South Shore: No need to ruin your beach day – differences between shark and sunfish fins

Before you see a fin sticking out of the water at the beach this weekend and scream “Shark!”, in the process ruining the beach day for you and everyone around you, here’s something to keep in mind from the Division of Marine Fisheries.

The best way we use to tell the difference between a sunfish and a White Shark is a shark fin will basically move straight through the water and remain vertical. However a sunfish uses that dorsal fin to swim and as such, the fin moves up and down, up and down.”

Sort of in a flowing motion, says Dr. Greg Skomal, Senior Marine Fisheries Biologist with DMF.

“The fin of the sunfish is more rounded than the White Shark.,” Skomal said. “The White Shark fin sweeps back and remains erect and rigid. The sunfish is more rounded.”

He says the two have been confused for each other for many years but they are very different animals, the shark a predator, while the sunfish mainly feeds on jellyfish.

Massachusetts has seen two shark attacks on humans in the past 75 years, according to Skomal.

About Steve Burns

Steve comes to the South Shore by way of the Jersey Shore. Upon arriving at Emerson College in Boston back in 2010, and eventual graduation in 2014, Steve was immediately attracted to radio as an outlet for his reporting. Previous stops before the South Shore include WOBM on the Jersey Shore, WCCM in the Merrimack Valley, an internship at CBS Radio News' flagship station, WCBS 880 in New York City, and a few formative years at Emerson's WERS.