Bomb-Dated Growth Dynamics of Arctic Fishes

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ABSTRACTOPP-9985884JonesThis research seeks to independently validate age determinations of Arctic fish. It is believed that Arctic marine fish may be older than the dates typically assigned from annual growth rings in their otoliths (ear-bones). If fish ages are underestimated in population models, the models will overestimate the ability for the regional fisheries to recover from existing or planned catch limits. This may be one reason for drastic population declines in other fisheries which were associated with over-fishing. To evaluate the accuracy of age assessments based on otolith ring counts, otoliths from a variety of Arctic fish species will be tested for otolith age and measuring the carbon-14 (C14) content of the otolith rings. Because otolith C-14 content closely matches the C14content in surface waters, and because the surface water content of C14 has changed dramatically throughout the last 50 years due to bomb testing, this approach provides a unique and relatively simple test of the accuracy of the traditional method. A new approach based on measuring the fall-out derived strontium-90 (Sr90) content of otoliths will be attempted. In addition, dating of fish scales will be investigated by these methods.