New paper shows how much endangered seabirds dine on ocean debris

PUHI — Kauai Community College’s own Elizabeth Kain has published her first scientific research paper with the help of the Kauai Surfrider Foundation, and the findings have proven significant for Kauai’s endangered seabirds.

The paper is entitled “Plastic ingestion by Newell’s and wedge-tailed shearwaters in Hawaii,” and looks at the connection between ocean plastics and the seabirds.

Kain’s interest in seabirds and plastic pollution really began with a separate interest in both subjects. She worked with Laysan albatross in Midway Atoll National Wildlife Refuge and also worked for the Kauai Endangered Seabird Recovery Project for two seasons.

She fell in love with seabirds, particularly the albatross and the Newell’s shearwaters, and got involved with the Kauai Community College Marine Options Program.

That’s when Surfrider Kauai stepped in and used some grant money to fund the project.

“When I received a grant from Surfrider Foundation to conduct marine debris research, it was a natural fit to look at the Newell’s plastic ingestion,” Kain said.

She brought on mentors Jennifer Lavers, Alexander Bond, Carl Berg and Andre Raine, and they began research on her project.

“Each of us were helping this student and adding our expertise, but as we got involved and saw the data, we realized how important this was,” said Berg, a marine ecologist on Kauai.

Their most significant finding, Kain said, is that plastic ingestion has increased since the 1980s, for both the Newell’s shearwater and the wedge-tailed shearwater.

In fact, the frequency of plastic ingestion in Newell’s shearwater drastically increased from 11 percent in 1987 to 50 percent in the recent study.

“Hawaiian populations of shearwaters, like many seabird species, provide useful but worrying insights into plastic pollution and the health of our oceans,” Kain said.

A total of 30 Newell’s shearwater fledglings were sampled, along with 19 adult and 13 fledgling wedge-tailed shearwaters, according to the paper. Plastic items were found in the proventriculus — the part of the bird’s stomach between the crop and the gizzard — and the gizzard of both species, while no plastic was detected in the intestinal tract.

Fifteen of the Newell’s shearwater fledglings were found with no plastic. The Newell’s shearwater fledglings contained a total of 36 pieces of plastic, most of which were white and black. Wedge-tailed shearwater fledglings ingested a total of 31 pieces of plastic, the majority of which was white.

When birds eat plastic, whether it’s with a sardine they’ve caught or they picked it up off of the beach, it takes up room in their stomachs, so they risk starvation. There’s also a chance that plastic leaks toxins into the system through the stomach lining, Berg said.

During dissections, threads and hard plastics were found in the seabirds, and 70 percent of items ingested by the Newell’s and wedgetailed shearwater fledglings were classified as microplastics.

“It’s interesting and disturbing that both species of shearwater are ingesting plastics — albeit in small amounts,” said Raine. “While this isn’t on the same level as the fatal ingestion of huge amounts of plastic that albatross are famous for, it should serve to heighten awareness of the widespread presence of plastic in our oceans.”

The fact that plastics were found in the guts of the young seabirds was something that caught Berg’s attention, especially because the Nihoku seabird recovery project. That project aims to protect and rehabilitate Kauai’s endangered ground-nesting seabirds at Kilauea Point National Wildlife Refuge.

“It shows that our young, local seabirds contain plastic in their guts that may harm the babies by blocking food or by the toxins in the plastic itself,” Berg said. “This may add to mortality in the nest and add to decline in local populations.”

While the Newell’s shearwaters are only one species being targeted with the Nihoku seabird recovery project, Raine, who is with Kauai Endangered Seabird Recovery Project, said knowing their connection to plastics is helpful.

“We are always interested in anything that might potentially affect this species,” Raine said.

The project also documented an increase in the percentage of birds containing plastic over the years, and the number of items in the gut, as well as the mass of those items.

“It supports cause for alarm at the increasing amount of plastics in the ocean,” Berg said.

Seabirds are often used as an indicator for ocean health, Kain said, and this increase sends a clear message.

“More plastic is being produced now more than ever, and the threat of ingestion and entanglement in marine species is likely to also increase,” Kain said.

How to help

Recycling and reusing plastics are some of the best ways to help the situation at sea, according to scientists. The public can also make a huge impact on the rest of the ecosystem by not tossing the trash in the ocean.

“Our society is very much a throw-away society when it comes to plastic,” Raine said. “We use it every day and we tend not to think about it. Much of it does end up in our seas, often with huge negative impacts for native wildlife.”

Scientists and environmental experts encourage attending beach cleanups like the Surfrider Net Patrol cleanups, but the best way to stop plastic from inundating the ocean is to stop putting it in the ocean in the first place.

On Nov. 5, Net Patrol shipped off 18,900 pounds of nets which had been collected in eight months from Kauai beaches by volunteers.

The threads found in the bellies of the seabirds dissected in Kain’s research were from nets like those that had broken down over time in the ocean.

“We can’t clean up our oceans. We can’t even clean up our beaches on Kauai,” Berg said. “We’ve got to stop putting this stuff into the ocean.”

The scientists involved in the paper’s research said it’s important for the public to reevaluate the use of plastics, especially things like plastic utensils, plastic bottles, straws, plastic bags and lighters.

“There are simple steps and choices every person can make to eliminate or drastically reduce their use of plastics, and in turn help protect our oceans and marine life,” Kain said.


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