NC Diamondback Terrapin Conservation Network

NOAA, Tortoise Reserve, NC Audubon Society: Derelect Trap Removal Program

Page under development: April 2008

NOAA, The Tortoise Reserve, and NC Audubon have teamed up to do a program to remove abandoned crab pots from NC's waters. We will focus on areas where these pots will most impact terrapins. The first year's effort will test methods of location, removal and disposal of unwanted crab pots in different areas and habitats throughout our coastal waters. This program also has educational and preventive elements. We will be working closely with NC Maine Fisheries' existing programs.

Title: Derelict Crab Pots in North Carolina Waters and Their Effects on Diamondback Terrapin Populations: Proposed inventory, methodology development for effective location and removal, educational awareness campaign, and planning for long-term solutions.

Abstract: Derelict (ghost) crab pots are known to represent a major threat to diamondback terrapins, other marine life, and to economically impact local fisheries. We propose four mini regional surveys (at six sites) to assess the magnitude and variants of the problem through both inventory of ghost crab pot densities and geographical differences in species by-catch. Much of our activity will focus on detection and removal methodology (as the state’s estuarine system is highly variable in terms of water depth, water, clarity, intensity of the blue crab fishery, and accessibility). Information gained from this inventory will be used for both an educational awareness campaign and development of a working plan for abandoned crab pot removal. In that studies in other regions show extremely high annual accumulation rates of crab pot abandonment we also plan to use the information gained from this effort to help influence changes in legislation and regulation in ways to lessen the impact of abandoned crab pots in the future (by-catch reduction devices, owner identification system, bio-degradable panels).

We expect that this effort will provide working cost-efficient methodologies for the future removal of abandoned crab pots from North Carolina’s waters. Because of our highly diverse coast the situation is anticipated to be quite variable from one site to another, and alternate methodologies will probably need to be used for specific situations. Results of our inventories of by-catch will be used to encourage community involvement and to demonstrate the economic impact of abandoned crab pots on local fisheries. Information gained from this study also will be used in educational outreach programs to generate local support from organizations and agencies regarding the need to reduce the numbers of derelict crab pots.

We see this as a pilot study so that a planned, time and cost efficient program for trap removal can be developed and implemented in the immediate future.

Statement of Need: Terrapins are vulnerable to anthropogenic disturbances at every phase of their life cycle. The list of threats is long, but currently the most significant factor is their drowning in crab pots. In addition to losses from active commercial and recreational crab fisheries, large numbers of terrapins drown in derelict (ghost) pots that can continue to capture terrapins and other aquatic creatures for up to two decades after they are abandoned. The number of abandoned crab pots in North Carolina waters still actively capturing marine organisms is unknown but it is certainly in the tens of thousands, and probably much higher. We have seen thousands just around the Ocracoke Island area of NC. In Maryland, side scanning radar surveys indicated there are 42,000 derelict crab pots just in popular fishing areas.  In 1998 the estimate for NC’s fishery places 1,063,331 crab pots in local waters, nearly doubling the number of pots set just 10 years before. A study on the York River (VA) suggest that the cumulative abandoned pots may number as much as 2/3s the number of active ones with eighty-two percent of the abandoned pots still functional. The same study area also showed a 75% annual accumulation rate of ghost crab pots. In Maryland it has been shown that between 10 and 78% of local terrapin populations are captured just by recreational crabbing activities. Preliminary investigations in the Chesapeake Bay indicate that derelict pots may represent half the total of traps during prime crabbing season. The total impact of crabbing and derelict crab pots on terrapins, other marine life, and economically important species is obviously a major one. It is an issue that needs to be addressed, and it should be addressed quickly.

In addition to direct mortality, remaining terrapin populations exhibit skewed sex ratios; the crab pots tend to catch mostly male terrapins because the larger females cannot fit through trap openings. The turtles are attracted to the abandoned traps because of prey species already entrapped. Small to mid-sized trapped female terrapins will attract males, and sometimes dozens of males are lured into traps during the spring mating season.

Of course terrapins are just one of many species that are currently being impacted by both active and ghost crab pots. Some of the other species known to be captured in derelict crab pots include Atlantic croaker, oyster toadfish, white perch, white catfish, blue catfish, spot, black sea bass, flounder, sheepshead, red drum, pumpkinseed, eastern mud turtles, river otter, muskrat, whelks, horseshoe crabs, spider crabs, stone crabs, and of course blue crabs. The abandoned traps become self-baiting as various creatures are caught. Studies conducted elsewhere suggest as much as 15% of market size blue crab stocks perish annually in ghost crab pots. The abandoned crab pots also regularly snag fishing gear that could over time result in additional by-catch. These pots are responsible for boat damage and are a potential threat to recreational boaters. While we are deeply concerned with the impact of abandoned crab pots on terrapins, we are using terrapins as a proxy for the bigger issue of the total effect of abandoned crab pots on aquatic life and commercial fisheries of NC’s estuarine systems.

The conservation concerns for terrapins is high; they are declining (8 states) or the population status is unknown (5 states) in three quarters of the states where they occur. They are currently protected and of conservation concern in at least 12 of the 18 states they inhabit. Sites where long-term data are available suggest the species to be in peril. For decades, the US Fish and Wildlife Service listed this turtle as a status review candidate and range-wide concern for the species has recently been expressed. Terrapins are the only obligate estuarine turtle in North America. In North Carolina, diamondback terrapins are protected and listed as a species of special concern and as a high profile animal of conservation concern they can be used to generate awareness of the by-catch issue. It should be pointed out that two sub-species of terrapins occur in North Carolina’s estuaries—the Northern Diamondback Terrapin, Malaclemys terrapin terrapin, ranges from the Va. line south to the Cape Hatteras area. South of Hatteras it is replaced by the Carolina Diamondback Terrapin, M. t. centrata.

Fortunately, a considerable amount of research has been conducted on the effect of the blue crab fishery and derelict traps on terrapins, on the overall issues related to ‘ghost’ crab pots, and on methods for the identification and mapping of areas of concern.  Solutions for long-range management of the problem have already been developed and tested and will be incorporated in this project. While we think it is important to document by-catch (species, frequency and economic effects) in local waters in order to solicit interest from partnership agencies and organizations, much of the key information has already been determined by studies in adjacent states. We believe that funding for this proposed program will help facilitate local pro-active solutions.

In addition to pressing needs for a reduction in the number of derelict crab pots in North Carolina waters we want to use the results of this study to help prevent this from remaining an on-going issue. Through focused education efforts, public media outlets, and partnerships with agencies and organizations we hope to persuade recreational and commercial crabbers to start construction and use of traps with biodegradable panels, and terrapin excluder devices. In addition, all traps should have owner identification tags and standard secured attachment for buoy lines. These improvements could be implemented as old traps are replaced with new ones.

Note: During 2008 we will also document entangled waterbirds in derelict fishing gear (mostly fishing line and hooks) during field work conducted through this study and with the systematic patrols Audubon NC conducts in major waterbird nesting colonies. The fishing gear will be removed and we will document species involved, gear type, and event frequency through photographs and field notes. We have accumulated considerable data from previous years and will continue to collect this information and provide NOAA with a report.

References:

Anonymous. 2006.  NOAA, Virginia Institute of Marine Science Announces Plans to aid Chesapeake Bay Cleanup. Derelict crab pots and fishing gear focus of group’s effort. NOAA Magazine @ http://www.noaanews.noaa.gov/stories2006/s2693.htm

Bishop, J. M. 1983. Incidental capture of diamondback terrapin by crab pots. Estuaries 6: 426-430.

Blakenship, K. 2006. They check in but they don’t check out: abandoned, ghost crab pots haunt Bay bottom luring creatures to their doom. The Bay Journal Feb 2007 http://www.bayjournal.com/article.cfm?article=2729.

Brennessel, B. 2006. Diamonds in the Marsh: a natural history of the diamondback terrapin. University Press of New England, Lebanon, NH. 219 pp.

Butler, J. A. and G. L. Heinrich. 2004. Effectiveness of a bycatch reduction device on crab pots in Florida-Preliminary results. Presented at the Third Workshop of the Ecology, Status and Conservation of Diamondback Terrapins, Jacksonville, Fla.

Guillory, V and P. Prejean. 1998. Effect of terrapin excluder devices on blue crab, Callinetes sapidus, trap catches. Mar. Fisheries Review 60(1): 38-40.

Hart, K. M. and D. S. Lee. 2006. The Diamondback Terrapin: the biology, ecology, cultural history, and conservation status of an obligate estuarine turtle. Studies in Avian Biology No. 32: 206-213.

Havens, K. J., D. M. Bilkovie, D. Stanhope, K. Angstadt, and C. Hershner. 2006. Derelict blue crab trap impacts on marine fisheries in the lower York River, Virginia. Final report to NOAA Chesapeake Bay Program Office. 12pp.

Hoyle, M. E. and W. Gibbons. 2000. Use of a marked population of diamondback terrapins (Malaclemys terrapin) to determine impacts of recreational crab pots. Chelonian Conservation Biology 3(4): 737-737.

Roosenburg, W. M., W. Cresko, M. Modesitte, and B. M. Robbins. 1997. Diamondback terrapin (Malaclemys terrapin) mortality in crab pots. Conservation Biology 13(5): 1166-1172.

Roosenberg, W. M., K. L. Haley, and S. McGuire. 1999. Habitat selection and movements of diamondback terrapins, Malaclemys terrapin, in a Maryland estuary. Chelonian Conservation Biology 3(3): 425-429.

Rossenburg, W. M. and J. P. Green. 2000. Impact of a bycatch reduction device on diamondback terrapin and blue crab capture in crab pots. Ecol. Appli. 10(3): 882-892.

Seigel, R. A. and J. W. Gibbons. 1995. Workshop on the Ecology, Status, and Management of the Diamondback Terrapin (Malaclemys terrapin), Savannah River Ecology Laboratory, 2 August 1994: Final Results and Recommendations. Chelonian Conservation and Biology 1(3): 240-243.

Thomson, C. 2007. A swarm of ‘ghost’ raises alarm in bay. Baltimore Sun. Sept. 17, 2007.

Walker, G. and D. S. Lee. 1999. Unpublished data from preliminary ghost crab pot investigations on North Carolina’s Outer Banks.

Wood, R. C. and R. Herlands. 1995. Terrapins, tires and traps: Conservation of the Northern Diamondback Terrapin (Malaclemys terrapin terrapin) on the Cape May Peninsula, New Jersey, USA. International Congress of Chelonian Conservation, pp. 254-256. Gonfaron, France.

Scope of Work: The primary goal of this pilot project is to inventory derelict crab pot (DCP) density and associated by-catch species and their quantitative numbers within selected sites along the North Carolina coast. This information will be used to ascertain DCP magnitude in North Carolina coastal waters and their consequences to Diamondback Terrapins specifically, but also other species as evidenced by survey results.

The success of this endeavor will be measured by the long-term goal of reducing existing DCPs and the annual accumulation of new DCPs. This will be accomplished with the help of community-based conservation-education programs designed to engage both recreational and commercial crabbers. Specific project objectives include systematic surveys for DCPs within designated coastal areas including Currituck, Croatan, Pamlico, lower Albemarle, Core, Bogue, Topsail and Masonboro Sounds. Survey sites will be accessed by public and private boat ramps using shallow-draft boats equipped with side-scanning sonar and GPS. The proposed search area is vast and contains a range of waters from tidal mesohaline (salinity range 5-18 ppt) to tidal polyhaline (salinity range 18-30 ppt).

The search areas will be narrowed in part by presence and abundance of crabbing activities. This information will be garnered through personal interviews with community fish houses and boat docks combined with aerial surveys along with existing knowledge about the waters and known presence of DCPs based on project researchers’ prior experience and investigations. Recreational crabbing activity is generally restricted to private docks located along inland waterways including the Intracoastal Waterway and associated tidal creeks.

DCP surveys can take place year-round, but the scope of this project includes a DCP species inventory, including terrapins, which necessitates the need for DCP collection to occur during warm months of the year when target and by-catch species are most active and likely to be caught. Target goal is to retrieve, inventory and dispose of 100 traps per study area.

Permission will be obtained from appropriate regulatory agencies before any traps are removed from the water. Wildlife and fisheries collection/salvage permits will also be secured prior to project work. DCP disposal protocols have yet to be determined and this will also be arranged prior to onset of work.

Flat-bottom outboard boats equipped with side-scan sonar will be employed to locate submerged traps, and built-in GPS will mark each site on an electronic map. To gauge presence and abundance of DCPs over large areas, aerial surveys will be conducted using fixed-wing aircraft when water conditions permit. Due to military airspace restrictions, survey flights will be limited to the waters around Ocracoke Island, Cedar Island, eastern Pamlico Sound, Topsail and Masonboro Sounds and portions of the Lower Cape Fear River. Flights will be conducted during winter when commercial crabbing activity is at its lowest. Aerial GPS will record regions of greatest crab pot concentrations and boat surveys will ground truth densities of active versus derelict crab pots.

Using boat-mounted side scan sonar, researchers will survey probable sites for DCPs using NOAA protocols conducted in Chesapeake Bay. Once located and confirmed to be a DCP, the trap will be lifted from the water by hand or with aid of power winch. Contents within the trap will be identified as quickly as possible in the event some animals or their parts are small enough to fall through the trap mesh. DCP contents will be collected into trays, sorted, identified, photographed and documented before being returned to the water. Specimens may be retained for later identification if required.

Education objectives are included in this pilot project to assess crab pot users’ knowledge of the derelict crab pot problem. Target audiences will include commercial crabbers and recreational crab pot users. Verbal surveys will be conducted at residential piers, commercial fish houses and boat ramps used by fishers. Information gathered this way will be used to develop flyers and posters for distribution through various venues including fish houses, tackle and bait shops, restaurants, boat dealerships, boat ramps. We also anticipate being able to work with NC Marine Fisheries, NC State Parks, and the three NC Aquariums with programs geared to raise awareness about the DCP problem.

Outcome and Benefits to NOAA, NOAA Trust Resources, and Society: The removal of derelict fishing gear is a major concern to NOAA and is one of their key management goals. Both marine life and local fisheries based economies will benefit from the removal of abandoned crab pots. 

Timeline and Milestones: With funding secured, we anticipate beginning survey work in winter 2008 and continuing through early autumn 2008. The scope of this project is limited to initial survey work, user assessment and an education needs assessment conducted to shape education programs designed to raise public awareness about derelict crab pot issues in North Carolina.

Geographic Area: This first year project will focus on the coastal waters of North Carolina including the counties of Currituck, Dare, Hyde, Craven, Pamlico, Carteret, Onslow, Pender, New Hanover and Brunswick. Six representative sampling sites will be selected.

"There is no end to our grumbling; we want
Comfortable earth and sumptuous Heaven.
But the heron standing on one leg in the bog
Drinks his dark rum all day, and is content."

- Robert Bly, from the poem, "Wanting Sumptuous Heavens"