Distribution ofFarfantepenaeus aztecusandF. duorarumon submerged aquatic vegetation habitats along a subtropical coastal lagoon (Laguna Madre, Mexico)

Abstract

The spatial distribution ofFarfantepenaeusshrimp was analysed in the Laguna Madre of Tamaulipas, Mexico. Sampling was carried out on submerged aquatic vegetation (SAV) habitats at five sites located along the coastal lagoon. Two nocturnal surveys were conducted during winter in 2005 (January–February), collecting a total of 3268 shrimp individuals. SAV beds were composed of a mixture of drift algae (mainlyDigenia simplex), attached algae (mainlyPenicillus capitatusandUdotea occidentalis) and seagrass (mainlyHalodule wrightii).Farfantepenaeus aztecuswas more abundant (39.5%) thanF. duorarum(36.8%), and the remaining 23.7% corresponding to small unidentifiedFarfantepenaeusspp. were classified as recruits. Abundance ofF. aztecuswas significantly higher at sites 2 and 4, whereasF. duorarumdid not show significant distribution differences along the Laguna Madre. Recruits, juveniles and total shrimp tended to decrease significantly at the northern part of the lagoon (site 1), where substrate was dominated by drifting algae and seagrasses were scarce or absent. The abundance of shrimp was positively related to seagrass biomass and/or water temperature, whereas there was a negligible or negative relationship with algal biomass. With the exception of subadults, a significant positive linear relationship between seagrass and shrimp abundance was fitted, indicating an increase in number of individuals of both species with increasing seagrass biomass. This suggests that seagrass is the most important component of SAV beds influencing the abundance ofF. aztecusandF. duorarumalong this hypersaline coastal lagoon.