|Competitive interactions among beam trawlers exploiting local patches of flatfish in the North Sea|
Rijnsdorp, A.D.; van Mourik Broekman, P.L.; Visser, E.G. (2000). Competitive interactions among beam trawlers exploiting local patches of flatfish in the North Sea. ICES J. Mar. Sci./J. Cons. int. Explor. Mer 57: 894-902
In: ICES Journal of Marine Science. Academic Press: London. ISSN 1054-3139, more
|Authors|| || Top |
- Rijnsdorp, A.D., more
- van Mourik Broekman, P.L.
- Visser, E.G., more
The fishing pattern of individual beam trawl vessels comprises alternating searching and exploitation phases during a fishing trip. The searching phase is characterized by a below-average catch rate and a long distance between the midpoints of hauls. The exploitation phase is characterized by an above average-catch rate and a small inter-haul distance. During the exploitation of a local concentration of flatfish, the catch rate decreases on average by 10% over a period of 48 h. The rate of decline is a function of the engine power. Powerful vessels experience a small or no decline in catch rate, whereas less powerful vessels experience a decline of up to 16%. It is inferred that the decline in catch rate may be due to interference competition among vessels through a change in the behaviour of flatfish in response to fishing disturbance, although a reduction in local abundance may also have contributed to the decline. Areas with above-average catch rates may change on a weekly basis.