Assessing the distribution and habitat preference of spotted handfish (Brachionichthys hirsutus) for development of new artificial spawning habitat

The spotted handfish (Brachionichthys hirsutus) is a critically endangered benthic anglerfish species endemic to south-east Tasmania. Despite the necessity to conserve the species, the current understanding of B. hirsutus... [ view full abstract ]

The spotted handfish (Brachionichthys hirsutus) is a critically endangered benthic anglerfish species endemic to south-east Tasmania. Despite the necessity to conserve the species, the current understanding of B. hirsutus population and its biology is limited. This project aimed to 1) provide updated status on B. hirsutus population; 2) assess the relationship between B. hirsutus distribution and the benthic habitat; and 3) synthesise present and past population data to aid site selection and development process for new artificial spawning habitat (ASH) for B. hirsutus spawning facilitation. This study will be the first broad scale B. hirsutus survey utilising the georeferenced underwater visual census (UVC) technique, previously demonstrated to be more effective in surveying B. hirsutus population. Surveys will be conducted in multiple sites (n=11) across the Derwent Estuary and D’entrecasteaux channel with previous B. hirsutus sighting. Health and current status of surveyed B. hirsutus population will be determined by the estimated density and parametric data. Benthic habitat with B. hirsutus distribution will be assessed through remote sensing and sediment collection to construct a comprehensive profile on sediment geomorphology and community structure of both epifauna and infauna within the region. In particular this project will focus on species with high impact on B. hirsutus life history including stalked ascidians, Sycozoa sp. (critical spawning habitat); northern Pacific seastar, Asterias amurensis (threats to B. hirsutus); and sediment infauna (potential food sources). All preliminary data collected in this study will be used for deployment of ASH arrays prior to upcoming spawning season and devising new monitoring program for assessing B. hirsutus population health.