Distribution, habitat and biology of a rare and threatened eastern Australian endemic shark: Colclough's shark, Brachaelurus colcloughi Ogilby, 1908

摘要

Despite increasing research effort and conservation focus on sharks, small species of little commercial value are often overlooked, although they make a considerable contribution to global diversity. The poorly known Colclough's shark, Brachaelurus colcloughi, is naturally rare to uncommon and is encountered only irregularly. Collating all known records (n=50), we review the species' geographic and bathymetric distribution, habitat, reproductive biology and diet. All but four B. colcloughi records are from within a core distribution of <2° latitude on the Australian east coast. Bathymetric distribution is from less than 4 to 217m depth, with all but three records from less than 100m depth. The species shelters on rocky reefs during the day and is thought to forage nocturnally around reefs and adjacent substrates. B. colcloughi is viviparous, with litter sizes of 6-7. Mature males and females have been observed from 61.0- and 54.5-cm total length, respectively. Gravid females have been collected in austral winter months. Dietary analysis indicates a predominantly piscivorous diet. Our results are placed in the context of existing threats and future research and management directions, demonstrating that shark species with low abundances and restricted ranges, such as B. colcloughi, require a suite of management arrangements to ensure long-term population viability.