The influence of the trawl mouth opening size and net colour on catch efficiency during sampling of early fish stages

0349531 - BC 2011 RIV NL eng J - Journal Article
Jůza, T. - Čech, Martin - Kubečka, Jan - Vašek, Mojmír - Peterka, Jiří - Matěna, Josef
The influence of the trawl mouth opening size and net colour on catch efficiency during sampling of early fish stages.
Fisheries Research. Roč. 105, č. 3 (2010), s. 125-133. ISSN 0165-7836. E-ISSN 1872-6763
R&D Projects: GA ČR(CZ) GP206/09/P266; GA AV ČR(CZ) 1QS600170504
Institutional research plan: CEZ:AV0Z60170517
Keywords : trawl efficiency * fry density * perch
Subject RIV: EH - Ecology, Behaviour
Impact factor: 1.656, year: 2010

The efficiency of different sized and coloured trawls were investigated in surface stratum of the Římov Reservoir during two surveys in spring 2007. No significant differences in efficiency and body lengths of the fry were found for any taxa when black and white trawls were compared. Comparison of the efficiencies of different sized trawls revealed different patterns for the dominant perch and cyprinids during both day and night. For perch, the lowest efficiency was observed for the smallest trawl, whereas the greatest efficiency was observed for the largest trawl. The efficiencies were significantly different between trawls during day and night only for perch. For cyprinids, the efficiencies of different sized trawls were insignificantly different during both day and night. Our results indicate that for sampling perch fry during both day and night, trawl with a 1 m2 mouth is not sufficiently efficient and the density of perch fry is significantly under estimated with such small net.
Permanent Link: http://hdl.handle.net/11104/0189743