Habitat partitioning in Moreton Bay bug species to inform fisheries management

Abstract

Habitat preferences influence partitioning in many marine taxa that can inform fisheries management. Despite this, little is known about how habitat partitioning contributes to spatial distributions in many commercially important species. This study aims to investigate habitat partitioning and influential variables affecting the distribution in Moreton Bay bug species Thenus parindicus and Thenus australiensis for the benefit of management on the east coast of Queensland, Australia. These Scyllarid lobsters spend much of their lives buried within sediment, but little research focuses on what influences the distribution of each species. In this study, a fishery-independent survey was conducted in a key commercial trawling area off the coast of Townsville to determine Thenus species distributions and habitat preferences. Variables used to examine the habitat preferences and distributions of both species included depth, sediment grain size, Trask sorting coefficient and calcium carbonate content. We found that all variables evaluated significantly affected species distributions. Multivariate analyses suggest that Trask sediment sorting coefficient and depth were the strongest influential variables. This contrasts with previous findings that mean grain size is the most important sediment parameter influencing Thenus distributions. The results indicate habitat partitioning between T. parindicus and T. australiensis but not habitat exclusion. These findings, along with the likely influential variables of species’ distributions will help better understand the habitat ecology of these lobsters and inform management for the Moreton Bay bug fishery.