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Marine Debris Research: Ecological and Economic Assessment of Derelict Fishing Gear in the Chesapeake Bay

By: Amy Uhrin, Chief Scientist for the NOAA Marine Debris Program

The Chesapeake Bay blue crab fishery accounts for 50% of the United States blue crab harvest, and is worth about $80 million annually. It’s estimated that about 600,000 crab traps (also called “pots”) are actively fished on an annual basis in the Bay. Some crab pots become lost (derelict) when the pot’s buoy line becomes detached or cut, either by vessel propellers, faulty lines, or vandalism. Strong storms can also move pots from their original deployment location, making them difficult to relocate. In addition, pots may be abandoned, as has been observed at high rates in some regions of the Bay. Once lost, derelict pots can damage sensitive habitats and continue to capture blue crabs and other animals, often resulting in their death. To assess the ecological and economic impacts of derelict blue crab pots in the Chesapeake Bay, a diverse team of researchers from CSS-Dynamac, Inc.; Versar, Inc.; the Virginia Institute of Marine Science; and Global Science & Technology, Inc. recently completed a comprehensive Bay-wide assessment, funded by the NOAA Marine Debris Program.

A derelict drab trap.

Blue crabs are harvested using rigid, cube-shaped wire traps that are galvanized or vinyl-coated. Here, diamondback terrapins can be seen inside a standard pot. (Photo Credit: CCRM/VIMS)

This study estimates that some 145,000 derelict crab pots exist in the Chesapeake Bay, with 12-20% of actively-fished pots becoming lost each year. Not surprisingly, many derelict pots are found in areas of the Bay with heavy recreational and commercial boat traffic or fishing activity. These derelict pots kill over 3.3 million blue crabs annually. In addition, many other economically-important species can be impacted, such as white perch (3.5 million captured annually) and Atlantic croaker (3.6 million captured annually). Derelict pots thus “compete” with pots that are in active use —they catch or attract crabs that could otherwise be caught by active pots, and can therefore reduce commercial harvests.

Map of Chesapeake Bay with colors indicating density of derelict pots.

The predicted spatial distribution of derelict crab pot densities in Chesapeake Bay. (Photo Credit: CSS-Dynamac, Inc.; Versar, Inc.; Virginia Institute of Marine Science; and Global Science & Technology, Inc.)

Through statistical modeling, this study found that targeted derelict crab pot removal programs greatly increase the number of crabs caught by actively-fished pots, resulting in significant economic benefits for the fishery. The model estimated that derelict pot removals increased Bay-wide crab harvests by over 38 million pounds over a six-year period (2008 to 2014), amounting to $33.5 million in added revenue (in 2014 dollars). This study also found that pot removals are most effective when they focus on areas with intensive crab fishing activity.

This study also suggests management actions that may help in reducing the number of new derelict pots and their associated negative impacts. These include minimizing boat traffic in popular crabbing areas and educating boat operators about avoiding active crab pots, which would help reduce the number of cut buoy lines. Creating and maintaining derelict pot recovery programs, or incentivizing watermen to remove lost pots, would also help reduce the number of derelict pots in the Bay. In addition, outfitting crab pots with biodegradable “escape hatch” panels would reduce mortality of captured animals.

In addition to the Chesapeake Bay assessment, the team also created a Guiding Framework for derelict fishing gear assessments, which can be applied to other fisheries and/or regions interested in conducting similar studies. The final report for the Chesapeake Bay Assessment and the Guiding Framework document can be found on our website.


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The Remarkable Results of the Crab Pot Escapement Study

By: Nir Barnea, Pacific Northwest Regional Coordinator for the NOAA Marine Debris Program

Every year, about 12,000 crab pots are lost in the Puget Sound, mostly from recreational fishing. These lost pots can continue to capture marine life, a process called “ghostfishing.” Recreational crab pots may come in different models and designs, but all have an escape mechanism to allow trapped crabs to escape from the pot if it is lost. But— are all escape mechanisms equally effective? If not, can simple modifications make them more effective and decrease the ghostfishing problem?

An elegantly designed and collaborative study tested these questions. Thirty crab pots, representing ten commonly-designed recreational Dungeness crab pot models, were placed in water tanks at NOAA’s National Marine Fisheries Service facility in Mukilteo, near Seattle. Dungeness crabs were individually tagged (a total of 350 crabs were used!) and were placed in the pots. Food for the crabs was placed outside the pots, adding extra incentive for the crabs to escape. The escape mechanism was then activated (by cutting an escape cord which would disintegrate if left in the water for a period of time) and the number of crabs escaping from the pots was tracked daily for two weeks. The study was repeated three times.

The results were remarkable. In two models, nearly 100% of the crabs trapped in the pots escaped after the escape mechanism was activated. Another model allowed nearly 90% of the crabs to escape. But in the other three models, only 10% or less of the crabs escaped. Even two weeks after the escape mechanism was activated, 90% of the crabs remained trapped in those models. The study then explored modifications to increase escapement rates. The great news is that after implementing simple modifications and repeating the escape experiment, all pots achieved the desired nearly 100% escapement rate.

The study, a Fishing for Energy Partnership grant managed by the National Fish and Wildlife Foundation with funding from the NOAA Marine Debris Program, was led by the Northwest Straits Foundation, in partnership with Natural Resource Consultants, NOAA Fisheries, and the Washington Department of Fish and Wildlife. The results were shared with state agencies, and hopefully will contribute to gear modification and improvements of crab pot design and their escape mechanisms, and in a larger sense, reduce the mortality of crabs and other species associated with the loss of crab pots in the Puget Sound and elsewhere.

For additional information please contact Joan Drinkwin (drinkwin@nwstraitsfoundation.org), Kyle Antonelis (kantonelis@nrccorp.com), or Nir Barnea (nir.barnea@noaa.gov).

 

For more information on this project, visit the project profile page on our website.


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Innovative Research Aims to Prevent Derelict Fishing Trap Impacts

By: Dianna Parker

Every day, commercial fishermen around the country deploy hundreds of fishing traps into the ocean and coastal waters to land their catches. Far too often, the traps never make it back above the water’s surface, thanks to storms, tangled lines, or disturbance from passing vessels.

Now, researchers are testing innovative gear technologies and modifications to help fishermen hold on to their traps and prevent serious impacts from the derelict gear to the fishery, marine wildlife, their habitats, and the economy.

Studies show that derelict fishing gear is a widespread and persistent problem across fisheries in the United States. Lost traps are costly to fishermen, expensive to remove, and they continue catching valuable crabs and other commercial species – or “ghostfishing” – on the seafloor. Non-target species such as turtles also have the misfortune of wandering in the trap doors, baiting more animals. They eventually die without food or air.

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But what if we could find a good fix, such as modifying traps so they don’t get lost in the first place, or making them easier to recover? What if traps were designed to be ineffective fishers once they become derelict? Four gear innovation projects launched last year through Fishing for Energy with funding from the NOAA Marine Debris Program are trying to do just that.

The Smithsonian Environmental Research Center (SERC), South Carolina Department of Natural Resources, College of William & Mary, Virginia Institute of Marine Science (VIMS), and Northwest Straits Marine Conservation Foundation all received funding through Fishing for Energy’s gear innovation grants to test different solutions to this problem. The projects range from testing different ways to rig lines, to determining which pot design has the best crab escape rates.

At SERC, researchers in the Chesapeake Bay area are evaluating existing crab pot bycatch reduction technologies, such as side-scan sonar, and getting feedback on that technology – including which ones should be tested in the field – from Maryland watermen.

In South Carolina, the DNR is comparing different trap float and line rigging configurations by intentionally running over them with boats to see which one holds up. The pots they retrieve over the course of the project will become artificial oyster reefs.

VIMS is employing commercial fishermen to test biodegradable trap escape panels. Lead researcher Kirk Havens wrote in 2012 that VIMS created an escape panel with a “naturally occurring polymer that biodegrades completely in the marine environment.” The polymer is made from bacteria, and it disintegrates if the trap is left in the water.

The researchers are also testing whether terrapin turtles will avoid certain traps based on what color the trap’s doors are painted.

In Washington, the Northwest Straits Foundation is testing five different Dungeness crab pot designs used in the Puget Sound to determine which one has the best escapement rate. Some traps use cotton rot cords that are designed to disintegrate over time and allow the crabs to crawl out, but it doesn’t always work. The group estimates that over 30,000 crabs are killed each year in derelict pots with designs that prevent escape.

Groups all over the country are working to address derelict fishing gear, as the harmful impacts become more and more apparent. These innovative research projects are aimed at preventing those impacts down the line.

Fishing for Energy is administered by the National Fish and Wildlife Foundation (NFWF) and is a partnership with the NOAA Marine Debris Program, Covanta, and Schnitzer Steel Industries, Inc.

 


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Thousands of Chesapeake Bay blue crabs lost each year in derelict pots

By: Donna Marie Bilkovic, Guest blogger

Humans have been fishing the world’s estuaries and oceans for thousands of years. While techniques have changed over time, the availability of synthetic materials, such as plastics, has dramatically improved the efficiency, durability, and lifespan of our fishing gear. An unfortunate byproduct of these improvements, along with intensified fishing, has been an increase in the quantity and persistence of derelict fishing gear in our waters.

Derelict fishing gear possesses a long-list of unsavory traits and can last for multiple years. They damage habitat, trap and kill numerous animals including threatened, endangered, and economically important species, and pose safety hazards.

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The Chesapeake Bay supports several important finfish and shellfish fisheries that use a wide array of fishing gear including crab pots, eel pots, oyster hand tongs, gill nets, fyke nets, and purse seines. Of these, blue crab pots are by far the most abundant form of derelict fishing gear found in Virginia waters of the Chesapeake Bay. There are close to 800,000 commercial crab pots licensed in the Bay and about 20 percent are estimated to be lost every year. Commercial fishers removed about 32,000 lost and abandoned blue crab pots from 3,300 km2 of Virginia’s Bay bottom over four consecutive winters through the Blue Crab Fishery Resource Disaster Relief Plan, a program funded through NOAA in response to the declaration of a commercial blue crab fishery failure in Chesapeake Bay in 2008. In those pots, 40 species of invertebrates, fish, birds, and mammals and over 31,000 animals were captured. Because pots were recovered during the cold winter months, when most animals are less active or may not be present, we suspect that the total number of species and animals captured in lost pots to be much higher.

Map of the Chesapeake Bay identifying hot spots with high density clusters of lost pots in several general areas including Tangier Island, lower York River, and Eastern Shore tidal creeks.

Map of the Chesapeake Bay identifying hot spots with high density clusters of lost pots in several general areas including Tangier Island, lower York River, and Eastern Shore tidal creeks.

The target species, blue crab, experiences the highest mortality from lost pots. We estimated 900,000 blue crabs are killed each year in derelict pots in Virginia, which could mean a $300,000 potential annual economic loss to the fishery. Blue crabs are not alone, important fishery species also captured and killed were Atlantic croaker, black sea bass, American eel, white perch, and catfish.

It is not all bad news. While the derelict pots were widely distributed in the Bay, there were notable hotspot areas with high density clusters of pots. These areas can be targeted for derelict gear removal and enforcement of existing regulations that require the removal of all gear during the closed fishing season in winter months. Other solutions include better educating vessel operators on derelict gear impacts and gear avoidance techniques and the application of innovative biodegradable escape mechanisms to disarm lost gear and prevent needless mortality. For more information, see our new article in Marine Pollution Bulletin: Derelict fishing gear in Chesapeake Bay, Virginia: Spatial patterns and implications for marine fauna. You can also visit the Virginia Institute of Marine Science’s website.

Donna Marie Bilkovic is a Research Assistant Professor at Virginia Institute of Marine Science’s Center for Coastal Resources Management.


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It’s a trap!

By: Courtney Arthur

Fishing traps, often used to catch crustaceans such as lobsters and crabs, may be abandoned, lost, or otherwise discarded in the marine environment. This type of derelict fishing gear is important to consider due to its widespread nature, persistence for long periods of time, and impacts that include “ghost fishing” and damage to sensitive marine habitats. Since these traps sit on the ocean floor, they are often forgotten about as a type of marine debris.

The NOAA Marine Debris Program took a regional approach in funding derelict trap research in locations across the country. We were interested to know how many traps were out there, if they were “ghost fishing,” and how the traps were impacting habitat and fisheries. Three scientists led studies in Virginia, the U.S. Virgin Islands, and the Florida Keys, and they will share their stories about derelict fishing gear and its impacts here on our blog in the coming weeks.

There’s also a significant amount of trap removal work going on across the country (e.g. North Carolina!), so we’ll also share success stories from partners. To kick us off, here’s some good news we recently heard from Timothy W. Jones, Aquatic Preserve Manager at St. Martins Marsh Aquatic Preserve in Florida:

This spring, the St. Martins Marsh Aquatic Preserve staff removed approximately 640 pounds of marine debris, including 60 derelict crab traps from the St. Martins Marsh Aquatic Preserve in a single day.

Once discarded or lost, a blue crab trap can remain in the environment for over a decade, continuing to trap marine life. Blue crabs, stone crabs, diamondback terrapins, and fish are among the marine life unintentionally captured. The staff discovered a deceased diamondback terrapin in one derelict crab trap, an unfortunate reality when dealing with derelict traps. Fortunately, they also found and returned a mangrove snapper and two blue crabs that were still alive. Once collected, the derelict traps are crushed down and brought back to land for disposal.

The Big Bend Seagrasses Aquatic Preserve, Florida’s largest aquatic preserve, which protects over 900,000 acres of submerged land, is supported by NOAA’s Coastal Zone Management Program and is home to mullet, sea trout, redfish, shrimp, oysters, scallops, manatee, osprey, dolphins, and sea turtles. Preventing derelict fishing gear from entangling and trapping these valuable species, and keeping their habitat free of degradation and damage is essential to their success.

Stay tuned for more!

 

 


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This Ain’t Our First (Crab Trap) Rodeo

By: Kim Albins

Louisiana’s 2014 Derelict Crab Trap Rodeo, an effort to round up derelict and abandoned crab traps, was a success!

According to Marty Bourgeois of the Louisiana Department of Wildlife and Fisheries, the weather for this year’s Louisiana Crab Trap Rodeo could not have been better. The warm temperatures and calm sea conditions made it possible for volunteers to remove 1,051 traps during this annual single-day clean-up event.  Over 100 volunteers and 16 boats participated in this year’s rodeo, which was held in Terrebonne Basin on February 15, 2014.  In addition to the derelict crab traps, volunteers also removed tires, a gill net, and trawl net webbing.  Keep posted on upcoming Louisiana Crab Trap Rodeos at http://www.laseagrant.org/crabtraps/

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