October 7, 2008

Researchers Catch Deepest Ever Living Fish On Film

Scientists say they may have discovered the "deepest ever" living fish.

The 17-strong shoal were found by a UK-Japan team at depths of 7.7km (4.8 miles) in the Japan Trench in the Pacific where they were able to capture them on film.

The catch was made using remote-operated landers designed to withstand immense pressures to comb the world's deepest depths for marine life.

The 30cm-long (12in), deep-sea fish were surprisingly "cute", according to Monty Priede from the University of Aberdeen said.

The fish, known as Pseudoliparis amblystomopsis, can be seen darting about in the darkness of the depths, scooping up shrimp.

"It was an honor to see these fish," said Alan Jamieson, from the University of Aberdeen.

"No-one has ever seen fish alive at these depths before - you just never know what you are going to see when you get down there."

The Abyssobrotula galatheae holds the deepest record for any caught fish when it was pulled from the bottom of the Puerto Rico Trench at a depth of more than 8km (5 miles) in 1970. However, it was dead by the time it reached the surface.

The previous record for any fish to have been spotted alive was thought to have stood at about 7km (4 miles).

Started in 2007, the Hadeep project is a collaboration between the University of Aberdeen's Oceanlab and the University of Tokyo's Ocean Research Institute (Ori) and aims to expand our knowledge of biology in the deepest depths of the ocean.

The Nippon Foundation and the Natural Environment Research Council (Nerc) funded the project.

The team had been exploring the Hadal zone - the area of ocean that sits between 6,000 and 11,000m (20,000-36,000ft). It consists of very narrow trench systems, most of which are found around the Pacific Rim.

Using specially designed remote operated vehicles that are fitted with cameras, the researchers are able to better explore the trenches.

"There is the question of how do animals live at all at these kinds of depths," said Professor Priede, director of Oceanlab.

"There are three problems: the first is food supply, which is very remote and has to come from 8km (5 miles) above.

"There is very high pressure - they have to have all sorts of physiological modifications, mainly at the molecular level.

"And the third problem is that these deep trenches are in effect small islands in the wide abyss and there is a question of whether these trenches are big enough to support thriving endemic populations."

But Professor Priede said this species appears to have overcome these issues.

"We have spotted these creatures at depths of 7,703m (25,272ft) - and we have actually found a massive group of them.

"And this video is pretty tantalizing - the fact that there are 17 of them implies that they could well be a family group, begging the question of whether some form of parental care exists for these fish."

The researchers were surprised by the fish's behavior.

"We certainly thought, deep down, fish would be relatively inactive, saving energy as much as possible, and so on," Professor Priede told BBC News.

"But when you see the video, the fish are rushing around, feeding accurately, snapping at prey coming past."

Thriving in complete darkness, the fish use vibration receptors on their snouts to navigate the ocean depths and to locate food.

"Nobody has seen fish alive before at these depths - only pickled in museums - and by the time they come up from the depths they look in a pretty sorry state," Priede added.

"But these fish are actually very cute."

Alan Jamieson said he thinks the team would find more fish during their next expedition in March 2009, which would probe the ocean between depths of 6,000m and 9,000m.

"Nobody has really been able to look at these depths before - I think we will see some fish living much deeper."


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