title: Quantifying shark distribution patterns and species-habitat associations: implications of marine park zoning.
abstract: Quantifying shark distribution patterns and species-specific habitat associations in response to geographic and environmental drivers is critical to assessing risk of exposure to fishing, habitat degradation, and the effects of climate change. The present study examined shark distribution patterns, species-habitat associations, and marine reserve use with baited remote underwater video stations (BRUVS) along the entire Great Barrier Reef Marine Park (GBRMP) over a ten year period. Overall, 21 species of sharks from five families and two orders were recorded. Grey reef Carcharhinus amblyrhynchos, silvertip C. albimarginatus, tiger Galeocerdo cuvier, and sliteye Loxodon macrorhinus sharks were the most abundant species (>64% of shark abundances). Multivariate regression trees showed that hard coral cover produced the primary split separating shark assemblages. Four indicator species had consistently higher abundances and contributed to explaining most of the differences in shark assemblages: C. amblyrhynchos, C. albimarginatus, G. cuvier, and whitetip reef Triaenodon obesus sharks. Relative distance along the GBRMP had the greatest influence on shark occurrence and species richness, which increased at both ends of the sampling range (southern and northern sites) relative to intermediate latitudes. Hard coral cover and distance across the shelf were also important predictors of shark distribution. The relative abundance of sharks was significantly higher in non-fished sites, highlighting the conservation value and benefits of the GBRMP zoning. However, our results also showed that hard coral cover had a large effect on the abundance of reef-associated shark species, indicating that coral reef health may be important for the success of marine protected areas. Therefore, understanding shark distribution patterns, species-habitat associations, and the drivers responsible for those patterns is essential for developing sound management and conservation approaches.
authors.affiliation: Centre for Sustainable Tropical Fisheries and Aquaculture and School of Earth and Environmental Sciences, James Cook University, Townsville, Queensland, Australia; AIMS@JCU, Australian Institute of Marine Science, School of Earth and Environmental Sciences, James Cook University, Townsville, Queensland, Australia.
authors.forename: Mario
authors.initials: M
authors.lastname: Espinoza
authors.affiliation: Australian Institute of Marine Science, Townsville, Queensland, Australia.
authors.forename: Mike
authors.initials: M
authors.lastname: Cappo
authors.affiliation: Centre for Sustainable Tropical Fisheries and Aquaculture and School of Earth and Environmental Sciences, James Cook University, Townsville, Queensland, Australia; Australian Institute of Marine Science, Townsville, Queensland, Australia.
authors.forename: Michelle R
authors.initials: MR
authors.lastname: Heupel
authors.affiliation: Centre for Sustainable Tropical Fisheries and Aquaculture and School of Earth and Environmental Sciences, James Cook University, Townsville, Queensland, Australia.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Tobin
authors.affiliation: Centre for Sustainable Tropical Fisheries and Aquaculture and School of Earth and Environmental Sciences, James Cook University, Townsville, Queensland, Australia.
authors.forename: Colin A
authors.initials: CA
authors.lastname: Simpfendorfer
mesh_terms: D000818:Animals; D001315:Australia; D003247:Conservation of Natural Resources / Q000706:statistics & numerical data*; D017753:Ecosystem; D005398:Fisheries; D009792:Oceans and Seas; D016012:Poisson Distribution; D011235:Predatory Behavior; D012044:Regression Analysis; D012754:Sharks; D013045:Species Specificity; D013997:Time Factors