Using logbook-based catch-rate data to detect yellow eel population trends in the southern Baltic Sea |
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| Authors: | Malte Dorow Wolf-Christian Lewin Dietmar Lill Claus Ubl Jens Frankowski |
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| Institution: | 1. State Research Centre for Agriculture and Fisheries Mecklenburg-Vorpommern, Institute of Fisheries, Rostock, Germany;2. Thünen Institute of Baltic Sea Fisheries, Rostock, Germany;3. NAWA GbR, Broderstorf, Germany;4. German Fisheries Association, Hamburg, Germany |
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| Abstract: | Within recent years, a slight but significant increase of European eel Anguilla anguilla (L.) recruitment has been documented, but it remains questionable whether or not the increased recruitment levels resulted in higher eel numbers at the regional scale. To detect the changes in yellow eel numbers, logbook data covering a 15-year time series of catch per unit effort (CPUE) data from the German Baltic Sea were analysed. Monthly mean catch rates were calculated for two different size classes for two passive gears: fyke and stationary trap nets. Change-point analysis was applied to discover changes in the catch data. After a period of decreasing or constant catch rates, the fyke net data indicated that yellow eel numbers increased slightly in recent years in the Baltic Sea. Besides increasing numbers of immigrating juvenile eels, other population dynamics or conservation efforts might have added to the observed positive stock trend. |
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| Keywords: | Anguilla anguilla change-point analysis coastal waters commercial fishery eel management European eel stock dynamics |
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