The National Marine Fisheries Service (NMFS) Cooperative Shark Tagging Program (CSTP) is part of continuing research directed to the study of the biology of large Atlantic sharks. The CSTP was initiated in 1962 with an initial group of less than 100 volunteers. The Program has expanded in subsequent years and currently includes over 6,500 volunteers distributed along the Atlantic and Gulf coasts of North America, and Europe. The tagging methods used in the CSTP have been essentially unchanged during the past 30 years. The two principal tags that are in use are a fin tag (Jumbo Rototag) and a dart tag ("M" tag).

Rototag showing tag number and address.

The rototag is a two piece, plastic cattle ear type tag which is inserted through the first dorsal fin. These tags were primarily used by NMFS biologists on small sharks during the first few years of the CSTP. As the Program expanded to include thousands of volunteer fishermen, the dart tag

"M" tag displaying tagging needle (top) and legend (bottom).

was developed to be easily and safely applied to sharks in the water. The "M" tag is composed of a stainless steel dart head, monofilament line, and a plexiglas capsule containing a vinyl plastic legend with return instructions printed in English, Spanish, French, Japanese and Norwegian. These dart tags, in use since 1965, are implanted in the back musculature near the base of the first dorsal fin. More recently, a Hallprint tag has been used on a limited basis for use on small sharks in the nursery areas.

     Numbered tags are sent to volunteer participants on self-addressed return post cards for recording tagging information (date, location, gear, size and sex of shark), along with a tagging needle, tagging instructions, an Anglers Guide to Sharks of the Northeastern United States, and a current Shark Tagger newsletter. This newsletter is an annual summary of the previous year's tag and recapture data and biological studies on sharks which is sent to all participants in the CSTP. Tagging studies have been mostly single release events in which recoveries are made opportunistically by recreational and commercial fishermen. When a previously tagged shark is re-caught, information similar to that obtained at tagging is requested from the recapturer. Initially, a five dollar reward was sent as an incentive for returning tags; since 1988, a hat with an embroidered logo has been used.

     Between 1962 and 1995, more than 128,000 sharks of 40 species have been tagged and more than 6,000 sharks of 32 species have been recaptured, as a result of the CSTP. Eighty-six percent of the tags are represented by eight species: blue shark Prionace glauca, sandbar shark Carcharhinus plumbeus, dusky shark C. obscurus, tiger shark Galeocerdo cuvier, shortfin mako Isurus oxyrinchus, blacktip shark C. limbatus, scalloped hammerhead Sphyrna lewini and Atlantic sharpnose shark Rhizoprionodon terrraenovae. The number of sharks tagged varies from two for the smalleye hammerhead Sphyrna tudes to 70,303 for the blue shark.

     Numbers of recaptures by species range from one for the Greenland shark Somniosus microcephalus to 3,098 for the blue shark. Eighty-six percent of the recaptures are made up of seven species: blue shark, sandbar shark, tiger shark, shortfin mako, lemon shark Negaprion brevirostris, dusky shark, and nurse shark Ginglymostoma cirratum. The rate of recapture ranges from 1.4% for the Atlantic sharpnose shark to 10.6% for the nurse shark.

     Anglers using rod and reel accomplish the majority of the tagging for all species combined. Biologists, NMFS fisheries observers, and commercial fishermen using primarily longlines, handlines, and nets (gill, trawl) account for the remainder. Conversely, commercial fishermen using longlines and net gear, and rod and reel anglers are responsible for the majority of the recaptures.

     Distances travelled for the 32 species ranged from no movement to 3,740 nautical miles (nmi). In total, one species, the blue shark, travelled distances over 3,000 nmi, three species travelled distances between 2,000 and 3,000 nmi (shortfin mako, dusky and sandbar shark), eight species between 1,000 and 2,000 nmi (tiger, bignose C. altimus, galapagos C. galapagensis, bigeye thresher Alopias superciliosus, night C. signatus, oceanic whitetip C. Iongimanus, blacktip, and porbeagle shark Lamna nasus) and seven species travelled distances between 500 and 1,000 nmi (scalloped hammerhead, spinner C. brevipinna, longfin mako I. paucus, silky C. falciformis, sand tiger Odontaspis taurus, Atlantic sharpnose and white shark Carcharodon carcharias).

     The longest time at liberty for any shark in the CSTP is 27.8 years. Overall, one species of shark, the sandbar shark, has been at liberty over 20 years, three species have been at liberty between 10 and 20 years (dusky, night and tiger shark), and 13 have been at liberty between 5 and 10 years (scalloped hammerhead, shortfin mako, blacknose C. acronotus, bignose, porbeagle, blue, thresher A. vulpinus, nurse, Atlantic sharpnose, blacktip, silky, bull C. Ieucas, and bigeye thresher shark).

     Data from tagging programs, such as the NMFS CSTP, provide valuable information on migration. The need for international cooperation is underscored by the fact that many shark species have wide ranging distributions, frequently traverse national boundaries, and are exploited by multinational fisheries. The CSTP is also an important means to increase our biological understanding of sharks and to obtain information for rational resource management. The tagging of sharks (and other aquatic animals) provides information on stock identity, movements and migration (including rates and routes), abundance, age and growth (including verification/validation of age determination methods), mortality, and behavior.