Dolphins Are a Wonderful Sight

There is a difference between dolphins and porpoises, and many people get them confused. What you will see in this area are dolphins. Porpoises do not generally venture into North Carolina waters. The only porpoise species that occurs near the U.S. East Coast is the harbor porpoise, and it typically ranges from Virginia to Canada.

Bottlenose dolphins are long and streamlined, with a distinct blunt beak and a prominent dorsal fin that curves toward the tail. They are bigger than their porpoise cousins, with adults generally ranging in length from 8 to 10 feet (males are slightly larger than females) and weighing between 500 to 800 pounds. Dolphins' teeth are sharp and shaped like cones, not flattened like those of a porpoise. These aquatic creatures are cetaceans, the taxonomic order of marine mammals that includes all "the great" whales, dolphins and porpoises.

Dolphins are also members of the suborder odontocetti, meaning toothed whales. More than 70 species of toothed whales live in the waters of the earth, many of which are found in relatively shallow, temperate coastal waters. It's not unusual to spot bottlenose dolphins in groups of about a dozen, fairly close to shore. They usually have light-colored bellies and dark backs — colors that help them blend in with their surroundings. These graceful creatures are powerful swimmers and often frolic in the bow waves of boats or surf on large waves.

Bottlenose dolphins along the East Coast of the United States are severely and negatively impacted by human activities. After a die-off that killed up to half of the population, the National Marine Fisheries Service in 1993 listed them as depleted under the Marine Mammal Protection Act. Dolphins have washed ashore dead with evidence of having been struck by boats, entangled in fishing nets, and with foreign material (human trash) in their stomachs. Yet little basic information that is critical for their conservation is known, such as reproductive rates, residency and migration patterns, and habitat needs.

That information is being gathered by a small group of dedicated professionals. Keith Rittmaster, Natural Science Curator at the North Carolina Maritime Museum, directs a program that identifies local dolphins and records their movements, associations and reproduction information. The process used is called photo-identification and involves the use of photographs of the scars and notches that dolphins acquire on their dorsal fins to recognize and verify resights of known individuals. Rittmaster, along with his wife, Victoria Thayer, have been studying the bottlenose dolphins in this area since 1985. Individually identified dolphins that they first photographed in 1985 are still seen regularly in the waters around Beaufort. They have also matched dolphins identified in Beaufort with photographs from study sites as far south as central Florida, as far north as New Jersey and many sites in between. This collaboration is critical to the study, and researchers from the Virginia Marine Science Museum, National Marine Fisheries Service, Duke Marine Lab, Nags Head Dolphin Watch and UNC-Wilmington all share photographs and data.

In addition to studying the live, free-swimming dolphins, Rittmaster is authorized under the Marine Mammal Protection Act to respond to strandings of whales and dolphins as part of the Marine Mammal Stranding Network. Examining carcasses of beached dolphins has shown him many negative effects of human interactions. Dolphins tangled in fishing nets and lines die trapped in the debris. Dolphins are also sliced by boat propellers and ingest litter that can often be lethal.

People have fed wild dolphins, and Rittmaster cites reports of people even giving the dolphins Twinkies, sunglasses or whatever is in the boat with them when they run out of fish. Lens caps, fishing hooks and other litter have been found inside of dead dolphin stomachs. Dolphins are wild animals, and if they get used to coming to people, it can create danger to the animals as well as to humans. Some wild dolphins have come to expect the handouts, and have been known to become aggressive and bite. It is against federal law to feed or harass wild dolphins, punishable by imprisonment and/or fines.

To raise money to help protect and increase understanding of dolphin behavior and human impact on them along the North Carolina coast, the N.C. General Assembly approved the sale of a $30 special license plate with all revenues going to support the education, conservation and research programs of the N.C. Maritime Museum. For more information about the research program or the license plates, visit www.capelookoutstudies.org.