A Demographic Profile of Participants in Two Gulf of Mexico Inshore Shrimp Fisheries and Their Response to the Texas Closure

A social study of the shrimp fisheries of Galveston Bay, Tex., and Calcasieu Lake, La., was made during the summer of 1987 to examine the impacts of the seasonal closure of the Federal waters off Texas and to understand the infrastructure and demographic processes of these two diverse fisheries. Survey instruments were administered to 159 shrimp boat captains: 89 from Galveston Bay and 70 from Calcasieu Lake. Shrimp-house owners were interviewed in each region as well. The results suggest that the inshore fisheries (i.e., shrimpers and shrimp houses) are distinct from the offshore fisheries. The infrastructure of the two inshore fisheries examined differ in that the market distribution of shrimp from Galveston Bay was more diffuse than from Calcasieu Lake. Much more of the shrimp harvested from Galveston Bay was channelled into the surrounding community than from Calcasieu Lake. The distribution of age,years as a commercial fisherman, and family involvement in fishing suggest that participation in Calcasieu Lake's and Galveston Bay's inshore fisheries have expanded concurrent with declining economies. While overall the Texas closure had little impact on either of the inshore fisheries, the Galveston Bay shrimpers experienced more of a direct impact on their livelihood than Calcasieu Lake shrimpers.

A Comparison of Two Stratification Schemes Used in Sampling Canadian Atlantic Cod, Gadus morhua

Sampling is a key element in the assessment of any fish stock. It is often one of the most expensive activities of the management process; thus, improved efficiency can result in significant cost savings. In most cases a two-phase sampling strategy is employed. Two commonly used versions of such stratified random schemes were simulated using a test population based on Atlantic cod, Gadus morhua. A 1 otolith per 1 cm length frequency currently used for many flatfish and some smaller gadoids and a 3 otolith per 3 cm length frequency currently used for many of the larger gadoids. No difference was detected in the age composition or mean length at age for either scheme; however, 10 percent fewer otoliths were collected in 1 for 1 sampling than 3 for 3. There was an improvement of between 30 and 60 percent in the coefficient of variation of the estimated catch numbers at age using the 1 for 1 compared with the 3 for 3 stratified sampling. For these reasons and other operational considerations, the 1 for 1 stratified random design of sampling appears to be superior.