At least six deer carcasses were illegally dumped in the Oak Bluffs harbor last week, sending bacteria levels sky-high and prompting closure of the harbor to shellfishing two days later. Police have no suspects but said they are confident they will find those responsible for what one environmental official has called a hazardous waste site.

Bacteria counts were more than triple the acceptable level. "They were extremely high," said John Mendes, shellfish biologist at the state division of marine fisheries in Pocasset. "We don't usually get those counts anywhere. It's very unusual."

Officials were alerted early Monday morning, Dec. 3, after someone reported seeing deer skins floating in the outer harbor near the Island Queen dock.

Harbor master Todd Alexander and two workers from the town highway department used grappling hooks to pull the carcasses and remains to shore. According to Mr. Alexander, most of the carcasses had already been skinned and butchered, but they were unable to haul in everything.

"It was a first," said the harbor master. "There were some with the legs and head hanging off. Right where the Queen comes in, you could see a whole pile of bone and one sunken carcass, a doe or a small deer, that they began to skin."

Water quality tests conducted that day found high levels of bacteria, according to shellfish constable David Grunden, who said that a routine testing of the harbor by the state division of marine fisheries just happened to be scheduled for the day.

Making things worse, Mr. Grunden said, was that a rising tide most likely held the bacteria inside the harbor.

"Barring finding some other source, we presume that it's from the deer," said Mr. Grunden. Town workers did hit a sewer pipe on East Chop around the same time, he said, but the minimal leakage that resulted was quickly brought under control.

Mr. Grunden's decision last Wednesday to close the harbor to both recreational and commercial shellfishing came as particularly bad news to Islanders who were depending on quahaugging in the harbor as a way to rebound from a disappointing scalloping season.

"With the demise of the scallops, we were counting on that for Christmas and just living money," said Oak Bluffs fisherman Jeff Clements, 44. "It's killing us financially."

At least six shellfishermen were planning to work the harbor for quahaugs this winter, said Mr. Grunden. The harbor will remain closed for the next two to three weeks until subsequent tests can prove consistently clean water. Mr. Grunden added that he is considering using divers to help remove any remaining deer carcasses or animal parts still in the harbor.

Both the Oak Bluffs and state environmental police are investigating the dumping. Mr. Grunden said that police found an official tag on a carcass that could help them identify the hunter who weighed in the deer at one of three stations on the Island. The tag is a metal band typically placed around the deer leg.

State environmental police Sgt. William Searle would not comment on the evidence in the case, but he said, "I have a feeling we're going to find out who did it."

Expressing shock at the action, Sergeant Searle said hunters are supposed to dispose of deer carcasses as they would any other garbage, putting it in a plastic bag and taking it to the dump. They could even bury the deer in their backyard, he added.

"But a few lazy, immoral hunters have created an illegal dump," he said. "With that amount of rotting flesh, it's really hazardous waste."

Officials investigating the case suspect that warm weather could have prompted a hunter to take such action.

"Our presumption is that [the deer] were hung too long and the meat had gone bad," said Mr. Grunden.