Sea snakes in Northland waters

It's not just sharks that patrol our waters in the summer months - highly venomous sea snakes can also be found in Northland 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.

While all sea snakes are poisonous, Niwa says they generally require a lot of provocation before they will bite, and as their mouths are small and their fangs are set well back it is hard for them to bite a human.

Most of the recorded sightings of the snake in New Zealand waters are in the north east of North Island, however they are occasionally spotted as far south as Cook Strait.

Other tropical marine animals that venture into New Zealand waters during the warmer months are sea turtles and dolphin fish.

Five types of sea turtles venture south: the leatherback turtle, which is the largest, loggerhead turtle, the green turtle, the hawksbill turtle, and the olive ridley turtle.