Long-Term Mobility of a Harvested, Rocky-Reef Gastropod

Stocks of Turbo militaris (Turbinidae) are under increasing harvesting pressure, but management is currently hampered by data deficiency. Management decisions for rocky-reef gastropod fisheries should consider long-term species mobility, yet this is often poorly understood. Therefore, mark-recapture was used to evaluate annual displacement and upshore-to-downshore movement of T. militaris in Eastern Australia. Tags were glued onto 676 snails, their positions georeferenced and recapture surveys were conducted after 6 and 12 months. Overall, 25% of tagged snails were recaptured. Snails moved an average of 20–21 m year⁻¹ at subtropical sites and 34–44 m year⁻¹ at temperate sites. Movement was non-directional, limited in upshore-to-downshore mixing and unrelated to animal size. T. militaris is neither sedentary nor site-attached, and small and large snails move similarly. Our findings suggest a limited capacity for adults to repopulate other tidal zones, thus recreational harvesting could impact intertidal snails.