The changing times of Europe's largest remaining commercially harvested population of eel Anguilla anguilla L.

Autor: Aprahamian MW; Shandon House, Sale, UK., Evans DW; Agri-Food and Biosciences Institute, Belfast, UK., Briand C; Institution Aménagement de la Vilaine, La Roche-Bernard, France., Walker AM; Centre for Environment, Fisheries and Aquaculture Science, UK., McElarney Y; Agri-Food and Biosciences Institute, Belfast, UK., Allen M; Agri-Food and Biosciences Institute, Belfast, UK.
Jazyk: angličtina
Zdroj: Journal of fish biology [J Fish Biol] 2021 Oct; Vol. 99 (4), pp. 1201-1221. Date of Electronic Publication: 2021 Jul 01.
DOI: 10.1111/jfb.14820
Abstrakt: This study quantifies the processes involved in regulating the European eel population of Lough Neagh, a lake in Northern Ireland. The relationship between glass eel input and silver eel output for the 1923-1997 cohorts was best described by a Beverton-Holt stock recruitment model. Glass eel input time series was not complete and was thus derived from the relationship between catches elsewhere in Europe and Lough Neagh, together with the addition of stocked glass eel. Silver eel output was the sum of silver eel escapement, catch and yellow eel catch converted to silver eel equivalents. Natural mortality increased with glass eel density, ranging from 0.017 to 0.142 year -1 . The mean carrying capacity increased from ≈3.25 M silver eels (≈26 kg ha -1 ) for the 1923-1943 cohorts to ≈5.0 M (≈40 kg ha -1 ) for the 1948-1971 cohorts before regressing back to ≈3.25 M. The total silver eel output was highest during the late 1970s/early 1980s at 35-45 kg ha -1  year -1 and lowest during the early years of the 20th century and is currently at 10-15 kg ha -1  year -1 . The findings are discussed in relation to (a) the ecological changes that have occurred within the lough, associated with eutrophication and the introduction of roach (Rutilus rutilus L.), and (b) the decline of the wider European eel stock across its distribution range. The findings from this study have relevance for the wider management of the European eel stock.
(© 2021 Crown copyright. Journal of Fish Biology published by John Wiley & Sons Ltd on behalf of Fisheries Society of the British Isles. This article is published with the permission of the Controller of HMSO and the Queen's Printer for Scotland.)
Databáze: MEDLINE
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