Size of brown shrimp and time of emigration from the Galveston Bay System, Texas.

A study was begun to determine the time period of emigration, the vertical distribution, and the size of juvenile and subadult brown shrimp leaving the Galveston Bay System, Texas, through the Bolivar Roads tidal pass to the Gulf of Mexico. The sampling gear consisted of a bottom and a surface trawl. Samples were taken both day and night on ebbing tides from May 18 to August 1, 1966. Brown shrimp were caught throughout the sampling period. Two peaks occurred, the first in May and the second in June. Estimates of mean catch per unit of effort indicated that the shrimp were near the surface at night and near the bottom during the day. The mean lengths of brown shrimp taken during the day and night with bottom and surface trawls on the same sampling date were similar. The size of the emigrating shrimp increased significantly as the season progressed.