Woman thought she spotted an otter in marsh by her Cape Cod home. Then a fin surfaced

Looking out the living room window to the marsh by her Massachusetts home, Robin Rowe caught a glimpse of something moving in the water.

This time of year, it’s most often ducks she sees floating in the Bees River Marsh, or flying out from the tall grass -- but this was something else. She headed outside to get a closer look, thinking the figure circling around in the water might be an otter.

The figure turned again, breaching the surface.

“I saw there were two fins, and I said ‘Okay, that’s not an otter,’” Rowe told McClatchy News.

As a resident of Eastham, in Cape Cod, sharks are something Rowe and her husband consider when going for a swim in the bay. But in the marsh?

“We’ve been here seven years. We’ve never seen a shark in the marsh before,” she said. “A lot of people kayak in the marsh, and paddle board in the marsh. We’ve kayaked in the marsh before.”

Rowe was thrilled. She grabbed her phone and dashed out toward the marsh and started recording.

“I think I would be really nervous to bump into him,” she said, adding that the shark looked to be between 6 and 7 feet in length. The shark only stuck around the water by Rowe’s house for about 10 minutes before it moved on, she said.

Rowe and her husband estimate the shark must have swam at least half a mile inland, the marsh twisting and turning along the way.

“That’s one thing we love about living here, there’s always something to see out the window,” she said. “But that was different.”

Rowe shared her video of the unusual shark sighting on Facebook through the Eastham Chamber of Commerce’s page, where she works.

“It was exciting to me as a nature lover to see it and to share it with other people,” she said.

As of Thursday, the video had been shared more than 600 times.

Rowe contacted the Massachusetts Division of Marine Fisheries, which asked her to keep an eye out for the shark, or for its body.

They haven’t seen any sign of it.

“We’re hoping it made it out,” she said.

There was initially some debate over what kind of shark was seen roaming the waterway. Rowe learned it was a blue shark, thanks to a specialist.

“Blue sharks are curious, open-ocean predators that live throughout the global ocean, from the tropics to cold temperate waters,” according to Oceana, a conservation advocacy group. “They spend most of their lives far from the coast and are truly a pelagic species.”

In other words, it’s unusual to see a blue shark near the shore, much less in a marsh. So what brought it there?

The most likely answer is that the shark simply got lost, Greg Skomal, fisheries scientist for the state Division of Marine Fisheries, told The Boston Globe.

Often, sharks that end up in these situations are sick or injured, and weakened as a result, Skomal told the Globe, but the blue shark in Rowe’s video appears to be perfectly healthy.

Skomal said it’s a promising sign that the Rowes haven’t seen the shark again, and that it’s probably back in the ocean.

“This shark fortunately found its way out, you know. So good, healthy animals like this and because the water temperatures and the air temperature wasn’t that cold — it’s still … not December yet — we didn’t have to do anything,” he said. “The high tide came in, the shark found its way out. That’s the best solution.”

Rowe told McClatchy News that the shark sighting won’t discourage her from getting in the water, whether in the marsh, or out where it’s deeper.

“I still swim in the bay, my husband still swims in the ocean,” she said. “There’s sharks here and that’s where they’re supposed to be.”