Benefield, R.L.Baker, W.B., Jr.2010-02-152010-02-151980http://hdl.handle.net/1969.3/20153102 pgs.Brown shrimp (Penaeus aztecus) populations were monitored with marsh nets, bar seines, 3.0-m trawls, and 6.1-m trawls to determine relative abundance, growth and movement in Galveston Bay, Matagorda Bay, Aransas Bay, and the lower Laguna Madre. April-May bar seine and 3.0-m trawl sample results indicated a normal emigration of brown shrimp and a June 1979 closed Gulf season was recommended. Water temperatures after 1 April were >20 C. Salinities were generally < 10 ppt in each bag, except the lower Laguna Madre. Abnormal rainfall in 1979 influenced brown and white shrimp (P. setiferus) availability in Galveston Bay. Average rainfall was 25.7 cm in April, 41.2 cm in July and 34.6 cm in September. Salinities were < 7 ppt during April- September. July and September flooding lowered upper bay salinities to near 0 ppt and forced small white shrimp from shallow nursery areas into major bays. White shrimp were most numerous during fall and summer. Average sizes of white shrimp collected on commercial shrimping grounds were larger than those in bait bay areas with the exception of Galveston Bay where August and September bait catches were of a larger mean size. February-June 1979, 6.1-m trawl samples indicated the presence of large white shrimp in bay areas. White shrimp were more abundant in March and April but the largest mean sizes were found during May and June.penaeid shrimppopulation dynamicsabundancerainfalltrawl netsbrown shrimpwhite shrimppopulation numberbiological datacollecting devicesBook