A basking shark (Photo: MA Div. Marine Fisheries)

(AP Photo/Nick Caloyianis, Massachusetts' Division of Marine Fisheries)

A shark, estimated around 24-feet,  was seen by a man who was on his boat fishing in the Merrimack River Friday.

READ MORE: 9,909 At Massachusetts Schools Test Positive For COVID-19 In Last 2 Weeks

The man was cleaning a striped bass when he saw a fin in the water.

Newburyport Harbormaster Paul Hogg tells WBZ NewsRadio 1030 the shark apparently smelled the fish’s blood.

READ MORE: Fantasy Football Start Or Sit Week 13: Elijah Mitchell Looks To Take Advantage Of Seahawks' Defense

Hogg says it’s unusual to see a shark up here but thinks the warmer ocean temperatures have helped draw the sharks to the Bay State coast.

Authorities warned boaters and beach-goers along Salisbury Beach to be on the lookout.

Attempts by authorities to confirm the sighting were unsuccessful.

MORE NEWS: AJ Quetta Returns To Bishop Feehan As Assistant Coach, 10 Months After Severe Injury

There have been three confirmed sightings of sharks off the coast of Massachusetts so far this year, one each off Gloucester, Scituate, and Chatham.