A regular Source column, Undercurrents explores issues, ideas and events developing beneath the surface in the Virgin Islands community. This is the second of two parts.
It’s not quite time yet to throw the confetti, but something worth celebrating is stirring in Virgin Islands waters.
People who have been watching and hoping for the return of the popular Nassau Grouper are seeing signs that the species is making a comeback. That would be good news for fishermen and consumers.
And there might even be a bonus, since there’s some preliminary evidence indicating that the big fish could eventually help keep the invasive lionfish in check.
The Nassau Grouper was overfished throughout most of the Caribbean decades ago. It pretty much disappeared from Virgin Islands waters in the 1980s, according to Richard Nemeth, a fisheries biologist with the University of the Virgin Islands Center for Marine and Environmental Studies. In 1993, the federal government put a ban on fishing for them and the Virgin Islands government followed suit in 2006.
The ban seems to be working. Nemeth and Howard Forbes, Jr., coordinator of the Virgin Islands Marine Advisory Service, said very young Nassau Groupers are being sighted in large numbers. They made their first appearance last July and August.
They are “scattered around St. Thomas,” Forbes said.
“Just in Brewers Bay we counted 60,” Nemeth said.
The fish start life in shallow water, close to shore, and are so small that they are hard to see. They remain in the shallows, feeding and growing for two or three years and then move to deeper waters. Typically, they’ll become mature enough to reproduce at the age of five or six and by then they could be living as deep as 200 feet below the surface.
Eventually they grow to be one of the largest of the grouper family, weighing about 55 pounds with a length of nearly four feet. They have a relatively long normal life span, 20 years, and tend to be loners. Except that once a year, at the full moon during two or three months, they get together at so-called aggregate sites for mating and spawning.
It was that behavior that made them vulnerable. Once fishermen had the equipment to find the aggregate sites in deep water, it was easy to make an enormous catch a couple times each year and pretty soon the population was decimated – with negative consequences both for the fishing industry and for the ecosystem throughout the region.
In response, some islands closed aggregate sites during spawning season; some closed them permanently and some banned taking Nassau Grouper anytime or anywhere.
The recent sightings aren’t the only hopeful sign of a return in Virgin Islands waters.
In 2005 Nemeth discovered a small aggregate site that was closed the next year. “In 2006 we had a big pulse of baby Nassau,” he said. And in the last 10 years, researchers think some 300 to 400 of the fish have taken up residence on the Grammanik Bank, near the aggregate site.
“It’s kind of a critical time right now” for the current mass of young fish, Nemeth said. As they begin to make their way to deeper water, they may draw attention from human predators. The ban is still in place, but he worries that some people may not be aware of it and some may not even know that the fish they are seeing is endangered.
There’s also the times when fishermen accidentally catch Nassau while they’re fishing for other things.
And so, the “Bring Back the Nassau” campaign has started. Researchers and ecologists are enlisting the aid of sport and commercial fishermen in protecting the Nassau Grouper, and distributing small science kits to help in the effort.
The kits contain a hypodermic needle and a barbless hook with a weight attached to it.
“The air bladder expands” when a fish is brought rapidly to the surface from deep water, Nemeth said and it becomes buoyant. So you can’t just throw it back in the water and expect it to survive. “You have to get the fish back down.”
One method is to deflate the bladder by piercing the fish with the hypodermic. The other is to attach the weighted barbless hook on its lower jaw, throw it back and then pull out the hook once the fish is at the bottom.
“We want to make it as easy as possible” for fishermen to help in the recovery effort, Nemeth said.
He’d also like to see the Virgin Islands do more education. In Bermuda, for instance, there are signs on all the public beaches listing regulations covering various types of marine life.
“It’s very effective,” he said.
The return of the Nassau would not just be a boon for commercial and sports fishing. It could help in the control of the invasive lionfish that has started to crowd out indigenous species in part because it has no natural predator in the Caribbean.
“This could be a real positive thing,” Nemeth said. “The larger groupers have been found to have lionfish in their stomachs.”
It’s not always clear whether the grouper actually hunted the lionfish themselves or ate them after they had been killed by human divers trying to keep down the numbers of lionfish.
However, there’s at least one documented case – on video – of a Nassau Grouper hunting and eating a lionfish.
Frank Cummings, education and outreach director for the Caribbean Oceanic Restoration and Education Foundation, which is leading the charge against the lionfish, noted that it could be a long time before one or two groupers hunting lionfish turns into regular species behavior.
“It’ll be on a timescale that human beings are impatient with,” Cummings predicted.
“It is happening naturally, but slowly, in the wild,” Nemeth said.