Pretty good article I read


Delaware’s state fish -- the weakfish -- is in trouble and the reason isn’t what you’d expect.
Anglers aren’t out there reeling in fish by the dozens. In fact, state and regional managers have ratcheted back so much on recreational catch limits that you can keep one, 13-inch fish a day -- if you can find one. Commercial guys aren’t catching them either. Last year, the total commercial landings in Delaware totaled about 50 pounds, said John Clark, the state fisheries environmental program manager.
Instead, fisheries managers believe natural mortality may be the reason adult weakfish populations -- once the bread and butter of both commercal and recreational anglers in Delaware Bay -- aren’t recovering and the numbers are falling even lower.
And now researchers at North Carolina State University are use acoustic trackers to try to figure out where adult weakfish go when they leave Delaware Bay in the fall and head south to North Carolina.

“We want to know where the fish are moving,” said Jacob Krause, a doctoral student at the university.

Late last month, Krause, assisted by a state fisheries biologist, used everything from hook and line to nets to find weakfish in Delaware Bay. The fish had to be at least 12-inches long to be used in this study because of the size of the acoustic transmitter. It is slightly smaller than a tube of lip balm.

While much of the research Krause is working on is North Carolina-based, it has important implications in Delaware, too.

Among the questions he and fellow researchers are trying to answer are movement rates and stock boundaries of weakfish in both Delaware and North Carolina; an estimate of seasonal and annual mortality rates for catch-legal sized weakfish in North Carolina and specific waterways there; to look at survival of weakfish in Delaware Bay and to study whether weakfish predators are eating these young adult fish. Among the predators: Atlantic bottlenose dolphin, striped bass and spiny dogfish.

Money for the research is coming from the North Carolina Marine Resources Fund from the sale of coastal recreational fishing licenses.


The Atlantic States Marine Fisheries Commission, the regional regulatory board that manages fish species from Maine to Florida, already estimates that natural mortality of weakfish is two to three times the level of fishing mortality.

The traditional method for helping fish populations to rebuild is by managing fisherman, said Timothy Targett, a professor at the University of Delaware College of Earth, Ocean and Environment. Targett, a fisheries biologist and ecologist, served from 1987 to 2009 on the Atlantic States Marine Fisheries Commission as they tackled the weakfish population decline.

“It’s been a challenge for fisheries managers,” he said. “Something is preventing it from recovering.”

And a huge issue is that “natural mortality is not something you can control,” he said.
Buy PhotoCameron Luck holds a weakfish that will be implanted with a acoustic tag by the North Carolina State University research team. (Photo: Molly Murray/The News Journal)


Meanwhile, he said, young-of-the year fish in Delaware Bay seem to be doing fine.

Clark agreed and said that Delaware biologists have tagged 8-inch long, year old fish.
These young-of-the-year fish “Are all in very good shape,” he said. “They are definitely getting plenty to eat.”
As for anglers catching those tagged fish in subsequent years when they were large enough to be keepers, “We don’t get any tags returned,” Clark said.

And that leaves the question of what happens between that first year of life and the second, when they should be showing up in Delaware Bay as bigger fish.


Clark said there could be a correlation between striped bass populations -- which until recently were on the rise -- and weakfish. On charts, as the stripers increase, the weakfish decline, he said.


Another factor could be a rise in the populations of Atlantic Bottlenose dolphins. As a protected marine mammal resource, dolphins could be a predator of weakfish that is little understood.


And there is a growing population of spiny dogfish in the bay and they are another potential predator, Clark said.

Weakfish numbers were relatively stable in the Delaware Bay for decades and then, in the 1970s and 1980s, the population exploded. Commercial fisherman landed thousands of pounds of the fish and recreation anglers filled coolers.
In 1981, the Greater Milford Chamber of Commerce and organizers of the local World Champion Weakfish Tournament, pushed state lawmakers to name the weakfish the official state fish.

But within a few years, the population crashed. Eventually, the tournament was discontinued. The Atlantic States fisheries
commission stepped in and came up with a management plan. The focus: cutting back on fishing pressure.

Clark said that the 1995 plan to reduce fishing pressure seemed to be working and the population was starting to come back.

Then, “it was like everything was coming back and it hit a brick wall,” he said.

And the reversal wasn’t minor, it was dramatic, he said.
Between 1998 and 2008, there was a 98-percent decline in the population, he said.

One problem with weakfish is they may be especially vulnerable to predation as they are schooling up to head out of the bay and south, Clark said.


About the same time weakfish school, striped bass and dolphin are also beginning their coastal migrations.


In North Carolina, scientists looking at stomach contents from striped bass and found their main prey along the ocean was weakfish. But in the sounds, they were feeding on croaker, he said.

With the North Carolina State study, researchers hope to learn more about where Delaware’s state fish goes.
Each acoustic tag emits a distinct frequency and in the fall, the team will be able to track the fish as they move.
“With the big fish, we just don’t know what happens,” Krause said.
Meanwhile, young of the year populations have been holding at average levels, he said. So learning more about the adults will “at least get a puzzle piece to help answer” what is happening to the big fish.
Reach Molly Murray at 463-3334 or mmurray@delawareonline.com. Follow her on Twitter @MollyMurraytnj.

http://www.delawareonline.com/story/...fish/72506488/