Calculation of Stock Density Indices Based on Adjustments for Efficiency of Gill-Net Mesh Size
- 1 April 1985
- journal article
- Published by Oxford University Press (OUP) in North American Journal of Fisheries Management
- Vol. 5 (2A) , 126-137
- https://doi.org/10.1577/1548-8659(1985)5<126:cosdib>2.0.co;2
Abstract
This project was designed to allow adjustment in length‐frequency calculations for walleye (Stizo‐stedion vitreum), white bass (Morone chrysops), and gizzard shad (Dorosoma cepedianum), based on the efficiency of the gill‐net mesh size. Such adjustments in length frequency have effects on calculation of Proportional Stock Density (PSD) and Relative Stock Density (RSD). Mesh‐size efficiencies of the standard gill‐net complement used by the Kansas Fish and Game Commission were determined by plotting absolute catch of these three species in 25‐, 38‐, and 64‐mm mesh (bar measure) monofilament gill nets. Catches in 19‐, 32‐, and 51‐mm nets also were plotted to ensure that fish were available at lengths in the valleys between the peaks (effective catch) of the standard complement catch. An adjustment line was plotted from peak to peak of absolute catch in the three mesh sizes (adjusted for effort). Correction factors up to this adjustment line were developed by centimeter length groups for all three species. Empirical numbers caught in a mesh were multiplied by correction factors to yield an adjusted number for the length group that more accurately reflected the actual contribution of the length group to the population structure.This publication has 0 references indexed in Scilit: