Subject: US Atlantic shark fishery final report

From: [email-masked](Steve Branstetter)
Date: 1 May 1996 15:32:06 GMT

Through the cooperative efforts of the Gulf and South Atlantic Fisheries
Development Foundation and the University of Florida, observers monitored
the commercial shark fishery of the southeast US during 1994 and 1995; that
program continues at least through 1996.   
 
A final report (pending final granting agency approval) summarizing the
results of the first two years of this NMFS-funded program is now
available.  The report may be obtained for five dollars ($5.00 US) to cover
the cost of copying and mailing (sorry we can't send it for free; the feds
frown on using current grant monies to pay costs affiliated with previous
grants) . Payment must be in US funds; personal checks made payable to the
Gulf and South Atlantic Fisheries Development Foundation are acceptable;
sorry, we can't handle credit card orders.  Please reference "Project #56".

Should anyone have any questions, please contact me; contact info is listed
at the bottom of the message.  
 
ABSTRACT- (MARFIN Final Report - Cooperative Agreement NA57FF0008) 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.  In 1994 and 1995, three
observers logged 351 sea days monitoring 276 longline sets during 96
fishing trips.  Approximately 3,000,000 hook-hours of effort produced
nearly 11,000 sharks of 26 different species; this translated to more than
115 metric tons of landings (2.3% of the  U.S. Atlantic commercial shark
landings for the two-year period).  Two species - blacktip sharks
(Carcharhinus 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. 
About 15% of the large- coastal shark catch was released, and some cryptic
mortality (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, overall and depth-specific 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, and almost all blacktip
sharks were taken in these shallower waters.  Approximately 70% of the
sandbar sharks taken in the North Carolina area were female, but females
only comprised 30-60% of the catch in Florida waters.  For blacktip sharks,
only about 25% of the North Carolina catch was female, whereas on both
coasts of Florida, 50-60% was female.  Over the course of a calendar year,
only about 20-30% of the mature female sandbar sharks were documented as
pregnant, but about 50% of the adult female blacktip sharks were pregnant. 
With only two years of data, no conclusive trends can be determined
concerning the health of the shark stock, but given that much of the catch
inside 10-15 fathoms is immature fish, or 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.  Excluding these nearshore efforts, recruitment to the fishery is
substantial by the time sandbar sharks are 135 cm FL (12 yr of age).  Based
on this age structure, a minimum size limit of perhaps 140 cm FL for
sandbar sharks might be an appropriate management measure. Very preliminary
estimates indicate that with such measures, which would equal approximately
a 10% reduction in quota, the sandbar shark stock could increase in numbers
with continued fishing.  

-- 
 
Steve Branstetter, Program Director 
Gulf & South Atl. Fisheries Develop. Fndn. 
Suite 997 Lincoln Center, 5401 W. Kennedy  
Tampa, FL  33609 
 
ph:813-286-8390      fax: 813-286-8261 
e-mail:  [email-masked]