THE VIRGINIAN-PILOT
Copyright (c) 1995, Landmark Communications, Inc.
DATE: Saturday, July 1, 1995 TAG: 9507010464
SECTION: LOCAL PAGE: B1 EDITION: FINAL
SOURCE: BY DEBBIE MESSINA, STAFF WRITER
DATELINE: VIRGINIA BEACH LENGTH: Long : 135 lines
Homo sapiens isn't the only species that swarms Virginia Beach's shores in the summer to splash in the ocean and dine off its abundant seafood.
Tursiops truncatus, better known as the bottlenose dolphin, travels here for some of the same reasons.
About 75 percent of Virginia's dolphins summer off the coast of Virginia Beach, according to marine biologists who have counted coastal dolphins for the last two years and plan a third annual count Saturday morning.
The popularity of Virginia Beach has surprised Virginia Marine Science Museum researchers who expected to find greater concentrations of our finned friends off the Eastern Shore's barren barrier islands.
They assumed the dolphins would be attracted to the Eastern Shore's pristine habitat, undisturbed by major shipping channels, hordes of tourists and high rise hotels looming over the shoreline.
``They're not there and I'd like to be able to say why,'' said W. Mark Swingle, a marine biologist who heads the Virginia Marine Science Museum's dolphin research program. ``We don't know all the reasons for this yet, but we find it extremely interesting.''
One possible explanation, Swingle said, is that the food-rich waters around the mouth of the Chesapeake Bay attract dolphins, which feed on catfish, eels, sharks, rays, shrimp and other crustaceans.
Sharing the water with bathers, Swingle said, doesn't appear to bother dolphins. And because these dolphins are a coastal variety, they stay far from the path of heavy shipping traffic.
On Saturday, more than 100 trained volunteers will hit the beaches to count dolphins along 134 miles of Virginia coastline.
Between the North Carolina and Maryland state lines, counters will dot beaches, fly in airplanes, cruise in boats and survey from bridges and piers. Many Eastern Shore volunteers will be dropped off near remote barrier islands by boat and wade to shore to conduct their counts.
Hundreds more volunteers from Georgia to New Jersey will be counting dolphins at the same time for a regional snapshot of dolphin activity. Only South Carolina's count will be as comprehensive as Virginia's.
Last year, 407 bottlenose dolphins were counted in Virginia. In 1993, 335 were counted. These are considered minimum numbers becausedolphins spend 90 percent of their time underwater and are in constant motion.
While 75 percent were spotted in Virginia Beach, a majority of those dolphins were counted in the sparsely inhabited area between Rudee Inlet and the North Carolina line.
Another hot spot for dolphins is Cape Henry at the northern tip of the city. The numbers and energetic activities of dolphins at Cape Henry inspired researchers to name the point ``Dolphin Disneyland.''
With two years of consistent statistics under their belts, dolphin researchers feel confident in their conclusions about the distribution of dolphins along the coast.
This year, they'll be keeping a watchful eye on tiny dorsal fins poking from the water. In the last two years, the number and percentage of dolphin calves, or neonates, counted has risen enough to warrant closer study, Swingle said.
Last year 39 calves were counted, representing 9.6 percent of the total. In 1993, 20, or 6 percent, were counted.
``It's up fairly significantly, but it's too early to predict what that means yet,'' Swingle said.
There are several possibilities, though. Dolphin reproduction could have a cyclical trend and last year could have been its peak. Or a continued high reproductive rate could indicate the species is trying to rebound from a loss in population.
The bottlenose dolphin's population was designated as depleted by the National Marine Fisheries Service as a result of the 1987-88 dolphin deaths, in which about 750 dolphins died along the East Coast. It was the largest mass poisoning of marine mammals on record.
The counts will help piece together the mystery surrounding the bottlenose dolphin, the most common, yet one of the least understood, marine mammals on the East Coast.
``The information they gather is absolutely valuable,'' said Vicki Thayer, a fisheries biologist with the National Marine Fisheries Service in Beaufort, N.C. ``Little information is known about these migratory animals.''
Virginia is a critical area for studying the coastal migratory dolphin population. South of Cape Hatteras, dolphins live near shore yearround. But in Virginia, coastal dolphins appear in May and leave in November.
The Virginia Marine Science Museum has taken the lead in the effort to learn more about the number and migration of these dolphins, largely through Operation Dolphin. The program has identified more than 250 different dolphins in Virginia waters through research and photographs of their distinguishing dorsal fins.
The ultimate goal of the research is to conserve the species.
``Until we know a lot more about the animal, we have no hope of conservation because we don't know what it needs, where it lives or how many there are,'' Swingle said.
``Now that we know where the dolphins are and their approximate numbers, we are better able to anticipate or respond to potential threats to their population.'' MEMO: TO LEARN MORE
If you are interested in learning more about bottlenose dolphins, the
Virginia Marine Science Museum sponsors daily dolphin-watching boat
trips from Rudee Inlet.
Departures are 9 a.m. and 4:30 p.m. weekdays and 4:30 p.m. Saturdays
and Sundays through Sept. 3. The fee is $12 for adults and $10 for
children 11 and under.
For reservations, call 437-4949.
DOLPHIN FACTS
Migratory bottlenose dolphins travel as far south as Florida during
winter, and as far north as New Jersey in the summer. But their numbers
and migratory habits aren't understood.
Bottlenose dolphins can grow to 11 feet and weigh up to 1,000 pounds.
They live for at least 30 years.
They often travel in groups and frequently cooperate when they fish. A
single dolphin consumes 15 to 30 pounds of food each day.
Each dolphin has a signature whistle, a name of sorts, that other
dolphins recognize.
Bottlenose dolphins are noted for their care-giving qualities. They
will support a sick or injured individual, keeping it at the surface so
it can breathe. In some areas, notably Monkey Mia in Australia, they
will come into shallow waters to socialize with humans, showing a
preference for children. ILLUSTRATION: Color graphic by John Earle, Staff
Results of counts in 1993 and 1994. For complete information see
microfilm
by CNB