Pictures: "Supergiant," Shrimp-Like Beasts Found in Deep Sea

Catch of the Day

Photograph courtesy Oceanlab, University of Aberdeen

Members of the marine expedition hold up a few of the supergiant amphipods recovered from the abyss. (From left to right: Toyo Fujii, Alan Jamieson, and Ashley Rowden.)

The team has probed the depths of other deep-sea trenches around the Earth, but only the Kermadec Trench is known to harbor the huge crustaceans.

"We can't think of any one factor that would make these amphipods so much larger than amphipods in other trenches," Jamieson said. "It's a mystery."

Adding to the mystery is the animals' elusiveness.

"The weirdest thing was, on some spare days at the end of expedition, we went back to the same spot but never caught any or saw any on our camera," he said. "We caught seven in eight hours on the first day, then they completely disappeared."

(Related: "Giant Shrimplike Predator Was a Weakling After All.")

Published February 6, 2012

Belly of the Beast

Photograph courtesy Oceanlab, University of Aberdeen

Like other amphipods, the supergiant variety seems to be a scavenger that's highly attracted to any decaying flesh that sinks to the ocean bottom.

"They have an incredible sense of smell. If there's dead or decomposing tissue around, they'll pick up the plume [of scent], swim upstream, and start feeding," Jamieson said.

Also in their armory: crushing mandibles that help the amphipods tear off and gorge on chunks of dead flesh.

(Related: "Three-Foot 'Shrimp' Had More Than 30,000 Lenses Per Eye?")

Published February 6, 2012

Supergiant Appetite

Photograph courtesy Oceanlab, University of Aberdeen

Competition for any food that falls into a deep-sea trench is fierce.

To survive, amphipods stuff themselves silly at every opportunity. "Their gut is incredibly expandable. Food is so limited down there, they'll eat absolutely ridiculous amounts," Jamieson said.

"Some amphipods are adapted to extremely long periods of starvation—perhaps a year."

(Related pictures: "Surprising Creatures Found Deep off Australia.")

Published February 6, 2012

Elusive Snailfish

Photograph courtesy Oceanlab, University of Aberdeen

The supergiant species of amphipods wasn't a wish-list item on the expedition, as no one knew they existed until now.

The marine scientists' top quarry—shown here munching on a decaying mackerel about 4.7 miles (7.5 kilometers) deep in the Kermadec Trench—was a species of snailfish not spotted in the region since the 1950s.

"It doesn't matter which trench you're at in the world, you'll find quite a dense population of snailfish," Jamieson said. "They always find some ecological niche halfway down the walls of a trench and thrive."

(Also see "New Deep-Sea Pictures: Snailfish, Eels Found in Trench.")

Published February 6, 2012

Simple Trap for a Supergiant

Photograph courtesy Oceanlab, University of Aberdeen

You can't be too picky about what you haul up from the depths in a trap like this. Once a hunk of bait is inside and it's dropped into the water, it's first come, first served—and amphipods almost always turn out in the largest numbers.

Jamieson and his team are gathering genetic data from amphipods recovered in deep-sea trenches around the world to understand how they're related and how far they can travel. So far, the team's results suggest the creatures—against all odds—can travel thousands of miles to reach another trench.

"There is some kind of gene flow going on, so there must be a mechanism by which they can spread around," Jamieson said.

"It must be [in the] egg phase, where they float then sink back down," he said. "I just can't picture one of these amphipods going from point A to point B any other way. It'd be like a cockroach walking from one end of New Zealand to the other."

More: "Life Is Found Thriving at Ocean's Deepest Point" >>

Published February 6, 2012