"Like any marine animal, they'll pretty much follow the food and the tide," said Dittmar. "When there's abundant food, you can almost follow their day as they swim back and forth. Obviously, there's no way to tell whether a group of dolphins heading south might have been the pod you saw an hour ago, but it often seems that way."
Yesterday's count was as much about educating people as it was in spotting dolphins, at least in the short term, said Dittmar. The annual tally has proved to be a sure-fire method of getting volunteers excited about helping the wild cousins of the mammals that star in aquatic shows in downtown Baltimore.
To dolphin watchers, the animals are notoriously unpredictable. The best action yesterday came two miles offshore near a 47-foot Coast Guard vessel piloted by Petty Officer 1st Class Christopher Karpf. Spotters tallied 36 in just a couple of hours.
"We see pretty much everything out here - whales, sea turtles, seals," Karpf said. "The dolphins usually hang out around offshore shoals or at the Ocean City Inlet. When the tide starts to go out, it pulls their food right through the inlet to them."
For scientists, the annual census provides a baseline for long-term comparisons of the numbers and habits of a sea animal that always seems to appeal to humans.
"What we're really getting here is a snapshot, a quick picture of their numbers and even a little information about their habits," Dittmar said. "Over the long term, we can see patterns, or maybe we'll see problems developing."
Like other stranding teams on the Atlantic coast, the aquarium's researchers organized the annual count of Atlantic bottlenose dolphins in 1989, two years after nearly 1,500 of the animals died, beached at sites throughout the region.
Perplexed scientists still aren't certain what happened, but the dolphins apparently died of a virus similar to the flu in humans. Continued strandings are another mystery, but researchers have learned much about the mammals' behavior.
After the dolphin watch concluded yesterday and the spotters reported in, aquarium officials put the Maryland count at 66, a disappointing showing after last year's tally of 119 but not definitive proof of any problem.
Yesterday, a few miles to the north, Delaware volunteers and researchers organized by the MERR Institute, a Nassau, Del., nonprofit group that also rescues stranded mammals and sea turtles, conducted its dolphin count from the state line to the mouth of Delaware Bay.
The two groups are sharing data this year and have plans for coordinating their efforts with similar programs in nearby states.
"It's something that people want to be a part of," said MERR director Suzanne Thurman. "Every year, we're inundated with calls. Some people even time their vacations to time it during the count."
Figures from Delaware's dolphin watch were not available.
chris.guy@baltsun.com
