Farming of Cold-Water Marine Fish PDF

6. Farming of main cold-water marine fish Norway Fish species  Atlantic salmon  Wolffish  Cod  Lumpfish Atlantic salmon (Salmo salar) (Fishbase.se)  Salar = from Latin word ‘salio’ meaning to ‘leap’.  Teleostei (teleosts) > Salmoniformes (Salmons) > Salmonida...

6. Farming of main cold-water marine fish Norway Fish species  Atlantic salmon  Wolffish  Cod  Lumpfish Atlantic salmon (Salmo salar) (Fishbase.se)  Salar = from Latin word ‘salio’ meaning to ‘leap’.  Teleostei (teleosts) > Salmoniformes (Salmons) > Salmonidae (Salmonids) > Salmoninae.  In nature, live up to 13 years. Juveniles feed mainly on aquatic insects, molluscs, crustaceans and fish; adults at sea feed on larger fish and invertebrates.  Max length 150 cm, max weight 46 kg. Atlantic salmon (Salmo salar) Life cycle (Fishbase.se)  At the onset of sexual maturity, they return from the ocean to the specific area they were born (from June to November).  Spawns at 6-10°C in gravel river areas far upstream. The female digs a depression. The male guards and defends the female against other males.  A female releases 8,000-25,000 eggs. Eggs are covered. Period of spawning lasts for 1-2 weeks. Most males die after spawning, while 10-40% of females may survive and return to the sea.  Eggs hatch in spring, usually after 70-160 days. As their yolk sac is absorbed, the fry emerge from the bottom and move to shallow riffles just downstream. Mortality of young individuals during the first months may range from 14-61 %. Parr (i.e. juveniles) may remain in freshwater environments for 1-7 years (depending on temperature and feeding conditions).  Parr undergo smoltification. Sexual maturation  Decreasing day length triggers sexual maturation  During sexual maturation: 90% of lipids and 50% of proteins from muscles to growing ovaries Salmon Farming Industry Handbook 2023 mowi.com Salmon farming 2 phases:  Freshwater (land-based) 10-16 months  Brood stock  Hatchery for eggs/alevins  First feeding to early fry  From fry to smolts (outdoors tanks)  Seawater phase (cages) 12-24 months Broodstock - fertilization  In the same population, females ovulate at different times – breeding season lasts about 2 months  Time of stripping is important – eggs start to decay about one week post- ovulation  For stripping, anaesthesia, gentle handling  No contact of gametes with water initially.  Oocytes and milt in contact first for 1-2 mins  Freshwater covers the eggs – important for the motility of spermatozoa  Eggs are washed  Hardening starts after contact with water – eggs undisturbed for some time!  Before incubation, eggs are disinfected Production of mono-sex salmon  Problem with early maturation of males  Better management of broodstock – supply of eggs.  The procedures cannot be used directly on fish for human consumption – reversed fish used to produce the fish for consumption.  Use of hormones  Irradiation of sperm – they do not contribute to the genetic profile of the offspring, but then the embryo needs to become diploid (percentage of fish with second maternal chromosome can be increased using temperature manipulation  Use of sterile populations, eg triploids (production of nonfunctional gametes)  Hatchery – incubation of eggs  High water temperature in the first stages increases mortality  CO2 affects pH  pH can affect the toxicity of some ions. Hatching – alevins – pre- feeding  Usually, eggs will hatch after 480-520 degree days – hatching lasts a few days  Water parameters are very important – dark conditions critical.  Sub-optimal water conditions will also affect alevins – reduced handling and stress.  If yolk sack is cracked, then alevins will not survive.  Temperature can slowly increase the last 10 days before feeding.  First feeding about 370-440 degree days post hatching (when about 90% have absorbed the sack). efaidnbmnnnibpcajpcglclefindmkaj/https:// www.adfg.alaska.gov/static/species/disease/pdfs/ fishdiseases/coagulated_yolk_disease.pdf First feeding  Hand feeding allows better observation of the behaviour (e.g. aggression) before moving to automated feeding systems.  It is important to properly spread the feed in the tank.  First feeding pellets should float on the surface before sinking gently with minimum amounts of fragmentation.  The amount and type of feeders can be adjusted based on the size and shape of the tank.  As feeding behaviour develops, the alevins move from resting on the bottom to active shoaling and feeding. Stocking density should therefore initially be based on the surface area and then by volume. Further growth – fry and parr Grading and transporting fish Fish pump s Smolt production  Outdoors tanks – usually follow normal photoperiod. Over 1 year  Possible to produce ‘autumn’ smolts (early eggs, short days/12:12 L/D for some weeks then increase the L period, transfer in September but smaller fish)  Seawater test (40 ‰) for 24 h (mortalities, blood ions)  Before transfer to the sea, addition of seawater, when temp is > 7-8 °C, feeding stops some days before.  Seawater phage - cages  Appropriate location  Good water quality  Adequate mesh size  Appropriate construction  Diameter up to 60 m, up to 20-50 m deep (possible temperature differences!), fish density up to 25 Kg/m3 Slaughtering of salmon  Fish are starved for a certain period of time.  Fish are first transferred to a holding pen.  They are anesthetised (blow on the head or electrical stunning – then slaughtered.  In Norway they follow the Aquaculture Operations Regulations.  Regardless of the anaesthesia used there are welfare concerns: Crowding, pumping, poor water quality, time out of the water.  Fish that are stressed before slaughter go into rigor mortis faster after slaughter and develop a harder rigor mortis. This reduces the possibility of pre-rigor filleting. In addition, the final pH of the fillet becomes higher, which reduces its shelf life of the fresh product. Video  Lumpfish (Cyclopterus lumpus)  (Fishbase.se) The name refers to the modified pelvic fins that form a suction disc.  Perciformes > Cyclopteridae  Max length 61 cm, max weight 9.5 Kg, max reported age 13 years.  Mainly solitary fish. Adults inhabit rocky bottoms – max depth about 870 m.  During spawning season males become reddish and females blue-green.  After an extended courtship, the female lays eggs which are fertilized by the male. The male lumpfish cares for the eggs by aerating and guarding them against predators, while the females leave the  Norwegian Directorate of Fisheries Utsett (kjøp/interne mottak) av oppdrettet og villfanget rensefisk til lakselusbekjempelse fordelt på art. Antall i 1000 stk. Verdi i 1000 kroner Use of farmed and wild cleaner fish in the production of Atlantic salmon and Rainbow trout by species. Number in 1000 individuals. Value in 1000 NOK 2022 2021 2020 2019 2018 2017 2016 2015 Art Antall Verdi Antall Verdi Antall Verdi Antall Verdi Antall Verdi Antall Verdi Antall Verdi Antall Verdi Species Number Value NOK Number Value NOK Number Value NOK Number Value NOK Number Value NOK Number Value NOK Number Value NOK Number Value NOK Rognkjeks/Lumpfish 17,650 329,719 27,655 554,750 34,347 798,085 42,978 942,746 31,130 691,379 29,723 650,257 16,201 332,062 10,325 177,076 Berggylt/Ballan wrasse 2,205 149,448 4,603 227,396 3,317 194,775 2,286 91,471 3,676 98,961 2,449 76,373 2,252 54,605 869 19,098 Bergnebb/Gold-sinny wrasse 5,467 97,756 6,256 124,006 7,388 154,288 7,965 150,858 7,423 138,771 11,178 162,635 5,939 69,284 2,078 21,112 Grøngylt/Cork wing wrasse 7,867 154,042 6,940 115,198 6,321 111,788 7,218 121,029 6,300 109,094 7,731 105,597 5,102 66,225 2,768 32,046 Gressgylt/Rock cook 254 4,182 120 1,927 170 2,526 588 8,397 400 6,669 - - - - - - Uspesifisert/Non spesified 0 3 0 0 0 0 0 0 0 0 3,493 53,670 7,864 130,174 10,369 121,372 Totalt/Total 33,443 735,151 45,575 1,023,277 51,543 1,261,461 61,035 1,314,501 48,929 1,044,873 54,575 1,048,532 37,359 652,351 26,409 370,704  The use of cleaner fish is reduced due to health issues and welfare challenges Use of cleaner fish – welfare challenges  Almost all lumpfish are farmed, while the majority of wrasse are wild.  Different natural habitats (e.g. currents, temperatures).  Different life-style (most are poor swimmers).  Wrasse tolerate high temperatures better – cannot be used in the northern areas.  Many deformities are observed in farmed wrasse.  Removal of cleaner fish before delousing is either problematic or not done! Atlantic cod (Gadus morhua) (Fishbase.se) Gadiformes (Cods) > Gadidae (Cods and haddocks)  Benthopelagic, oceanodromous (Migrates within oceans, between spawning and different feeding areas)  Max length 200 cm, max weight 96 kg, max reported age 25 years.  Spawning in winter - beginning of spring. Spawning sites are in offshore waters, at or near the bottom, in 50-200 m depth and 0-12 °C (main area Lofoten). Different spawning areas may be used in subsequent years. Embryo development lasts about 14 days (at 6°C) and larval phase lasts about 3 months(at 8°C). Juveniles prefer shallow (10-30 m  Cod farming – brief history  In the 1880s the Norwegian sea-captain G.M. Dannevig started experiments.  Juvenile cod were fed on natural zooplankton in seawater enclosures  In 1983 one farmer was able for the first time to produce a significant amount (75 000) of cod juveniles.  Around 2000, cod aquaculture developed mainly in Norway.  In 2008, the market crisis and many challenging biological problems forced many farms to close down.  Low survival rates and escapees  Early sexual maturity low growth and high FCR  Diseases Production cycle https://thefishsite.com/articles/cultured-aquatic-species-atlantic-cod Capture-based cod farming  Long history – since 1880s when ships provided live fish to England.  Can improve issues related to bad quality due to fishing practices.  Better production planning - resources are secured during ‘low season’.  Consistent product supply – better control on the price.  Regulations are a mix – fisheries and aquaculture (could be problematic sometimes). Dreyer, B.M.; Nøstvold, B.H.; Midling, K.Ø.; Hermansen, Ø. 2008. Capture-based aquaculture of cod. In A. Lovatelli and P.F. Holthus (eds). Capture-based aquaculture. Global overview. FAO Fisheries Technical Paper. No. 508. Rome, FAO. pp. 183–198. https://www.fao.org/docrep/pdf/011/i0254e/i0254e09.pdf Stages: capture – recovery (about 24 h) – weaning (transition to commercial diets) – after some months fish are slaughtered (2.5-5 kg) Spotted wolffish (Anarhichas minor) (Fishbase.se)  Perciformes/Zoarcoidei > Anarhichadidae (Wolffishes)  Oceanodromous – short migrations  Max Length 180 cm, Max weight 28 Kg, Max age 40 years  Spawning happens between the months of September and January at 250 m depth. Females lay great egg bunches in nests built on the ground. Farming of wolffish  First real production in Norway around 2004 – Tomma Marinfisk.  Studies started in mid 1980s.  Temperature reference drops as the fish grow older (e.g. 4-8℃ for fish >200g)  Fish tolerate a wide range of salinities – not so sensitive to low oxygen.  Social fish – create large groups on the bottom of the tanks – shelved tanks.  Generally low fecundity – about 1500-4000 eggs per kg female.  Eggs incubated at 4–6°C.  Yolk sacs absorbed within 2 weeks – feeding starts with microparticulate diets.  Farming first in tanks then in various systems – 2-3 years (about 4.4 kg). Challenges For most cold-water species:  Not standardised feeds.  Usually reproduce easily in captivity (cod, is an exception).  In wolfish, normal behaviour of males is disrupted in captivity artificial fertilisation.  High mortality of eggs and sperm.  Limited genetic selection.