Abundance of Young Brown Shrimp in Natural and Semi-Impounded Marsh Nursery Areas: Relation to Temperature and Salinity

Samples of brown shrimp (Penaeus aztecus, 10 to 130 mm in total length) were collected with otter trawls weekly from 14 March to 20 August 1971 in brackish marsh areas at Marsh Island, Louisiana. Catches were largest from 1 May to 4 June in the natural marsh and from 1 May to 4 July in the semi-impounded marsh (influenced by weirs). Total catch was four times greater in the natural than in the semi-impounded marsh. However, brown shrimp apparently stayed longer in the semi-impounded areas, and emigrated at a larger size. Water temperatures above 20°C were apparently more conducive to the growth of young brown shrimp than was a particular salinity range. The range of recorded salinities was 0.57-12.85 ‰; catch per sample was highest in salinities from 2.0 to 2.99 ‰