Resistance of aquaculture net cage materials to biting by Atlantic Cod (Gadus morhua)

Moe, Heidi; Gaarder, Rune Harald; Olsen, Anna; Hopperstad, Odd Sture

doi:10.1016/j.aquaeng.2009.02.001

Cited by 24 publications

(12 citation statements)

References 4 publications

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“…The net damage in the present tests was similar to what is found on used nets from commercial cod farms (Moe et al 2009), but their trials were not accompanied by behavioural observations and did not quantify biting rates in relation to type of mending. Our results show that cod may cause substantial damage to standard nylon netting if they focus the biting on specific areas of the net.…”

Section: Discussionsupporting

confidence: 59%

“…After the tests, the panels were photographed again and visually examined for damage. The assessment of damage included the entire panel surface, and the holes and repairs, as described by Moe et al (2009). Damage to net thread and mending thread was categorized according to the scores 0 (no visible wear), 1 (partly fluffed ends and abrasion) or 2 (severely fluffed ends and abrasion.…”

Section: Methodsmentioning

confidence: 99%

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Net-biting and escape behaviour in farmed Atlantic cod Gadus morhua: effects of feed stimulants and net traits

Damsgård¹,

Høy²,

Uglem³

et al. 2012

Aquacult. Environ. Interact.

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Preventing farmed fish from escaping sea cages is a major challenge for developing sustainable aquaculture practices. In this study, the individual behaviour of Atlantic cod Gadus morhua to inspect and bite the net was investigated in 4 replicate multi-patch experiments, using underwater video techniques and behavioural event recording. The experimental system included a tank enclosure where cod were presented with 6 separate net panels: duplicate pairs of plain control nets and 2 different treatment panels. Four holes were made in the treatment panels, 3 of which were mended with different repair techniques including short and loose thread ends and contrasting colour repair threads. Behavioural effects of feed stimulants were studied before, during and after a feed source was placed outside the net. The cod inspected and bit the net systematically, significantly focusing on loose threads or minor damage on the net, and the fish were capable of causing severe net damage within a few days. The observed behaviours were related to hunger level and feed stimulation, and increased significantly during times when a feed source was present outside the net wall. Few bites were observed, and almost no measureable damage was recorded to plain control panels and the area around unrepaired holes during the treatment. Repairs made with white and black threads, and loose, long ends were significantly more damaged than repairs made with short thread ends and threads of similar colour as the net. The experiments demonstrated how a behavioural approach might be used in interpretation of a practical problem in aquaculture, and the results will be useful in the development of technology and escape mitigation strategies.

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Section: Discussionsupporting

confidence: 59%

Section: Methodsmentioning

confidence: 99%

Net-biting and escape behaviour in farmed Atlantic cod Gadus morhua: effects of feed stimulants and net traits

Damsgård¹,

Høy²,

Uglem³

et al. 2012

Aquacult. Environ. Interact.

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“…Farmed salmon have been documented to spawn with wild salmon (Webb et al 1991, Carr et al 1997, Hindar et al 2006, resulting in the genetic introgression of farmed traits into wild gene pools (Crozier 1993) and potentially lowering the overall fitness of wild stocks (Utter 1998, Youngson et al 2001, Hutchings & Fraser 2008. Compared to salmon, cod are more prone to escape from sea cages based on reports of biting at holes in nets to enlarge them to facilitate their escape (Moe et al 2007(Moe et al , 2009, though other factors also contribute to fish escapes including marine accidents, creation of holes in nets by predators and damage to sea cages from storms. Unlike salmon, cod also spawn within sea cages, resulting in embryos being released into the natural environment (Jørstad et al 2008).…”

Section: Introductionmentioning

confidence: 99%

Competitive spawning success and fertility of triploid male Atlantic cod Gadus morhua

Feindel¹,

Benfey²,

Trippel³

2010

Aquaccult. Environ. Interact.

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Farmed Atlantic cod Gadus morhua have been hypothesized to pose a risk to the natural environment through escape of fish or release of their gametes from sea cages. The use of sterile triploids has been suggested as a way to prevent spawning of farmed fish, whether escaped from their cages or still contained within them. This laboratory study examined the reproductive potential of triploid male Atlantic cod, both in vivo and in vitro. We demonstrated that triploid males in competitive, size-matched mating with diploid males were successful at siring young. Spermatozoa produced by triploid males were larger than those of diploids, but did not differ in swimming velocity or ability to fertilize eggs. Hatch and larval survival rates, however, were reduced for progeny of triploid males. These diagnostic characteristics of aneuploidy suggest that although farmed triploid male cod may compete successfully with wild diploids for spawning access to wild females, their offspring will not survive.

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“…In finfish aquaculture, high-density polyethylene (HDPE) and nylon are major constituents used to fabricate cages and netting. Fouling on these polymers decreases cage volume, flow and buoyancy while it increases physical damage and deformation as well as cage weight and therefore mooring stress (Braithwaite & McEvoy 2005;Fredriksson et al 2007;Moe et al 2009;Fitridge et al 2012). In geophysical exploration, polyurethane seismic streamers are used to protect sensitive electronic equipment.…”

Section: Introductionmentioning

confidence: 99%

Assessing the antifouling properties of cold-spray metal embedment using loading density gradients of metal particles

et al. 2014

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Particles of copper, bronze and zinc were embedded into a polymer using cold-spray technology to produce loading density gradients of metal particles. The gradients were used to identify the species with the highest tolerance to the release of copper and zinc ions. The gradients also established the minimum effective release rates (MERRs) of copper and zinc ions needed to prevent the recruitment of fouling under field conditions. Watersipora sp. and Simplaria pseudomilitaris had the highest tolerances to the release of metal ions. Copper and bronze gradient tubes were similar in their MERRs of copper ions against Watersipora sp. (0.058 g m(-2) h(-1) and 0.054 g m(-2) h(-1), respectively) and against S. pseudomilitaris (0.030 g m(-2) h(-1) and 0.025 g m(-2) h(-1), respectively). Zinc was not an effective antifoulant, with failure within two weeks. In conclusion, cold-spray gradients were effective in determining MERRs and these outcomes provide the basis for the development of cold-spray surfaces with pre-determined life-spans using controlled MERRs.

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Resistance of aquaculture net cage materials to biting by Atlantic Cod (Gadus morhua)

Cited by 24 publications

References 4 publications

Net-biting and escape behaviour in farmed Atlantic cod Gadus morhua: effects of feed stimulants and net traits

Net-biting and escape behaviour in farmed Atlantic cod Gadus morhua: effects of feed stimulants and net traits

Competitive spawning success and fertility of triploid male Atlantic cod Gadus morhua

Assessing the antifouling properties of cold-spray metal embedment using loading density gradients of metal particles

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