Triggerfish on rapid rebound

Published 12:00 am Wednesday, August 2, 2017

By David Rainer

Department of Conversation and Natural Resources

Plenty of red snapper, the Alabama Gulf Coast’s premier reef fish, crossed the scales at the 84th annual Alabama Deep Sea Fishing Rodeo (ADSFR) at Dauphin Island last weekend, but one reef species was conspicuously absent for the second year in a row.

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The gray triggerfish season is closed for all of 2017 because NOAA Fisheries determined that the recreational sector exceeded its quota for the past several years. Triggerfish recreational landings in the Gulf were estimated to be 422,436 pounds in 2016. The annual catch limit was 201,223 pounds.

If an annual catch limit is exceeded, then the following year’s annual catch limit must be reduced to account for the overage. Because the 2016 estimated triggerfish catch was double the annual catch limit, the payback clause in the regulations left the recreational sector with zero quota for 2017.

However, encouraging evidence indicates that triggerfish stocks may not be in the dire straits some suggest.

Dr. Sean Powers, head of the Marine Sciences Department at the University of South Alabama (USA) and one of the ADSFR judges, said the research work done with grants from the Alabama Marine Resources Division shows a resilient triggerfish population.

“We’ve been watching the stock and watching a couple of indices that we measure in state waters,” Powers said. “So, in 2015, it started showing an increase. By 2016, we had a tripling of the level, and so far this year, we expect that it’s just as high.”

Powers said two to four triggerfish are found on each of the reefs the USA research team studies. He said triggerfish will be a little higher in the water column and will eagerly take just about any bait dropped down in front of them.

A couple of weeks ago, several friends went snapper fishing and had to throw back numerous triggerfish before they hooked their first red snapper.

“Triggerfish and snapper are very aggressive,” he said. “Of the two, the triggerfish is going to be the most aggressive, so it makes sense that some anglers are dropping down and catching triggerfish on their red snapper spots.”

For the past eight-plus years, the USA Marine Sciences team has deployed an ROV (remotely operated vehicle) to explore the offshore reefs to determine what species inhabit the reefs and in what abundance.

“One of the reasons we use video is that video gives us an unbiased view of what’s going on on the reefs because of the competition for the bait,” Powers said. “We use catch data, but we also use the data from the remotely operated vehicles.”

Powers said he’s not sure exactly why the triggerfish population off the Alabama coast appears to be rebounding so quickly.

“I’m sure the catch limit had something to do with it, but it also may have been that our population of triggerfish off Alabama might have been healthier than what (NOAA Fisheries) expected,” he said. “Remember, the assessment is Gulf-wide. We focus our sampling off Alabama, and Alabama has terrific habitat (more than 15,000 artificial reefs) for reef fish out there.”

Another reason Powers is confident with their assessment of the triggerfish is the fish’s proclivity to remain close to structure, whether it’s artificial reefs, petroleum platforms or natural bottom.

“You’re not going to see triggerfish free-swimming away from the reefs,” he said. “You’ll see big red snapper free-swimming sometimes, but we’ve probably had 3,000 longline sets during our research, and we’ve never collected a gray triggerfish away from structure.”

Powers hopes NOAA Fisheries will use the data collected by the USA team and incorporate it into the management plan for triggerfish so at least there can be a season in 2018.

“I’m not sure what that catch limit might be, but hopefully we’ll get the return of the triggerfish season,” he said. “Triggerfish are out there. But that’s what you expect when you ease up fishing pressure with these reef fish populations. We see it with red snapper. We see it with gray triggerfish. They have the ability to rebound a lot quicker than most scientists thought a decade or two ago.

“The state has sponsored a large monitoring effort offshore since 2010 with the idea that it would help inform the federal models, but also give the states data if they ever get to manage their reef fish on their own. The thing about our data is that it is near real-time. We’ll be able to provide the data to the state by the end of that year. A lot of times with stock assessments, that data is two or three years old before they enter the model. A much more timely assessment can be done if you focus regionally, because the turnaround of the data is so much quicker.”

Recreational anglers and charter boat captains have reported catching huge triggerfish during red snapper trips this year, which is encouraging to Powers.

“That’s a great sign, because the larger ones are going to produce more eggs,” he said. “Our average size has also increased.”

Powers said there may be a connection between the availability of sargassum seaweed and survivability of the juvenile fish.

“Triggerfish are nest guarders,” he said. “The female will lay eggs in the mud or sand around the reef. Those eggs will hatch and float up in the water column. What they really need for protection is floating sargassum. Once they live in the sargassum for the first six months of their lives, then they’re going to recruit to the structure habitat. A lot of us think the ups and downs of the triggerfish fishery can probably be correlated to good and bad sargassum years.”

“The partnership with Dr. Powers and the University of South Alabama has been very rewarding,” said Acting Conservation Commissioner Chris Blankenship. “In 2010 when I became Marine Resources Division Director, my staff and I worked with Dr. Powers to formulate the research priorities that needed to be done to better assess the population of red snapper and other reef fish in our extensive artificial reef zones.  Now in our seventh year, we are really seeing dividends from his work. We are very fortunate to have a marine scientist of his caliber here in coastal Alabama.”

Some anglers have also posed the possibility that the triggerfish populations have suffered because the abundant red snapper are preying on triggerfish eggs and juvenile fish. Powers, however, said they don’t have the data to support that theory.

“We haven’t seen that in the snapper guts we have checked,” he said. “We’ve seen very few triggerfish or vermilion snapper in the red snapper gut contents. It’s been hypothesized that’s been occurring, but the data so far shows that is an infrequent occurrence.

“But, gut contents are just a snapshot in time. You really need to be out there when the vermilions or gray triggerfish really recruit heavily to see if they’re part of the prey. Given the gut contents we’ve collected, it doesn’t appear to pose a problem.”

However, another species does potentially pose a problem. When the ROV camera dropped down on reefs on a recent research trip, lionfish, an invasive species, were hanging tightly on the reefs. Lionfish only grow to about 18 inches, but they are very aggressive feeders that compete with the other reef species for prey.