A dolphin exhibited a feeding behavior dubbed “mouth open” in the Shrewsbury on Tuesday. (NOAA photo)
Marine scientists remain convinced that the 12 Atlantic bottlenose dolphins still in the Navesink and Shrewsbury rivers six months after their arrival are neither wayward nor trapped, and in fact are healthy, unstressed and able to survive the winter in inland coastal waters.
A panel of nine experts in dolphin health, behavior and acoustics told callers in a telephone seminar Wednesday night that there was no evidence that noise from the rebuilding of the Highlands-Sea Bright Bridge was deterring the dolphins from making a run beneath it for Sandy Hook Bay.
They also sought to quell fears that a freeze of the rivers would mean an inevitable death sentence for the coastal bottlenose dolphins.
“We’re letting these dolphins be wild dolphins,” said Teri Rowles, lead veterinarian for National Oceanic and Atmospheric Administration‘s Fisheries Service, adding that it would not be surprising for the dolphins to stay all winter and even for a full year.
“They may become frequent residents of that area,” she said. “We are not as an agency trying to limit the habitat of the recovering coastal bottlenose dolphins.”
NOAA officials organized the event amid rising concern that the dolphins, which attracted national media attention this summer, might be unable to make their way back out to sea for their customary migration toward the waters of North Carolina before a possible freeze.
Falling temperatures and the prospect of winter icehave brought back memories of 1993, when a NOAA effort to capture four dolphins instead drove them under river ice, where they died.
But the agency decided in late October not to try to try herding, luring or capturing the dolphins to get them back out into the bay, and the scientists on last night’s call stuck by that decision. They said those approaches ranged from impractical and unlikely to work to dangerous.
In addition, they said such efforts were unnecessary given that the dolphins showed no signs of inability to take care of themselves.
“I can assure you that our decision not to move the animals was not based on a lack of resources, expertise or willingness to mount an intervention effort,” said David Gouveia, a NOAA marine mammal program coordinator. “We think attempts to intervene are unlikely to work and include a high risk of harming or even killing some of the animals, regardless of who is doing the actual intervention.
“They are exhibiting normal behavior,” said Gouveia. “In fact, there’s a good possibility they’re just reclaiming an area they had traditionally inhabited in the past. This is a normal sort of way of life for these critters, and we’re optimistic things will work out just fine.”
One official said last night that the agency does have an action plan should the dolphins strand themselves in river shallows, but offered no details.
Moreover, panelists said, the results of continued monitoring of the pod suggest the dolphins are not disoriented, stressed or starving.
The consensus of the scientists is that “the animals are in an appropriate habitat, good body condition, and engaged in typical behavior, including foraging and feeding,” Gouveia said.
Local attention has been focused in particular on the loud pile-driving and a cluster of crane-bearing barges near the bridge as possible impediments keeping the animals from making a dash through the strait. Some individuals have called on NOAA, which has sole jurisdiction over the animals, to halt construction.
NOAA officials said that noisy work is stopped when the dolphins are within 500 meters of the bridge. But they said there’s no evidence that the dolphins are reluctant to pass under the structure.
Still, Cindy Zipf, founder of Clean Ocean Action, based at Sandy Hook, asked the experts to try a combination of a temporary halt in bridge construction in combination with acoustical luring. “If we do nothing and something happens, it going to be just awful.”
Other callers expressed concern about ice.
State Senator Sean Kean, whose district runs along the Monmouth County coast, asked what would happen if there was a sudden freeze. “How much time do we have here?” he asked.
Larry Hansen, a NOAA bottlenose dolphin researcher, said that the animals “have the option of moving into deeper parts of the river that are unlikely to freeze over.” Other panelists said that while they don’t know if the dolphins can sense the onset of a bay freezing over, they expect the animals will follow the fish on which they prey.
Reports, photos and other materials referred to in the discussion are available on NOAA’s website. A recording of the two-hour conference call is also to be made available on the site.
NOAA says the next seminar is planned for January 13 at a Monmouth County location to be determined.
