Commercial Trawler Discards of Four Flounder Species in the Gulf of Maine

Abstract

The objectives of the research were to quantify commercial trawler discards of American plaice (Hippoglossoides platessoides), witch flounder (Glyptocephalus cynoglossus), yellowtail flounder (Limanda ferruginea), and winter flounder (Pseudopleuronectes americanus) and to examine variables that potentially influence discard rates. Data were obtained from 135 tows in six areas of the Gulf of Maine. Four different types of trawls were used. Mean discard percentages per tow, on a weight basis, were 25, 18, 13, and 5% for American plaice, witch flounder, yellowtail flounder, and winter flounder, respectively. Mean discard percentages were higher on a numerical basis, with 57, 27, 25, and 12% of the respective species discarded per tow. Both trawl type and area fished affected the discard percentages of American plaice and witch flounder. Stepwise multiple regression analyses indicated that six variables combined to explain 66.8% of the variation in discard percentage of American plaice, and that three variables combined to explain 31.2% of the variation in discard percentage of witch flounder.