Shark Tagging Program Details

NMFS Cooperative Shark Tagging Program

The National Marine Fisheries Service (NMFS) Cooperative Shark Tagging Program (CSTP) is a collaborative effort between recreational anglers, the commercial fishing industry, and NMFS to study the life history of Atlantic Sharks. The CSTP was initiated in 1962 with an initial group of less than 100 volunteers. The program has expanded in subsequent years to include thousands of volunteers distributed along the Atlantic and Gulf coast of North America and Europe. The tagging methods used in the CSTP have been essentially unchanged during the past 52 years. The two principal tags that are in use are a fin tag (Jumbo Rototag) and a dart tag (“M” tag).

The rototag is a two piece, plastic cattle ear 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 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.

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, current management information, and shark ID placards. 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.

Shark Swimming

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.

Between 1962-2016, over 290,000 fish of 52 species have been tagged and more than 17,000 fish of 33 species have been recaptured. The rate of recapture ranges from 1.2% for the blacknose shark to 13.5% for the shortfin mako. Distances traveled for the 33 species ranged from negligible movement to 3,997 nautical miles (nmi) (blue shark). The longest time at liberty for any shark in the CSTP is 27.8 years (sandbar shark).

Data from tagging programs, such as the NMFS CSTP, provide valuable information on migration and the extent of fish movements. The need for international cooperation in such work 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 and validation of age-determination methods), mortality, and behavior.




All identifiable shark species except smooth dogfish (Mustelus canis) and spiny dogfish (Squalus acanthias) can be tagged. Tagging area is the North Atlantic, Gulf of Mexico, and the Caribbean & Mediterranean Seas.


Please do not open the capsule prior to tagging. Capsules contain the following message in English, Spanish, French, Norwegian, and Japanese:M Tag


tag pole

Commercial tag poles are available for purchase, or you may construct your own.

Tagging needles should be firmly mounted in 1″ to 1¼” diameter hardwood doweling 6′ to 8′ long, and should protrude from the pole 2½”.

The dart head fits loosely into the slotted point in the needle, and the entire tag is held in place by rubber bands 2″ to 3″ up on the pole. The dart head should be curved so that the two rear points will face downwards into the muscle when the tag is inserted.

tags on tagging pole

Tags should be driven into the back near the first dorsal fin. This area lies to the side of the backbone and above the body cavity. The ideal location on large sharks is in the muscle at the very base of the first dorsal fin.

Position of tag on shark

It is most important that the capsule assumes a TRAILING POSITION on the shark. Insert the dart at an angle toward the head end of the fish. The skin of a shark is well known for its toughness, but by holding the pole 2′ to 3′ above the shark and making a strong, quick thrust, the dart should penetrate even large fish.

When the tag is correctly inserted, the dart head will come to rest approximately 1″ to 1½” beneath the shark’s skin. If you fish from shore or catch many small sharks, the tagging needle can be mounted in a short handled dowel (8″). In tagging small sharks, care must be taken to avoid injury to the backbone. To control the depth of penetration of the dart head, an incision can be made with the point of a knife and the dart head then carefully forced into the muscle. We do not recommend tagging sharks less than 3′ in length with dart tags.




Male diagram

adult male photo
juvenile male photo


female diagram

female photo