Effective fisheries management reduces humpback entanglements

Western Australia’s western rock lobster fishery is helping to protect migrating humpback whales as they move north through lobster fishing areas.

An estimated 30,000 to 35,000 humpback whales make the journey along the WA coast to warmer North West waters every autumn, returning south in spring and Department of Primary Industries and Regional Development (DPIRD) research shows the greatest risk to whales from entanglement is on their northward migration in water depths of 55 to 73 metres.

Fishers from the WA rock lobster industry are global leaders in sustainability and, seven years ago, embraced measures to help reduce the risk of entanglement of large whales in fishing gear. The measures focussed on reducing rope and floats and eliminating floating rope in waters deeper than 20 metres and there was an immediate uptake of the new requirements. Less rope and more of it held vertical in the water column proved successful.

Senior Research Scientist for DPIRD, Dr Jason How said in 2013, there were 17 whale entanglements – the new management rules came into place in 2014 – and research shows the entanglements dropped to single figures in the following four years – seven in 2014, just two in 2015, four in 2016 and six in 2017.

“This means modifications to lobster fishing gear in WA helped cut whale entanglements by an average of 64%,” explained Dr How.

“Even since 2017 and the main focus period of our research, entanglements have remained in single figures – there were eight entanglements with rock lobster fishing gear off the WA coast in 2018, six in 2019 and eight last year (2020).”

“We also worked with whale experts from the Department of Biodiversity Conservation and Attractions (DBCA) and Australian Antarctic Division to develop and assess these management changes. WA leads the world in documenting the effectiveness of these gear modifications.”

“This is significant research that reinforces the sustainability credentials of WA’s important rock lobster fishery. It also shows how the department’s ongoing commitment to adaptive fisheries management can achieve effective and beneficial changes, when challenges arise.”

DPIRD scientists also developed Whale Buoy technology used to help track entangled whales, increasing the opportunity to undertake disentanglement operations. In their partnership with DBCA and the lobster industry, a range of other mitigation strategies have also emerged that may be required as the ever-increasing number of whales travel along WA’s coast.

“Ongoing monitoring of whale migration off WA is vital to ensure interactions remain low,” said Dr How.

The international Marine Mammal Science journal has published this peer-reviewed WA study, which Australia’s Fisheries Research and Development Corporation funded.

The research is also available on the DPIRD website.