Pilot whale encounters 30 miles offshore

Our Research Team has begun surveying the deeper waters southwest of Maui as part of our new false killer whale study. The first day of research took us ~30 nautical miles off the coast of Maui in waters >2,500 feet. Although we didn’t see any false killer whales, we did have two encounters with short-finned pilot whales, a species we do not typically observe in the near-shore waters of the Maui 4-island region. This species has distinctive bulbous heads, wide dorsal fins, and sleek black bodies. Short-finned pilot whales are sexually dimorphic, which means that males and females look different. Males typically grow to 18 ft long compared to females who grow to an average length of 12 ft. The dorsal fins on males are also larger and wider than females, making it easy to tell the two apart.

During our encounter with short-finned pilot whales, two researchers were taking above water photographs of the whale’s dorsal fins, another researcher was collecting underwater footage using a pole-mounted camera, while a fourth research was collecting detailed observations on pod behavior and composition. We observed two mother-calf pairs, two subadults, and the rest were adults, spread out into smaller sub-groups of 2-3 individuals. During the encounters we observed the pod feeding and resting at the surface of the water.

The majority of our research takes place after our field work ends, because the data we collected in the field must be processed. This involved looking through 520 pictures of dorsal fins, assessing each image’s quality, and matching each image within the encounter to see how many different individuals we saw. After data processing was completed, we had photographically identified 19 different animals. These individuals were then compared to our existing catalog of 133 short-finned pilot whales to see if any have been previously sighted. One individual matched to our catalog and was sighted back in September 2002. The other 18 animals had never been seen before and were added as new individuals, increasing our catalog size to 152 individuals. Since we do not often see this species, it was expected that there would be many new individuals to add, as the estimated population size for the entire Hawaiian Islands EEZ is 12,422 whales (Bradford et al. 2013).

This was a very successful day offshore! Stay tuned for other research updates from this exciting new study.

FACT OF THE WEEK: False Killer Whales Call Hawaii Home

MORE ON THIS: False killer whales, while a globally distributed species, have a special tie to Maui and the four-island region. Recent research has found that a very small group of this odontocete, or toothed whale species,  calls Hawaiian waters home, making them genetically different from offshore groups. This makes this population especially interesting because false killer whales are generally thought to prefer deep ocean environments far from any land.

Genetic tests were completed on samples collected from groups of false killer whales around the main Hawaiian islands and locations throughout the North Pacific. Researchers found samples collected from individual whales close to the Islands were most genetically unique when compared to samples from whales in the Pacific Ocean, Panama and Mexico. The uniqueness of the samples indicates there are two separate populations; an inshore population and an offshore population.

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Mugged on the first Ultimate Whalewatch of 2015

On January 13th, the research team ran the first Ultimate Whalewatch cruise of the 2014/2015 whale season. Mother Nature was on our side that day, with perfect calm weather conditions.

Over the past week or so, the research team had been sighting more and more humpback whales in Ma’alaea Bay, including mother-calf pairs, so our 30 guests were in for a good whalewatch trip on Ocean Liberty.

As expected, a few whale pods were sighted a few minutes into the trip. At a later stage, we were even spoiled for choice, with whales left, right and center. Captain Curtis decided to follow one of the competition pods that displayed a lot of surface activity, very close to Ma’alaea Harbor and Sugar Beach. That decision paid off.

Over time, the number of escorts dwindled down from five to just two. At one point, one of the adults, presumed to be the female in the original pod, approached the vessel so close that, when it exhaled, the blow hit a few passengers. The whale then slowly swam under the vessel, giving everyone on board enough time to admire the sheer size of this animal. What a great photo opportunity that was.

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Sightings of baby spinner and spotted dolphins

Recently the research team set out towards the island of Lanaʻi to continue our odontocete and marine debris surveys. Around 9:30 am, we came across a pod of approximately 100 spinner dolphins, including five calves. Even better, two of the calves were neonates: newborn dolphins!

Neonates can be distinguished by their small size: only 75-80 centimeters long in spinner dolphins — about the length of a skateboard. They also have “fetal folds” on their sides. These vertical, lightly-colored “stripes” are the result of being folded up inside mom, and they fade with time as the calf grows.

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Freeing the Whales

Entanglement in fishing gear is responsible for the death of an estimated 300,000 whales and dolphins each year. Last year, a total of 13 individual humpbacks were confirmed entangled in Hawai’i waters. It was the highest annual number of confirmed large whale entanglements in Hawai’i since reporting began in 2002. While 13 confirmed entanglements is a far cry from 300,000 animals, the issue hits home when it happens right in your backyard.

On Maui, the Hawai’i Disentanglement Network is responsible for responding to large whale entanglements. The Network is comprised of Sanctuary staff, tour boat operators, commercial airline pilots, tugboat captains, fishers, researchers, and private citizens. The Network relies on these individuals to alert the proper authorities of an entanglement. On-the-water efforts to disentangle animals are led by the Sanctuary’s Large Whale Disentanglement Coordinator, Ed Lyman.

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