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The Dilemma of Derelict Gear

A boat full of derelict crab pots. (Photo Credit: Center for Coastal Resources Management (CCRM)/VIMS)

Derelict crab pots can be damaging in many ways. (Photo Credit: Center for Coastal Resources Management (CCRM)/VIMS)

Derelict fishing gear can create a lot of problems: hazards to navigation, damage to sensitive habitats, and ghostfishing. Ghostfishing occurs when lost or discarded fishing gear that is no longer under a fisherman’s control continues to capture marine life. This is obviously bad news for local marine animals that can end up ensnared in derelict gear, but it can be harmful to local fisheries too. That’s what scientists at the Virginia Institute of Marine Science (VIMS) think and set out to prove.

VIMS researchers considered that apart from the obvious financial loss of losing gear, fisheries may suffer due to competition between active and derelict gear, specifically blue crab pots. Their research and analysis, funded in part by the NOAA Marine Debris Program, evaluates the hypothesis that derelict crab pots compete with active gear by attracting target species that might otherwise be attracted to actively-fished crab pots. This reduces commercial fishery harvests and revenues and is thus a lose-lose situation for both the crabs and crabbers.

A side-scan sonar image of an active crab pot (on the left, with attached buoy) and a derelict crab pot (on the right, missing an attached buoy) in the Chesapeake Bay. (Photo Credit: CCRM/VIMS)

A side-scan sonar image of an active crab pot (on the left, with attached buoy) and a derelict crab pot (on the right, missing an attached buoy) in the Chesapeake Bay. (Photo Credit: CCRM/VIMS)

To test this hypothesis, VIMS researchers created a model that allowed them to assess fishery harvests in Virginia with and without derelict gear present. Using this model, they compared fishery harvests with derelict crab pots removed via a large-scale removal project, and a hypothetical scenario where no pots were removed. The comparison also accounted for other factors that could potentially impact harvests, such as stock abundance and environmental conditions, so that the effect of derelict gear removal could be isolated.

The results of this comparison indicated that the Virginia Marine Debris Location and Removal Program, which removed 34,408 derelict crab pots over six years, increased crab harvests in Virginia by 27%, or by 30 million pounds valued at $21.3 million for fishermen! This was the direct result of reduced gear competition and thus the improved efficiency of active crab pots. Removal was found especially effective in highly-fished areas with higher rates of pot loss. Extending their findings globally, VIMS researchers speculate that removing about 10% of derelict pots and traps could increase crustacean harvests by over 600 million pounds per year. These findings exhibit just one of the many damaging effects of derelict fishing gear.

A figure demonstrating the Virginia crab harvest with derelict crab pots removed (blue line) and without the pots removed (red line). (Photo Credit: VIMS)

A figure demonstrating the Virginia crab harvest with derelict crab pots removed (blue line) and without the pots removed (red line). (Photo Credit: VIMS)

This study and its results were accepted for publication by the journal Nature Scientific Reports (for you non-science folks, that’s a big deal), with VIMS researchers A. M. Scheld, D. M. Bilkovic, and K. J. Havens as authors on the paper. For more on these and associated efforts, check out the NOAA Marine Debris Program 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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Know Your Enemy: Marine Debris Research is Essential to the Fight Against It

Microplastics are at the forefront of marine debris research. (Photo Credit: NOAA)

Microplastics are at the forefront of marine debris research. (Photo Credit: NOAA)

In the fight against marine debris, research plays an important role. New studies have helped us to better understand the issue, although research into marine debris, its sources, and its impacts is still fairly new and there are questions that remain unanswered.

The NOAA Marine Debris Program supports research projects that help to address some of these unanswered questions—questions like: What are the biggest debris sources and what types are most abundant? How is marine debris really affecting natural resources and our economy? Are the chemicals in plastics leaching out into the marine environment? By answering some of these unknowns, research can help us to mitigate impacts, improve current fishing gear setups, and raise awareness of the issue by improving our understanding of marine debris’ harmful impacts.

Here is a small sampling of the research supported by the NOAA Marine Debris Program. Click each project to learn more:

Analysis of Microplastics in Chesapeake Bay and Coastal Mid-Atlantic Water Samples: For this project, the University of Maryland’s Wye Research and Education Center Aquatic Toxicology Group looked at water samples from different areas of the Chesapeake Bay to assess the presence of microplastics and to find any trends between location and microplastic concentration.

Influence of Environmental Conditions on Contaminants Leaching From, and Sorbing To, Marine Microplastic Debris: The Virginia Institute of Marine Science is researching how various factors, like characteristics of the environment, may affect the contaminants leaching from (or attaching to) microplastic debris.

Examining Microplastic Occurrence in the Gut Contents of Sargassum-Associated Juvenile Fishes: The University of Southern Mississippi is investigating if fish that use floating algae as habitat (where marine debris can often be found) are eating microplastics with their natural diet and if so, how much.

Quantification of Marine Microplastics in the Surface Waters of the Gulf of Alaska: The University of Washington Tacoma and UW’s Joint Institute for the Study of the Atmosphere and Ocean used water samples from the Gulf of Alaska to determine the general distribution and quantity of microplastics, as well as to determine if the 2011 Japan tsunami had an effect on microplastic accumulation in that area.


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Northeast Region: Derelict Fishing Gear

By: Keith Cialino and Leah Henry

Ghost fishing occurs when lost or discarded fishing gear, that is no longer under a fisherman’s control, continues to trap and kill fish, crustaceans, marine mammals, sea turtles, and seabirds. Derelict fishing nets and traps can continue to ghost fish for years after they are lost. Every year marine species, from lobsters and fish to sea lions and birds, become trapped or entangled in lost, abandoned or discarded fishing gear. Fishing for Energy works to prevent those impacts.

In 2014, the Fishing for Energy partnership successfully diverted 328,580 pounds of gear at 11 bin locations located within the Northeast region. 

 Map of Fishing for Energy bin locations in the Northeast (Photo Credit: NFWF)

Map of Fishing for Energy bin locations in the Northeast (Photo Credit: NFWF)

Fishing for Energy is a partnership between the NOAA Marine Debris Program, Covanta Energy Corporation (link is external), National Fish and Wildlife Foundation (link is external) (NFWF), and Schnitzer Steel Industries (link is external), to prevent and reduce the impacts of derelict fishing gear in the marine environment. The program provides the fishing community no-cost options for disposing of old or unwanted gear, nets, line, and rope and together Fishing for Energy partners convert that gear into energy.

Since 2008, the Fishing for Energy partnership has provided collection bins at 37 participating ports in nine states, drawing over 2.8 million pounds of fishing gear. Gear collected at the ports is first sorted at Schnitzer Steel for metals recycling, and the remaining non-recyclable material is converted into energy at Covanta Energy locations. Approximately one ton of derelict nets equals enough electricity to power one home for 25 days.

Additionally, the NOAA Marine Debris Program released its Ghost Fishing Report earlier this year to provide a summary of the current scientific knowledge on the topic.

Find out more about Marine Debris efforts in the Northeast at http://marinedebris.noaa.gov/northeast


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Is Beach Litter Rerouting Your Summer Vacation?

By: Leah Henry

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Debris on beaches is unsightly! And like the residents in the NOAA Marine Debris Program-funded economics study in Orange County, California, you too might be deterred by beaches with high levels of marine debris and that concern may influence which beaches you visit. In this study, led by Industrial Economics Inc., we discover how marine debris influences decisions to go to the beach and what it may cost.

Southern California residents lose millions of dollars each year avoiding littered, local beaches in favor of choosing cleaner beaches that are farther away. By reducing marine debris by 25 percent at beaches in and near California’s Orange County could save residents roughly $32 million over three summer months by decreasing travel distances to enjoy the beach. Reducing marine debris on beaches can prevent financial loss and provide economic benefits to residents and given the enormous popularity of beach recreation throughout the United States, the magnitude of recreational economic losses associated with marine debris has the potential to be substantial.

For more information and to download the study, please visit our website. 


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Microplastics Found in Chesapeake Bay Surface Water Samples

By: Leah Henry

In partnership with the National Oceanic and Atmospheric Administration (NOAA) Oxford Labthe NOAA Marine Debris Program collected surface water samples from four tributaries of the Chesapeake Bay, using the techniques described in the document, “Marine Debris Monitoring and Assessment: Recommendations for Monitoring Debris Trends in the Marine Environment,” and found microplastics in 59 of 60 samples.

Though the impacts of these tiny plastic particles (smaller than 5.0 mm in size) on wildlife and the environment is unknown, many ongoing studies are hoping to soon answer those important questions.

University of Maryland Professor Dr. Lance Yonkos was not surprised by what they found in the bay. As the lead author of this study, Yonkos’ take home message is one of prevention, “If we want to reduce microplastics in the oceans we need to limit their release at the source.” Find out more from the Photo Essay: Microplastics in the Chesapeake Bay.

All Photos by Will Parson, courtesy of the Chesapeake Bay Program.


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Southeast Region: Marine Debris Research

By: Leah Henry

The South Carolina Department of Natural Resources tests the effectiveness of different float configurations to reduce or prevent derelict crab traps. Recovered crab traps will be used to create oyster reef habitat that will promote new reef development.

To learn more about this marine debris research project visit our website.

This project is part of a Fishing for Energy gear innovation grant, administered by the National Fish and Wildlife Foundation and funded by the NOAA Marine Debris Program.

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