Overharvest means changes coming to Louisiana’s blue-crab fishery

 
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June 10, 2016
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From Nola.com

By Todd Masson 

Most bays and tidal lakes in Louisiana these days look like obstacle courses, where the first boater to make it across without wrapping a crab-trap line in his prop wins. Hard to believe that less than half a century ago, the crab trap hadn't yet been invented. Now, they're more prevalent in state marshes than mosquitoes.

All those wire cages mean it's getting harder for female crabs to run the gauntlet and make it to the salty waters of the coast to lay their eggs. As a result, Louisiana has seen a concerning decline in its blue-crab population, according to Jeff Marx, a crustacean biologist with the Louisiana Department of Wildlife and Fisheries.

Marx has spent two of the last 10 days explaining to two different boards the challenges currently facing Louisiana's crab population. The first presentation was to the Louisiana Wildlife and Fisheries Commission, the regulatory board that ultimately will make decisions on how to attack the problem. The second was to the state's blue-crab task force, which serves as a policy liaison between the department and crabbers in the field.

Marx said it's clear something needs to be done. To obtain sustainability certification, department biologists put in two benchmarks to gauge the health of Louisiana's blue-crab population.

"We didn't have any benchmarks at all, so we set the fishing mortality benchmark at the highest spot ever seen previously because we knew (the population) could sustain that level of fishing," Marx said.

The agency also used the total biomass of all crabs in the wild as another benchmark, averaging together the three years with the lowest biomass in department sampling.

"We knew we didn't want to go below that," Marx said. "We took a percentage of those benchmarks, and called it our target, and we don't ever want to get out of that target area if we can avoid it."

But all those traps in the water 365 days a year made that impossible.

"The 2016 stock assessment we completed about a month ago showed we were close to the overfishing limit, which means our fishing mortality was very high, and the biomass was just below the limit, which is not good," Marx said.

That means for the crab population to remain sustainable, some management actions need to be taken, Marx said.

Predicting that this day would come, the department tried to avoid it by establishing the Louisiana Fisheries Forward program, which required crabbers entering the fishery to find a mentor who could train them before they could venture out on their own. The program, though, had a large grandfathering loophole that allowed more burgeoning crabbers to slip through than the department had hoped.

The department attempted to tighten that loophole this year as well as making the program itself more stringent, but the Louisiana Legislature wasn't on board.

"We took it all to the Legislature, and they didn't like limited-entry in any aspect, so it got shot down," Marx said. "That means we can probably take limited-entry out as a management tool for now."

The department considered, instead, imposing trap limits on licensed crabbers but ultimately decided against it because of logistical challenges.

"We could issue trap tags, but we can't ask our enforcement agents to go pick up every trap in the water," Marx said. "It's nearly impossible to enforce."

With limited-entry and trap limits off the table, the department opted to begin a push for its other remaining management tool: season closures.

As soon as the next commission meeting in July, Marx will present the regulatory board with a plan to close Louisiana's blue-crab fishery for 30 days beginning near the end of February.

Since that's generally the slowest crabbing season of the year, a closure at that time wouldn't devastate the industry, Marx said, but it would allow escapement of some important crabs.

"The ones that are harvested during March are called skinny crabs," he said. "They're not a good quality of crab, and the majority are immature female crabs at that point.

"If we can increase the chances for those females to get out and spawn, I think that's the way to go."

A regulated season closure would mimic what nature occasionally forces on the industry. Crabs have been hit hard in recent years, Marx said, because the fishers who pursue them haven't.

"We haven't had any sort of environmentally driven closures. We haven't had a big storm recently that closed down the fishery for a couple of weeks," he said. "Tropical storms do two things: They shut the fishery down for a while, and they also blow in a lot of (crabs) that could be offshore and unavailable to the fishery."

Also, Marx said, the lack of severe freezes in recent years means predator species like redfish and black drum have thrived and their populations have grown.

"Crabs have really taken a hit for most of the last 10 years," Marx said.

The exception to that, he pointed out, was in 2010 during the BP spill. Fishing mortality declined dramatically because crabbers were required to take their traps out of the water while oil was present and fisheries were closed.

In addition to the season closure, the department will also propose to the commission a ban on harvest of immature female crabs. When a female crab molts into her final, mature shell, the apron on her abdomen is wide and dome-shaped. Young, growing females have aprons that are triangular, which makes them easy to identify.

Fortunately, Marx said, no long-term damage has been done to the crab fishery. Crabs are short-lived creatures, with a lifespan of about three years. They're also extremely prolific. Females spawn multiple times from one mating session, and young crabs have a high survival rate.

After fishing pressure is reduced, it shouldn't take long for populations to rebound, Marx said.

"(Crabs) can almost be considered an annual crop, like shrimp," he said. "If you have a good set of weather conditions and environmental conditions, and you don't get a whole lot of predation, you can go from a bad crop to a great crop the very next year. We've seen that before."

Todd Masson can be reached at tmasson@nola.com or 504.232.3054. 

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