Could our fisheries be more productive? Indirect negative effects of bottom trawl fisheries on fish condition
Article first published online: 23 AUG 2011
© 2011 The Authors. Journal of Applied Ecology © 2011 British Ecological Society
Journal of Applied Ecology
Volume 48, Issue 6, pages 1441–1449, December 2011
How to Cite
Hiddink, J. G., Johnson, A. F., Kingham, R. and Hinz, H. (2011), Could our fisheries be more productive? Indirect negative effects of bottom trawl fisheries on fish condition. Journal of Applied Ecology, 48: 1441–1449. doi: 10.1111/j.1365-2664.2011.02036.x
- Issue published online: 1 NOV 2011
- Article first published online: 23 AUG 2011
- Received 11 January 2011; accepted 3 June 2011 Handling Editor: Melanie Austen
- beam trawl;
- ecosystem approach to fisheries management;
- ecosystem-based management;
- fisheries yield;
- otter trawl;
- predator–prey interactions
1. The nets used in bottom trawl fisheries cause mortality of benthic invertebrates and this can decrease the long-term availability of prey to exploited fish species by reducing the abundance of benthic invertebrates. This may have consequences for the sustainability of fisheries.
2. We assessed the impact of bottom trawling on the food availability of fish by comparing the condition of fish (as weight-at-length) in an area that had a steep commercial bottom-trawling gradient in the Irish Sea but otherwise homogeneous environmental conditions.
3. We found that the condition of the important commercial flatfish plaice Pleuronectes platessa was negatively related to trawling frequency, and this could be explained by a reduced production of the infaunal invertebrates they feed on. Density-dependent changes in competition over food could not explain this difference. No effect of trawling on the condition of the flatfish dab Limanda limanda was detected. Whiting Merlangius merlangus feeds primarily on fish, and therefore, no effect of bottom trawling on its condition was expected or detected.
4. This study therefore indicates that bottom trawl fisheries may have a negative effect on the condition of some of their target species, but not others, by reducing the abundance of their benthic prey.
5. Synthesis and application. Bottom trawls may indirectly affect the population size and growth rate of the target fish species and result in lower fishing yields. Such reductions in the yield and sustainability of fisheries are highly undesirable. The effects of bottom trawls may be mitigated by the modification of fishing gears or by minimizing the area of the seabed fished by bottom trawls.