Rare deep-water fish caught for first time in 60 years

APNZ·

5 Mar, 2014 06:50 AM2 mins to read

This hadal snail fish was caught in a trap at a depth of 7000m in the Kermadec Trench. It is the first time this species has been caught in more than 60 years. Photo / University of Aberdeen

A set of rare, slimy deep-water creatures, last caught more than 60 years ago, have been fished up in New Zealand waters.

The five hadal snail fish were caught in the Kermadec Trench during a special research mission between Niwa and Scotland's University of Aberdeen.

The fish are the second deepest fish ever seen alive and have been caught only once before. They were now being analysed at Niwa's Wellington laboratories.

Marine ecologist Dr Ashley Rowden said capturing the fish required a lot of skill.

"It's pretty tricky at that depth. A lot of effort went into it."

The snail fish were caught by deploying baited traps. The bait lured in small organisms, which attracted the fish. Cameras were also deployed so video and still photos of the fish and other trench-dwelling organisms could be taken.

They were also observed at 7500m, scientists said.

Dr Alan Jamieson of the University of Aberdeen said they wanted to use the trip to examine the biochemistry of fish living in deep water.

Scientists paid particular attention to the presence of a compound - trimethylamine oxide (TMAO) - in fish because it indicated the depths which they inhabited.

Levels of TMAO in the Kermadec snail fish at 7000m were the highest ever recorded. Combined with previous data, researchers determined that the maximum depth a bony fish could survive was 8200m.

As a result, the deepest 25 per cent of the ocean - between 8200m and 11,000m - have been deemed uninhabitable for fish by scientists.

The findings around the research were published in the US scientific journal Proceedings of the National Academy of Sciences earlier this week.