The blue shark was released originally off Port MacDonnell, Australia on the 20th May 2005. The shark was estimated to be 9kg in weight when first tagged and was released on a day when Williams had tagged fifteen using circle hooks. When recaptured, the shark weighed 47kg.

the NNW Game Fish Tagging Program of Australia is the largest saltwater tagging program of its kind in the world and has been in operation since 1973. It is used to obtain information on the biology (distribution, movement, growth, exploitation) of billfish, tunas, sharks and sport fish and encourages game fishers to participate in the management of the fishery.

How the program works
Tags are issued to anglers and when an angler catches, tags and releases a fish, the details of the capture are recorded on a tag card with the corresponding tag number. The card is returned to the I&I NSW in Sydney, Australia. When a tagged fish is recaptured, catch information is linked to the original tag and release and compared to the recapture information. Details of the distance that the fish travelled and its growth are sent to the anglers who first tagged the fish and later recaptured it. A recapture certificate is also issued.

The tagging data is used by scientists to study the lives and habits of these highly mobile fish species. The migratory habits of the tagged fish are observed by measuring the distance and direction travelled between tagging and recapture, and this can be linked with environmental factors. Growth patterns are also monitored. The observations also enable scientists to study the structure of fish stocks and assess whether there is any mixing between populations that are geographically distant from one another. This information is vital to improve the understanding and management of valuable game and sport fish species.

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