Derelict Crab Traps

Background Information The wire crab trap dramatically affected the Gulf of Mexico blue crab (Callinectes sapidus) fishery. By the middle 1950s, crab traps were widely accepted throughout the Gulf of Mexico and came to dominate the fishery as the main gear type used. The total number of traps has increased because of increases in the number of trap fishermen and an increase in the number of traps used per fisherman. Adoption of the crab trap improved fishing efficiency, but exacerbated problems associated with derelict, abandoned, or lost traps. Problems include ghost fishing, bycatch mortality, and user group conflicts.
	Ghost fishing occurs when blue crabs or bycatch are caught and retained inside the derelict trap. Fishing practices and physical characteristics of crab traps contribute to derelict trap impacts by either facilitating trap loss or magnifying ghost fishing mortality. Traps are effective in capturing blue crabs but inefficient with respect to size selection. Ghost fishing mortality is directly related to the ability of a trap to retain blue crabs and bycatch.
The replacement of galvanized wire by vinyl-coated wire resulted in more durable traps with a longer ghost fishing period. Traditionally, hexagonal mesh traps have dominated the fishery, but now one and one-half inch square mesh traps have become popular in Louisiana and other areas. These traps are constructed of a heavier gauge wire and may lead to higher rates of ghost fishing mortality, longer ghost fishing periods, and greater potential for vessel or motor damage than hexagonal mesh traps.
Origin of Derelict Traps Abandonment of traps by fishermen who leave the fishery seasonally or permanently Improper disposal of old traps Loss of actively fished traps resulting from tides, currents, or storms deterioration of floats, lines, or knots negligence by fishermen in assembling and maintaining floats and float lines clipping of float lines by vessel propellers intentional cutting of float lines by vandals Number of Derelict Traps Annual estimates of trap disposal and overall trap loss due to inadvertent loss or theft: 30-50% in Florida 20-50% in Alabama 20-30% in Mississippi up to 100% in Louisiana - (257 lost traps/year/fisherman) 35-50% in Texas - (103 lost traps/year/fisherman)
Although an accurate count of derelict traps is unavailable, a rough estimate can be generated using the number of fishermen, average traps per fisherman, and trap loss rate. Recent numbers of licensed commercial crab fishermen by state and the average number of traps fished by each fisherman are: 2,381 fishermen using 152 traps each in Florida Gulf waters 174 fishermen using 150 traps each in Alabama 256 fishermen in Mississippi - no estimate on the number of traps used per fisherman 3,347 fishermen using 250-270 traps each in Louisiana 259 fishermen using 200 traps each in Texas
Conservatively assuming a total of 5,000 commercial blue crab fishermen, fishing 200 traps each, and losing 25% approximately 250,000 derelict traps are added to the Gulf of Mexico each year.
Impacts of Derelict Traps Negative impacts created by derelict traps include: mortality of blue crabs and bycatch user group conflict visual pollution negative impacts to sensitive habitats
Ghost fishing continues until the trap deteriorates sufficiently for holes to develop in the wire mesh, allowing captured animals to escape. The life expectancy of vinyl-coated wire traps averages two years or more. Blue crab ghost fishing mortality in Louisiana averaged: 25.8 crabs/trap over one year 17.3 crabs/trap in traps without escape rings over a three-month period 5.3 crabs/trap in traps with escape rings over a three-month period Assuming that Louisiana fishermen lose 30-50% of their traps each year and a mortality rate of 25.8 crabs per trap, this ghost fishing rate leads to a loss of 4 to 10 million blue crabs each year in Louisiana. Other animals besides crabs are captured in blue crab traps. Important recreational fish species found in crab traps include spotted seatrout, red drum, black drum, and southern flounder. In addition to fish, diamondback terrapin, river otter, and raccoons have also been observed in derelict traps.
Conflicts between crab fishermen and other groups have occurred as the number of derelict traps have increased. For example, derelict traps may pose navigation hazards to waterfowl hunters, recreational fishermen, pleasure boat operators, and shrimp fishermen, and may entangle hooks of recreational fishermen. Economic costs may also be incurred because of derelict traps. Derelict traps can damage shrimp gear and result in loss of catch and fishing time.
	Derelict crab traps are visually unattractive. Exposed derelict traps in the water or along shorelines may be aesthetically degrading to other user groups.

Derelict Trap Removal Programs Texas, Louisiana, Mississippi, and Alabama have instituted derelict traps removal programs to address the problems that derelict traps create. Partial funding for these programs was made possible in 2004 by funding from the NOAA Community-based Restoration Program.

A detailed report on the derelict crab trap problem. For more derelict crab trap photos, view the derelict crab trap photo page.