A white shrimp mark-recapture study

Marked sub-adult white shrimp (Penaeus setiferus) were released in Galveston Bay in Aug 1963. Recoveries indicated there was no emigration from the bay between Aug and mid-Oct. Using the Bertalanffy growth function estimates of L sub(infinity) equals 214 mm, K=0.09 (sexes combined). Shrimp increased rapidly in size, 98 to 133 mm in 4 wk and to 146 mm in 6 wk during the warm summer months. Reliable estimates of natural and fishing mortality could not be obtained. Several techniques were used to obtain estimates but they varied to such a degree that results were questionable. Probable causes of these inaccurate estimates are non-random distribution of the marked population, fishing effort, or a combination of both