UNC-SG-BP-12-01
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BLUEPRINTS
North Carolina
- NORTH CAROLINA SEA GRANT * NC STATE UNIVERSITY BOX 8605 RALEIGH, NC 27695-8605
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Blue Crab Aquaculture in Ponds
Potentials and Pitfalls
North Carolina’s Blue Crab Fishery
As North Carolina's number one fishery, blue crabs,
Calllnecte s sapidus, are part of an important industry
for numerous coastal communities. The fishery supports
commercial fishermen, dealers, gear providers and processors
throughout the year. Fluctuations in landings have led to
concerns over crab populations and the livelihood of the
commercial crabbers they support.
Continued demand for blue crab, coupled with fishery
concerns, have driven some to consider the species for
aquaculture, either for restoration efforts or for food
production. Further, crabbers have expressed interest in using
farm ponds as holding areas for shedding operations and for
growing smaller, lower-grade crabs for more profit.
Although various forms of crustacean aquaculture have
succeeded, mainly for shrimp, commercial blue crab
aquaculture has yet to be proven viable. To date, such efforts
have been limited to research projects, several of which are
outlined in this report.
Supplying Juveniles
Commercial production of any species relies on a supply of
larvae or juveniles for growing to market size. For most marine
Figure 1. Two larval stages of the blue crab, Callinectes
sapidus (Stuck and Perry, 1982).
species, producing larvae or juveniles is difficult because of
the numerous developmental stages that occur during their
early life history. Blue crabs are no different, spending 31
to 49 days as zoea and 6 to 20 days as megalopa before
becomingjuvenile crabs (Figure 1).
The first successful attempt at mass producing juvenile blue
crabs was completed in 2005, by researchers at the Center for
Marine Biotechnology, University of Maryland Biotechnology
Institute (Zmora et al., 2005). Over four culture cycles, 40,000
juvenile blue crabs were produced. The major limitation was
cannibalism during the megalopal and early juvenile stages
of production. Additional work has also been conducted
at Southern Mississippi University’s Gulf Coast Research
Laboratory. However, there have been no commercial efforts
to create a supply of juvenile blue crabs.
Producing Market-Size Crabs in North Carolina
Blue crabs harvested from North Carolina waters are sold
as soft or hard crabs, with dramatically different market
value. Depending on grade and availability, soft crabs may
cost substantially more than hard crabs. For this reason, and
because soft crabs may be legally sold at a smaller size (male
hard crabs must be 5 inches or greater in North Carolina),
production of soft crabs will likely be the targeted product for
aquaculture.
Producing market-sized crabs from juveniles has been
accomplished, with varying success, in farm or aquaculture
ponds. While it is common for candidate aquaculture species
to be first evaluated in tanks, pond aquaculture was evaluated
primarily for cost savings, in addition to the availability of farm
ponds in Eastern North Carolina, where interest was present.
Further, it was assumed that cannibalism posed less of a risk
to production because of the space advantage present in
ponds.
Between 2001 and 2007, the North Carolina Blue Crab and
Shellfish Research Program (BCSRP), administered by North
Carolina Sea Grant, supported four projects evaluating the
growth and survival of juvenile blue crabs reared in ponds. The
results are summarized below.
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