Tagging sharks

Anglers can help scientists find out where sharks go and how fast they grow by measuring, tagging, and releasing them. Tens of thousands of sharks have been tagged since the 1950s, off the coasts of the USA and Australia as well as the UK and Africa. A few tags are recovered when fishermen catch these sharks again. The record is for a male Australian tope, which was first tagged in 1951 and recaptured in 1986, 214 km (130 miles) from its original release site. Its length had increased by 17 cm (7 in). Blue sharks are among the greatest ocean travellers. One tagged near New York was caught 16 months later off Brazil, 6000 km (3600 miles) away, while another tagged off the UK’s Devon coast was recaptured off Brazil, 7000 km (4200 miles) away.