Poster Presentation Australian Society for Fish Biology Conference 2022

Habitat partitioning in Moreton Bay bug species to inform Queensland fisheries management (#215)

Nora Louw 1 , Matthew McMillan 2 , Naomi Gardiner 1 , James Daniell 1 , Eric Roberts 1
  1. James Cook University, Townsville, QLD, Australia
  2. Department of Fisheries, QLD, Australia

Moreton Bay bugs have been enjoyed as a trademark of Australian cuisine since 1888 and the value of the commercial fishery has only continued to rise recent years. Despite this, little is understood about the ecology and distribution of these animals critical in ensuring effective fisheries management.  This study aims to investigate habitat partitioning and drivers of distribution in Queensland Moreton Bay bug species Thenus parindicus and Thenus australiensis for the benefit of management decisions of the Thenus spp. fishery. These lobsters spend most of their lives buried within benthic sediment, but next to nothing is known about what factors drive the distributions of each species. In this study, a fishery independent survey is conducted in a key commercial trawling area off the coast of Townsville to sample Thenus species distributions and habitat preferences.  Burying invertebrates have intimate relationships with the sediment in which they live. Analysis of sediment grainsize through wet and dry sieving as well as determination of calcium carbonate content provided a range of sediment parameters used to compare distributions of the species and understand potential drivers of this distribution. These species have significantly different distributions influenced by a suite of variables including depth, mean grain size, calcium carbonate content, skewness, kurtosis, and sorting of sediments. Multivariate analyses suggest that sediment sorting and depth could be the strongest drivers of habitat partitioning between the species. This contrasts previous findings that considered mean grain size to be the most important sediment parameter influencing Thenus distributions. There is evidence of habitat partitioning between T. parindicus and T. australiensis but not habitat exclusion.  This information, along with the likely drivers of species’ distributions will help better understand the habitat ecology of these organisms and inform sustainable management decisions for the Moreton Bay bug fishery.