More than two-thirds of the 16 bottlenose dolphins inhabiting New Jersey rivers since summer have died or disappeared, federal officials say.
The National Oceanic and Atmospheric Administration counted five dolphins in the Shrewsbury River and none in the Navesink this week. The whereabouts of the others are unknown and the possibility some survivors made it out to sea was only speculation, the agency said Wednesday.
The other dolphins are likely to die or strand themselves as winter progresses, NOAA said. The agency has refused to permit a rescue or relocation attempt and stood by its decision Wednesday.
"We do not improve their prospects by attempting to force them from the area," agency spokeswoman Teri Frady said in an e-mail. She noted a rescue attempt would have risks itself and was no guarantee of the dolphins' long-term health and survival.
Bottlenose dolphins normally winter south of Cape Hatteras, N.C. Groups advocating a rescue attempt say the animals can't handle the colder waters and have less food available.
A dozen dolphins had been counted in early December, and NOAA said then that many of the survivors had lost weight.
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