Brenda L. Norcross
Derek Wilson
Jennifer L. Nielsen
Andrew C. Seitz
2006
<p><span class="EXLDetailsDisplayVal">We evaluated <span class="searchword">light</span>-<span class="searchword">based</span> <span class="searchword">geolocation</span> estimates from pop-up satellite tags in high <span class="searchword">latitudes </span>because some of the largest fisheries in the world are in areas where this technique has not been assessed. Daily longitude and latitude were estimated by using two Wildlife Computers software programs: 1) Argos Message Processor (AMP), which summarizes <span class="searchword">light</span> intensity data transmitted to satellites, and 2) Time Series Processor (TSP), which uses more detailed data obtained from retrieved tags. Three experiments were conducted in the <span class="searchword">northern</span> Gulf of Alaska using tags placed on 1) Pacific halibut in outdoor aquaria, 2) a fixed mooring line at various depths and 3) wild Pacific halibut. TSP performed better than AMP because the percentage of days with <span class="searchword">geolocation</span> estimates was greater and the mean error magnitude and bias were smaller for TSP and increased with depth for both programs; however, latitude errors were much greater than longitude errors at all depths. <span class="searchword">Light</span>-<span class="searchword">based</span> <span class="searchword">geolocation</span> enabled us to discern basin-scale movements and showed that the Pacific halibut in our study remained within the Gulf of Alaska. We conclude that this technique provides a feasible method for inferring large-scale population structure for demersal fishes in high latitudes.</span><span> </span></p>
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NOAA National Marine Fisheries Service
Evaluating light-based geolocation for estimating demersal fish movements in high latitudes
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