WELLFLEET - Eleven more dolphins were discovered beached on Cape Cod yesterday, bringing the tally of grounded dolphins to 177 since Jan. 12 in the largest single-species stranding ever reported here.
Rescue workers and volunteers rushed to the Herring River, near Wellfleet Harbor, after the dolphins were spotted about 7:30 a.m., nearly immobilized atop shin-deep muck in a lowering tide.
Rescuers from the International Fund for Animal Welfare and volunteers found 10 of the dolphins alive, took blood samples, and enlisted the waterborne help of the Wellfleet harbor master to try to shepherd the pod back to deeper waters in Cape Cod Bay. The animals are known as common dolphins.
By late afternoon, four of the dolphins had reached the bay while six had not yet been corralled through the winding channels in the harbor and past its shallow creeks, said Michael Booth, a spokesman for the animal welfare group.
Earlier, the rescue team decided to re-float the dolphins in Wellfleet rather than haul them to nearby trucks and release them into the open ocean off Provincetown, said Katie Moore, manager of marine mammal rescue and research for the International Fund for Animal Welfare. The difficulties of extracting the dolphins from the thick mud flats here during a fast-turning tide led to that decision, Moore said.
The team placed identification tags on all of the living dolphins, nine males and one female.
“This offered the greatest opportunity for the greatest number of animals,’’ Moore said. “They were doing well, thankfully.’’
Rescuers remain baffled by the mass strandings, which dwarf the annual average of 37 groundings of common dolphins on Cape Cod over the past dozen years.
Moore said that the hook of Cape Cod, which can trap sea life within the bay, and the highly social behavior of dolphins, which can prompt a pod to follow one dolphin’s lead, are possible factors. But those influences alone do not seem to explain this dramatic aberration.
“We don’t know what’s causing this event,’’ Moore said.
Samples from dolphins that did not survive the stranding have been sent to labs across the country, she said, but the results will not begin arriving for weeks.
“A lot of times, these animals aren’t sick or injured,’’ said Kerry Branon, a spokeswoman for the International Fund for Animal Welfare, who stood on a mud flat as she watched the rescue effort unfold. “They just took a wrong turn.’’
Of the 177 dolphins reported stranded in the past month, primarily between Wellfleet and Dennis, 70 have been found alive. Before yesterday, 43 had been released successfully into the ocean.