisheries

01/23/2009

•

FAO data indicated that 50^ of FRPs have been overexploited (fished down), while about 25% are fully exploited or in early stages of overexploitation

•

Only about 25% of FRPs are considered underexploited (recent Science article – 2040)

•

Note!: fished-down FRPs often don’t rebound for long periods after fishing pressure is relaxed due to bio-ecological reasons

•

Also, any signs of modest population recovery often bring about renewed fishing pressure

Influences on aquaculture’s growth

•

Environmental impacts from aquaculture: as aquaculture grows, an environmentally concerned public keeps watch

•

Logic suggest that aquaculture should avoid rearing carnivorous species (salmon, trout, cod, halibut, tuna, walleye, perch, HSB, LMB, but rearing of carnivores is increasing fast due to high demand and profit potential

01/23/2009

•

At current rates of increasing carnivore production supplies of fish (high-fat species) for fish oil and fish meal projected to be extinguished by 2010 and 2050

•

Aquaculture thought to “spare” capture fishery species, but has increased overfishing of some; already extending to additional species: mackerel, herring, shifting. Norway pout and krill; fishmeal prices will increase

General points •

World harvest from capture fisheries has fluctuated annually since 1996 around 90 MMT/ YR

•

Total harvest from aquaculture has shown a steady increase since 1996, reaching 37.5 MMT in 2005

•

Currently about 30% of total harvest comes from aquaculture, while 70% comes from CFs

•

75% of total fish harvest going to human consumption 25% going to animal production

•

Per capital availability of fish has been increasing reaching 35.7 lbs per person per year

01/23/2009

China’s Major influence •

s for 18% of capture fisheries

•

Aquaculture harvest 69% and total harvest 33%

•

China believed to be overstating their harvest levels from all sources, such that globally we’re not as well off as we think

•

Without china, no increase in world harvest since 1988

Suitability of aquatic organisms for culture in any rearing setting is critical to success and depends on many factors.

•

General: a species may have high market value but not be economical due to high competition from other producers (e.g. yellow perch) or due to requirement of conditions/resources not available (e.g., rainbow trout which require continuous high volumes of cold water)

•

Alternatively, local conditions may be ideal to rearing a species but acceptability/demand may be low (e.g. Macrobrachium – rw prawn)

01/23/2009

•

Typically, only well-established producers able to “test the waters” for a new culture species (Kahrs have profited greatly with paddlefish but had firm base prior to that)

•

Many culture aspects may be favorable for rearing a species in a given setting but a single weakness may be economically fatal

•

E.g., many MO producers must “live haul” their products to market: this 1 increases operational costs (hauling truck, travel costs, personnel) 2 renders some culture species infeasible to due to long distances to major buyers

•

Curt Harrison has established purchase agreements (paid good prices) with Chicago fish housing plants.

•

Selected species must be amendable to culture conditions examples of “problems”

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E.g., some MO entrepreneurs invested in large, recirculation systems (RASs) and started by rearing walleye (have high market value in northern Midwest)

•

Walleye present severe probelsm due to cannibalism (must size grade, keep satiated); growers lost initial product and whole facility due to insufficient research hybrid walleye better choice)

01/23/2009

•

Must interest in rearing crappie – strong demand – but species prone to becoming overstressed at harvest and

•

Temperature: many culture species eurythermal, but most grow optimally only with a narrow temp. range e.g., 4-5C

•

E.g. bluegill survive and exhibit some growth from 4-31C (39-88F), but grow best at 22-26C

•

To be competitive, must be able to provide optimal temp to growth of species for substantial portions of year

•

This is why advantages exist for certain species at different latitudes in ponds e.g. perch / walleye to north: bluegill to south

•

Maintaining constant favorable temps possible with, heated effluents, springs, underground, indoor pools

Biological considerations

•

Temperature: optimal-growth temperature ranges for juvenile fishes are typically higher than for adult stages (7C)

•

Water quality:

01/23/2009

○ In addition to temperature, DO, ammonia (NH3) and nitrite (NO2) are often the most critical water quality parameters in aquaculture (DO monitored daily) ○ Range of tolerance for DO: trout species typically require >56 mg/L and so require large volumes of cold water for production; tilapia can tolerate <1 mg/L DO ○ Ammonia is excreted over the gills in fish and is toxic. It is readily broken down to nitrite by de-nitrifying bacteria (less toxic) causing brown-blood disease, and then to non-toxic nitrate

•

Salinity: Many culture species grow best in either fresh-brackish- or sualt water (35 ppt) a few species grow well over a wide range of salinity

•

Some species cultured at extremes of tolerance range to produce other benefits e.g. channel catfish reared at 6 ppt as this reduces off-flavor problems, negates reproduction in ponds, no effect on growth

01/23/2009

Natural feed:

•

Blankton, macrophytes, benthos, detritus, molluscs and other smaller animal species

Prepared (artificial) feed: •

Complete diets supply all the nutrients necessary

Importance

•

Supplies nutrients required for optimal growth

•

Increases fish production

•

Also, reduces culture period as fish gains body weight at their maximum potential

○ Feed costs 40-60% of operational costs in fish farming

Major components of a feed

•

Complete feed ○ Water

01/23/2009

 nutrients 

Dry matter •

Inorganic ○ Minterals (salts)

•

Organic ○ Proteins, lipids, carbohydrates

Nutrients •

Nutrients are organicia nad inorganic compounds needed to essential life processes

•

Nutrient is considered to be essential if an animal can not synthesize them – has to be provided via food.

Proteins •

Made up of amino acids

•

Fish consume protein to build new proteins (as during growth and reproduction) to replace existing proteins (maintenance)

•

Protein also serves as an energy source

•

Essential amino acids vs. Non essential amino acids

•

EAA – fish can not synthesis

01/23/2009

Carbohydrates

•

Carbohydrates are compounds made up of sugars

•

Function: Sources of energy

•

Fish, particularly carnivores, are not efficient in utilizing carbohydrates as energy

•

Classified by size

○ Monosaccharides / simple sugars (glucose) ○ Disaccharides (sucrose) ○ Oligosaccarides and polysaccarides

Lipid

•

Five major classes: fatty acids, triglycerides

•

Phospholipids, sterols and sphingolipids

○ Functions

01/23/2009

 Source of energy  Components of cell membranes  Serve as a vehicle for the absorption of fat-soluble vitamins

Vitamins

•

Required for normal metabolism, and normal biological functions

•

Vitamin deficiency causes growth deficiency

Minerals

•

Needed for the formation of bones, scales, teeth, etc and for many physiological functions

•

E.g. Calcium, phosphorous, sodium, chloride, etc

•

Fish can absorb part of the required minerals from water through gills

01/23/2009

Energy

•

Intake energy: gross energy content of food soruces

•

Digestible energy: difference between gross enerhy and energy available to animals

•

Metabolizable energy: Difference between digestible energy and energy lost

Feedstuff

•

Feed incredient suitable for production of animal feed

•

Sources of nutrients

•

Protein rich foodstuffs:

○ Animal protein sources ○ Plant protein sources

•

Energy rich feedstuffs: corn, wheat, oil

01/23/2009

•

Fish meal: ground product of dried, defatted fish or fish processing waste

•

Pultry by-product meal: made from rendered parts of slaughtered poultry

Types of GI Tract

•

Herbivores ○ Small stomaches and long intestine  Tilapia  Car

•

Omnivores ○ Moderate size stomach and intestine  Catfish

•

Piscivores/Carnivores ○ Large stomach and short intestine  Trout  Striped bass

01/23/2009

Factors in choosing feedstuff

•

Nutrient content

•

Digestibility

•

Price

•

Availability of feedstuff at your area

•

Palatability

Feed types

•

Floating pellets, slow sinking pellets

•

Diets for different life stages (2-3 diets)

○ Fry feed ○ Fingerling feed ○ Adult feed

•

Juvenile level: high protein

01/23/2009

Importance for providing right amount dietary nutrients

•

Provides optimum growth and health

•

Reduces feed cost and feed waste

•

Reduces nutrient pollution

Biological Considerations

•

Biological Considerations ○ Growth Rate  In general, fast-growing species preferred in aquaculture  Less obvious benefit of faster growing species is reduced risk of “crop” loss  Investment in a crop increases exponentially as the growth period progresses  But-so does the likelihood of mass mortality as the increasing fish biomass approaches CC of system

01/23/2009

 Acceptable maximum grow-out time (growing juveniles/fingerlings to larger market size) in U.S. is typically two years (e.g., blugills)  High-value, slower-growing species (>2 years) are sometimes still reared b/c high prices paid; offsets “risks” of longer rearing times  E.g., Signal crayfish (Pacificus leniusculus) takes up to three years to rear, but commands high market values, producers more likely to take risk  Fast growing



Red swamp crawfish •



Hatch to market size: 3 months

Paddlefish •

Polyodon spathula – ave. 2.2 lb weight gain per month (in ponds vs. rivers)



Grass carp 1.1 lb per month under ideal conditions

01/23/2009



(note: MO producers unable to maintain fast grass carp growth for long, due to running out of pond veg. need prepared diet; larger fish desired; tier method – Paula Moore

 Even fast-growing species reach natural slow-down points – usually association with maturation; slower growth continues  Often, culture species are harvested once “slow-down” point reached, to avoid loss of time efficiency  E.g. recall milkfish grow rapidly to 1 lb and then slow down, commonly harvested at 1 lb despite capacity to reach 10 lbs  Main Points – faster-growing species are generally advantageous (time efficient, less risk) but there is sometimes good reason to rear slower growers market size etc

○ Feeds and Feeding – preliminary points

01/23/2009

 Must be able to accommodate a culture species’ shifting nutritional needs with life stage  Protein and energy requirement change with stage – often, only generic diets available – too little P&E for young, too much for older fish (e.g. fatty liver problem)  Local e.g. Currently can rear LMB well with available prepared foods (e.g. trout diet) to .75 to 1 lb range 

When intensively rearing early life stages of finned fish, precise sizes/species of zooplankton must be provided post yolk-sac absorption

 Must be in proper sequence to avoid tendency for starvation (point of no return)  “brine shrimp” (Artemia) are often provided towards end of feeding sequence to “transition” young fish onto prepared feeds  Situation much simplified for some culture species like (shellfish and crayfish) that remain on natural feeds throughout all life station

•

01/23/2009

○ Reproduction  Often, undesirable for culture species to reproduce during grow-out phase (occurs mainly in earthen pond culture)  Why? Growth rates of larger fish (maturing/adult) impeded by competition from vast numbers of young for natural pond foods (zoop. Algae, benthos)  Natural foods important in ponds b/c prepared diets are often “incomplete” – required nutrients provided  As young grow they may also compete with larger fish for prepared feeds as well  Monosex populations, male-skewed hybrids, or sterile triploid populations, commonly used to prevent minimize in pond reproduction  Advantageous that culture species reach market size before maturation  Developing monosex populations of the later maturing sex improves growth rate  Use of MT, TBA, estradiols common for “sex reversal”

01/23/2009

 Hardiness – ability to tolerate culture conditions – high rearing density, periods of poor WQ, handling, harvesting, incomplete feeds, disease resistant  In nature, food supply defines carrying capacity of aquatic environments; restricts fish population densities from becoming too high  For many species, group rearing promotes aggressive social interaction among fish, can result in graded dominance hierarchies where “dominant” )often larger) fish eat well and lower status fish “trained” to eat less subordinated fish may carry high stress loads (MET costs) Arctic char an exception  Social costs reduce average growth rate (20% in sunfish) cause low Fes and much size disparity

01/23/2009

Biological Consideration

•

Hardiness con’t

•

For many species, group rearing promotes aggressive social interaction among fish

•

Can result in graded dominance hierarchies where “dominant” (often larger) fish eat well and lower status fish “trained” to eat less; subordinated fish may carry high stress loads (MET costs); Arctic char an exception

•

Social costs reduce average growth rate (e.g. ~30% in sunfish), cause low Fes, and fish size variation

•

Size grading sometimes reduces hierarchies but does not eliminate totally; extreme high density rearing and forced swimming also can be effective as can duoculture and cull-harvesting (aka – “topping off”)

•

Despite strong efforts to maintain high water quality in intensive culture, breaches are common

•

Culture species that will tolerate episodes of low DO, temperature swings, increased NH3-nitrite-nitrate, will perform better overall.

01/23/2009

•

Fish that are less stressed under intensive culture conditions are less prone to disease/mortality (e.g., blue catfish x channel catfish hybrid)

Further considerations in culture-species selection

•

Productivity: aim is to achieve high production of culture species in form that is marketable.

•

If only 2+lb fish are marketable and less than 50% of all you rear reach this size within grow-out time limit, this may be inadequate for “profitability”

•

Unless high market price allows this inefficiency (common impediment for “emerging” culture species industry facing this problem with raising large food-size sunfish.

Marketing Consideration

01/23/2009

•

Rearing culture species that have diverse markets tends to reduce risk and increase profit potential

•

E.g., channel catfish can be sold as; fingerlings; food fish; for private pond stocking (various sizes), for fee-fishing; as brood stock; for by-products (catfish oil for crayfish bait); for feeds: carcass and viscera to feed mills.

•

Contrast with producer with 2,000,000 small bluegills

Considerations

•

Channel catfish ○ Rapid growth of industry in SE U.S. after 1960s (210,000 metric tonnes as of 1993) increased further – now declining – represents ½ U.S. production ○ Vs. 2.9 mmt for silver carp ○ Spawn in captivity at 21C (70F) fail to spawn at higher temps and elevated salinity (2-11 ppt) but still grow well under these condictions ○ Fignerlings stocked in grow-out ponds

01/23/2009

○ Fed daily with prepared diet

•

Cull harvesting now more common than batch harvesting ○ Batch harvesting ponds drained all fish removed ○ Cull harvesting only larger market size fish removed by size selecting seining every 3 weeks ponds not drained one fingerling stocked for ever lb removed ○ Culling promotes more consistent supply of marketable fish ○ Reduced water use reduced environmental impact ○ Culling might reduce social hierarchies

•

Typical pond production: 10,000 lbs/acre/yr

•

Sales to: processing plants; local stores-restaurants; liver haulers; backyard sales; fee-fishing; niche markets (local grocery stores, rest)

•

Summer water quality problems; DO swings (extremes at mid-day vs. sunrise-why?) late afternoon prediction/aeration

•

NH3 to nitrite *causes brown blood disease) – nitrite binds with hemoglobin producing methemoglobin – poor O2 transport

01/23/2009

•

Brown blood common in spring/fall? Heavier feeding produces more NH3 then nitrite (less efficient at warm temps)

•

Water quality problems cont

○ Off flavor problem is major issue ○ Common source of origin – fish eat decaying feed/OM on pond bottom when feed supply insufficient for satiation (salinity / depuration) ○ Common disease – Enteric septicemia (bacterium targeting fingerling channel catfish) GI tract ailment) =- antibiotic treatment ○ Note: recent study apply our CG-inducing off/on feeding resulted in reduced presence of ESC in challenged fingerling CC ○ Blue and white catfish grown to lesser extent than channel catfish (CC) in US Why? ○ White catfish – slower growing low “dress-out weight” weight when gutted, head off / whole fish weight due to large head ○ Blue catfish – high dress out (60%) less size variation than CC; slower 1st year growth; but grows larger than CC in 2nd yr

01/23/2009

•

BC x CC hybrid ○ Bc x cc hybrid shows substantial “hybrid vigor” (hardiness traits) in pond settings ○ Tolerates crowding well (possibly due to low aggressiveness) ○ Disease tolerant ○ High feed efficiency (FE = wt. gain / feed provided; FCR = 1/FE (MUST BE ABLE TO CALCULATE) higher FE is better, lower FCR is better ○ Fe is feed efficiency ○ Fcr = feed conversion ratio ○ Problems with producing seed stock – insufficient availability of hybrid

Yellow and brown bullhead (I. natalis, I nebulosus); slow growth is major impediment – however – Flathead catfish (Pylodictus olivaris); highly piscivorous aspect is a drawback (cannibalism)

01/23/2009

Clarias bactachus (walking catfish in FL) and C. macrocepalus highly valued culture species in SE Asia / India – tolerates low DO high density rearing frow well on fish scraps and rice

Clarias gariepinus reared at subsistence levels in Africa – also reared in

Other catfish

•

Pangasius spp – reared in Asia, India-China in floating cages

•

6” fingerlings reach 2.25lbs in 8-10 months

•

Pangasius spp. Also reared in polyculture with Oreochromis niloticus in Thailand – wild fly captured in rivers

•

Siluris glanis (sheatfish; Wels catfish) reared in Europe – used as provider

Heterobranchus bidorsalis = highly prized culture species in Liberia, reared in combination with O niloticus Rhamdia spp. Catfish species receiving some attention in Brazil

01/23/2009

Tilapia Culture

•

Tilapia is general name for group of cichild fishes endemic to Africa and Middle East

•

Tilapia laterally-compressed body shape resembling U.S. sunfish – this similarity was exploited early on for market purposes in U.S. (fish species recognition is important to product acceptance)

•

Tilapia fishes used in aquaculture comprise 3 genera: Oreochromis, Tilapia and Sarotherodon

•

Tilapia are nest builders; fertilized eggs guarded by parent (often male)

•

In Oreochromis and Sarotherodon, additional parental care is given via “mouth brooding” of eggs to post-hatch stage

•

Major positive features of Tilapia for aquaculture (FOR TEST)

○ High tolerance of poor water quality ○ Ability to use broad range of natural food organism – important extensive and intensive culture in ponds

•

Major constraining features (FOR TEST)

01/23/2009

○ Inability to tolerate cold water (50-53F) ○ Early sexual maturation leading to unwanted reproduction in ponds – overcrowding, stunting, marked size variation, slow growth ○ Predator stocking is common in extensive pond culture for control (e.g. Clarias Hemichromis) ○ Primary large-scale culture species are Nile tilapia (O. niloticus), followed by blue tilapia (O aureus) and Mossambique tilapia (O. mossambica); hybrids have become common in part for preferred color, high % male (faster growth vs. female)

•

Production ○ Annual global production of Tilapia – 1.5 Million tons/year; among cultured finned-fishes 2nd only to Chinese carps ○ International trade of Tilapia growing rapidly ○ Major producers – Central America (Costa Rica, Ecuador, Honduras) – exporting mainly to U.S. ○ Major Asian producers (Taiwan, China, Indonesia, Thailand) also export to U.S. and Japan

01/23/2009

○ Largest exporter (Taiwan) supplies high-quality fillets to Japan for Sashimi market ○ Taiwan also supplies frozen Tilapia to U.S. (40,000 tons/yr) China also exports 12,500 tons/year of frozen Tilapia in US ○ Zimbabwe and Viet Nam recently entered global market as exporters ○ Tilapia now 3rd highest imported aquaculture product to U.S., behind only shrimp and salmon ○ Exporting of Tilapia to Europe has begun with vast increases

•

U.S. Perspective ○ In general, Tilapia are imported to U.S. from Asia as frozen whole fish or fillets ○ Mainly fresh fillets are imported from Latin Americato US. Via airfreight into Miami, then to U.S. distributors ○ This leaves “live Tilapia” as the primary “open Tilapia niche” for U.S. growers ○ US consumption of Tilapia sured rainbow trout in 1994 only salmon and catfish exceed Tilapia for finned-fish consumption

01/23/2009

○ 17 million labs (8,500 tons) of Tilapia produced annually in U.S; 2 million lbs (12%) produced in Midwest (ND – in RASs); 6.7 million pounds (highest) in CA (39%) ○ among most rapidly increasing culture species ○ Three major Tilapia species are grown in the U.S. plus hybrids (differences in: low-temp, tolerance limit, color, % male fish)

01/23/2009

Grown in every state, either in ponds, cages in ponds, RASs (indoor tanks) In Midwest most Tilapia grown in RASs due mainly to temperature constraint; also eliminates reproduction problem – why? No substrate ○ Major markets: NYC, Toronto, DC, Los Angeles, San Fran, Seattle ○ Substantially untapped domestic market potential through to exist in Chicago, STL, KC, Atlanta, Denver, Soutwest USA

•

Recommendations for Midwest Tilapia Producers ○ Feeds/Nutrition:  Complete feeds needed for Tilapia rearing in RASs – why? 

No nutrients in RAS, must provide

 Also less solid wastes by 1 reducing waste feed 2 increasing feed digestibility (% digestibility of feed components often not determined) Compensatory Growth Studies at MU – Examining two impediments to fuller use of CG in fish culture:

01/23/2009

•

Compensatory growth ○ Natural capacity of fish to undergo a period of rapid, catch up growth once food supply recovers after a period of low availability

Culture Systems

•

Ponds ○ Usually earthen, sometimes concrete water impounding structures: liners now common ○ For aquaculture, ponds typically in range of 0.5-10 surface acres. ○ Largely closed systems; water added at filling, and periodically to compensate evaporative loss and seepage; draw-downs needed on occasion (harvest, repair, mud removal) ○ Few ponds have continuous, low-level flow-through e.g., wellknown KS pond with very high catfish production. ○ Favorable attributes:

01/23/2009

 Relatively few legal/social concerns if privately owned  Effluent impacts tend to be low, esp. if complete drawdown is not done frequently  Natural foods in ponds supplement prepared diet (fare, complete diets less required)  Lower “fish” densities vs. other culture systems: reduces disease and parasite problems  Nutrient rich pond water can be applied to agriculture land crops (integrated aquaculture)

○ Less favorable aspects:  Large land area required  Construction costs can be high (heavy equipment required)  Periodic maintenance required: mowing of levees, repairing leaks  Require maintenance/storage facility for farm equipment, harvesting gear  Large supply of good-quality water needed to fill; may require digging of wells (costly)

01/23/2009

 Costly to treat disease due to high, static water volume  Very limited control over water environment: temp., DO, introductions, preds/pests, reproduction (vs. e.g., tanks, raceways  Harvesting requires equipment, personnel, time consuming  Difficult to “stage” production (serial harvesting: continuous supply of marketable fish) multiple harvests costly; non-continuous growing season

○ Pond Types  Watershed pond – constructed on rolling land by damming at a strategic location; (+) no digging; filled by run-off (inexpensive); (-) uneven bottom impedes seining; but, suitable for cage culture  Excavated pond – dug below ground level; no levees constructed (borrow-pit ponds: common along highways) usually filled by rainwater

01/23/2009

 Usually not constructed with aquaculture in mind; yet, may be suitable for cage culture and spotfisheries (OH program);  Problems pollutants from highway and public access  Embankment ponds (levee pond) – contructed by excavation: removed soil used to build levees (banks); built on flat land



Water supplied from wells or by pumping from nearby stream / often have drain and inflow pipes



Top choice of inland fish farms – good control over filling/draining; size, shape, depth by design vs. “what you get”

 Marsh Pond – constructed in coastal marsh areas; ponds dug and levees constructed; often filled and drained by pumping; water salinity variable; 

Sometimes with weirs (low-level dams that allow tidal water inflow/outflow w/o loss of culture species or intro of unwanted species)

01/23/2009

 Beach pond – constructed in sandy coastal areas; water seepage reduced by liners; sometimes made of concrete; common in Taiwan, Indonesia, other island nations for rearing salt- and brackish-water species (shrimp, milkfish) weirs common – 2005? Tsunami  Intertidal pond



Located just offshore in marine cove or bay, blocked off by levee (net or rock piles); water interchange with tide; levees used to contain culture species; common in Hawaii

•

Cage Culture ○ Cage culture practiced for many species; not just salmon (net pens are cages) ○ In U.S. these include bluegill and hybrid BG, hybrid striped bass, channel catfish, tilapia, many others ○ Cage culture also very prominent outside of U.S. – globally one of the fastest-growing aquaculture rearing systems – e.g., cages in many impoundments in China

01/23/2009

○ Small farm ponds and lakes not designed for AQC often wellsuited for cage culture ○ Unlike in ocean, water currents in ponds, impounds often don’t facilitate movement of water and wastes, out of cages 0 creates substantial risk.

•

Benefits of Cage Culture ○ Can be applied in water bodies not suited for conventional harvest methods (e.g. where seining/pond draining not possible) ○ Can readily observe fish in cage – helps to gauge feeding rates, assess growth, identify disease onset, WQ problems, incipient mortality ○ Ease of harvesting – important as harvesting of ponds requires time and expensive equipment ○ Can facilitate due culture – cage rear one species rear another in the poen pond can feed both groups separately rear predators (out) and prey (in)

•

Downside

01/23/2009

○ Increased potential (vs. open-pond rearing) for water-qualityrelated stress (death) on fish b/c restricted (laterally and vertically) ○ Fish can’t escape cage conditions, fish in open pond have much advantage – WQ in open pond usually better vs. cage; fish can seek viable micro-environs in ponds ○ High fish density increases likelihood of disease ○ Close proximity can promote agonistic social interaction (competition) leading to growth dispensation and substantial size variation at harvest, yet some species may show more uniform growth (e.g., Large mouth bass, hybrid blue gill?) ○ High potential for predator problems and theft

•

Cages ○ Agriculture and fish farming supply companies sell cages (or construction materials) ○ Common configurations: cylindrical, square, rectangular

 4ft deep for winter/summer

01/23/2009

○ Common frame material: wood, iron, steel, aluminum, fiberglass, PVC ○ A depth allows fish to access cooler water, avoids access to pond bottom, poor WQ

•

Points ○ Overall stocking densities in open pond setting (3,000-8000 catfish/pond acre) are greater than for caged fish (2,0004000); production levels (lbs/acre, kg/ha) parallel stocking densities ○ Why? The water volume available for fish production is lower in cage-culture than in open-pond setting, even when max # cages used ○ Pond/cage, Density Comparison; catfish in open pond = 0.02fish/ft3 cage = 1.5 fish/ft3 (75x) ○ Tilapia in cages = 6 fish / ft3 this becomes very crowded as fish reach final sizes

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Cages- DO

01/23/2009

○ DO levels in cage will drop quickly if water exchange is not sufficient ○ On calm days DO outside of cage may be good, but not so inside, continual water movement in/out of cage is critical. ○ Situating a aerator close to cage can promote water flow through, too close can stress fish, air lift pumps located inside cages have shown much promise (quiet, efficient) ○ Conditions where DO must be carefully monitored in cages, summer in general 24 h DO swings, low-ind periods, cloudy weather (limited photosynthesis/algae respire, summer tstorms, plankton die-off (id by loss of greenish color) plankton decay has BOD ○ Cages should be located where emergency airation can occur ○ At least 4ft deep to allow fish to escape warm water in summer and water too cold in winter ○ Alkalinity of pond with cages should be maintained at >50 ppm CACO3 buffer against nitrification process ○ Biofouling of cages from algal buildup. Bryozoans is common and must be countered, high pressure washing small sock of CuSO4, other herbicides used

01/23/2009

○ More complete diets appropriate – reduced access to natural foods (unless fish are plankton feeders) ○ Use of floating vs sinking feeds beneficial in cages ○ Feeding rings used PVC to keep feed from exiting cage from feeding activity wind ○ Still, feed and feces tend to accumulate on bottom below cage caused localized WQ problems, “diaper” small mesh net situated below cage) often used for periodic removal of waste feed and feces ○ During summer (favorable growth period) feeding more than one daily beneficial for many species growth; season max feed amounts for ponds usually known. ○ Rectangular cages with long side facing prevailing winds maximized water circulation through cage ○ Cage mesh size of > 0.5 inch recommended – due to biofouling – consiquences usually start with larger fish in cage-culture vs. open-pond rearing ○ Cages should be at least two feet off bottom ○ Minimum distance of 15 ft between cages

01/23/2009

○ Cages may be anchored to bottom or attached at intervals to rope stretch across pond ○ Placing multiple cages around a pier can limit flow

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Salmon aquaculture – major species ○ Atlantic salmon: single species: Salmo salar (Atlantic salmon) ○ Pacific salmon: Major culture species ○ Pink salmon (oncorhynchus gorbuscha) ○ Sockeye (O. nerka) [Kokaneese, freshwater race] ○ Coho (silver) (O. kisutch) ○ Chinook (spring, king) (O. tshawytscha) ○ Shum (O. keta)

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General background ○ Anadromous, coldwater species ○ Pacific salmon are semelparous

 Go to ocean, mature, come back 2,3,4 years, spawn, die. Nutrients from body provide nutrients to young. ○ Atlantic salmon are iteroparous

01/23/2009

 Spawn 2-4 times ○ Culture techniques well developed due to long history as high-value sport and commercial sp. ○ E.g., many federal hatcheries for pacific salmon on U.S. west coast to counter population declines (overfishing, dams impeding upstream (adults) / downstream *(smolt) movement, domestication) ○ Majro commercial production of salmon in: Japan, Norway, Scotland, Ireland, Chile, Canada, Maine, U.S. west coast ○ Culture systems used: ponds, raceways, nearshore net-pens, ocean ranching, open-ocean pens/cages ○ Commercial salmon farming on U.S. west coast under much scrutiny – likely arising from competition with capture fishery communities ○ Some of salmon culture’s blame for negative environmental impacts likely emanates from commercial fishers being outcompeted

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Ocean Ranching ○ Popular in Oregon, Alaska (Prince William Sound)

01/23/2009

○ Facing much criticism b/c “domesticated fish” are intentionally released into ocean – believed to be diluting the “wild fish” gene pool ○ Pink salmon is major species in salmon ranching

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General process ○ Returning brood fish selected for quality “hand-stripped” eggs and milt for artificial spawning: wild fish often marked by DNRs to distinguish from “ranching” fish ○ Indoor jar-hatching of eggs – fish offered prepared floating diet near swim-up phase (small feed particles feed frequently, e.g. 5x per hour) ○ Feeding of larger fingerlings typically in land-based tanks/pens with freshwater until saltwater phase is reaching *duration of fw phase varies among species) ○ Fish in sw phase released into ocean; return within 1-2 years and harvested ○ Most growth occurs free of charge, courtesy of ocean number of fish returning highly valuable

01/23/2009

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Net-pens and raceways ○ Floating nearshore net-pens have become most common culture system for salmon ○ Complete ground-based Atlantic salmon culture using raceways containing pumped saltwater still done in some areas (nearshore)

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Atlantic salmon culture ○ 100 year history ○ parr: early juvenile freshwater phase (vertical bars on fish called “parr marks”) ○ smolts – smolt stage is reached as fish begin to enter saltwater phase and in nature begin to migrate downstream to sea (silvery color develops) ○ 1st year at sea fish called grilse ○ in nature atlantic salmon have returned to freshwater up to five times to spawn (2-3 times typical) ○ typical culture sequence for Atlantic salmon

01/23/2009

○ broodfish artificially spawned in hatchery – young are feed trained at 1-2 inches, parr stocked into outdoor, freshwater tanks with feeding ○ smolt stage reached in 1-2 years (fairly protracted freshwater phase) fish then stocked into floating saltwater net pens ○ within 1-2 more years, marketable fish are produced (4-10 lbs) ○ Most popular of culture species is ○ Fry to smolt survival rates : nature <1%

 Culture: >80% ○ In saltwater phase (net pens), viable temp. range is typically 31-60f ○ Below31f freezing occurs, above 60F growth favorable, but lower DO and higher temps promote stress/disease ○ In east coats U.S. waters, temperature ranges limit number of desirable sites ○ Survival rates in saltwater phase >90% (in net-pens) ○ Predation by birds and seals are a major problem-storms impair predator exclusion nets

01/23/2009

○ For netpen systems FCRs of 1.3 have been achieved (Fes of 1/1.3 = 0.77; ideally ~1.0 ○ Much research done on feeds (for all life stages) and feeding strategies; protein:fat ratios for life stages ○ Selective breeding done to improve FCR ○ Underwater video used to reduce waste feed (waste feed costly, water quality impacts) ○ Two aspects to feed efficiency

 Amount of feed thrown that gets consumed  Part of that going into growth

○ Selective breeding  Has led to most major improvements in Atlantic salmon culture; growth rates, FCR, flesh color, disease resistance  Fish/shellfish have higher genetic variance among individuals and higher recundity than farmed land animals – allows higher selection intensity for favorable traits in aquaculture

01/23/2009

 Useful changes within 2 generations are common  Mono-sex female populations commonly reared for faster-growth; new marketing approach (Organic Rearing) directed towards reducing sex hormone use (e.g. estrodiols)  Brood stock rotation (to reduce degreee or domestication of fish_ is practiced to reduce susceptibility to disease in net pens)

Pink salmon (O. gorbuscha) •

Named for pink-colored flesh

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Negligible freshwater phase 0 young fish go quickly to sea (few weeks)

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Typically reach 4-6 lbs within 2 years of hatching.

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Major “ocean ranching” species

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Few fw phase means little early investment (e.g., feed costs)

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Small initial investment allows risking poor returns in some years

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Culture hardy; first salmon species reared in net-pen culture on U.S. west coast

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Popular in European sea-farming

01/23/2009

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Matures early in the grilse stage – slowing growth

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Consequently, cultured to smaller “pan-sized” (12 oz.) within 6-8 months

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Can be cultured completely in freshwater

Coho salmon •

Coho salmon valued because resistant to many common salmonid viruses (including IHN)

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Interspecific hybridization of coho with other salmon species and rainbow trout often evaluated for disease resistance

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Increased disease resistance often achieved but negative attributes (poor viability and growth) common

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Triploidization after hybridization improves viability in some crosses

Sockeye salmon •

Historically harvested for canning industry (deep red flesh) canned fish sales declined causing sockeye to be less cultured vs. other “Pacifics”

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Renewal of interest in sockeye for “upscale” smoked, packaged salmon fillets have led to their increased production in aquaculture

01/23/2009

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Feshwater races (Kokanee) popular for stocking inland fisheries (including Lake Taneycomo, Mo in 1970s)

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Kokanee least piscivorous of the Pacific salmon

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Populations highly prown to IHN, viral disease affecting fish liver

Chum salmon •

Flesh is not considered sufficiently high-quality for high U.S. consumption

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Japan and former Soviet Union countries have been involved in culturing

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Some culturing of chum salmon as food fish in the U.S. is done; e.g. in Alaska

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Popular sportfish in Alaska, some commercial fish producers funded by DNR to produce chum salmon

Chinook salmon •

Major production off British Columbia coast – in floating net-pens

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Enters saltwater phase early

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Unlike the coho Chinook mature late and so grow large

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Limitation to egg supply noted as current impediment to production

01/23/2009

Salmon culture – general •

Salmon culture has experienced major social/legal issues associated with rearing in nearshore marine environments

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Net-pens: concerns over pollution of nearshore waters from feed waste (BOD, P, N) antibotics (terramycin) in fish themselves, plus in aquatic environment; vaccination required in some states, escapement of fish is major concern

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Market competition is notoriously high

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Aquaculturist’s competitors include capture fishers, salmon culture from other countires, including mega-companeis with rearing facilities spread globally (e.g. Nutreco Aquaculture)

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High volume producers can endure periods of low profit margins

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Crowding in net pens has led to numerous disease problems

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Vibreo sp. Bacterial disease – can be trnasmited to humans that consume infected fish causing GI-tract illness

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Samon louse, causes discolor and devalue

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Feed costs are generally most expensive component of fish culture % protein in diets greatly influences feed costs

01/23/2009

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Feed cost is particularly high in net-pens (>50% of total var costs) – feed falls through pens contributing to feed wastage *underwater photography for judging satiation)

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Fish that grow well on lower protein diets or will tolerate animal protein substitutes. Will have economic advantage

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Pink-red flesh color as in wild fish is desired – feed additives (astraxanthin) used to achieve flesh color

Choice sites for net-pens limited Some degreee of waste movement desirable for water replacement and removal of wastes Optimal sites are a compromise between sufficient water movement and safety of workers

Open-Ocean rearing in development •

Wastes dispersed well by stronger offshore currents

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Salmon forced to swim – leaner with higher flesh density

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Being out-of-sight will reduce problems with the public

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Larger space available for increasing production

01/23/2009

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Larger pens will allow lower-density rearing with potential for lower social costs and less disease transmission (less medicated feed)

Tank Culture Systems •

Involve circular or rectangular tanks made typically of fiberglass, plastic (300=25,000+ gallons)

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Can involve open systems – water trickles in and exits tank via a standpipe (which controls water depth)

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Typically used in low-productivity settings e.g., rearing fry to fingerlings or for holding a few larger fish – otherwise substantial water flow through required

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Intensive culture involves closed systems where water is reconditioned and reused

Basis for RASs (recirculating aquaculture system) •

Filling a typical production pond requires 10to the six gallons of water per acre

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An additional equivalent volume needed per acre to make up for evaporative and seepage losses annually

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Assuming annual pond yield of 5,000 lbs of fish/acre

01/23/2009

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400 gallons required per pound of fish produced

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RASs require <10% of water volume needed by ponds to produce similar fish biomass

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RASs require far less land

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Major reductions in water demand and land requirement vs ponds

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Costs on construction and particularly operation can be high: also higher feed costs (complete diets)

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RAS does

○ Removes solid wastes ○ Reduce/alter by-produces of fish metabolism ○ Replenish DO lost from fish respiration and breakdown of waste feed and egesta

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Solids ○ Settleable, suspended, fine and dissolved  Settleable 

Re=suspend settleable solids via agitation and move water through separate settling tank (clarifier)

01/23/2009

 Suspended solids (limit fish production: irritate gills – removed by filtration (screens or granules)  Fine and dissolved solids (<30 microns: >50% of total suspended solids; create BOD and gill irritation

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Foam fractionation – air bubbled up through tube creates surface foam to which fine/dissolved solids adhere – film is skimmed off along with solids

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Nitrogen management ○ Total ammonia-nitrogen: includes NH3 and NH4+ ○ Excreted across gills of fish as feed is consumed assimilated by-product of protein breakdown ○ NH3 highly toxic to most fish, NH4+ less so. ○ Difference between the two depends on PH (ph7=NH4+ ph=8.0, mostly NH3) ○ TAN is oxidized to nitrite (NO2) by nitrifying bacterium Nitrosomonas

01/23/2009

○ Colonies grown on surfaces of substrate located in biofilter component of RASs over which water moves (biofilters contain high surface area media – (sand,gravel, plastic) ○ Nitrosomonas will establish naturally on substrate if fish in tank, but initial colony growth expected by seeding ○ Nitrobacter oxidizes nitrite for nitrate (NO3) which is essentially non-toxic (up to >100 mg/L) ○ Nitrification = NH3 – NO2 – NO3

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PH ○ Sometimes important to be monitored

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Nitrification is an acid producing process – hydrogen ions given off

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As hydrogen ions given off they combine with bases; this reduces alkalinity and tends to lower pH

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Concern – Low pH in RAS-tanks (<4.5) can harm fish; ph<7 reduces activity of nitrifying bacteria, leads to toxic NH3 and NO2

Ammonia build-up is the major factor that limits carrying capacity of RASs However, adequate DO is clearly of high importance as well

01/23/2009

Maintaining adequate BO requires that oxygen use rate is compensated for by oxygen replacement

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Major sources of DO uptake in RAS ○ Respiration of the fish ○ Oxygen demand of bacteria

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CO2 is produced in RASs from fish respiration ○ Under low DO, CO2 can reach high levels in blood

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Dissolved nitrogen gas ○ Rarely a problem, particularly in warm water systems readily exits RAS

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Can be problem when pressurized by aeration oxygenation is done as nitrogen can become supersaturated in water

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Causes gas bubble disease

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Addition of oxygen or release of CO2 can be accomplished by: air diffs, agitators or by packed columns

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FACT – system aeration is often done in a culture tank itself, however is not the most optimal location to perform aeration

01/23/2009

○ Oxygen transfer efficency of aerators drops with increasing DO concentration ○ Better location to aerate is in water flow stream JUST PRIOR TO RE-ENTRY TO TANK; WHERE DO LEVELS ARE LOWESTA NAD CO2 LEVELS ARE HIGHEST ○ Packed column aerators (PCAs) are effective at re=aerating water in a stream flow ○ In highly intensive RASs DO uptake can be too high

 Pure gaseous O2 diffusion is used  Typical DO saturation levels are <8.75 mg/L at >20C with pure O2 diffusion immediate receiving water becomes supersaturated with O2 (>40 mg/L) at STP results in rapid diffusion into tank water

Raceway systems •

Can produce substantial quantities of fish in much less land area than is required by ponds: fish held at high density due to high water flow through

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Used for cold and cool water species

01/23/2009

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Cells often arranged in step down series, sometimes in parallel.

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Require large quantities of water

○ Springs, artesian wells, hypolimnetic releases ○ Gravity flow is a major benefit ○ Water volume requirement ○ Raceway construction size based on water flow capacity ○ Water inflow requirement can be reduced if in-raceway aeration is used (costly!) ○ Closed/semi-closed systems eveloped to conserve water and reduce effluents ○ Some fish farmers combine raceways with ponds for closed systems: ponds serve to restore water quality (solids removal, natural biofiltratyion, reaeration ○ Rule of thumb: total pond volume should hold 7x daily discharge from raceway system: deep ponds not suitable for aquaculture may be used. ○ Biofiltration (NH3 to nitrate) and reaeration, sometimes UV treatment for decreasing disease organisms ○ Loading density

01/23/2009

 Lbs of fish/cubic foot of water flow/minute ○ Fish stocking densities (ON TEST)  Sometimes set so crop at harvest will be close to system carrying capacity 

Result underutilizes the potential carrying capacity of system



But

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Low risk of loss

Alternatively •

Stocking density can be started at carrying capacity ○ Remove fish as they grow to prevent exceeding carrying capacity  Plus side: max production of system  Downside: more risk

 Demand feeders 

Reduce labor

01/23/2009



May not reduce overfeeding

 ON TEST  Feed efficiency = total weight gain / weight feed provided

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Higher values better

 Feed conversion ratio = FCR = 1/FE 

Lower values are better

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Values close to 1 considered favorable

 Bad FCR 

Improper feeding

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Inadequate diet composition

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Adverse environmental factors

TEST •

5-7 book chapters

01/23/2009

Fish nutrition, feeds and feeding Complete diets

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contain all protein 18-50%, lipid 10-25%, carbohydrates 15-20%, ash<8.5%, phosphorus(<1.5%) and trace amounts of vitamins and minerals that a species requires

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Supplemental diets

○ Do not contain full vitamin and mineral requirement  Intended to supplement natural food by providing extra protein and carbohydrate and/or lipid •

Protein ○ Most expensive feed component  Important not to overprovided ○ 10 of the 20 needed AAs in fish can not be synthesized by fish, must be in diet  are essential amino acids 

lysine, methionine ON TEST •

are most limiting essential amino acids in fish diets

01/23/2009

○ growth rate reduced if not sufficient ○ When soybean meal is substituted for fishmeal protein in fish diets, methionine levels are too low and must be added ○ Important to add proper protein requirement and AA requirement for each fish species/life stage ○ Protein requirement typically higher in intensive culture and in juvenile fish ○ Protein requirements also vary with temperature, water quality, feeding rates and genetic strain (influence growth rate ○ Protein in diet should be used for fish growth

 Occurs when adequate energy levels are present in diet ○ Protein made of carbon, nitrogen, oxygen and hydrogen ○ Up to 65% of protein in feed can be lost to environment ○ Excreted nitrogen from diet protection, plus that from wasted feed contributes to eutrophication problems associated with aquaculture

Lipids (fats)

01/23/2009

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High energy nutrients

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Keep protein from becoming energy source

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Supply essential fatty acids (EFAs)

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Serve as transporters of fat-soluble vitamins

○ Lipids provide  Energy  EFAs  Transport vitamins

○ Fish typically require fatty acids  Omega 3 and omega 6 families  Fatty acids can be saturated, polyunsaturated or highly unsaturated  Marine fish oils



High in omega-3 HUFas (>30%)

○ Marine fish require omega 3 HUFAs in diets ○ Two major EFAs

01/23/2009

 Eicosapentaenoic acid (EPA)  Docosaphexanoic acid DHA)

○ Freshwater fish do not require long-chain HUFAs directly like marine fish Carbohydrates •

CHOs are most economical (inexpensive) energy source in fish diets

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Not essential but used to reduce feed costs (protein sparing) and for “binding” qualities

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Causes it to float

○ Cooking starch makes it more bio-available •

CHOs stored as glycogen

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Major energy source for mammals

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Mammals extract 4kcals of E per gram

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1.6 k calls by fish

Vitamins •

Normal growth and health

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Water-soluble

01/23/2009

○ Vitamin C  Antioxidant needed for healthy immune system •

Fat soluble

Minerals •

Micro-minerals (trace minerals)

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Macro-minerals

01/23/2009