It's not just sharks that patrol our waters in the summer months - highly venomous sea snakes can also be found in New Zealand waters.
The Yellow-bellied sea snake, Pelamis platurus, is usually found in warm waters, but regularly washes up on North Island beaches, Niwa principal scientist Dr Malcolm Francis says.
"They live near the surface, hang around with logs and drifting seaweed, and feed on the fish that aggregate in those areas," Dr Francis says.
The snake, a relative of the cobra, has a pair of fangs that inject venom into its victim.
After biting its fish prey, the snake will eat its head first. It has four teeth that hold the prey in place as it swallows it.