Oral Presentation Australian Society for Fish Biology Conference 2024

Snails pace: nomadic movement of a harvested rocky shore gastropod (108613)

Kate M Seinor 1 , Steven W Purcell 1 , Hamish Malcolm 2 , Bob Creese 3 , Stephen D A Smith 1 4
  1. National Marine Science Centre, Southern Cross University, Coffs Harbour, NSW, Australia
  2. NSW Department of Primary Industries and Regional Development (Fisheries), Coffs Harbour, NSW, Australia
  3. NSW Department of Primary Industries and Regional Development (Fisheries), Taylors Beach, NSW, Australia
  4. Aquamarine Australia, Mullaway, NSW, Australia

Turbo militaris is a large Australian turbinid gastropod under increasing harvesting pressure, yet deficient biological and ecological data, including studies on movement, impede management. We conducted a study to evaluate movement and, thus, the potential for stock replenishment at depleted sites. Mark-recapture experiments were used to measure annual displacements and evaluate the extent of cross-shore migrations at two subtropical and two temperate sites. At subtropical sites, displacements averaged 20–21 m year-1; at temperate sites, displacement was highly variable and averaged 34–44 m year-1. Displacements were non-directional and were not related to animal size. We found limited cross-shore migrations, suggesting a strongly constrained potential for stock replenishment by up-shore movement to the intertidal zone where harvesting is concentrated. Therefore, localised impacts such as intense intertidal harvesting may considerably affect local populations. Our findings will directly support the management of turban snail fisheries in Australia; however, more broadly provide insights into the variability in movement patterns for gastropods generally. We recommend that harvested species with nomadic movements, such as T. militaris, are best managed through spatial protection measures; ideally including a network of optimal habitats, covering areas identified as highly targeted or accessible to human harvesting.