[Black Agnes]

The bull shark is found close to shore and can live for a while in fresh water, frequenting estuaries, rivers and lakes. It has been found up to 1,750 miles (2800 km) up the Mississippi River in the USA..

Could be this one maybe?

Bull Shark

[rmlew]

Could a Bull Shark get into the great lakes? it would have to swim up the Hudson (possible) and then take the Erie canal to Buffalo, and then get through the locks into the lake.
I doubt this could happen.

Frankly, I consider Bull Sharks far skarier than Great Whites. Unlike Great Whites, Bulls hunt in relatively shallow and murky water, where people swim.
They also go into rivers and ponds. (I'm pretty sure I say one in the bay in Southampton NY. (that would have done wonders for teh multi-million dollar waterfront estates.) No one believed me.