Conservationists counted 615 dead dolphins along a 90-mile stretch of beaches in Peru, a wildlife group said Wednesday, and the leading suspect is acoustic testing offshore by oil companies.

"If you can count 615 dead dolphins, you can be sure there are a great many more out at sea and the total will reach into the thousands,” Hardy Jones, head of the conservation group BlueVoice.org, said in a statement after he and an expert with ORCA Peru walked the beaches.

Indeed, the head of a local fishermen's association told Peru21.pe that he estimated more than 3,000 dolphins had died so far this year, based on what he saw in the water and on beaches.

BlueVoice.org stated that "initial tests ... show evidence of acoustical impact from sonic blasts used in exploration for oil."

The ORCA Peru expert, veterinarian Carlos Yaipen Llanos, said that while "we have no definitive evidence," he suspects acoustic testing created a "marine bubble" -- in essence a sonic blast that led to internal bleeding, loss of equilibrium and disorientation.

Another possibility is that the dolphins suffered from a disease outbreak, Yaipen Llanos said.

Reuters

Carlos Yaipen Llanos of ORCA Peru examines a dead dolphin on Feb. 11 in Lambayeque, Peru.

"It is a horrifying thought that these dolphins would die in agony over a prolonged period if they were impacted by sonic blast," said Jones.

Numerous dolphins first started washing ashore in January, with the largest amount coming in early February. Thousands of dead anchovies were also seen.

BlueVoice.org noted that the U.S. has suspended similar testing in the Gulf of Mexico due to recent sightings of dead and sick dolphins. The ban was set to last through the dolphins' calving season, which ends in May. 

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Police in Tasmania, Australia, are investigating whether personal watercraft riders broke any laws when they raced through a pod of dolphins near Hobart.

Video footage apparently shot by an onlooker shows two personal watercraft, each with a man and a woman on board, coming up behind the pod before racing through them on Saturday in Frederick Henry Bay, The Mercury newspaper of Tasmania reported.

Witnesses said the watercraft managed to separate a pod of about 30 dolphins, according to Australian Broadcasting Corp.

According to Marine and Safety Tasmania, Jet-Skiers and boaters must not exceed 8 knots within 100 meters (330 feet) of dolphins and they must withdraw immediately if the animals show signs of disturbance, The Mercury reported.

Inspector Stuart Scott told the newspaper police would be interviewing the watercraft riders to determine if marine mammal protection laws were broken.

One of the riders, Todd Tatnell, claimed they did nothing wrong and that the dolphins had been following them before and after the video was taken. He denied that the dolphins were distressed.

"It's just been blown right out of proportion over nothing really," he was quoted as saying by the Australian Broadcasting Corp.

"We were only just playing with the dolphins as you do when you go out on the boat and Jet Skis and they'll come and play with you all the time."

Wildlife biologist Kris Carlyon of the Department of Primary Industries, Parks, Water and the Environment told The Mercury it’s likely the marine mammals were scared away and would not  return.

"The dolphins will have felt harassed and basically will clear out, at least in the short term," said Carlyon.

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