Swimmers Were Harassing Dolphins

Hawaii authorities say 33 swimmers were harassing dolphins

Hawaii authorities on Tuesday say they have referred 33 people to U.S. law enforcement after the group allegedly harassed a pod of wild dolphins in waters off the Big Island.

It’s against federal law to swim within 50 yards (45 meters) of spinner dolphins in Hawaii’s nearshore waters. The prohibition went into effect in 2021 amid concerns that so many tourists were swimming with dolphins that the nocturnal animals weren’t getting the rest they need during the day to be able to forage for food at night.

The rule applies to areas within 2 nautical miles (3.7 kilometers) of the Hawaiian Islands and in designated waters surrounded by the islands of Lanai, Maui and Kahoolawe.

The state Department of Land and Natural Resources said in a news release that its enforcement officers came upon the 33 swimmers in Honaunau Bay on Sunday during a routine patrol.

Aerial footage shot by drone shows snorkelers following dolphins as they swim away. The department said its video and photos showed swimmers “who appear to be aggressively pursuing, corralling and harassing the pod.”

Enforcement officers contacted the group while they were in the water, and told them about the violation. Uniformed officers met the swimmers on land where state and federal officials launched a joint investigation.

Hawaii’s spinner dolphins feast on fish and small crustaceans that surface from the ocean’s depths at night. When the sun rises, they head for shallow bays to hide from tiger sharks and other predators.

To the untrained eye, the dolphins appear to be awake during the day because they’re swimming.

But because they sleep by resting half of their brains and keeping the other half awake to surface and breathe, they may be sleeping even when they’re maneuvering through the water.

The spinner dolphin (Stenella longirostris) is a small dolphin found in off-shore tropical waters around the world. It is famous for its acrobatic displays in which it rotates around its longitudinal axis as it leaps through the air. It is a member of the family Delphinidae of toothed whales.

The spinner dolphin is sometimes referred to as the long-snouted dolphin, particularly in older texts, to distinguish it from the similar Clymene dolphin, which is often called the short-snouted spinner dolphin. The species was described by John Gray in 1828. The four named subspecies are:

• Eastern spinner dolphin (S. l. orientalis), from the tropical eastern Pacific.
• Central American or Costa Rican spinner dolphin (S. l. centroamericana), also found in the tropical eastern Pacific.
• Gray’s or Hawaiian spinner dolphin (S. l. longirostris), from the central Pacific Ocean around Hawaii but represents a mixture of broadly similar subtypes found worldwide.
• Dwarf spinner dolphin (S. l. roseiventris), first found in the Gulf of Thailand.

The species, though, displays greater variety than these subspecies might indicate. A hybrid form characterized by its white belly inhabits the eastern Pacific. Other less distinct groupings inhabit other oceans.

The species name comes from the Latin word for “long-beaked.”

Spinner dolphins are small cetaceans with a slim build. Adults are typically 129–235 cm long and reach a body mass of 23–79 kg. This species has an elongated rostrum and a triangular or subtriangular dorsal fin. Spinner dolphins generally have tripartite color patterns. The dorsal area is dark gray, the sides light gray, and the underside pale gray or white. Also, a dark band runs from the eye to the flipper, bordered above by a thin, light line. However, the spinner dolphin has more geographic variation in form and coloration than other cetaceans. In the open waters of eastern Pacific, dolphins have relatively small skulls with short rostra. A dwarf form of spinner dolphin occurs around southeast Asia. In these same subspecies, a dark dorsal cape dims their tripartite color patterns. Further offshore, subspecies tend to have a paler and less far-reaching cape. In certain subspecies, some males may have upright fins that slant forward. Some populations of spinner dolphin found in the eastern Pacific have bizarre backwards-facing dorsal fins, and males can have strange humps and upturned caudal flukes.