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Spatial extent and isolation of marine artificial structures mediate fish density

Published Article

United States

Publication date: September 11, 2023

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Research across 31 artificial reef structures on North Carolina’s continental shelf shows that larger, taller, and more isolated marine structures support higher fish densities. Echosounder surveys reveal how spatial design and placement of artificial reefs can enhance habitat value and guide future deployment strategies.

Subject Tags

  • Reefs
  • Marine protected areas

Abstract

Installations of artificial structures in coastal oceans create de facto habitat for marine life. These structures encompass wide varieties of physical characteristics, reflecting their multiple, diverse purposes and creating a need to understand which characteristics maximize fish habitat. Here, we test how physical characteristics – horizontal area, vertical relief, and spatial isolation – relate to fish density from echosounder surveys over artificial structures like concrete pipes, train boxcars, and ships purposely sunk to function as reefs. Echosounder mapping of 31 artificial reef structures and associated fish across a 200 km linear length of the continental shelf of North Carolina, USA, revealed that structures with greater horizontal area and vertical relief host higher fish densities than smaller, shorter structures. Artificial structure spatial arrangement also relates to fish density, as isolated structures are generally associated with greater localized fish densities than structures closer to one another. Patterns in the relationships between fish density and reef characteristics differed for schooling fish, as there was some evidence that reefs of intermediate area exhibited higher schooling fish density. These results suggest that intentional design and spatial arrangement of marine built structures like artificial reefs relates to and can be deliberately incorporated into siting and deployment decisions to enhance their role as fish habitat.

Citation

Gilliland, V. A., Fessler, A. E., Paxton, A. B., Ebert, E. F., Tharp, R. M., Runde, B. J., ... & Taylor, J. C. (2023). Spatial extent and isolation of marine artificial structures mediate fish density. Frontiers in Marine Science, 10, 1240344.

TNC Authors