Your window of time to catch gag grouper in the Gulf has been shrinking for years. It's a way to help the species bounce back from being overfished.
Warming waters have also been making the difficult task of rebuilding the fish stock even harder.
Now, a new tool is helping wildlife officials set lengths for fishing seasons to prevent anglers from exceeding the allowable catch limit.
Managing a popular catch
Gag grouper is a brownish-gray reef fish with dark worm-like markings on its sides. The mild-taste makes it a popular catch.
It’s been so popular that in 2009, the National Oceanic and Atmospheric Administration declared the Gulf species overfished — meaning it fell below the sustainable threshold.
In 2014, the stock was back up only to fall again by 2021.
Gag grouper has been called a “poster child” for the challenges of recovering an exploited fish stock.
Challen Hyman is a researcher at the University of South Florida College of Marine Science in partnership with the Florida Fish and Wildlife Conservation Commission.
He said there's no way to manage the number of people fishing in the Gulf.
"But we can set recreational season limits," he said.
Fishing season lengths have traditionally been determined by calculating past catch averages.
Anglers used to have six months to hook them back in the day. It then went down to 41 days in 2023, 15 days in 2024, and 14 days last year.
The years of shrinking fishing seasons backfired, though. Turns out, the shortened timeframe put pressure on anglers to get on the water more often.
"People are concentrating their behavior. They're changing their behavior in light of these different regulations," Hyman said.
They were still catching more than the quota allowed to keep the population healthy.
Climate change and fewer males
Gag grouper fish are hermaphrodites, born female in seagrasses and estuaries, like Tampa Bay, before moving offshore and transitioning into males with age. The largest gag are often males.
So, scientists say having a robust age structure within the population, which supports a healthy male population, is critical.
An assessment in 2014 predicted 2% to 3% of the Gulf population was male, down from 17% historically.
“Two percent male is not a healthy population, by any standard, in any other species, terrestrial or marine,” UF/IFAS marine fisheries ecology research professor Susan Lowerre-Barbiei told the nonprofit Ocean Conservancy.
It can take nearly a decade for a gag fish to maybe transition to male.
“That means that a large number of fish need to be allowed to get old. High discard rates and impacts from climate change mean that not many fish are getting old enough for the population to reproduce,” said Catherine Bruger, fish conservation manager for the Ocean Conservancy.
She said on the organization’s website that she thinks fisheries managers should consider the climate vulnerability of fish stocks when making decisions.
“Gag grouper are highly vulnerable to climate change, meaning that they are expected to be highly susceptible to the impacts of climate-driven environmental changes, yet managers haven’t quite figured out how to account for this climate vulnerability with proactive management,” she said.
“The good news for gag grouper in the Gulf of Mexico is that scientists and fishermen are reporting a lot of small fish. If we can take actions to ensure that more of these young fish survive and mature into adults so they can reproduce, these actions could help rebuild the fishery in the future," she added.
A tool to prevent overfishing
Challen Hyman and his colleagues created a statistical model that includes angler behavior as a factor in predicting the probability of exceeding fishing quotas.
“We tested it against the traditional methods of using past averages, and we found that it performed quite a bit better, especially when you have drastic changes in season regulations,” he said.
The tool used data gathered since 2015, like the length of seasons and whether it was simultaneous with seasons for other highly desired species.
“There were seasonal variables … so you had higher concentrations of people going out fishing in summer months than in fall and winter, when things were a little bit cooler,” he added.
“And then on top of that, the biggest variable we found was that change in angler behavior when you had shorter seasons, there were overall, on average, higher harvest rates," he said.
The computer model predicted that anglers had a 50% probability of hitting the 2025 annual catch target in 12 days.
And looks like it worked for the 2025 season, which was 14 days.
"So far, preliminary data has indicated that we are for the first year in several years under the quota," he said.
The researchers hope to eventually use this method for other overfished species, like red snapper.
Their work has been peer-reviewed and published in the North American Journal of Fisheries Management.
