Habitat preference of Penaeus duorarum Burkenroad (Crustacea: Decapoda) in a tropical coastal lagoon, southwest Gulf of Mexico

Abstract

Pink shrimp ( Penaeus duorarum Burkenroad) are common in seagrass beds dominated by turtle grass ( Thalassia testudinum Koenig and Sims) where density and biomass have been found to be significantly greater ( p < 0.05) than on unvegetated soft substrata (USS). This preference was first observed in the field and later experimentally tested. Three variables were included in the sampling design: 1) habitat type (seagrasses and USS), 2) seasonal variation (dry and rainy seasons) and 3) extremes of shrimp activity (light-low tide and dark-high tide). Density and biomass were significantly greater during the dark-high tide than during the light-low tide periods, with no effect on the shrimp's distribution in the seagrass beds. The number of shrimp on the seagrass and the number of shrimp in the water column were experimentally recorded considering two factors: shrimp density (3.3, 6.7 and 10 ind./m 2) and light (light and dark). Preference for seagrass was significantly lower ( p < 0.001) in the dark condition than in the light condition. This did not affect the number of shrimp which was experimentally observed to be on an average 13 × greater on seagrass than on USS. Both the spatial (seagrass beds) and the temporal (night) scales should be considered in future analysis of the value of this physical refuge for the estuarine phases of the pink shrimp.