Entering uncharted waters: Long-term dynamics of two data limited fish species, turbot and brill, in the North Sea
Kerby, T.K.; Cheung, W.W.L.; Van Oosterhout, C.; Engelhard, G.H. (2013). Entering uncharted waters: Long-term dynamics of two data limited fish species, turbot and brill, in the North Sea. J. Sea Res. 84: 87-95. https://dx.doi.org/10.1016/j.seares.2013.07.005
In: Journal of Sea Research. Elsevier/Netherlands Institute for Sea Research: Amsterdam; Den Burg. ISSN 1385-1101; e-ISSN 1873-1414, more
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| Keywords |
20th century
Abundance
Catch per unit effort
Distribution
Fish stocks
Fisheries
Fishes > Osteichthyes > Pleuronectiformes > Bothidae > Scophthalmus > Turbot
Forestry > Forestry practices > Logging > Landings
Otter trawlers
Scophthalmus maximus (Linnaeus, 1758) [WoRMS]; Scophthalmus rhombus (Linnaeus, 1758) [WoRMS]; Scophthalmus rhombus (Linnaeus, 1758) [WoRMS]
ANE, British Isles, Scotland [Marine Regions]; ANE, North Sea [Marine Regions]
Marine/Coastal |
| Author keywords |
Turbot, Brill, Long-term dynamics, Distribution, Abundance |
| Authors | | Top |
- Kerby, T.K.
- Cheung, W.W.L.
- Van Oosterhout, C.
- Engelhard, G.H.
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| Abstract |
In the North Sea, turbot (Scophthalmus maximus) and brill (Scophthalmus rhombus) represent highly valuable species in commercial fisheries. Still, available data for both species are limited, making stock assessment difficult. Long-term fisheries data have the potential to improve the understanding of stock dynamics such as long-term distribution changes or development in species' abundances. Historical British otter trawler lpue (landings-per-unit-effort) data from 1923 to 2009, and at the spatial scale of ICES rectangles, revealed that the distribution patterns of turbot and brill were different for most of the 20th century and only became similar in the recent decade. Further, between the 1920s and 1960s, turbot was commonly caught in the northern North Sea and in particular on Turbot Bank, at that time a turbot hotspot off the east coast of Scotland. Within a short time period turbot nearly disappeared from this region. Brill, in contrast, revealed a stable distribution in the southern and central North Sea with a slow expansion into the central North Sea. We used survey cpue (catch-per-unit-effort) from the International Bottom Trawl Survey (IBTS; 1970-2009) and the Beam Trawl Survey (BTS; 1985-2009), as well as British otter trawler lpue, as proxies for the abundance of adult turbot and brill. Commercial lpue suggested for brill and turbot a long-term decrease in abundance. IBTS cpue suggested an increase in abundance for turbot, but this was not confirmed by the BTS. For brill, both surveys did not show a clear trend |
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