Comparison of shrimp and finfish catch rates and ratios for Texas and Louisiana.

A comparison was made between 1980 and 1981 commercial fishing to judge effects of the 1981 Texas closure on shrimp and finfish catches off Texas and Louisiana. Historical data (1973-78) for the two areas were used as baselines, and comparisons were made of finfish/shrimp catch ratios and species composition. Mean shrimp catch rates (heads-on) standardized to 100-foot trawls for Texas and Louisiana in 1980 were 42.56 pounds/hour and 42.53 pounds/hour, respectively, and in 1981 were 89.03 pounds/hour and 62.0 pounds/hour. Mean finfish catch rates for Texas and Louisiana in 1980 were 333.90 pounds/hour and 242.84 pounds/hour, respectively, and in 1981 were 156.19 pounds/hour and 408.88 Differences between 1980 and 1981 shrimp catch rates off Texas and Louisiana, and between Texas and Louisiana in 1981, were significant at the 95 percent confidence level. Finfish catch rates off both states were significantly influenced by depth, with no significant differences found between years for either state when the effect of depth was removed. Species composition of the bycatch in waters 10 fathoms or less was relatively consistent regardless of state or year. The composition of bycatch from deeper waters was much more variable and significantly different from catches made in the shallower waters. Overall, the analyses supported a hypothesis of increased shrimp catch rates due to the Texas closure. Finfish catch rates and compositions, however, were not shown to change as a result of the closure. This latter conclusion assumes the distribution of fishing effort by depth zone was unaffected by the closure.