Voss et al.: Factors driving the density of derelict crab pots and associated bycatch in North Carolina 
389 
landings of Florida stone crab are highly valued in Flor- 
ida and prized along the U.S. Gulf Coast (NCDMF 9 ). 
Species of concern, such as the diamondback terrapin 
and several coastal birds and mammals, are perhaps 
the most serious captures among DCP bycatch (Bish- 
op, 1983). The results of this study and others (Bishop, 
1983; Havens et al., 2011) indicate that crab pots that 
become derelict near marshes, essential terrapin habi- 
tat, are likely to attract terrapins and often result in 
their drowning. All 5 diamondback terrapins found in 
this study were associated with marsh habitat: 1 ter- 
rapin in a DCP in a marsh creek of the Cape Fear River 
and 4 juvenile terrapins in a DCP in Topsail Sound, 
where the ICW traverses marsh habitat. All 5 diamond- 
back terrapin were dead yet sufficiently intact for clear 
identification. Hart and Crowder (2011) found that all 
terrapin captures in Jarrett Bay occurred between April 
and mid-May in baited hard-shell and peeler crab pots 
located <321 m from the estuarine shore. 
If they are improperly stored when not in use, crab 
pots can become a threat to wildlife. In Core Sound, 115 
crab pots were tagged and properly outfitted for crab- 
bing, stacked, and stored neatly on the marsh adjacent 
to the area where they were likely to be deployed. We 
found the remnants of bycatch organisms that included 
blue crab, portly spider crab, whelks or hermit crabs, 
and juvenile birds (skulls) in the area of dead marsh 
vegetation adjacent to the stacked pots and presumably 
where pots had been stacked previously. Large numbers 
of crab pots were also stacked along marsh edges at lo- 
cations within Topsail Sound. Neither the stacked crab 
pots found on marshes nor their contents were included 
in the results of this study. 
Derelict crab pots can provide structural habitat for 
organisms, initially supporting a fouling community, 
which subsequently provides forage and refuge habitat 
for other organisms. Organisms, such as Florida stone 
crab and mud crabs, may have chosen to reside in the 
DCPs that were recovered, and others, such as bivalves, 
algae, and tunicates, may have dispersed as propagules 
and then have settled on the pot surfaces. Many of the 
organisms that could freely pass through the pot mesh 
obviously elected to be part of the DCP living commu- 
nity and were probably subsidized energetically by or- 
ganisms that became entrapped and died in pots. East- 
ern oysters had recruited to 17% of the retrieved DCPs 
and therefore specific environmental conditions and pot 
features may have facilitated bivalve recruitment. Per- 
haps DCPs made incapable of retaining bycatch could 
be left in the estuary to support structural habitats 
such as oyster reefs (Fodrie 16 ). 
Future management considerations 
Various management actions have been used to reduce 
the bycatch in DCPs: 1) reduction of the numbers of 
DCPs (e.g., as per NCDMF 9 ); 2) promotion of the use of 
16 Fodrie, J. F. 2010. Personal commun. Inst. Mar. Sci., 
Univ. North Carolina Chapel Hill, Morehead City, NC 28557. 
pots with panels that allow bycatch species and legally 
undersize blue crab to escape; and 3) promotion of the 
use of pots with replaceable biodegradable materials 
that will not remain intact for long after a pot becomes 
derelict. The results of our study may help to evaluate 
the potential effectiveness of these actions and guide 
strategic planning to improve fishery yields and reduce 
wildlife mortality attributable to DCPs. For example, 
our project showed that substantial numbers of DCPs 
were in the water despite the seasonal crab pot clean- 
out program of the NCDMF. That program is limited in 
its effectiveness by the low numbers of marine patrol 
staff available to participate. The clean-out program 
could yield a greater positive effect if other groups or 
individuals were allowed to remove crab pots during 
the crabbing moratorium period, with a requirement 
that they report their findings to NCDMF. 
Commercial and recreational crab pots in North 
Carolina are distinguishable only by the color of their 
float; therefore, when the float is no longer attached, it 
is almost impossible to determine whether a DCP came 
from the recreational or commercial fishery. Through 
establishing separate recruitment study sites in ar- 
eas known to be used exclusively by each fishery, the 
rate at which pots become derelict could be determined 
from the activities of each fishery. This information 
could help fishery managers better allocate between 
the fisheries incentives used for reducing crab pot loss 
or abandonment and resources used for DCP retrieval. 
Our observations of bycatch associated with stacked 
crab pots on the marsh revealed that terrestrial species 
may also be killed as bycatch associated with the blue 
crab fishery. In addition, strong storms may transport 
these stored pots into the estuary and turn a crabber’s 
lost investment into DCPs that ghost fish and kill fish- 
es, crabs, terrapin, and other wildlife. Mandatory rules 
for permit holders that specify proper storage of crab 
pots might reduce the effect of stored crab pots on fish- 
ery species and other wildlife. 
The geographic area of this study was limited by lo- 
gistic and budgetary constraints to selected waterbod- 
ies in North Carolina, within the Central and South- 
ern Districts of the NCDMF. Because Albemarle Sound, 
which is within the Northern District, produced an av- 
erage of 52% of the blue crab landings in North Caroli- 
na from 2006 to 2008 (NCDMF 7 ) and was not included 
in our study, a similarly designed study conducted in 
the Northern District, especially in Albemarle Sound, 
would likely expand the knowledge of DCP density in 
the waters of North Carolina. 
Acknowledgments 
This study was funded in part by the NOAA Marine 
Debris Program, with thanks to H. Bamford, S. Mori- 
son, and C. Arthur. Specific thanks to D. Lee of The 
Tortoise Reserve for input on study protocols. We thank 
C. Rivero for providing essential GIS support for our 
sampling plan. We thank J. Purifoy for sharing his 
