Premium
Spawner escapement of E uropean eel ( A nguilla anguilla ) from the R iver E rne, I reland
Author(s) -
McCarthy T. Kieran,
Nowak Dariusz,
Grennan Jon,
Bateman Anne,
Conneely Barbara,
MacNamara Ruairi
Publication year - 2014
Publication title -
ecology of freshwater fish
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 55
eISSN - 1600-0633
pISSN - 0906-6691
DOI - 10.1111/eff.12091
Subject(s) - escapement , fishery , hydropower , fishing , population , environmental science , biology , ecology , demography , sociology
Knowledge of silver eel production and escapement is essential for conservation of the E uropean eel ( A nguilla anguilla ) stock. Silver eel trap and transport, being undertaken (2009–2012) to mitigate for negative impacts of hydropower on eels in some I rish rivers, was therefore monitored in the R iver E rne (catchment area 4375 km 2 ). Eel population analyses at an experimental fishing weir involved mark–recapture experiments and sonar ( DIDSON ) surveys. Silver eel mortality rates at two hydropower stations were assessed by acoustic telemetry. The combined results of these studies enabled estimation of silver eel production and escapement for two migration seasons. For the 2010 season, production and escapement estimates were 42.5 t (1.62 kg·ha −1 ) and 38.8 t (1.48 kg·ha −1 ), respectively. For the 2011 season, production and escapement estimates were 44.6 t (1.70 kg·ha −1 ) and 41.8 t (1.59 kg·ha −1 ), respectively. Closure of all commercial eel fisheries and initiation of silver eel conservation fishing in 2009 resulted in 9.36, 19.33 and 25.25 t of silver eels being transported downstream of the hydropower dams in 2009, 2010 and 2011, respectively. The protocols developed in this study can be used to test models being used for eel population management in I reland.