Contributions to the Biology of the Cutlassfish (Trichiurus lepturus) in the Northern Gulf of Mexico

Abstract

Analyses are made of catch per unit of effort and length-frequency data of over 11,000 cutlassfish trawled off Grand Isle, Louisiana in 3.5–20 fm depths. Trimodal seasonal variations in apparent relative abundance are recorded with minor modes occurring during February-March and October-November and a dominant spring-summer mode from May or June through August. Smaller fish were usually most abundant at 15–20 fm depths, whereas largest size groups were most frequent at 3.5–7.5 fms. An offshore-inshore recruitment of young fish is indicated during summer months together with an autumnal offshore migration of larger size groups. Growth, estimated from length-frequency analyses, approximates 250 mm for 0-class fish. Early I and II class fish may attain total lengths of 400 mm and 700 mm, respectively. Data are provided on the offshore occurrence of postlarvae and length-weight relationships.