GRANT
NUMBER:
NA57FD0067
NMFS NUMBER:
93-SER-060
REPORT
TITLE:
An Expansion of Observer Program to Characterize and Compare
the Southeast U.S. Directed Shark Fishery to Include the
East Coast of Florida
AUTHOR:
Branstetter, Steve; Gulf and South Atlantic Fisheries
Development Foundation
PUBLISH
DATE:
August 1996
AVAILABLE
FROM:
National Marine Fisheries Service, Southeast Region, 9721
Executive Center Drive, North Koger Building, St. Petersburg,
FL 33702. PHONE: (813) 570-5324
ABSTRACT

To garner otherwise
unobtainable information, and thus enhance the reliability
of management strategies, observers aboard voluntarily
participating commercial shark vessels documented a sample
of the catch and effort of the southeast U.S. commercial
shark longline fishery. Specific to this award,
one observer monitored the fishery along the Atlantic
coast of Florida from January 1995 through May 1996. During
that time, he logged 97 sea days, and monitored 107 longline
sets during 30 fishing trips. More important, this effort
extended coverage of a region-wide survey. Since
1994, three observers have logged 460 sea days monitoring
365 longline sets during 127 fishing trips. Approximately
3,700,000 hook-hours of effort produced over 15,000 sharks
of 27 different species; this translated to about 153
metric tons of landings(2.4% of the U.S. commercial shark
landings for the period). Two species, blacktip sharks
(Carcharhninus limbatus), common inshore of the
10 fathom contour, and sandbar sharks (Carcharhinus
plumbeus), dominant in deeper continental shelf waters,
constituted 60-75% of the catch and 75-95% of the landings.
Between 15-20% of the large-coastal shark catch was released,
and some non-documented mortality catch (catch that is
used for bait or discarded) occurred in the fishery; landings
accounted for approximately 90% of the total mortality
on this stock. Nearly 100% of the small-coastal
shark catch (dominated by the Atlantic sharpnose shark,
Rhizoprionodon terraenovae) was landed or used
for bait. Within a region, catch rates between years and
seasons were, for the most part, not statistically different.
For all regions combined, approximately 50% of the documented
catch of sandbar and blacktip sharks was immature. Small
sandbar sharks were more common inshore of the 10-15 fathom
depth range, especially off North Carolina. Almost
all blacktip sharks were taken in shallower (<10 fm)
waters. Given the short term nature of this database (2.5
yr), no conclusive trends can be determined concerning
the health of the shark stock, but because much of the
catch inside 10-15 fathoms is immature fish, and during
the spring include pregnant females, continued fishing
pressure in nearshore (< 10 fm) waters may have substantial
negative impacts on the stock; to the long-term detriment
of the stock and fishery. Reduction of fishing effort,
either through size limits or area-season closures should
reduce mortality on these younger cohorts, thus enhancing
stock recovery.