“Some become entangled in fishing line which they drag along and it can cut in and embed into their body and become infected which can be fatal.

“Others become tethered to the bottom of the sea floor and drown.”

The department said it did not publish an official list of causes, saying the source of whale entanglements were varied and often difficult to determine.

But in a research report published in September the Department of Primary Industries and Regional Development (the regulatory agency for fishing, pearling and aquaculture industries in WA) shows historically the western rock lobster industry has been responsible for a significant proportion.

Between 1990 and 2010 entanglements involving the lobster industry between ranged from zero to six, but from 2010 reported entanglements increased, reaching 17 in 2013. The spike in entanglements came as the year-round quota system was phased in, allowing fishers to have ropes and floats in the ocean during peak whale migration periods.

Whale entanglement in fishing gear has posed a major threat to the western rock lobster industry over the past decade, both from negative media attention from the deaths and also responders attempting to free the whales from the gear.

To address potential negative public perception and the possibility of stricter conditions on the fishery from federal and state governments, a suite of management measures, including gear modifications were introduced in 2014 during the migration period between May and October. Further measures were implemented in 2020.

Researcher Pirotta said there was still room for improvement.

“Along the WA coast whale populations are increasing which is a good news story but that also brings with it an increased chance of entanglement anywhere you have fishing activity overlapping with migrating whales,” she said.

Department of Primary Industries western rock lobster research scientist Jason How co-authored a report in 2021 that warned due to the increasing numbers of humpback whales migrating along the coast, the overall number of entanglements were increasing.

The Fisheries Research and Development Corporation along with the rock lobster industry is looking further into the problem with fears it could erode the industry’s “social license”.

How is leading the three-year $750,000 investigation to better understand factors such as migration dynamics and how gear was involved in entanglements.

He said being the state’s largest fishing industry they were leading the sector in funding this work with findings were already being applied in several other fisheries.

How said the lobster industry’s impact on the humpback population had been assessed by independent scientists as low risk.

“Last year there was only one entanglement reported in lobster gear and it appears to be at a similar level this year though these reports have yet to be confirmed and validated,” he said.

“Any additional management changes would be informed by the research that we are currently undertaking.”

In July 2021 a humpback was cut free after becoming entangled at an oyster farm off Albany owned by Harvest Road Group, billionaire mining magnate Andrew Forrest’s food business with oyster and mussel operations also in Carnarvon and Garden Island.

A company spokesman said in June 2022, a decomposing whale carcass became entangled in the outer lines of the company’s lease and came free naturally.

In 2021 a live whale became entangled in Harvest Road’s aquaculture lease at Mistaken Island and was successfully released by government officers.

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Harvest Road said it conducted daily inspections throughout whale season to ensure any entanglement event is detected early.

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