Selectivity of Four Trawl Cod Ends toward Smelt

Abstract

Three short-term experiments on selectivity of cod ends with various mesh sizes for smelt, Osmerus mordax (Mitchill), were conducted in Lakes Ontario and Erie during 1961. In each experiment the paired tow method was used. Four cod ends were attached alternately to a “Western bottom trawl” fished by the MV Erie I. Estimates of percent retention within 0.3-inch length strata were obtained from a comparison of length-frequency distributions in catches made by the different cod ends fishing approximately the same population of smelt on the same date. Additional information was gained from the weight of catches by different cod ends. Under the conditions of the experiment, cod end mesh sizes of 1 3/16 to 1 3/8 inches appeared most suitable for smelt trawling given market preferences as they existed in October 1961.