When fisherman Patrick Melograna felt a tug on his line near Gladesville Bridge over the Parramatta River, he knew he was on to something big.

But the 2½-metre, 150-kilogram mako shark exceeded even his wildest expectations, and he took almost two hours to haul in the mammoth catch.

Mr Melograna, who was fishing for jewfish to celebrate his father's birthday, said he initially thought it was a bull shark.

"It was a team effort to bring this beast on board," Mr Melograna told local newspaper The Weekly Times.