Long-term trends and a risk analysis of cetacean entanglements and bycatch in fisheries gear in Australian waters

• Published in: Biodiversity and Conservation
• Main Authors: Tulloch, Vivitskaia, Pirotta, Vanessa, Grech, Alana, Crocetti, Susan, Double, Michael, How, Jason, Kemper, Catherine, Meager, Justin, Palmer, Carol, Peddemors, Victor, Waples, Kelly, Watson, Mandy, Harcourt, Robert
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Springer 2020
• Subjects: baleen whale; baleen whales; toothed whales
• Online Access: https://researchonline.jcu.edu.au/58956/1/JCU_Tulloch_BIOC-D-18-00365_R2.pdf

Assessments of fisheries interactions with non-target species are crucial for quantifying anthropogenic threatening processes and informing management action. We perform the first multi-jurisdictional analysis of spatial and temporal trends, data gaps and risk assessment of cetacean interactions with fisheries gear for the entire Australian Exclusive Economic Zone. Bycatch and entanglement records dating from 1887 to 2016 were collected from across Australia (n=1987). Since 2000 there has been a substantial increase in reported bycatch and entanglements and this is likely the result of improved monitoring or recording by some jurisdictions and fisheries as well as changing fishing effort, combined with continuing recovery of baleen whale populations after cessation of commercial whaling. A minimum of 27 cetacean species were recorded entangled, with over 30% of records involving interactions with threatened, vulnerable or endangered species. Three times the number of dolphins and toothed whales were recorded entangled compared to baleen whales. Inshore dolphins were assessed as most vulnerable to population decline as a result of entanglements, though humpback whales, common bottlenose dolphins, and short-beaked common dolphins were the most frequently caught. Only one-quarter of animals were reported to have survived entanglement, either through intervention or self-release from fishing gear. Spatial mapping of the records highlighted entanglement hotspots along the east and west coast of the continent, regions where high human population density, high fishing effort, and high density of migrating humpback whales all occur, augmented by high captures of dolphins in shark control gear along the east coast. Areas of few entanglements were more remote, highlighting substantial bias in entanglement reporting. Our gap analysis identified discrepancies in data quality and recording consistency both within and between jurisdictions. Disparities in the types of fisheries data provided for the analysis by different ...