Nate Rouette and his brother Nelson experienced an unexpected thrill while shark fishing on Cape Cod. Both were surprised by their catch—a tropical species of shark known for its voracious appetite. This shark was a juvenile tiger shark, which they released after catching it from a beach in late July.

The brothers, seasoned sport fishermen from Massachusetts, found this encounter especially notable because the tiger shark is usually found in warmer waters like the Caribbean Sea. Scientists pointed to its appearance off Falmouth, Massachusetts, as a sign of climate change, highlighting the effects of warming seas.

After spending hours fishing for more common brown sharks, the brothers caught the five-foot tiger shark, a species known to grow up to more than 15 feet and weigh 1,400 pounds. Tiger sharks consume a wide range of oceanic life, including fish, crustaceans, and sometimes even man-made items found in their stomachs.

Nate, who works with On The Water magazine as social media manager, shouted to his brother when he realized the shark species they had caught. He described seeing the horizontal lines that identified the shark as a tiger shark.

“And I saw those horizontal lines, indicating it was a tiger shark, which was super cool,” Nate said.

John Chisholm, an adjunct scientist at the New England Aquarium’s Anderson Cabot Center for Ocean Life, noted the increasing presence of juvenile tiger sharks in northern waters. He attributed this trend to rising sea temperatures, which make the Atlantic Ocean more suitable for these sharks.

According to Chisholm, young tiger sharks have historically been less common in northern waters compared to adults. The Rouette brothers’ discovery adds intrigue to this phenomenon.

“Maybe they are coming up here because conditions are right. There’s food, there’s warm waters,” Chisholm said. “Maybe it’s becoming a nursery—that’s one of the issues that we will investigate.”

Other sea life, including many kinds of sharks and black sea bass, have also migrated northward as seas have warmed, scientists stated. Sightings of great white sharks have become more frequent off Cape Cod and even in regions like New Hampshire and Maine.

For the Rouette brothers, catching the tiger shark was a memorable experience. Nate emphasized the importance of the discovery as a reminder of the changing ocean conditions.

“People are definitely seeing more species that indicate that,” Nate said.