Age and Growth of Hardhead Catfish and Gafftopsail Catfish in Coastal Louisiana, USA

Abstract

The Hardhead Catfish Ariopsis felis and Gafftopsail Catfish Bagre marinus are marine catfishes that have low recreational and commercial landings in U.S. waters, although they are among the most abundant species in coastal waters of the Gulf of Mexico. Few biological studies exist on marine catfishes, with most studies focusing on their unique reproductive biology. This study evaluated weight–length relationships for Gafftopsail Catfish (n = 264) and Hardhead Catfish (n = 823) sampled from across coastal Louisiana, USA, during 2016–2018; subsamples (93 and 266, respectively) were aged using lapilli for age and growth analyses. Hardhead Catfish showed a small but significant difference in weight as a function of length between males and females, with females being slightly heavier than males at any given length. No sexual dimorphism in weight and length was observed in Gafftopsail Catfish. Ages ranged from 0 to 10 years for Gafftopsail Catfish and from 0 to 24 years for Hardhead Catfish. Both sexes of Gafftopsail Catfish attained larger maximum average sizes (asymptotic length L∞) and exhibited larger growth coefficients (k) than both sexes of Hardhead Catfish. Length at age of Hardhead Catfish in Louisiana was greater than that of Florida fish. The estimated k for Gafftopsail Catfish in Louisiana was almost three times greater than that observed in Florida, with fish reaching their L∞ rapidly compared to those in Florida. Given the increasing evidence for an equilibrium life history strategy (i.e., K strategy), the spatial differences in size at age, and the potential for increased exploitation, continued investigations into both species’ biology and life history should be undertaken.