Porbeagle fishing

I know they are seen pretty offten by the cod boats in mass during the winter and early sring. Early this spring while mackrel fishing about 5-8 miles outside fire island my buddy saw a huge swirl in the school of macks we never got a 2nd look at it so i have know idea what it was my guess would be a Porbeagle, whale, or one real lagre and confused blue fin i think the water was a bit on the chilly side for one of those but you never know... if i were to target porbeagle i think id head out in the spring find some mack in like say 120-150 ft of water put a can of chum over and a live mack of 2 then contiune on mack fishing because i think you might have a long wait trying to catch mr.shark i think fishing around the mack schools would be your best bet i dont see why they wouldnt follow them.