Shark Science
In meeting its Congressional mandate under the Magnuson-Stevens Fishery
Conservation and Management Act to rebuild shark populations in the United
States, NOAA Fisheries conducts shark research on a periodic basis to
determine the abundance of shark species. The data collected by scientists
in these research programs provide fishery managers with critical information
they need to monitor shark populations and implement fishery regulations
to maintain population levels.
Unfortunately, our scientific data collections lagged behind the rapid technological advancements that allowed fishermen to catch large numbers of sharks in a relatively short period of time. Since the mid-1980s, a number of shark populations in the United States have declined, primarily due to overfishing.
But our knowledge about sharks and shark fisheries is getting better. In 1993, NOAA Fisheries implemented a management plan for Atlantic sharks that limited the amount of sharks that commercial and recreational fishermen could catch per day. The agency also began collecting standardized information about the fisheries, such as the average size and age of species caught in certain areas. The standardized information is helping scientists to identify which stocks are depleted and in need of further protection under the law as well as determine when stocks are rebuilding.
Also since 1993, shark
data collection programs have been growing and evolving. Besides collecting
its own scientific data, NOAA Fisheries has created partnerships with
other shark science organizations, universities, and fishermen to collect
and analyze the information managers need to adequately manage shark resources.
Below are only a few of the research programs that are being conducted.
Data Collection Programs
Tagging Studies & Bottom Longline Surveys
Partnering fishermen with tagging programs helps scientists determine
shark migration patterns and distributions. In one tagging program, between
1962 and 2000, more than 165,000 sharks (40 species) were tagged and more
than 9,500 (32 species) were recaptured. Another tagging program using
acoustic telemetry has documented that certain shark species return to
their birthplace in annual cycles. A satellite archival tagging program
in the Pacific Ocean has revealed that white sharks are not restricted
to shallow waters but that they are also found in deep pelagic waters.
Bottom longline surveys, using standard commercial fishing gear, help scientists determine the status of the fishery based on effort (the number of hours the gear is in the water), gear (the number of hooks on a line) and catch (how many sharks were caught and how many species). These surveys also help determine if the gear catches untargeted species, such as protected sea turtles.
Commercial Fishermen Logbooks
Fishermen have been keeping records of their fishing activities for decades.
Logbooks help them keep track of the best fishing grounds and provide
them with an historical account of their catches. Likewise, successful
fishery management programs benefit from this kind of information, which
tracks the catch trends in fisheries over time. From fishermen's logbooks,
NOAA Fisheries can determine which species are caught in which habitats,
what kind of gear is most efficient and catches the least amount of bycatch,
and how many non-targeted species are caught dead and thrown back. Logbooks
are pertinent for determining over time how many sharks a fisherman can
catch based on how many hours he is fishing. If fishermen increase their
hours at sea, but find that their catch is decreasing, that signals a
problem with the stock abundance.
Habitat
NOAA Fisheries is participating in a number of studies designed to determine
shark habitat needs and essential fish habitat. These studies include
shark tagging and reproductive studies. Along the Atlantic coast, the
Cooperative Atlantic States Shark Pupping and Nursery Survey is a cooperative
program between States and the Federal government that conducts ongoing
investigations of shark nursery grounds. Similar habitat studies in the
Pacific Ocean has resulted in the designation of essential fish habitat
for blue, common thresher, bigeye thresher, pelagic thresher, and shortfin
mako.
Observer Programs
Fishermen targeting sharks are required to allow official observers to
accompany the vessel on any given fishing trip when NOAA Fisheries requests
observer coverage. By observing fishing activities, scientists can gather
information not required in logbooks, such as size and sex of the fish.
Observer coverage also helps verify logbook data.
Telephone and Dock-Side Surveys
Information from recreational fishermen is collected via random telephone
and dock-side surveys. These surveys provide NOAA Fisheries with state
and regional estimates of recreational catch, effort, and participation
in marine fisheries. This information can be used in stock assessments.
For Further Information Contact: (301) 713-2370