| Summary: | Published by PLoS ONE and copyright of Costa et al. The definitive version of this article is available at: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0008677 Background: ARGOS satellite telemetry is one of the most widely used methods to track the movements of free-ranging marine and terrestrial animals and is fundamental to studies of foraging ecology, migratory behavior and habitat-use. ARGOS location estimates do not include complete error estimations, and for many marine organisms, the most commonly acquired locations (Location Class 0, A, B, or Z) are provided with no declared error estimate. Methodology/Principal Findings: We compared the accuracy of ARGOS locations to those obtained using Fastloc GPS from the same electronic tags on five species of pinnipeds: 9 California sea lions (Zalophus californianus), 4 Galapagos sea lions (Zalophus wollebaeki), 6 Cape fur seals (Arctocephalus pusillus pusillus), 3 Australian fur seals (A. p. doriferus) and 5 northern elephant seals (Mirounga angustirostris). These species encompass a range of marine habitats (highly pelagic vs coastal), diving behaviors (mean dive durations 2???21 min) and range of latitudes (equator to temperate). A total of 7,318 ARGOS positions and 27,046 GPS positions were collected. Of these, 1,105 ARGOS positions were obtained within five minutes of a GPS position and were used for comparison. The 68th percentile ARGOS location errors as measured in this study were LC-3 0.49 km, LC-2 1.01 km, LC-1 1.20 km, LC-0 4.18 km, LC-A 6.19 km, LC-B 10.28 km. Conclusions/Significance: The ARGOS errors measured here are greater than those provided by ARGOS, but within the range of other studies. The error was non-normally distributed with each LC highly right-skewed. Locations of species that make short duration dives and spend extended periods on the surface (sea lions and fur seals) had less error than species like elephant seals that spend more time underwater and have shorter surface intervals. Supplemental data (S1) are provided allowing the creation of density distributions that can be used in a variety of filtering algorithms to improve the quality of ARGOS tracking data. This research was conducted as part of the Tagging of Pacific Predators (TOPP) program, and was supported in part by the Dr. Earl H. Myers and Ethel M. Myers Oceanographic, Marine Biology Trust, the Friends of Long Marine Lab, the Charles Darwin station, UCMEXUS, Center For Remote Sensing (UCSC), the National Ocean Partnership Program (N00014-02-1-1012), the Office of Naval Research (N00014-00-1-0880, N00014-03-1-0651 and N00014-08-1-1195), National Science Foundation OPP grants ANT-0523332 and ANT-0440687-02, International Association of Oil and Gas Producers contract JIP2207-23, the Moore, Packard, and Sloan Foundations and the Australian Research Council. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
|
|---|