A model of gillnet catch in relation to the catchable biomass, saturation and soak time and sampling period

0352000 - BC 2011 RIV NL eng J - Journal Article
Prchalová, Marie - Mrkvička, T. - Peterka, Jiří - Čech, Martin - Berec, L. - Kubečka, Jan
A model of gillnet catch in relation to the catchable biomass, saturation and soak time and sampling period.
Fisheries Research. Roč. 107, 1-3 (2011), s. 201-209. ISSN 0165-7836. E-ISSN 1872-6763
R&D Projects: GA AV ČR(CZ) KJB600960810
Institutional research plan: CEZ:AV0Z60170517
Keywords : catch interpretation * catch correction * video recording * reservoir * CPUE
Subject RIV: DA - Hydrology ; Limnology
Impact factor: 1.586, year: 2011

We developed a new approach for evaluating gillnet catches. A model of a gillnet catch was built to differentiate the effects of gillnet saturation, fish activity and fish escapement from the gillnet catch. We also observed the effects of soak time (2, 5, 8, 11 and 13 h) and sampling period (August vs. September) on the catch. Our results show that saturation and fish escapement from gillnets are important events occurring during each use, thus violating the assumption of a linear relationship between gillnet catch and fish density. We created a conversion table and a slide rule, from which the catchable biomass rates can be determined. We also developed a method for the conversion of catches based on different soak times. Our findings help to better understand the processes underlying gillnet catches and improve the interpretability and reliability of this method in comparing different gears used and assessing fish communities in general.
Permanent Link: http://hdl.handle.net/11104/0191614