Scientists may have found a type of fishing that could actually benefit the Bay's beleaguered blue crab population.
Fishing for crab pots.
After two years of research, biologists estimate that nearly 42,000 abandoned crab pots are lying on the bottom of Maryland's portion of the Bay. Many of them may continue to catch-and kill-crabs for years.
Crab pots are typically set on the bottom and connected to a buoy on the surface with a line. They are "lost" when lines are cut by boats passing through, or when storms rip buoys lose and move pots around.
"There are no villains in this," said Steve Giordano, fisheries program manager with the National Oceanic and Atmospheric Administration's Chesapeake Bay Office. "No one wants to lose traps. It's expensive for the watermen, and it's probably bad for the fishery. Everyone wants to be part of the solution, I think."
In fact, watermen, recreational anglers and conservationists are planning to team up, possibly as soon as this spring, to fish out hundreds-possibly thousands-of abandoned pots along part of Maryland's Western Shore.
The removal would be the latest piece of research that began more than two years ago when Giordano and colleagues began noticing a large number of rectangular shapes popping up on their computer screens as they used sonar equipment to map bottom habitats.
The rectangles turned out to be abandoned crab pots. Since then, they've been investigating whether unmanned gear creates a problem by continuing to catch crabs-something dubbed "ghost fishing."
In the last two years, NOAA scientists have surveyed areas with various degrees of crab fishing pressure to see how many pots were still in the water after crabbing season. The answer: A lot. In one high density area, they found 900 pots in a single square kilometer. No survey failed to find lost pots.
Combining that information with data from the Maryland Department of Natural Resources about crabbing levels in different regions resulted in an estimate that more than 41,900 abandoned crab pots are in the state's portion of the Bay.
Surveys this year by NOAA's Bay Office and the Virginia Institute of Marine Science will try to estimate the number of abandoned crab pots in Virginia waters; scientists say that number will likely reach tens of thousands as well.
"We suspect there are a lot of traps out there," said Kirk Havens, assistant director of the Center for Coastal Resources Management at VIMS. "But in Virginia, we only have anecdotal information, except for the lower York, where we did a census."
A survey by VIMS scientists using sonar near the mouth of the York River in early 2006 found between 635 and 676 abandoned and derelict traps.
The proportion of abandoned pots to actively fished pots is high. Havens said the same area of the York River had 905 active buoyed traps during early October 2006.
In Maryland, more than 150,000 pots are fished during the peak of crabbing season in the summer. But in some months, as few as 21,000 are fished-or half of the estimated number of abandoned pots.
No firm numbers are available, but scientists say 10-30 percent of pots may be lost each year.
Crab pots are cages with openings designed to allow crabs to enter, but it's difficult for large crabs to escape. The crab pots are typically baited with dead fish to lure crabs inside.
Actively fished pots account for a bit more than 60 percent of the commercial crab catch in Maryland, and 83 percent of the catch in Virginia.
The impact of abandoned pots is not clear, though.
Over time, they degrade, develop holes and fall apart. Also, they can become so coated with fouling organisms that they no longer trap crabs. "Not every trap down there is fishing," Giordano said. "We know that."
Research has been under way to quantify how long the pots last. Experimental traps deployed in Maryland waters more than 14 months ago are still in very good condition and continue to fish. Giordano and Havens said the pots appear to function for several years in low-salinity waters; a bit less in high-salinity water.
Giordano said that between half and three quarters of the abandoned pots examined are still able to trap crabs.
Surveys in both Maryland and Virginia indicate that even unattended pots continue to lure crabs.
Havens said tests with 56 unbaited pots in four sites off the York River have a catch rate of one crab every four days-or 50 crabs per pot during the crab season. That's roughly a bushel. When traps have bait, the catch rate doubles.
More study is needed to determine whether that catch rate is representative of other areas, scientists say.
In Maryland, Giordano began "ghost fishing" 65 pots in fall 2006. The traps were initially baited to simulate what would happen if the traps were deployed like typical commercial gear, then lost. The study is ongoing, but results so far show that untended traps continue to "bait" themselves by trapping crabs and fish which, in turn, may lured more animals into the traps. Scientists have found a variety of fish in the traps, including white perch, oyster toadfish, spot and pumpkinseed.
"Once one of our traps collected animals during the experiment, it was very rare to find it empty again," Giordano said.
The study has had the same problems faced by watermen-more than 10 percent of his pots have been lost.
Also of concern is that the traps seem to lure so many fish. Giordano has seen as many as a dozen trapped fish in a single pot. Havens said pots in his study capture croaker at the rate of about a dozen per year. In Virginia tidal creeks, where pots may be legally fished, there's evidence the pots may be catching other species, such as terrapin turtles.
Officials in both Maryland and Virginia say the research could lead to action.
"It's not just a crab issue. It is about the other fish out there entangled in these things as well," said Lynn Fegley, a fisheries scientist with the Maryland Department of Natural Resources. "It's something we're very interested in. It's something that would definitely be good to mitigate."
Scientists caution that their work is ongoing, and more detailed results may be a year or more away.
Some question whether the studies conducted so far are representative of what happens throughout the Bay. Larry Simns, president of the Maryland Watermen's Association, said watermen typically find few crabs in unbaited traps, and that fouled gear quickly loses its ability to effectively catch crabs.
Most pots on the bottom, he said, are likely too old to effectively catch crabs. "They're just junk. A pot will only catch for so long before they get fouled up with dirt or they get a hole in it or something. There's a lot of other junk out there that people put out that is a lot more harmful to the environment than pots."
"We're not saying it's not a problem," Simns added. "We're saying it's not as big a problem as people would make it out to be. But it is enough of a problem that we are going to try to do something about it."
Watermen, scientists and conservation groups do agree that fishing for derelict crab pots would be a good idea. Giordano has been working with Simns, and a number of other stakeholders on a pilot project to pull pots out of the water.
Recovery efforts pose problems, too. Dragging the bottom with a grappling hook while trying to snare lost pots may cause more harm to the ecosystem than ghost fishing because it damages bottom habitats. Using divers to retrieve aging metal pots in often-murky Bay conditions could risk injury.
Other issues need to be addressed as well. Simns said it's unclear whether pots can legally be "salvaged" from the bottom. In the past, he said, watermen who brought seemingly abandoned pots out of the water have been accused of stealing pots that belonged to others. "That kind of stopped everybody from going out and getting them," he said.
Simns said he wants the state General Assembly to clarify the issue.
Further, he said, some method is needed to fairly distribute any useable pots among watermen who may have lost them. "It's more complicated than what meets the eye," he said.
This year's pilot project, which will likely target a high-density pot area at the mouth of a Western Shore tributary, will help provide information about the best ways to get pots out of the water and figure out how to distribute what's usable, and recycle or dispose of what's left. After the pots are gone, the site will be monitored to learn how quickly new pots accumulate.
"We are going to see if it really is feasible to take a well-defined area and completely clean them out," Giordano said. "It will be a good mitigation effort, but also a science effort."
Cleanups alone will never remove tens of thousands of pots from the Bay, he said. But it may be possible to target areas such as the mouths of rivers where large numbers of abandoned pots might be particularly problematic as crabs are squeezed through a narrow area.
And, if combined with other actions, such as requiring biodegradable fasteners or other components on crab pots so they fall apart, the accumulation of new pots could be minimized. "If they fall open, at least they don't fish," Giordano said.
Other actions, such as improved trap marking and identification, better channel marking and educational efforts aimed at recreational boaters could reduce the rate of loss, he said.
Indeed, unlike many problems in the Bay that often seem intractable, the ghost pot issue is one that might have a resolution-and one everyone agrees upon.
"It's a win-win type of thing," said Bill Goldsborough, senior scientist with the Chesapeake Bay Foundation. "I think this will be a good thing for the Bay and for the watermen. They certainly don't like to lose pots."
Indeed, Simns said every missing pot costs $35-$50 to replace. But, he added, "the big loss is what you would have caught in the pot." During crabbing season, fishermen often don't have time to replace lost pots, Simns said. As they lose pots, their total catch begins to drop. That adds up: Watermen can get $110 a bushel for crabs, and an individual pot can catch several bushels during the course of the April through November crabbing season.
And, Simns said, derelict pots can interfere with the effectiveness of active pots. They are also an obstacle for other gear. "If you're fishing a net for fish and stuff, if you get a whole pot in your net, that's the worst mess in the world," he said. "That's the reason we want to get them all cleaned up."