Mystery: Cause of death for Koala, a great white shark found on Cape Cod beach

A great white shark that washed ashore at a Cape Cod beach earlier this week is named Koala, and was known to local researchers, investigators said. Its cause of death is still a mystery, as a necropsy was inconclusive.

Tipping the scale at 1,240 pounds, the shark was recovered from Nauset Beach on Tuesday morning after it was discovered by the beach patrol. Dennis Reed, who operates Nauset Recovery Inc., was called in by Orleans Police to tow the carcass away after it was dragged to the beach parking lot by staff with the town's natural resources department.

A necropsy conducted Wednesday to determine the animal's cause of death was inconclusive, and the investigation team will have to wait for more in-depth pathological analysis to determine the cause of death, Massachusetts Division of Marine Fisheries scientist and lead investigator Greg Skomal , an expert on white sharks , said.

Koala was first identified by researchers in 2022, the Atlantic White Shark Conservancy said.

Koala wasn't the only shark to turn up dead on Cape Cod beaches this week. On Wednesday, Dennis resident Bob Amaral, a photographer, came across a dead porbeagle shark on Chapin Beach in Dennis. In an email, he reported he found the shark while taking photos at low tide, around 5:30 p.m.

"From what we can tell, it's been scavenged by coyotes on the shore," he said. Because the remains were disturbed, it's not likely a cause of death could be determined.

'No bite marks'

There were no obvious signs of trauma on the 12 1/2-foot-long great white shark, Koala. Its weight and length are typical for an adult white shark.

"There were no bite marks or anything on it," Reed said, describing the condition of the shark's body when he picked it up. "It seemed like it had a lot of internal bleeding because there was a lot of blood around its mouth."

Reed said all of the shark's fins were intact, so it wasn't finned – a practice of fishermen to cut off the fins of sharks and discard the rest of their often still living bodies. There also wasn't any sign of the shark being hooked.

It's not the first time Reed has been called upon to haul a deceased great white shark from the town's shores. "About four years ago, I had an 18-foot one," he said.

The Orleans Police Department shared photos of the shark getting hauled away on the department's Facebook page, commenting it wasn't "one of our typical calls for service." In the photos, the shark appears bloodied but there is not evidence of obvious external injuries.

White sharks do sometimes succumb to chronic infections, Skomal said. There were several cases of shark deaths owing to pathological causes between 2014 and 2016, he said.

Another potential cause could be simply beaching and suffocating to death. This can happen, Skomal said, "when you have a big fish in shallow water," tidal changes and shifting sandbars, and situations where the shark may become confused and it "zigs when it should have zagged and can beach (itself)."

White sharks common in Cape Cod waters

For almost 11 years, the conservancy has focused on white shark research and conservation. Its research team, led by Megan Winton, collaborates closely with Skomal to tag and catalog white sharks off the Cape's shores and learn more about their behavior.

The organization also developed a free app called Sharktivity , which tracks the presence of white sharks swimming in Massachusetts' coastal waters using real-time receivers. The app has more than 750,000 users.

According to last year's white shark population study, at least 800 individual white sharks visited the waters off Cape Cod over a four-year period, and the team has tagged more than 300 of them. But all of those sharks aren't in local waters at the same time, the researchers emphasize. The sharks come and go, some just stopping by and then heading elsewhere, some sticking around for weeks. Some come back year after year, and others are only occasional visitors.

Activity of white sharks off Cape Cod

Over the last decade, white shark activity has increased in the waters around the Cape . According to the conservancy, there was evidence of white sharks – seals with observed bite marks – before the first few successful taggings off the Cape in 2009, when the activity began ramping up.

White sharks have historically been found off Cape Cod, but due to fishing pressures, the population may have declined as much as 80% before the species gained federal protection in 1997 and 2005 in state waters. Gray seals, a white shark prey species, were also hunted, which led to a significant population decline until that species was protected in 1972 under the Marine Mammal Protection Act .

Recolonization of seals along the Cape Cod coastline is thought to have drawn white sharks back to the area. The rebounding population of both species is viewed as a conservation success story.

Heather McCarron writes about climate change, environment, energy, science and the natural world, in addition to news and features in Barnstable and Brewster. Reach her at hmccarron@capecodonline.com , or follow her on X @HMcCarron_CCT

This article originally appeared on Cape Cod Times: Mystery: Cause of death for Koala, a great white shark found on Cape Cod beach