Supergiant crustacean found in New Zealand trench

By: Duncan Geere

Down in the depths of the oceans, sea creatures can grow to alarming sizes. In a trench off the coast of New Zealand, a crustacean has been found that’s 10 times larger than its regular-sized cousins.

The 34cm-long amphipod was found at a depth of around 7km in the Kermadec Trench, which lies between New Zealand’s North Island and Fiji. It was discovered by a team led by University of Aberdeen marine biologist Alan Jamieson, who told in an email: “We weren’t actually looking for them. We were after one of the deepest living fish, which we did actually get but the surprise of the supergiants kind of overshadowed that.”

That deepest living fish is a type ofSnailfish — notoliparis kermadecensis. Only one specimen of the species had ever been caught, in 1952, so the team were using a cage baited with mackerel chunks to collect more. The cage is dropped into the depths, and then releases its weights after 12 hours and floats back to the surface. When it came up, the team were pleased to see that they’d found the fish — but also flabbergasted to see several of the enormous amphipods.

Little is known about the creatures, but Jamieson says that they’re likely to be scavengers. “This means they rely on material raining from the surface waters to feed.  If a fish dies in the surface and isn’t eaten straight away then it will hit the seafloor irrespective of depth and species such as these consume them.”

The next task for the team is to try and solve the mystery of why the creatures grow so large. “That’s the million dollar question,” says Jamieson. “There are literally hundreds of species of amphipods that inhabit the same depths and environmental conditions as these yet none of them grow to anywhere near the same size as the supergiants.”

Edited by: Nate Lanxon

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