Researchers refine spawning of sea cucumber

From the Daily Newsminer: Researchers refine spawning of sea cucumber
KENAI, Alaska - They weren't completely surprised.

It had been three days and the researchers at the Alutiiq Pride Shellfish Hatchery in Seward had seen signs they were close to their goal.

The male red sea cucumbers were spawning already, induced by water, light and temperature manipulations conducted by Charlotte Regula-Whitefield and hatchery director Jeff Hetrick.

"It's a gradual process - usually a male will spawn first, then you know you've kind of got them ready and then another male will go," Hetrick said.

However, the female was finicky, seemingly blocking Regula-Whitefield's efforts to do what few could before - achieve a successful spawn of red sea cucumbers in captivity. But based on previous research, Hetrick knew it was the right time of the year for the animals to feel the urge to spawn. The hatchery's inducing factors just hadn't been quite right.

However, on June 14, the females got comfortable enough with the conditions Regula-Whitefield created and a breakthrough was achieved with the release of egg and sperm.

"It was exciting," Regula-Whitefield said. "I was kind of surprised - I wasn't expecting to get it to work so quickly."

The first spawn of the sea cucumbers produced 10,000 juveniles and Hetrick expects the second spawn to produce more than 100,000.

"In northern climates, to my knowledge, no one has been near as successful as this," he said.

"I can't say we are doing cartwheels up and down the hallway, but sure, this is a three-year effort in the making," he continued. "I am extremely pleased we had a controlled spawn and multiple ones and that those larva had set."

The hatchery is the only one of its kind in Alaska and has a component dedicated to performing research on new species in addition to regular work with geoducks, razor clams, red and blue crabs and others.

Hetrick and staff have been looking into sea cucumber spawning for several years with the support of the Southeast Alaska Regional Dive Fisheries Association.

"They have commercial diving on mostly geoducks and sea cucumbers," Hetrick explained. "They are looking at the possibility of enhancing some of the populations because, like all things, they are concerned about the diminishing resource."

Phil Doherty, executive director of SARDFA, said last month's spawning breakthrough gives the association a bit of hope for long-term enhancement ideas for the multi-million dollar sea cucumber fishery.

"We are putting our money where our mouth is," he said. "We are interested in sea cucumber enhancement and we think it can work and we realize we are in the very, very early stage of this. This is not like a salmon hatchery...this is all brand new stuff. No one has done this before."

The reasons such a spawn hadn't been achieved before was because shipping the animals often caused damage to their health.

"They have a peculiar response to stress , which is called evisceration where they basically extrude all their internal organs and they have to recover from the shipping stress and make it on to be reproductive or even live," Hetrick said.

Regula-Whitefield, a University of Alaska Fairbanks graduate student and Ph.D. candidate, took the sea cucumber spawning efforts at the hatchery from a side project to a full-scale effort, Hetrick said.

The researchers credit both the healthy sea cucumbers they received and their accurate mimicry of natural environments for the success of the first and subsequent spawns.

Regula-Whitefield can now achieve fertilization of more than 90 percent of red sea cucumber eggs without killing the adults, which differs from previous captive fertilization - or strip spawning - efforts that required killing the brood stock and did not achieve high rates of fertilization.

She has segregated groups of larvae to study the effects of varying types of feed and thinks it would take 4 to 6 years for sea cucumbers to reach adult size.

The research is a blend of production science - seeing how many they can make at what cost and how healthy they can keep the animals - and research science - looking at their diets and other life activity.

"We'll be able to learn things like how fast they grow, what kind of manufactured or artificial diets that may or may not work and just see if we can make juvenile sea cucumbers," Hetrick said.

The sea cucumber has been studied since the mid-1970s, but there wasn't a reliable way to get them to spawn for research purposes.

"There hasn't been any motivation for the production of sea cucumbers," Hetrick said. "There has been some attempts in labs that has been done by researchers for different things but nothing to the scale that would be applicable to what we are doing."

The Alaska sea cucumber fishery - prevalent in Southeast - started in the mid-1980s.

The fishery has grown in its brief history . In its opening season, seven divers harvested 34,043 pounds at an estimated ex-vessel value of $7,149 in 1986, according to the Alaska Department of Fish and Game.

Now, according to statistics, 169 divers harvested 1.6 million pounds for an estimated value of $3.7 million during the 2009 season.

"Apparently there are some things that are unique about Alaskan (sea cucumbers) that the buyers like and exactly what that is, I'm not sure," Hetrick said.

Doherty said the market for sea cucumbers has improved over the last several years with a ballooning demand internationally. Fishermen in Puget Sound are currently seeing $4.25 per pound for cucumbers, but that price might not hit Alaska due to added operational costs, he said.

In addition to being considered luxury food items in the Orient - the skin is dried and used in soups, the meat cut up and added to sushi - other extracts from the animal have uses in the pharmaceutical, cosmetic and medical fields, Doherty said.

In some areas, the sea cucumber population has remained fairly stable, Doherty said, but other areas have shown decline and some have shown enough reductions that fishermen don't fish them anymore.

However, the increasing population of sea otters and their appetite for the sea cucumber in Southeast has influenced some of those areas.

"There are areas we think we can go back into if we get this spawning in the hatchery (to happen) on a regular basis," Doherty said. "If you can grow out the juveniles and then transport them down here and start to enhance the wild population, then that's the long term goal. We are still a long ways a way from realizing that."

Scott Walker, an area biologist for the Department of Fish and Game's Ketchikan Commercial Fisheries Management Area, said the issue of enhancing the natural stock of sea cucumbers is a "very complex" one that's often discussed.

"There are real issues here," he said. "It is one of those things that potentially could happen if it happened to be in the right place. You can dump a bunch of sea cucumbers into an area at a small size and they could instantly be gobbled up by sea stars and not have a good grip on the bottom and not have enough food there. Or you could drop into an area and its very good cucumber habitat and there is very little predation and the temperatures and everything is just right and you do really well."

For now, Hetrick and Regula-Whitefield are still happy with their first breakthrough step.

"It is always exciting to do something like this especially with an animal like this because it is...completely out of our comfort zone," Hetrick said. "...You learn so much about animals in captivity that we don't know about otherwise in nature."