Tagged Shark

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).

Rototag showing tag number and address

Rototag showing tag number and address.

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
'M' tag displaying tagging needle (top) and legend (bottom)

"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.

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.

For more information on the NMFS Cooperative Shark Tagging Program, please contact:

Apex Predators Program
28 Tarzwell Drive
Narragansett, RI 02882-1199 USA

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(File Modified Jul. 25 2017)