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. 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.
Anglers using rod and reel accomplish the majority of the tagging for all species combined.
Conversely, commercial fishermen using longlines and net gear, and rod and reel anglers are responsible for the majority of the recaptures. The longest time at liberty for any shark in the CSTP is 27.8 years. 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.