Poster Presentation Australian Marine Sciences Association Annual Meeting 2023

Spatial influences on the use of restored shellfish reefs by fish (#380)

Charlotte A McAneney 1 , Michael Sievers 1 , Simon E Reeves 2 , Ainsley Leaning 1 , Jasmine A Rasmussen 1 , Sebastian Lopez-Marcano 1 , Rod M Connolly 1
  1. Coastal and Marine Research Centre, Australian Rivers Institute, School of Environment and Science, Griffith University, Gold Coast, Queensland , Australia
  2. The Nature Conservancy, Carlton, Victoria, Australia

Restoring shellfish reefs to enhance fish productivity often involves creating an array/matrix of individual reef patches within a larger permitted restoration area, under the assumption this maximises benefits for a given location and level of investments. However, a lack of information about the spatial influence of individual patches on fish habitat utilisation hampers efforts to optimise restoration designs and evaluate fisheries benefit. We used remote underwater video stations (RUVS) to evaluate fish abundance at 2, 7 and 12 m from reef units for two habitat zones; an inner zone that penetrates into the reef array, and an outer zone that surrounds the array. We detected 19 species across 54 cameras, and found that the abundance (MaxN) and the frequency with which most species occurred were unrelated to distance from reef patch or habitat zone; community composition was similar across deployments, and; fish densities were considerably lower in unstructured habitat further from restored reefs. This research shows that the enhanced abundance of many species extends at least 12 m beyond the reef edge. This provides a larger area of influence beyond the physical reef, and means the area of restoration impact may be six times the size of the individual patches.