UNIT 11 SOUTHEAST/CARIBBEAN INVERTEBRATE FISHERIES

INTRODUCTION

	Important recreational and commercial marine invertebrates in the
southeastern United States include shrimp, spiny lobster, stone
crab, conch, and coral (Table 11-1). Some fisheries, as for coral,
are almost nonexistent. Others, like the penaeid shrimp fishery,
are both extensive and extremely valuable: Shrimp are one of the
most valuable U.S. fisheries based on ex-vessel revenue. Some
fisheries, such as those for spiny lobster and stone crab, have
only moderate value on a national basis but are very important
regionally. Because of the diversity in species, fisheries,
geographic locations, yields, values, etc., each species group in
the marine invertebrates must be examined separately for proper
perspective.
	Penaeid shrimp have been fished commercially since the late 1800's.
The first fishery used long seines in shallow water, until the
otter trawl, introduced in 1915, extended shrimping to deeper
waters. At first, most vessels towed one large trawl, sometimes 120
feet wide at the mouth. Soon, a two-trawl arrangement (each about
40-75 feet wide at the mouth) was found more effective. Some
shrimpers are using a twin-trawl system which tows four trawls of
about 40 feet wide at the mouth. The twin-trawl system is now very
common gear on commercial offshore shrimpers. 
	Regulations in the Gulf of Mexico shrimp FMP restrict shrimping by
closing two shrimping grounds. There is a closure of fishing
grounds off Texas for brown shrimp and a closure off Florida for
pink shrimp. Also, there are size limits on white shrimp caught in
Federal waters and landed in Louisiana. These regulations strive to
improve the monetary value of the shrimp fishery.
	In the South Atlantic, white shrimp stocks are centered off the
Georgia and South Carolina coasts. Brown shrimp are centered off
the North and South Carolina coasts. The Atlantic fishery is much
smaller than in the Gulf and currently is managed under a Federal
FMP implemented in November 1993. This FMP provides for compatible
state and Federal closures if needed to protect overwintering
shrimp stocks.
	Spiny lobsters are managed under a joint FMP, coordinated with
regulations by the State of Florida. Current regulations specify a
3-inch minimum carapace length, a closed season from 1 April to 5
August, protection of egg-bearing females, closure of some nursery
areas, recreational bag limits, and a controversial two-day  sport 
season.
	Caribbean spiny lobsters are caught primarily by fish traps,
lobster traps, and divers. The Caribbean Fishery Management
Council's (CFMC) spiny lobster FMP includes the Federal waters of
Puerto Rico and the U.S. Virgin Islands. The Federal plan is based
on a 3.5-inch minimum carapace length and protection of young
egg-bearing lobsters.
	The conch fishery targets the queen conch but also takes other
species. Most conch are taken by divers, and the resource can be
easily depleted. Conch are currently protected in state and Federal
waters off Florida and in the territorial waters of the U.S. Virgin
Islands. An FMP is being developed for the Federal waters off
Puerto Rico and the U.S. Virgin Islands by the CFMC.
Corals are managed as two groups, hard and soft. Because they are
generally slow growing and provide critical habitat for many
fishes, hard corals are protected except for very small collections
taken by permit for research and educational purposes. Regulations
are based on the fact that the value of coral as habitat is far
more important than their commercial use.
	Soft corals include gorgonians and sea fans. Some gorgonians are
taken (about 50,000 colonies per year) for the aquarium and
pharmaceutical industries. Growth potential for most species is
considered limited. Sea fans are completely protected except for
research and educational use by permit.
	Stone crabs are caught mainly off southern Florida, though
some are landed farther north along Florida's west coast. The Gulf
of Mexico stone crab FMP, approved in September 1979, generally
extended Florida's regulations into the EEZ. These regulations are
based on a minimum claw size of 2.75 inches, biodegradable trap
panels, protection of egg-bearing females, and closed seasons.
Minimum size regulations assure that crabs have reproduced at least
once before being caught.

SPECIES AND STATUS

Shrimp

	Brown, white, and pink shrimps account for 89% of the total Gulf of
Mexico shrimp catch. In 1992 alone, these three important species
produced 88,009 t valued at over $367 million in ex-vessel revenue
(Fig. 11-1). They are found in all U.S. Gulf waters inside 60
fathoms (fm). Most of the offshore brown shrimp catch is
taken at 11-20 <%8>f<%0>m depths, white shrimp are caught in 5
<%8>f<%0>m or less, and pink shrimp in 11-15 <%8>f<%0>m. Brown
shrimp are most abundant off the Texas-Louisiana coast, and the
greatest concentration of pink shrimp is off southwestern Florida.
In the South Atlantic, white and pink shrimp landings are about 20%
of their Gulf counterparts, while brown shrimp are less than 10% of
the Gulf yield. <%-3>Current, recent, and long-term potential
yields <%0>for these species are given in Table 11-1.
	Gulf brown and white shrimp catches have increased significantly
over the past 34 years. Pink shrimp catches were stable until about
1985; then they declined in recent seasons and are now at an
all-time low. The numbers of young shrimp for each species entering
the fisheries have generally reflected the level of catch. All
commercial shrimp are harvested at maximum levels. The fishery is
believed to have more boats and gear than needed (i.e. reducing
fishing effort would not significantly reduce the shrimp catch).
Reducing the bycatch of the shrimp industry, <%-3>however, would
help protect finfish resources.
	The number of young brown shrimp produced per parent has increased
significantly, but not in white and pink shrimp. The brown shrimp
increase appears related to marsh alterations. Coastal sinking and
a sea-level rise in the northwestern Gulf inundates intertidal
marshes longer, allowing the shrimp to feed for longer periods
within the marsh area. In the Gulf, both factors have also expanded
estuarine areas, created more marsh edges, and provided more
protection from predators. As a result, the nursery function of
those marshes has been greatly magnified and brown shrimp
production has expanded. However, continued subsidence will lead to
marsh deterioration and an ultimate loss of supporting wetlands,
and current high fishery yields may not be indefinitely
sustainable. Parent stock rates for the three major Gulf species
are shown in Figure 11-1.

Spiny Lobster

	Annual Florida spiny lobster landings were fairly stable during the
1980's, running about 2,700 t from the Gulf of Mexico, but
<%-2>yielding record landings in 1989 of 3,200 t,<%0> with
ex-vessel revenue of about $20 million. On Florida's Atlantic
coast, landings have averaged 230 t, valued at $2 million. The
fishery is considered  overcapitalized,  with about 900,000 lobster
traps in use. Less than half that number of traps would provide the
same catch. Fishermen use live undersized lobster to  seed  traps,
but owing to a high mortality rate for these animals, about 30-50%
of the potential yield is lost. The recreational fishery is large
at the beginning of the season, but its total harvest is unknown.
However, the status of these southeast lobster stocks remain below
their long-term potential yield.
	Annual spiny lobster landings for Puerto Rico have averaged 144 t
over the past 23 years, varying from 108 t in 1972 to a high of 233
t in 1979, then declining to a low of 65 t in 1988. No precise data
are available on fishing effort, but the Puerto Rican stock
produced landings of 72 t in 1992 and now appears to be
overutilized. U.S. Virgin Islands landings for 1980-88 were fairly
stable, averaging 19 t. 
	Spiny lobster larvae may drift at sea for 9 months, and thus
identification of their source or parent stock is almost
impossible; however, we need to know far more about their origins
and movements to improve our management of them. 

Stone Crab\

	Annual catches of stone crab (claw weight) varied from 1,200 to
1,400 t in the Gulf of Mexico through the 1980's. Recent annual
ex-vessel revenue averages $12-15 million. <%-2>Atlantic coast
landings average around 34 t,<%0> worth $120,000 in ex-vessel
revenue. The number of crab traps set increased from 295,000 in
1979-80 to 567,000 in 198<%6>4<%12>-<%0>85 but have been relatively
stable in recent years, though estimated seasonal trap hauls
(fishing effort) increased from 3.6 million in 1985 to 4.8 million
in 1987. Thus, more of the total landings were harvested earlier,
and this shortened the effective length of the fishing season. It
is unlikely, however, that recent maximum production figures can be
sustained on a long-term basis. 

ISSUES

Habitat Concerns

	Estuarine and marsh loss remove critical habitat for young shrimp.
Additional studies are needed to further assess the impacts of
human-induced changes in quantities of habitat, environmental
conditions, predator abundance, and pollution in the nursery areas.
Florida spiny lobsters depend on reef habitat and shallow-water
algal flats for feeding and reproduction. These habitat
requirements may conflict with expanding coastal developments. The
productivity of stone crabs in Florida Bay is related to water
quality and flow through the Everglades. Specific water
requirements need to be identified and maintained through
comprehensive Everglades water management. A unified program to
integrate and study the effects of environmental alterations,
fishing technology, regulations, and economic factors on shrimp,
lobster, and crab production and restoration is needed,
particularly in the reef habitats of south Florida. Steps need to
be taken to mitigate or restore lost estuarine habitats.

Transboundary Stocks and Jurisdiction

	Spiny lobster stocks in Florida could be of Caribbean origin and
swept into the region by currents of the Gulf Stream. Another
hypothesis is that they could comprise a number of different
spawning stocks. The actual sources of all Florida and Caribbean
lobster stocks (both U.S. and foreign) need to be identified and
international management established to prevent overharvesting.

Management Concerns

	Many small spiny lobsters are caught in the Puerto Rican fishery.
If these lobsters were allowed to grow to a larger size before
harvest, there would be a substantial increase in yield by weight.
Modification of the traps to allow more of the small lobsters to
escape needs to be investigated. Small lobsters are sometimes used
to bait traps in the lobster fishery. This current practice is
wasteful and hinders rebuilding the stock.
	A gear conflict between stone crab trappers and shrimp trawlers off
southwestern Florida has been mostly resolved in the EEZ with a
line separating the fishing areas and seasonal area closures. This
approach requires continued monitoring to gauge its success and
prevent renewal of conflicts.
	The shrimp fisheries are currently overcapitalized, with more
fishing effort being expended than needed to harvest the resource.
In addition, the harvesting of small shrimp inshore is sacrificing
yield and value of the catch by cutting short future growth.

Bycatch and Multispecies Interactions

	Shrimp fisheries use small-mesh nets and can catch nontarget
species such as red snappers, croakers, seatrouts, and sea turtles.
For finfish, this harvest is often of juveniles and may be a major
source of mortality on these young fish. Some fish caught by
shrimpers are currently at low stock levels (Unit 9). This bycatch
may slow or prevent recovery if not mitigated.
	Sea turtles are all listed as endangered or threatened under the
ESA. Shrimp vessels have been required to use turtle excluder
devices in their nets during certain times of the year since 1988
to avoid capturing sea turtles and thus protect the stocks.

Progress

	NMFS and the fishing industry are working together to prepare a
research plan to address the problems of finfish bycatch by shrimp
fisheries in the Gulf of Mexico and South Atlantic.