Population Structure Indices of Largemouth Bass and Smallmouth Bass Determined from Angler Catches

Abstract

Increased angling effort on black bass (Micropterus dolomieui and Micropterus salmoides) requires more efficient and effective management to maintain the quality of the resource. Baseline data needed to develop effective management policies were collected for largemouth bass and smallmouth bass in 19 lakes and 1 river in Maine, representing 19,000 hectares of water. A card requesting only information on bass was distributed to anglers at bass club fishing tournaments and to the general public at sporting shops, general stores, and fishing lodges. Fishing diaries were given to selected anglers who had received specific instructions. Data were analyzed by the Proportional Stock Density index (PSD), a measure of population size structure. Populations of largemouth bass in eight waters had significant PSD values greater than 60%, indicating too few small fish. In three lakes, PSD was between 40 and 60%, indicating balanced populations. Populations of smallmouth bass in eight waters had significant PSD values greater than 60%, also indicating too few small fish. PSD was less than 40% in two waters, indicating too few large fish. Smallmouth bass in the one river had a PSD between 40 and 60%, suggesting balanced numbers. Regulation changes of increased size limits to increase sizes of predators are recommended for three of eight waters that were analyzed in detail. A slot limit protecting intermediate-size fish is recommended for the river.