Warming seas, invading king crabs, bad news for life that evolved without them

Good news for crab lovers, bad news for less robust critters like sea lilies, brittle stars, asteroids and sea urchins.

(Image: The invasive king crab, Neolithodes yaldwyni, from the Antarctic shelf waters. It’s similar looking and is related, but is a different genus and species from the Alaskan or red king crab, Paralithodes camtschaticus. Photo courtesy University of Hawai’i.)

University of Hawai’i oceanography professor Craig Smith is part of a team that found that king crabs have invaded across the West Antarctica continental shelf and now inhabit the Palmer Deep along the west Antarctic Pensinsula. Their paper on the subject is here.

And lots of creatures that should be there, aren’t.

“This is a very interesting discovery for several reasons,” Smith said

“First, it provides evidence that king crabs can now disperse across the Antarctic shelf, and reproduce in at least some Antarctic shelf waters. It also suggests that these predatory king crabs will cause a major reduction on seafloor biodiversity as they invade Antarctic habitats because they appear to be eating all the echinoderms in the Palmer Deep.”

Smith recently joined researchers from Duke University, Ghent University, Hamilton College and Lamont-Doherty Earth Observatory in Antarctica. They used a remotely operated vehicle (ROV) to inspect the seafloor life in the area. They found that a king crab species called Neolithodes yaldwyni is dramatically altering the ecosystem.

The result is the demise of a whole ecosystem that had developed in the absence of crushing predators like big crabs. Echinoderms like the stars and urchins are common in most of the Antarctic ocean, but they’re not now found in the parts of the Palmer Deep where the king crabs are found.

The researchers believe the rapid pace of ocean warming has allowed the crabs to move into the new habitat, where they dig into oceanfloor sediments and feed on seafloor animals there.

Smith and the team said they believe the continued warming will allow the king crabs to further expand their range within as little as 20 years at the expense of the native creatures that compose Antarctica’s unique seafloor animal life. The team hopes to use genetic tests to track the continuing colonization of the crabs.

Their research has been funded by the National Science Foundation and the Special Research Fund of Ghent University.

The University of Hawai’i release on the issue is here.

More images and story here.

© Jan TenBruggencate 2011