Featured Image Credit: rollingharbour.com
By Eva Gruber
The Pacific Islands Region NOAA Response Team was alerted to the presence of a stranded marine mammal on the morning of November 22, 2016, at around 7:30 am. The stranding team responded immediately, and dispatched to the location where the animal was reported – off Sugar Beach on the southern part of the island of Maui, in Hawaii.
The marine mammal was identified as a melon-headed whale, a member of the dolphin family. It was 8.5 feet long, and was stranded in the shallow waters off the beach. While this species is typically found in deep waters of at least 5,000 feet. They are highly gregarious and are typically found in large pods numbering from 100 up to as many as 1,000 individuals (on rare occasions).
Melon-headed whales (Peponocephala electra) are closely related to false killer whales and pilot whales, belonging to the Delphinidae family. They have a cosmopolitan distribution around tropical and temperate ocean waters of the world. They are currently classified as non-threatened by the IUCN.
Their diet is primarily made up of squid, and in Hawaii they can frequently be seen resting at the surface. Hawaii is unique in that it has two groups of melon-headed whales: a population that stays far offshore in the deep Pacific waters moving between islands, and a second group that stays closer to shore in shallower waters around the Big Island itself. Based on where this individual stranded, it likely belongs to the deeper-water group.
Unfortunately when the animal was assessed by marine mammal veterinarians and mammalogists, it was determined it would not be able to survive in the wild or be rehabilitated in captivity. Every effort was made to find a way to save the animal. However, the decision was made to humanely euthanize it on location, and a couple of hours later the animal peacefully passed away.
The reasons for its stranding behavior are currently unknown, and will become available once results of the necropsy and pathological testing are released. While mass strandings usually occur as a result of human behavior such as sonar or underwater guns, single strandings like this might be caused by a pathogen, or other natural causes. It has been noted in mass strandings in this species that the ratio of females to males is 2:1 – this may reflect behavioral segregation on their part, where groups of females travel together more so than with males. It is not known whether this single stranded individual was male or female. At 8.5 feet long, it may have been a smaller individual, or a subadult still growing to the species’ adult size of 9.8 feet long.