Gadoid mariculture: development and future challenges

Kjesbu, Olav Sigurd; Taranger, Geir Lasse; Trippel, Edward A.

doi:10.1016/j.icesjms.2005.12.003

Cited by 41 publications

(28 citation statements)

References 5 publications

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“…One of the primary constraints to commercially viable production of farmed Atlantic cod and haddock is early (pre-harvest) sexual maturation (Kjesbu et al 2006). The flesh quality of farmed fish is affected when sexual maturation begins, as protein and lipid energy stores are transferred from the muscle to the developing gonads.…”

Section: Introductionmentioning

confidence: 99%

Gonadal differentiation in Atlantic cod, Gadus morhua L., and haddock, Melanogrammus aeglefinus (L.)

Chiasson¹,

Benfey²,

Martin-Robichaud³

2008

Acta Icth et Piscat

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. 2008. Gonadal differentiation in Atlantic cod, Gadus morhua L., and haddock, Melanogrammus aeglefinus (L.). Acta Ichthyol. Piscat. 38 (2): 127-133.Background. The purpose of this study was to determine the timing of gonadal differentiation in two gadoids: Atlantic cod, Gadus morhua L., and haddock, Melanogrammus aeglefinus (L.). This information is required to develop a practical protocol for the production of monosex populations of these species for aquaculture. Materials and Methods. Cultured larvae and juveniles were collected weekly, measured (total length; TL), prepared histologically and then examined microscopically for the presence of characteristic stages of gonadal differentiation. Results. In Atlantic cod, undifferentiated gonads were present by 18 mm TL, at 84 days post hatch (dph), and definitive germ cells by 19 mm TL (90 dph). Ovarian cavities were first observed at 27 mm TL (102 dph), and by 35 mm TL (112 dph) anatomical divergence into two types of gonads was clear. In haddock, undifferentiated gonads were observed at 21 mm TL (64 dph) and an ovarian cavity was evident at 29 mm TL (71 dph). Conclusion. Gonadal differentiation in Atlantic cod and haddock occurs at roughly the same size in both species (27 and 29 mm TL, respectively). For successful sex reversal, the administration of steroids should therefore begin at approximately 25 mm TL, shortly after weaning onto dry feed.

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Section: Introductionmentioning

confidence: 99%

Gonadal differentiation in Atlantic cod, Gadus morhua L., and haddock, Melanogrammus aeglefinus (L.)

Chiasson¹,

Benfey²,

Martin-Robichaud³

2008

Acta Icth et Piscat

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“…This represents an approximately 40-fold increase since 2000 (169 t), demonstrating a rapid growth in the farmed volume for this species. As intensive cultivation of cod is fairly new, the growth potential is estimated to increase sharply worldwide, and the largest growth is predicted to take place in Norway (Kjesbu et al 2006). However, a major concern is the impact of diseases, as gadoid fish in culture are known to suffer from a variety of infectious diseases (Bricknell et al 2006, Samuelsen et al 2006.…”

Section: Introductionmentioning

confidence: 99%

Nodavirus in farmed Atlantic cod Gadus morhua in Norway

Patel¹,

Korsnes²,

Bergh³

et al. 2007

Dis. Aquat. Org.

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Viral encephalopathy and retinopathy (VER) was diagnosed in 5 to 24 g sized farmed Atlantic cod Gadus morhua kept in sea cages at Parisvatn, Hordaland county, on the west coast of Norway. Moderate mortality (10 to 15%) was observed, along with anorexia and abnormal swimming behaviour, such as looping or spiral swimming and reduced coordination. Nodavirus was detected by 2 different real-time RT-PCR assays, and this was later confirmed by immunohistochemistry. This is the first report of an outbreak of VER in farmed cod in Norway, and the first report that VER affect cod exceeding 5 g in size.

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“…First, the effects of effluent discharge in the form of excessive nutrients from sea-cage farming is a long-standing issue (Folke et al 1994;Gowen, 1994;Naylor et al 1998;Powell, 2003;Goldburg & Naylor, 2004;Naylor & Burke, 2005;Kjesbu et al 2006). Abnormally high levels of nutrients can alter the structure of benthic (seabed) ecosystems and cause algal blooms that are toxic to fish and shellfish (Anderson et al 2002).…”

Section: Over Exploited (Overfished)mentioning

confidence: 99%

“…Infestations can prove fatal to fish and early studies indicate that sea lice affect cod (Walden, 2000). As cod farming develops, new diseases are likely to appear (Kjesbu et al 2006), as indicated by the outbreak of Francisella in one cod farm in Norway that saw a 40% mortality rate over a five-month period (Fish Farmer Magazine, 2006). 4 Finally, reliance on wild-caught fish in aquaculture feed has attracted criticism since aquaculture operations for carnivorous fish can contribute to fishing pressure on certain stocks, such as the Peruvian anchoveta (Engraulis ringens) and Chilean jack mackerel (Trachurus murphyi) (Naylor et al 1998;Pauly et al 2002;Hannesson, 2003;Powell, 2003;Asche & Tveterås, 2004;Naylor & Burke, 2005;Kjesbu et al 2006;Opstad et al 2006).…”

Section: Over Exploited (Overfished)mentioning

confidence: 99%

Investigation into the sustainability of organic aquaculture of Atlantic cod (Gadus morhua)

Birt

Rodwell

Richards

2009

Sustainability: Science, Practice and Policy

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Wild stocks of Atlantic cod (Gadus morhua) are low. With fisheries in decline, continued demand for cod has led to a fledgling aquaculture industry and current forecasts call for rapid growth. However, critics blame aquaculture of carnivorous species for further depleting fish stocks and for its wider effects on the marine environment. We examine the activities of Johnson Seafarms, a sea-cage organic cod farming facility in the Shetland Islands, to investigate whether "organic" cod farming can be environmentally, economically, and socially sustainable. Data were collected via public questionnaires and interviews with aquaculture experts. The results show that, before it closed in 2008, Johnson Seafarms was addressing the environmental concerns traditionally associated with aquaculture of carnivorous species and that economic viability is possible as a market exists for organically farmed cod at prices higher than for wild fish. We conclude that organic cod farming, as was practiced in the Shetland Islands, is sustainable on that scale. While the industry has room for measured expansion, overexpansion would increase pressure on natural systems, undermining environmental and, ultimately, social and economic sustainability. Producers and regulators should consider alternative techniques, including land-based or integrated aquaculture systems. Any development should be accompanied by further research regarding the industry's sustainability.

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Gadoid mariculture: development and future challenges

Cited by 41 publications

References 5 publications

Gonadal differentiation in Atlantic cod, <I>Gadus morhua</I> L., and haddock, <I>Melanogrammus aeglefinus</I> (L.)

Gonadal differentiation in Atlantic cod, <I>Gadus morhua</I> L., and haddock, <I>Melanogrammus aeglefinus</I> (L.)

Nodavirus in farmed Atlantic cod Gadus morhua in Norway

Investigation into the sustainability of organic aquaculture of Atlantic cod (Gadus morhua)

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