Nocturnal sampling reveals usage patterns of intertidal marsh and subtidal creeks by penaeid shrimp and other nekton in south-eastern Australia

Abstract

The life cycle of most penaeid prawns includes a juvenile phase in protected coastal environments such as estuaries and embayments. In the tropics, some penaeids are known to utilise intertidal habitats, yet in temperate regions of Australia the use of marshes has not been investigated. We focused on determining the extent to which Melicertus plebejus and Metapenaeus macleayi directly utilise intertidal marsh habitat using fyke nets. Using cast nets, we also assessed the abundance of the two focal species in middle and edge habitat of adjacent subtidal creeks. Despite collecting 8300 crustaceans and 4259 teleosts, only 8M. plebejus were sampled on the marsh. Abundances of M. macleayi were greater with 90 individuals collected. Within the subtidal creeks larger M. macleayi were collected in the middle habitat and the abundance of both penaeids varied among different creeks. The nekton community as a whole also differed among creeks within marshes. This study has demonstrated that juvenile M. plebejus and M. macleayi do not directly utilise intertidal marsh habitats. Despite this, marshes may provide important resources for prawns through the export of carbon. Future isotope studies would provide valuable information in this regard, providing a broader understanding of penaeids and specific estuarine habitats.