Sea urchin - By: Marco Busdraghi

The coral reefs off of Hawaii are being smothered by tons of algae, and efforts have been made to help solve this dilemma. The answer comes from an unlikely source.. Sea Urchins. Sea urchins, commonly known as the “cows of the sea”, are being used along side a new underwater vacuuming system aptly named the “Super Sucker” in an attempt to finally start getting the algae off the reef and get them healthy again.

Researchers from the state Department of Land and Natural Resources Division of Aquatic Resources are pleased to announce that the project has been a success, as it has been using sea urchins alongside the Super Sucker for the past year in Kaneohe Bay.

“It exceeded our exectations,” Tony Montgomery, a state aquatic biologist commented. “It actually worked better than we thought.”

The project began in August of last year, where divers were manually removing the offending algae from the reef. Once harvested, the algae was then sucked up using the super sucker.. On another part of the reef however, a bunch of sea urchins were left to do their business. The results were that these cows of the sea were quite the eating machines. While the project is being deemed a success there is still a lot of algae to be removed, and Montgomery is remaining casually optimistic. “We will see how they do with thousands of pounds of algae to eat,” He said.

Genetic pattern analysis strongly suggests that California and British Columbia urchins are not connected via larval dispersal and comprise two distinct populations. Sea urchins have one of the longest larval periods of any known marine invertebrate and it has therefore been tempting to assume that ocean currents must be mixing urchin larvae all over the place, making it difficult for any distinct populations to form. But research results from the University of California now indicate that these two Pacific populations are two clearly separated ones.

Sea urchins –  Picture from the Red Sea

Together with former* graduate student Celeste Benham, marine biology professor Ron Burton of the University of California at San Diego have analyzed 500 adult sea urchins from Californian waters across five microsatellite markers and then compared the genetic patterns to an existing, similar database of 1,400 urchins from British Columbia. The Californian specimens were collected off the coast of San Diego, Los Angeles and Mendocino counties.

The genetic signatures found by Burton and Benham strongly suggest that the southern and northern populations are not connected via larval dispersal.

“From my evolutionary perspective, our results are important because they imply that, even on long time scales, there is no mixing, Burton explains. This means there is at least the potential for populations to adapt to different ocean conditions and gradually diverge. This is the first step in the two populations potentially becoming different species.”

This is the first time scientists have detected any population structure in the species. Similar studies carried out in the past have used fewer genetic markers and found no population genetics structure in the species despite having tested many different patches across its range.

“The take-home message of this study is that if you use more markers and newer techniques you will find some population differentiation that before nobody found,” says Burton.

* Benham is now a research assistant at the marine mammal laboratory at Hubbs-SeaWorld Research Institute in San Diego.