The variability in the catches of charr, Salvelinus alpinus L., and perch, Perca fluviatilis L., from multi‐mesh gill nets

• Published in: Journal of Fish Biology
• Main Authors: Craig, J. F., Fletcher, J. M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1982
• Subjects: Salvelinus alpinus
• Online Access: http://dx.doi.org/10.1111/j.1095-8649.1982.tb03952.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1095-8649.1982.tb03952.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1095-8649.1982.tb03952.x

Multi‐mesh gill nets set at Rawlinson's Nab in the south basin of Windermere for 24 months from 1979 to 1981 caught predominantly charr and perch. Nets set parallel to the shore caught significantly fewer fish than those set perpendicular to the shore. Variability in the mean catches of perch increased from winter to summer when the size of the catches also increased. Charr were mostly caught from November until February. Estimates of variance associated with the geometric mean catch of a single net (set perpendicular to the shore) were calculated for the periods winter for the charr and winter, summer, spring and autumn for the perch. These variances were used to calculate 95 and 99% C.L. of the geometric mean. For limits to be below half or twice the geometric mean, 12 nets would have to be used for charr during winter. For perch the number of nets needed would be six in winter, 20 in spring and autumn and 40 in summer. It is concluded that the nets are of little value in assessing changes in stock abundance.