KILAUEA — Climate change and overfishing in Hawaiian waters could be having an affect on the populations of Newell’s shearwater seabirds, according to the Kauai Community Cat Project.
The group emailed a letter to Suzanne Case, chairwoman of Hawaii Department of Land and Natural Resources, on Thursday asking for further investigation.
“In spite of extensive knowledge of overfishing in Hawaiian waters, El Nino, ocean temperature rise, and general agreement that these factors likely affect them, no studies have been performed that assess the impact on Newell’s shearwater from oceanic factors,” said the letter signed by Basil Scott, KCCP president.
The letter alleges studies have “consistently focused solely on terrestrially based impacts in attempting to explain the observed decline of these shearwaters.”
DLNR, however, researches the considerable amount of time shearwaters spend at sea through the use of satellite tags.
“We have been investigating these issues for many years now, through the deployment of geolocators to look at wintering sites and satellite tags to look at key feeding areas,” said Andre Raine, with Kauai Endangered Seabird Project. “This is an important and critical step in assessing where the birds concentrate their activity at sea.”
With the data retrieved from geolocators and satellite tags, Raine said DLNR is able to see whether issues like climate change, El Nino or overfishing and bycatch are ”priority conservation issues to tackle.”
Researching impacts and threats at sea for the birds has “always been a priority for DLNR,” Raine said, but those factors have to be balanced with the threats that are on land.
“Those threats include the killing of endangered seabirds by introduced predators such as feral cats and rats, power line collisions, light attraction and changing habitat due to invasive plants,” Raine said. “Those threats are immediate and have far-reaching ramifications at a population level and so need to be tackled quickly.”
Overfishing and bycatch by the commercial fishing industry is another concern for the people over at KCCP, and the letter points to National Oceanic and Atmospheric Administration data that shows “nearly 100 percent of all fish stocks in the Hawaiian Large Marine Ecosystem are overexploited or have collapsed.”
To date, though, according to Raine, by-catch “does not appear to be a major issue for Newell’s shearwater or Hawaiian petrel,” but he said DLNR continues to monitor for the possibility.
He pointed to a 2014 NOAA seabird report, which states:
“To date there have been no observed interactions – hooking or entanglement — between either of the Hawaii longline fisheries and the short-tailed albatross, Newell’s shearwater or Hawaiian dark-rumped petrel.”
Overfishing is a more complex problem, though, and it’s one that’s more difficult to immediately assess.
“However, the monitoring of burrows at multiple colonies in the mountains each year suggests that chicks are being fed sufficient food to achieve fledging,” Raine said. “If food resources were a major issue, we would expect to see large scale annual failures not immediately attributed to issues such as predation.“
DLNR will continue to look into at-sea distribution of the shearwaters and the petrels, Raine said, and the possible impacts of threats to those species at sea, through their ongoing tracking and will continue to review data that comes in from other organizations on the birds.