Download or read book Manual on Estimation of Selectivity for Gillnet and Longline Gears in Abundance Surveys written by Holger Hovgêrd and published by Food & Agriculture Org.. This book was released on 2008-04-29 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: This manual defines methods for estimating selectivity of gillnet and longline gears, with particular reference to the use of these gears in abundance surveys. The manual illustrates how gear design, the basic concepts of size selection and fish morphometric data can be used to model selectivity. Statistical estimation methods are described in detail, and examples given of their application in spreadsheets. The efficient use of these gears in abundance and research surveys is also discussed. Although the manual concentrates on gillnets and longlines, the methods given are general enough to be relevant to any research involving gear selectivity