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Marine debris likely a contributing cause in Kaua‘i sperm whale death

LIHU‘E — Following a 15-hour long examination of the 60-ton sperm whale that washed up on the reef fronting Lydgate Beach Park on Friday, researchers believe ingestion of artificial marine debris contributed to its death.

Upon inspection of the whale’s stomach, researchers from the University of Hawai‘i at Manoa Health and Stranding Lab discovered several human-made objects that had been ingested.

“In addition to squid beaks, fish skeletons and other prey remains, we found at least six hagfish traps and we also found significant amounts of at least seven types of fishing net, at least two types of plastic bags, a light protector, fishing line and a float from a net,” said Kristi West, Health and Stranding Lab director. “We did find a number of things in the stomach of the sperm whale that may have contributed to its death and are certainly concerning.”

When whales and other marine animals ingest artificial debris, the pieces are often unable to be digested. If the debris is large enough, it may block off the animal’s digestive tract, killing it.

“The size of the opening from the intestinal tract into the stomach is relatively small and there is certainly substantial enough volume of foreign objects to cause a blockage,” West said.

West added that the presence of undigested fish and squid in the whale’s stomach lends further evidence of a blockage.

Hagfish traps are a rudimentary fishing tool consisting of a plastic, funnel-shaped entrance connected to a cylinder or bucket. The entrance’s funnel shape allows hagfish or other eel-like creatures to enter the container but prevents them from exiting, allowing fishers to easily catch them.

However, when the plastic trap entrances are discarded into the ocean, they can wreak havoc on marine life. Typically around 5 inches wide and 7 inches long, they’re the perfect size to get stuck on seal pups’ mouths, causing abrasion, infection, starvation and eventually death.

In the case of the sperm whale, Surfrider Foundation Kaua‘i‘ Chapter staff scientist Carl Berg says the traps could easily have gotten caught in the whale’s gastrointestinal tract, causing blockage and eventual death.

“If you get a ball of nets, they may squish through,” Berg said. “But if you get something like a big trap — or six of them all clumped together — they can just block that little opening between the stomach and (the intestine). So, it’s not a factor of how big is the stomach.”

Surfrider Foundation, in collaboration with a number of environmental groups, has discovered and collected over 10,000 hagfish traps from the Hawaiian Islands in the last two years. On Kaua‘i alone, the organization retrieved more than 1,000 traps in 2022.

Between 2000 and 2021, the National Oceanic and Atmospheric Administration found 16 Hawaiian monk seal pups and one yearling with trap entrances caught on their snouts. Still, the difficulty of examining marine life means experts believe the impact of this debris is much greater.

“We are only able to examine a small number of our dolphins and whales that die in our waters, and we think that each individual we are able to examine represents as many of 20 other animals, who are likely to ultimately die from these types of impacts,” West said. “It’s heartbreaking to see this kind of destruction in an individual animal.”

Most marine debris in Hawaiian waters doesn’t originate in Hawai‘i. Rather, currents sweep debris from the mainland U.S. and East Asian coasts into a portion of the North Pacific Ocean commonly known as the Great Pacific Garbage Patch. As the garbage patch twirls in the ocean, currents spin off, sending 75,000 pounds of debris annually to Kaua‘i alone.

“These man-made items persist in the ocean for a very long time, and we hope we can learn from this,” said Edward “Luna” Kekoa, Recreational Fisheries program manager with the DLNR Division of Aquatic Resources.

“Every few days we hear about another whale, or dolphin, turtle, or monk seal entangled in fishing gear or lines. At an absolute minimum, let’s prevent any more gear, plastic bags and other items from getting into the system.”

The NOAA encourages members of the public to report distressed, injured and dead marine mammals at 1-888-256-9840.


Jackson Healy, reporter, can be reached at 808-245-0427 or
Source: The Garden Island

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