Effects of fish density distribution and effort distribution on catchability

Ellis, Nick and Wang, You-Gan (2007) Effects of fish density distribution and effort distribution on catchability. ICES Journal of Marine Science, 64 1: 178-191. doi:10.1093/icesjms/fsl015

Author Ellis, Nick
Wang, You-Gan
Title Effects of fish density distribution and effort distribution on catchability
Journal name ICES Journal of Marine Science   Check publisher's open access policy
ISSN 1054-3139
Publication date 2007-01
Sub-type Article (original research)
DOI 10.1093/icesjms/fsl015
Volume 64
Issue 1
Start page 178
End page 191
Total pages 14
Place of publication Oxford, United Kingdom
Publisher Oxford University Press
Language eng
Abstract The effects of fish density distribution and effort distribution on the overall catchability coefficient are examined. Emphasis is also on how aggregation and effort distribution interact to affect overall catch rate [catch per unit effort (cpue)]. In particular, it is proposed to evaluate three indices, the catchability index, the knowledge parameter, and the aggregation index, to describe the effectiveness of targeting and the effects on overall catchability in the stock area. Analytical expressions are provided so that these indices can easily be calculated. The average of the cpue calculated from small units where fishing is random is a better index for measuring the stock abundance. The overall cpue, the ratio of lumped catch and effort, together with the average cpue, can be used to assess the effectiveness of targeting. The proposed methods are applied to the commercial catch and effort data from the Australian northern prawn fishery. The indices are obtained assuming a power law for the effort distribution as an approximation of targeting during the fishing operation. Targeting increased catchability in some areas by 10%, which may have important implications on management advice.
Keyword Aggregation
Catch and effort data
Density distribution
Effort distribution
Stock assessment
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Mathematics and Physics
Version Filter Type
Citation counts: TR Web of Science Citation Count  Cited 23 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 25 times in Scopus Article | Citations
Google Scholar Search Google Scholar
Created: Wed, 17 Nov 2010, 13:48:56 EST