Title: Use of rod catch-effort data to monitor migratory salmonids in Wales : a report submitted in part fulfillment of the requirements of the course
Author: D.A. Bunt
Document Type: Monograph
Annotation: EA additional title info: Diploma of the Institute of Fisheries Management
Abstract:
Rod catch and effort data for salmon and sea trout were analysed from over 11,600 returns for 57 Welsh rivers for the 1988 season. Total reported effort was 159,113 visits with a median of 7 visits per angler. Larger rivers (measured as average daily flow, A.D.F.) received greater fishing effort and yielded larger catches than smaller rivers. CPUE (fish per visit) for the whole region was 0.0582 for salmon and 0.1894 for sea trout, with considerable variation between rivers. CPUE was underestimated as it was not possible to separate fishing effort between salmon and sea trout. An index of fish abundance (n) is proposed which reduces variability in catch (C) due to flow index (q) and fishing effort (f): n-C/qf. Calculation of n allows comparison between rivers in any one year and interyear trends in individual rivers, though more refined use of flow data is recommended to determine q more accurately. Changes to the method of reporting effort are proposed to allow separation of effort between species for future years, yet maintain comparability with earlier seasons. The issue of log books to season anglers is recommended to increase the quality of catch data. Detailed analysis of archived and future data is recommended to determine the need to collect effort and flow information, and if it is possible to accurately separate salmon and sea trout effort data.
Publisher: National Rivers Authority
Publication Date: [1991]
Publication Place: Cardiff
Subject Keywords: Fishery management; Salmon fisheries; Trout; Migration; Catches; Data analysis
Geographic Keywords: Wales
Taxonomic Keywords: Salmonidae
Extent: n.p. [27]
Permalink: http://www.environmentdata.org/archive/ealit:3474
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