Escapes of fishes from Norwegian sea-cage aquaculture: causes, consequences and prevention.
By Østen Jensen, T. Dempster, E. Thorstad, I. Uglem, A. Fredheim. 2010
305 citations recorded by the source corpus.
The escape of fish from aquaculture is perceived as a threat to wild fish populations. The escapes problem is largely caused by technical and operational failures of fish farming equipment. In Norway, 3.93 million Atlantic salmon Salmo salar, 0.98 million rainbow trout Oncorhynchus mykiss and 1.05 million Atlantic cod Gadus morhua escaped from 2001 to 2009. Salmonids primarily escape after structural failures of containment equipment, while a far greater percentage of cod than salmon escape through holes in the nets. Correlative evidence suggests that after the Norwegian technical standard (NS 9415) for sea-cage farms took effect in 2004, the total number of escaped Atlantic salmon declined from >600 000 (2001 to 2006) to <200 000 fish yr -1 (2007 to 2009), despite the total number of salmon held in sea-cages increasing by 44% during this period. No similar decrease in escaped cod has occurred, suggesting that other measures, such as improved netting materials for sea-cages, are required. In addition to escaping as juveniles or adults, cod may reproduce in sea- cages, and thus fertilised eggs escape to the environment. The ecological effects of 'escape through spawning' are unclear, and methods to inhibit escape by this mechanism are being explored. To pre- vent escapes of juvenile and adult fish as sea-cage aquaculture industries develop, we recommend that policy-makers implement a 5 component strategy: (1) establish mandatory reporting of all escape incidents; (2) establish a mechanism to analyse and learn from the mandatory reporting; (3) conduct mandatory, rapid, technical assessments to determine the causes of escape incidents involving more than 10 000 fish; (4) introduce a technical standard for sea-cage aquaculture equipment coupled with an independent mechanism to enforce the standard; and (5) conduct mandatory training of fish farm staff in escape-critical operations and techniques.
Subfields: Global and Planetary Change, Nature and Landscape Conservation
View Paper: https://www.semanticscholar.org/paper/fdfb287975aa8ca0432d37e9dd231832bc6de907
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In Global and Planetary Change
In Nature and Landscape Conservation
Citations in the corpus
- Differentiating the wild or farmed origin of Mediterranean fish: a review of tools for sea bream and sea bass (2013, background): “consequence of technical and operational failures (Jensen et al. 2010), but the proportions of escapes in the Mediterranean that are due to storms, holes in the netting caused by wear and tear, abrasion on cage ropes, predators or biting by farmed fish within the cage, or spills during handling of f”
- Impacts of marine and freshwater aquaculture on wildlife: a global meta-analysis (2018, unknown): “2017), and interference with spawning or competition with offspring and adults (Jensen et al. 2010; Sundt-Hansen et al. 2015).”
- The Political Economics of Marine Aquaculture in the United States (2016, background): “Potential risks cannot all be eliminated even in countries with well-developed aquaculture practices and environmental laws and years of research on environmental effects (Jensen et al., 2010; Johansen et al., 2011; Torrisson et al., 2011).”
- Half a century of genetic interaction between farmed and wild Atlantic salmon: Status of knowledge and unanswered questions (2017, unknown): “So long as facilities are not fully contained, the escape of farmed fish into the wild is inevitable (Bentsen & Thodesen, 2005; Jensen et al., 2010).”
- The impact and control of biofouling in marine aquaculture: a review (2012, background): “Cage designers and operators need to account for these increased loads in the design of cage floatation and mooring systems or devastating net failures result which lead to escapes of fish (Jensen et al. 2010).”