Abstract:

Conservation of chondrichthyan species (sharks, rays and ghost sharks) is an increasing priority globally as evidence of overexploitation of many species becomes increasingly apparent. While there are a range of potential stressors to chondrichthyan species, their primary threat comes from interactions with fisheries. Therefore, to improve the status of these species on national and international scales requires effective fisheries management. However, management and conservation of chondrichthyan species is complicated. A number of chondrichthyans are fishery targets and as such subjected to directed fishing effort, while others are encountered as bycatch in fisheries targeting other high value species (e.g. tuna). Species taken as bycatch are often retained as byproduct if they can be sold. The type of management applied, and amount of data collected vary depending on whether the species is target or byproduct. Finally, some species interact with fisheries but are discarded with little or no data are recorded on the number of interactions or condition of individuals. These differences in the amount and type of data available complicate management decisions and the situation is made even more complex by the broad distributions of some species which span national and international boundaries. As such, concerted efforts to understand population status and trends are required to facilitate management and conservation of chondrichthyan species.

Here we examined the status of chondrichthyan species within Australian waters in an effort to understand how well current protections are working. This work is placed in the context of national and international conservation measures. We also explore additional threats such as climate change, shark control programs and habitat loss relative to the current and future status of these species. Finally, we explore a framework for managing information and responses to international obligations for at-risk species.

Overall, the status of Australian chondrichthyan species is good. The majority of assessed Australian chondrichthyans were determined not to be in a threatened category and were assess as Near Threatened (9.8%) or Least Concern (69.4%). A further 9.2% are currently Data Deficient (insufficient information to assess their status). Thus 11.6% of assessed species fell within a threatened category. This is one of the lowest threat rates when compared to other regional or national level assessments for chondrichthyans. Of the 22 species identified as Critically Endangered or Endangered, all but five of these species are already protected in Australia or previously considered for protection. Five of 17 species considered Vulnerable are already protected in Australia. However, some of the Vulnerable species qualify for listing based on small distributions rather than as a result of an immediate direct threat. The national analysis confirmed the main threat to Australian chondrichthyan species is commercial fishing pressure through targeted harvest or bycatch mortality.

 

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