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In 2023 number of dead killer whales in fishing nets increased, why?

Dead killer whales under threat: 10 orcas trapped in Alaska in 2023. Reports of 5 deaths by commercial fishing since 2016.

By Ground Report
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In 2023 number of dead killer whales in fishing nets increased, why?

So far in 2023, ten orcas have been trapped between commercial fishing nets and equipment in Alaska, specifically in the Bering Sea and Alaska's Aleutian Islands.

This figure is significantly higher than previous years combined, according to reports received by the National Marine Fisheries Service (NOAA Fisheries) of the United States. And between 2016 and 2020, five orcas died in the middle of fisheries in this area.

“In 2023, our captains have reported an increase in the number of killer whales present near our vessels, where they appear to be feeding in front of the nets while fishing,” per the statement. “This new behaviour has not been previously documented and marine mammal scientists are not sure why this change has occurred.”

Killer whales behaving strangely, unknown reason

According to a statement from NOAA Fisheries, in one of this year's incidents, the orca was released alive. The others are being investigated by this entity “to determine the cause of injury or death and determine which populations they belong to through a review of genetic information.”

There are around 500,000 orcas in the world and approximately half are in the North Pacific Ocean, around Alaska. Among the vessels involved in the incidents, some are associated with the Groundfish Forum, a fishing trade association. The association stated in a statement that “our fishermen believe that orcas are attracted to fishing gear because fishing activities add fish and allow the orcas to feed on the catch.”

In the same statement, the association assures that so far in 2023 “our captains have reported an increase in the number of orcas present near our boats, where they appear to feed in front of the nets while fishing. "This new behaviour has not been previously documented and marine mammal scientists are not sure why this change has occurred."

Another possibility would be that the increase in killer whale deaths is related to an initiative to prevent the capture of halibut, whereby companies sort the nets on deck and return the fish to the sea. However, according to Groundfish Forum, “these claims are not true because our boats do not perform deck triage when orcas are present.”

While this is the panorama in Alaska, at least 18 incidents with orcas have been reported on the southern coast of Spain in 2023.

Orcas adapt to exploit fishing

Orcas, known for their intelligence and social nature, have displayed the ability to learn new behaviours, particularly when it comes to exploiting human fishing activities. In recent developments near Alaska, these clever marine creatures have been observed adapting to fishing practices.

To delve into the recent deaths and understand this phenomenon, the Groundfish Forum enlisted the help of Hannah Myers, a marine biologist from the University of Alaska Fairbanks. She spent a week on a fishing vessel in May to observe the orcas' behavior, as reported by Hal Bernton in the Anchorage Daily News.

During her time on the vessel, approximately two dozen orcas consistently congregated around the fishing operations. Specific pods of orcas seemed to target the vessel, suggesting that this behaviour was highly profitable for them. These orcas remained with the vessel around the clock.

Myers used an underwater microphone to record clicking sounds made by the orcas, which scientists believe are linked to their foraging activities. Based on these recordings, it appeared that the orcas were following the fishing net as the vessel towed it deep underwater. She also observed them at the surface as fishers retrieved the nets from the depths. These behaviours were described as "high-risk" for the orcas.

Preventing orcas from nets, ongoing efforts

Furthermore, Myers noticed the orcas positioning themselves near the discharge chutes, where fishers accidentally caught halibut, a prohibited species, back into the water.

The Groundfish Forum emphasized that they do not release halibut into the water when orcas are in the vicinity. They are actively seeking solutions to address this unprecedented challenge and are experimenting with gear modifications to prevent whales from entering the nets.

The entanglement and mortality of orcas are a cause for concern among scientists, as orcas have a slow reproductive rate, and even a few deaths can have broader population impacts in the future. However, it is worth noting that orcas tend to increase their breeding efforts when several members of their pod die, as noted by the Alaska Department of Fish and Game.

The population of orcas worldwide is estimated at around 50,000, with approximately 2,500 residing in the eastern North Pacific Ocean, according to NOAA (National Oceanic and Atmospheric Administration).

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