by Janet Krenn
Talk to any of the five interns at Virginia Tech’s Seafood Agricultural Research and Extension Center (VSAREC) in the days leading up to the cobia larval run, and the word that you’ll hear is intense. Or as Hannah Mark, a second-year student at Dalhousie University in Canada, puts it: “I’m equal parts excited and terrified.”
The larval run marked the end of this summer’s international marine aquaculture internship offered by Virginia Sea Grant Extension at VSAREC. The internship program has trained (and terrified) about six interns annually since 2004 and is just one of the ways VSAREC leads the global development of safe, profitable aquaculture.
The larval run is a process in which fish hatch and are gradually coaxed into eating pellet food. This is essential to making finfish aquaculture profitable. Pellets cost less than live algae or feeder fish and can be conveniently stored on a shelf. But it takes a lot of effort to convince a carnivorous baby cobia to accept a pellet diet.
For the first two weeks of life, the aquacultured cobia eat live microscopic animals called rotifers and artemia. They’re fed four times per day—every six hours. Starting on day 15, the cobia get three servings of pellets at each feeding, spaced out over 45 minutes, followed by one serving of live food 15 minutes later. The idea is that offering the pellets at the beginning of a feeding, when the little fish are hungriest, will encourage them to give pellets a try.
This schedule goes on for nine days, and then things get busier. Feedings stretch out to three hours each, with pellets offered at 30-minute intervals followed by a daily decreasing amount of live food until the cobia are completely dependent on pellets.
Fine-Tuning the Run
This around-the-clock intensive feeding process makes the cobia run feel more like a cobia marathon. But Steve Urick, VSAREC’s Hatchery Manager says the schedule is essential to successful cobia aquaculture.
“It’s like somebody offering a person lobster and filet mignon everyday—wonderful and beautiful foods. Then they take it away and say, ‘You’re going to have to eat cornflakes the rest of your life,’” he explains.
In a commercial hatchery, the fish continue on their pellet diet until they reach fingerling length, about two to three inches. Then the hatchery sells them to another business that raises the fish to market size. Ideally, hatcheries follow tested and proven guidelines for the weaning process that produce enough fingerlings to turn a profit.
For newer aquaculture species like cobia, these guidelines still need fine-tuning. Currently, about six fingerlings per liter of water survive the weaning stage. In contrast, established aquaculture species survive in much greater numbers. About 60 flounder fingerlings per liter make it through weaning and as many as 150 seabass fingerlings per liter.
“We actually have some of the best cobia numbers in the industry, but there’s still a long way to go,” says Mike Schwarz, VSAREC Aquaculture Extension Specialist. When it comes to international aquaculture, Schwarz is a key figure. Not only did he found VSAREC’s international internship program, but this fall, he also became President-Elect of the World Aquaculture Society.
Safe Aquaculture at Home and Abroad
Schwarz and the VSAREC team see international collaboration as the way to raise the bar on seafood production and safety today while advancing the industry of tomorrow.
“Through international collaboration, we get to share information with other laboratories and learn more together than we can by ourselves,” says Schwarz. “It’s already rapidly accelerated our research and extension efforts because we’re not duplicating effort; we’re learning from it.”
The cobia larval runs conducted at VSAREC are just one piece of a national push to increase domestic aquaculture and close the seafood trade deficit. Currently, at $10 billion annually, seafood imports are second only to petroleum. Half of seafood imports come from aquaculture. So in the meantime, keeping imports safe is an equally pressing priority.
To help address international seafood safety, the VSAREC staff has teamed up with the U.S. Food and Drug Administration’s Train-the-Trainer program. The program sends seafood experts around the world to teach best aquaculture practices that reduce disease and minimize the need for antibiotics. Currently, the program focuses on America’s number one seafood import—shrimp.
Schwarz and Mike Jahncke, VSAREC Director and an expert in food safety, have helped lead trainings in seven countries to date. Already, Jahncke sees evidence that the program is working.
In 2009, buyers from the European Union detected the presence of antibiotics in freshwater shrimp from Bangladesh. To head off the problem and avoid getting banned from the EU market, Bangladesh opted to stop exporting shrimp to the EU for six months while working to eliminate the use of these antibiotics.
To keep its future shrimp products safe, Bangladesh hosted Train-the-Trainer workshops on good aquaculture practices in 2009, 2010, and 2011. In 2011, scientists from Bangladesh came to the United States for advanced training. These trainings seem to have had a lasting impact on aquaculture in that country, Jahncke says, noting that a few Bangladeshi universities have incorporated the Train-the-Trainer program content into their course offerings.
“I was very impressed with how Bangladesh took this and ran with it,” Jahncke says.
Training for the Future
Back in the VSAREC hatchery, Amandene Lecrenais is admittedly exhausted on day 21 of the larval run, but she has no regrets. Lecrenais, an intern from France, learned a little bit about rearing larval cobia when she worked with adult cobia during an internship in Madagascar. At the time, the facility didn’t have the capacity to have a run.
“It’s important for me to learn this process,” she says. She believes that between her work with larval and adult cobia, she’ll have the well-rounded experience needed to give her a leg-up when she starts job hunting. But for Lecrenais, these experiences will be the gateway to more than just a career. She sees it as an opportunity to contribute to global society.
“I think aquaculture’s the future of food production,” she says, “and I want to be in on that.”
