Capture-Based Aquaculture - Main Species
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Capture Based Aquaculture (CBA) BIO 208 - 2016 9.0 Capture Based Aquaculture What happens in a hatchery? Life Cycle Closure BIO 208 - 2016 9.0 Capture Based Aquaculture Capture -based aquaculture - many socio-economic benefits to local communities Catfish, West Africa Groupers, S.E. Asia Environmental Issues: A. Direct effects - Resource removal - overfishing - bycatch and discards - direct physical disturbance and habitat destruction B. Indirect effects - use of raw fish as feed ( ¨trash fish ¨) - organic pollution - disease BIO 208 - 2016 9.0 Capture Based Aquaculture Capture-based aquaculture - main species BIO 208 - 2016 9.0 Capture Based Aquaculture BIO 208 - 2016 9.0 Capture Based Aquaculture BIO 208 - 2016 9.0 Capture Based Aquaculture Estimates for capture -based aquaculture production of eels, groupers, and tunas in 2009 (FAO) Species group Estimated production (thousand tonnes) Eels 275 Groupers 75 Tunas 9 Value (FAO data) US$1.7 billion BIO 208 - 2016 9.0 Capture Based Aquaculture CAPTURE -BASED AQUACULTURE A. Direct effects - Resource removal 1. Use of wild seed By definition, CBA relies on the use of wild-caught ¨seed ¨(a term that covers fry, juveniles, and in some cases larger fish) for stocking on-growing facilities. Many of the species targeted are already threatened. There is particular concern over the targeted high value species (grouper, tuna, spiny lobster), especially those which have a low reproductive capacity (mature at a large size) such as tuna and groupers. The source of seed will be unsustainable in the long term as the catch per unit effort of seed declines with increased exploitation. The transfer of seed to CBA farms is often characterized by high mortality rates. BIO 208 - 2016 9.0 Capture Based Aquaculture CAPTURE -BASED AQUACULTURE A. Direct effects - Resource removal 2. Bycatch and discards The collection of seed for CBA can lead to high mortality of non-target species. Milkfish fry constitute 15% of total finfish fry collected by inshore netting - remaining 85% are discarded and left to die. - thus the 1.7 billion wild fry stocked annually in the Phillipines results in the loss of about 10 billion fry of other non target finfish species. In India and Bangladesh, ca. 160 fish and shrimp fry are discarded for every fry of the giant tiger shrimp, Penaeus monodon collected. 3. Direct physical disturbance and habitat destruction Dredging for seed mussels. BIO 208 - 2016 9.0 Capture Based Aquaculture CAPTURE -BASED AQUACULTURE B. Indirect effects 1. The use of raw fish as feed ( ¨trash fish ¨) Many forms of capture-based aquaculture still use raw fish as the main form of feed (generally referred to as ¨trash fish ¨). This raises a number of environmental issues, including: - depletion of stocks - poor quality of feed - potential transfer of disease vectors to farmed fish, and indeed wild fish - the transfer of human pathogens is also possible. - very high feed conversion rations and high waste levels - leads to enhanced organic pollution. BIO 208 - 2016 9.0 Capture Based Aquaculture CAPTURE -BASED AQUACULTURE B. Indirect effects 1. Organic pollution Can be high levels of localized organic pollution, especially when the CBA farm is using trash fish as the main source of feed (groupers, spiny lobster). Can lead to algal blooms 2. Disease Intensive cultivation in cages can increase the risk of transfer of diseases and parasites. This risk is increased with the use of trash fish (often of poor quality) BIO 208 - 2016 9.0 Capture Based Aquaculture Capture -based Aquaculture Two internationally important species. Bluefin tuna, Thunnus thynnus European eel Anguilla anguilla BIO 208 - 2016 9.0 Capture Based Aquaculture Bluefin tuna:life, fisheries and aquaculture implications Beatriz Morales-Nin IMEDEA, Esporles, Spain BIO 208 - 2016 9.0 Capture Based Aquaculture The most valuable fish in the world! January 2013: A single 220 kg fish sells in Tsu Kiji’s market for € 1 350 000 !!!!!!!!!!! 6 000 €/kg first sale price 1 fish= 10 million NOK, 1 kg=45000 NOK BIO 208 - 2016 9.0 Capture Based Aquaculture Bluefin tuna Thunnus thynnus • Family Scombridae • Very evolved species • Adaptations in the circulatory system to recover heath generated by muscles • Body temperature control up to 21º C over water temperature • High metabolism • High swimming speed (up to 30 km/h) • Aceleration 70-100 km in 2 seconds • Fast growth • Maximum size 6 m and 700 kg • Life span up to 30 yr • Maturity 5-8 yr(16-25 kg) • 45.000.000 eggs/spawning • Top predator BIO 208 - 2016 9.0 Capture Based Aquaculture Thunnus thynnus • Very mobile fish • Wide habitat range • Spawning and foraging seasonal migrations • Aristotle (4th cent) & Plinio (1st cent) first descriptions in the Mediterranean • 17th cent. the connectivity between Med& Atlantic postulated and accepted in 1960 • Spawning site fidelity in Mediterranean and Gulf of Mexico BIO 208 - 2016 9.0 Capture Based Aquaculture Vertical migrations • Top predators with opportunistic diet • Exploiting the water column fishing down to 800-1.000 m • Exploiting deep scattering layer BIO 208 - 2016 9.0 Capture Based Aquaculture Stock structure • Two main stocks • 50% tuna fished in North America of Mediterranean origin • Probably intermixing albeit 90% fish returning to their natal origin for spawning • 30% population doing cross Atlantic migrations (60 days) BIO 208 - 2016 9.0 Capture Based Aquaculture Spawning areas related to oceanographic conditions F.Alemany, IEO-COB BIO 208 - 2016 9.0 Capture Based Aquaculture Explotation Almost 4000yrs of exploitation! Commercial fishery from boat Purse seine nets Surface long liners Hand lines Commercial fishery from land Almadrabas Recreational angling 2800 BC – 470 AD Phoenicians and Romans had factories in Spain for dry & salt tuna and BIO 208 - 2016 9.0 Capture Based Aquaculture garum Almadrabas • Fix traps used since ancient times first in the Gibraltar Strait and after in all Mediterranean • In Spain records from the 12th cent. • Azahara de los atunes: • 1558 catch: 140.152 bluefins • 1949 catch: 43.500 bluefins • 2006 catch: 1.600 bluefins • Mean catch in Italy and Spain 15000 tonne/yr from 16th – 20th century BIO 208 - 2016 9.0 Capture Based Aquaculture BIO 208 - 2016 9.0 Capture Based Aquaculture • Interannual fluctuations related to oceanographic Tuna catches conditions and variations in fishing effort ICCAT In 50 yr 90% reduction landings, ex. Almadrabas: 1980 60 tm/week, mean weight 65 kg/atún 2000 5 tm/week, mean weight 22 kg/atún catches are over 2.5 x the sustainable level BIO 208 - 2016 9.0 Capture Based Aquaculture Overexploitation •Expansion of the fleet capacity •Technological improvement •Expansion ofthe fishing areas In 50 yr 90% reduction landings: 1980 60 tm/week, mean weight 65 kg 2000 5 tm/week, mean weight 22 kg catches are over 2.5 x the sustainable level ICCAT/ICES 19th cent hand-line fisheries G.Vizcaya, live bait 1930 N Atlantic purse seiners 1960 W Atlantic hand line for juveniles and 1970 for reproducing adults 1980 Central and E Mediterranean BIO 208 - 2016 9.0 Capture Based Aquaculture Management • Trans frontier migratory species: resources shared by several countries • Fished by diferent gears and fleets • Managed by International Comision Conservation Tunas (http://www.iccat.int/en/) • Regulations based on quotas by countries, minimum lengths, gear restrictions, closed seasons BIO 208 - 2016 9.0 Capture Based Aquaculture Management Compliance: systematic failure and cheating •Changes of ship flags •Use of forbidden gears and methods •Catches of fish under legal size (30 kg) •Cheating minimum size because of “traditional activity” •Declaring farms produce as aquiculture (without quota) •Unreporting catches………… •2005 ICCAT set quota at 32 000 tn •2005 WWF/Adena estimated catches at 45 000 tn •2005 France+Libya quota 7 500 tn, captured 12 800! •Estimated catches 4 times over the reccomended by ICCAT BIO 208 - 2016 9.0 Capture Based Aquaculture Tuna farming –problems , not solutions . Why ? • Domestication not yet completed • Spawning in captivity • Not closed cycle • Main problem survival larvae- juvenile • Wild fish fattening 90’s • Mediterranean tuna captured by purse-seine transferred to floating cages • Captivity from 6-7 month up to 2 yr • Market reasons: • Fat fish better prize in Japan • Available supply all year BIO 208 - 2016 9.0 Capture Based Aquaculture Tuna farming expansion • 60’s Canada first farm • 1979 Ceuta (Spain) fattening of spent adults (>150 kg) from the traps for 5 months (200 t) • Australia farms introduce change to middle-small fish • 1996 expansion to the Med farming 20-80 kg immature fish up to 2 years • Inclusion of very small fish down to 10 kg BIO 208 - 2016 9.0 Capture Based Aquaculture Rapid expansion BIO 208 - 2016 9.0 Capture Based Aquaculture Where else are tuna being farmed? Mediterranean (Spain, Croatia, Malta) - Thunnus thynnus Japan - Thunnus thynnus Canada - Thunnus thynnus South Australia - Thunnus maccoyii Mexcio - Thunnus thynnus, bigeye, Thunnus obesus, yellowfin, Thunnus albacares BIO 208 - 2016 9.0 Capture Based Aquaculture Capture of live tuna 1. Purse seine 1-2 km in length. Pulled in until c.100 m in diameter. Purse seining accounts for 60-80% tuna catch. 2. Hook and line Uses barbless hooks, baited with live fish. Mediterranean 2003 21,000 tonnes of wild-caught tuna were introduced to pens (compared to a total quota for the Mediterranean and eastern Atlantic of 32,000 tonnes). BIO 208 - 2016 9.0 Capture Based Aquaculture Tuna aquaculture: the farming