I Frequently get interviewed by various organisations about fish welfare. Currently, I provide feedback to queries raised by the RSPCA and also, by the animal ethics committees of universities and schools. I try to provide the most up to date information, however, there remains more work to be done.
What we need to understand is that ‘fish’ are a diverse range of animals. one fish species is not necessarily the same as another and so we cannot generalise in some cases.
Let me illustrate an example using ‘birds’ as a group. When you compare what the requirements for ducks – need water to paddle and dive, ability to fly, balanced diet including greens and aquatic invertebrates… This cannot be applied to an ostrich! An ostrich would drown!
work such as the one in this article attached would be needed in a wide range of fish. And we need to be objective about things.
| Aquaculture | |||||||||||||||||
| Volume 323, Number 1 (December 2011) | |||||||||||||||||
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Short- and long-term effects of fish density and specific water flow on the welfare of Atlantic cod, Gadus morhua | ||||||||||||||||
| Authors: | Børge Damsgård, Frode Bjørklund, Helge K. Johnsen, Hilde Toften | ||||||||||||||||
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| Source: | Aquaculture, Volume 323, Number 1 (December 2011) | ||||||||||||||||
| Page Numbers: | 184 – 190 | ||||||||||||||||
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| Abstract: | Intensive rearing of farmed fish may have potential welfare related consequences on a short-term and long-term scale. Groups of individually tagged juvenile Atlantic cod, Gadus morhua, were held in eight tanks for 9weeks at different rearing intensities, given as combinations of fish density and specific water flow (litrewaterperkg-1fishpermin-1). The control groups (LD-HF) had low density (~30kgm-3) and high specific water flow (0.84lkg-1min-1), while the other groups had high density (~60kgm-3) and either high specific water flow (HD-HF, 0.84lkg-1min-1), or low specific water flow (HD-LF, 0.17lkg-1min-1). Oxygen was added to maintain an O2level of 80% saturation in all tanks. The groups were pooled after the nine week treatment period, transferred to a sea cage and reared under standard conditions for 14.5months, until reaching an average body size of approximately 1.4kg. A combination of high fish density and low water flow (HD-LF) resulted in accumulation of CO2in the water. This, in turn was associated with significantly higher blood pCO2, a higher frequency of nephrocalcinosis, and a 20–30% reduction in growth, as compared with the other groups. The sub-optimal growth observed in the HD-LF groups was not fully compensated for after transfer to the sea cage, with the fish of the LD-HF and HD-HF groups being 5–10% larger than the HD-LF fish by the end of the experiment. | ||||||||||||||||
| Citation: | Børge Damsgård, Frode Bjørklund, Helge K. Johnsen, Hilde Toften . Short- and long-term effects of fish density and specific water flow on the welfare of Atlantic cod, Gadus morhua. Aquaculture, Volume 323, Number 1 (December 2011), pp. 184-190, | ||||||||||||||||
| URL: | http://ejournals.ebsco.com/direct.asp?ArticleID=4E76982CA2056EA97165 | ||||||||||||||||
