LAHAINA — Researchers discovered one thing surprising inside a uncommon, false killer whale that stranded useless on Maui final month, and it might in the end assist the endangered species.
The whale was an insular false killer whale, probably the most critically endangered species of dolphins and whales in Hawaiian waters. Whereas investigating its reason behind demise, the College of Hawai‘i Marine Mammal Well being and Stranding Lab discovered the stays of octopuses in its abdomen, which was beforehand an unknown a part of the species’ eating regimen.
“Understanding their meals habits is foundational to their biology and ecology, and has relevance to fishery interactions (an recognized risk to the inhabitants) and in defining important habitat for this endangered species,” mentioned Kristi West, lab director and an affiliate researcher at UH Manoa’s Hawai‘i Institute of Marine Biology.
The UH lab carried out a necropsy, an animal post-mortem, in cooperation with Nationwide Oceanic and Atmospheric Administration Fisheries Service, to acquire organic samples and study the person for indicators of reason behind demise and proof of fishery interactions. Inspecting an insular false killer whale in Hawai‘i is a uncommon alternative for the UH lab, because the final stranding occurred in 2016.
The abdomen contents within the current stranding revealed the significance of a brand new meals merchandise, the pelagic octopus, to false killer whales in Hawai‘i. The stays from 25 particular person pelagic octopuses have been recognized among the many abdomen contents of this particular person.
There are three distinct populations of false killer whales that decision Hawaiian waters house, with one that’s endangered.
The perfect estimate is that there are roughly 170 false killer whales remaining within the endangered insular most important Hawaiian islands inhabitants.
Fishery interactions and excessive pollutant masses have been recognized as inhabitants threats. A lot of the remaining people have been individually recognized by their dorsal-fin profile, with sightings cataloged by Cascadia Analysis Collective. The stranded whale was matched to the catalog and represents a identified particular person first sighted off Maui in 2000.
“This work is just potential due to an especially devoted group of graduate college students, undergraduate college students and different program volunteers,” mentioned West. “UH companions with collaborators comparable to Cascadia Analysis Collective, the state Division of Land and Pure Sources and NOAA Fisheries to maximise the data that may be obtained on false killer whales and the threats that they face.”
The eating regimen composition of endangered false killer whales is understood from the abdomen contents of beforehand stranded people and observations of dwell animals within the wild. Stay false killer whales are mostly noticed by Cascadia Analysis Collective foraging on gamefish, together with mahimahi, ono, aku and ‘ahi. Prior stomach-content analyses have recognized gamefish comparable to ‘ahi, mahimahi and the big diamondback squid as essential to the species’ eating regimen.
Future analysis on this animal will embody steady isotope evaluation, contaminant evaluation and body-condition evaluation on the time of stranding by blubber examination. That is anticipated to offer additional data to evaluate eating regimen and predator/prey relationships within the species, and to higher perceive the specter of pollution and dietary stress.
If members of the general public have the chance to take images of this species, picture contributions to Cascadia Analysis Collective’s photo-ID catalog are helpful for monitoring the inhabitants. Researchers additionally depend on public reporting of distressed or useless dolphins and whales. To report strandings, name the NOAA Fisheries hotline at 1-888-256-9840.