North Pacific Research Board
Age validation of big (Raja binoculata) and longnose (R. rhina) skates using bomb- derived radiocarbon (14C)
Recently, directed fisheries for big (Raja binoculata) and longnose (R. rhina) skates have re-emerged in the Gulf of Alaska. Because of their unique biological traits (e.g. long life span, slow growth, low fecundity, and late age at maturity) these species may be at risk of severe population declines that may eventually lead to a compromise in their ability to sustain fishing pressure and recover from overexploitation. Accurate age estimation is fundamental to robust assessment and management of these species since accurate ages are essential for growth, maturity and fecundity parameter estimation. Accurate ages can only be provided with age determination methods that have been validated. To provide age validation, bomb radiocarbon dating techniques on archival big and longnose skate vertebrae will be employed. Standard vertebral age determination methods using thin sectioning will be compared to an innovative histological method to develop improved ageing criteria for skates, both of which will be compared to a known age reference via the bomb-radiocarbon. Successful completion of this project will provide fishery scientists and resource managers with improved biological information critical for effective assessment and management of these species. Big skate and longnose skate fisheries in Alaska are an emerging fishery and accurate biological data will help establish species-specific regulations and quotas ensuring sustainability in these vulnerable species.
Data and Resources
Start Date: 2012/07/01
End Date: 2014/02/28