A New Zealand fisherman was left baffled when he pulled in a completely see-through shrimp-like creature off Northland's east coast.

Stewart Fraser told the MailOnline he was fishing about 70km off the Karikari Peninsula with his two sons when he spotted the translucent creature floating near the surface.

"I was in two minds whether to haul it in, but curiosity got the better of me and I decided to take a closer look," he said.

"It felt scaly and was quite firm, almost jelly-like, and you couldn't see anything inside aside from this orange little blob inside it."


He said it was like nothing he had ever seen before and had no idea what it could be.

Niwa's primary scientist for biodiversity and biosecurity Dennis Gordon said the creature was a type of salp, which moves through the ocean by contracting and pumping water through its gelatinous body.

Salps played an important role in the food chain because they were able to feed on the smallest organism which were captured in internal filters.

"They can eat the smallest plant plankton and can even eat bacteria so they can exist in parts of the ocean where nothing else can live. The significance of that is they are an intermediary in the food chain,'' Dr Gordon said.

They were also an important food source for some fish, sea turtles and seals, and were far more nutritious than jellyfish.

They were not as rare as one might think and had an amazingly rapid reproductive rate - some salps could double their population in just a day.

However they were not often spotted because of their highly-effective camouflage.

"Their transparency is quite remarkable,'' Dr Gordon said.

The creature Mr Fraser pulled up was about as big as they got.