Deaths of young dolphin, humpback calf highlight importance of responsible boating in Hawaiʻi waters

Within the span of just a few weeks in February, a Hawaiian spinner dolphin yearling and humpback whale calf stranded dead in Hawaiʻi, both suffering injuries consistent with being struck by a vessel.

Following the recent and untimely deaths of those and several other young marine mammals in Hawaiʻi waters, the National Oceanic and Atmospheric Administration is urging boaters to slow down and enjoy marine wildlife from afar.

“It’s heartbreaking when we lose these animals, especially when they’re so young,” said Diana Kramer, regional stranding coordinator for the NOAA Fisheries Pacific Islands Regional Office. “These whales and dolphins are part of what makes Hawaiʻi the place many of us love. To protect and preserve them, we have to practice wildlife-friendly boating behaviors.”

NOAA Fisheries and the Hawaiʻi Department of Land and Natural Resources responded Feb. 12 to a report of a dead Hawaiian spinner dolphin in west Kauaʻi. A necropsy by the University of Hawaiʻi Health and Stranding Lab determined the female dolphin was about 1 year old.

The internal exam found the yearling died of trauma to the head consistent with a vessel strike.

Where the animal stranded is near a known resting area for Hawaiian spinner dolphins, which are nocturnal. They feed offshore at night and use nearshore habitat during the day to rest, socialize and nurture their young.

In 2021, the NOAA published a final rule that prohibits swimming with, approaching or remaining within 50 yards of Hawaiian spinner dolphins. The rule applies to any vessel, person or object.

Just a few weeks after the dead young dolphin was discovered, a humpback calf was found dead Feb. 26 in northeast Lānaʻi.

NOAA Fisheries, the DLNR’s Division of Conservation and Resources Enforcement and Pūlama Lāna‘i responded. The University of Hawaiʻi Health and Stranding Lab conducted a necropsy.

The internal exam indicated the calf had multiple skull fractures also consistent with a vessel strike.

The area where the keiki humpback was found is within the Hawaiian Islands Humpback Whale National Marine Sanctuary.

Every winter, thousands of humpback whales travel to Hawai‘i waters to mate, give birth and raise their young. The sanctuary was created to protect these whales and their habitat.

Federal regulations prohibit approaching humpback whales in Hawaiʻi within 100 yards, both within the sanctuary and anywhere in the waters around Hawaiʻi out to 200 nautical miles.

So far in 2024, the NOAA has received six confirmed reports of vessel strikes to humpback whales in Hawaiʻi. One of the most recent involved another calf in waters off Maui.

On Feb. 23, NOAA officials with Hawaiian Islands Humpback Whale National Marine Sanctuary and members of the Pacific Whale Foundation responded to a live humpback calf about 300 yards off Maʻalaea Bay.

The calf had suspected vessel strike injuries to its tail. No recent sightings have been reported.

Here’s how you can be a responsible boater and help protect and preserve spinner dolphins and humpback whales while piloting your vessel in Hawaiʻi waters.

Go slow, whales below

Reduce speed in areas commonly used by marine mammals and turtles and always post a lookout. The recommended speed for vessels transiting coastal waters during whale season, which is from November through April, is 15 knots or less. Recommended speed is 6 knots or less when within 400 yards of a whale or when making a directed approach to or subsequent departure from the animals.

The speed recommendations are aimed at minimizing the risk of striking a whale. They were developed by the Hawaiian Islands Humpback Whale National Marine Sanctuary, DLNR, Pacific Whale Foundation and members of the Hawaiʻi on-water community.

Click here to learn more about Hawaiʻi guidelines for boating with whales.

Keep a safe distance

Vessel collisions don’t just pose danger to marine species. They can also harm people. Federal regulations prohibit approaching humpback whales in Hawaiʻi within 100 yards. And under the Hawaiian spinner dolphin approach rule, it is illegal to approach spinner dolphins within 50 yards. The rule applies to any vessel, person or object.

Report injuries, entanglements and deaths

If you see an injured, entangled or dead marine mammal, keep a safe and legal distance. Call the statewide NOAA Marine Wildlife Hotline at 888-256-9840 or the U.S. Coast Guard on VHF channel 16 as soon as possible. While an entanglement might not impact an animal immediately, it can result in starvation, physical trauma and infections. Entanglements can also contribute to vessel strikes since the animals are less mobile. Quick reporting is invaluable to NOAA’s trained responders.

Click here to learn more about reporting stranded or injured marine animals.

Report potential violations

You can report a vessel strike or potential violations several ways:

• Call the NOAA Fisheries Enforcement Hotline at 800-853-1964
• Email respectwildlife@noaa.gov (for non-emergencies).
• Contact the DLNR at 808-643-DLNR or via the DLNRTip app.