Weight-Length Relationships in Gafftopsail Catfish (Bagre marinus) and Hardhead Catfish (Ariopsis felis) in Louisiana Waters

TL;DR

This study establishes weight-length relationships for gafftopsail and hardhead catfish in Louisiana, providing new data and equations that improve understanding of their growth patterns and regional differences.

Contribution

It provides the first detailed weight-length equations for these species in Louisiana waters, filling a gap in regional ichthyological data.

Findings

Louisiana gafftopsail catfish weigh less than Florida counterparts at similar lengths.

Louisiana hardhead catfish weights are comparable to those in Florida.

Strong correlation between total length and fork length with high R^2 values.

Abstract

In spite of the abundance and commercial importance of these two species, there is little published weight-length data for the gafftopsail catfish (Bagre marinus) and hardhead catfish (Ariopsis felis). For this study 84 catfish were caught (hook and line) from the Calcasieu Estuary in Southwest Louisiana near the Gulf of Mexico and estuaries and near shore waters close to bayou Lafourche. Using least squares regression, best fit curves were determined for weight (W) vs. total length (L) relationships in gafftopsail catfish, W(L) = 1000(L/484.73)^3.2660, while the best-fit equation for the hardhead was W(L) = 1000(L/469.53)^3.0188, where W is the weight in grams and L is the total length in millimeters. Results showed that, when compared to gafftopsail and hardhead catfish caught in Florida, Louisiana gafftopsail catfish tend to weigh less at similar lengths; whereas, the Louisiana hardhead catfish tend to weigh about the same. Results also show that the total length (TL) can be related to the fork length (FL) as TL = 1.184 FL in gafftopsail catfish with R^2 = 0.9922 and TL = 1.140 FL with R^2 = 0.9667 in hardhead catfish.