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HARBOR SEAL TRACKING AND TELEMETRY BY SATELLITE
Author(s) -
Stewart Brent S.,
Leatherwood Stephen,
Yochem Pamela K.,
HeideJørgensen MadsPeter
Publication year - 1989
Publication title -
marine mammal science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.723
H-Index - 78
eISSN - 1748-7692
pISSN - 0824-0469
DOI - 10.1111/j.1748-7692.1989.tb00348.x
Subject(s) - harbor seal , telemetry , elephant seal , seal (emblem) , satellite , oceanography , southern elephant seal , drifter , fur seal , aerial survey , satellite tracking , remote sensing , environmental science , geology , phoca , fishery , geography , engineering , telecommunications , documentation , archaeology , computer science , physics , lagrangian , aerospace engineering , mathematical physics , biology , programming language
A bstract We tested a satellite Platform Transmitter Terminal (PTT) in the laboratory (on a float and on captive seals) and on a free‐ranging harbor seal in the Southern California Bight to investigate the utility of satellite telemetry in documenting seals’at‐sea behavior and movements. We used records from a microprocessor‐based time‐depth recorder (TDR) to interpret location and diving records from the PTT. For the free‐ranging harbor seal, we obtained at least one uplink during 70% (while the seal was at sea) to 82% (while she was ashore) of satellite passes and at least one location each day. Of 62 locations determined by Service Argos for the free‐ranging seal, 20 were verified from TDR records to have been at sea; these indicated that the seal may have ranged up to 48 km from the haul‐out site, although most locations were within 5 km. The accuracies of locations calculated when the seal was at sea (±15 km) were substantially less than when it was ashore (±1.5 km), thus limiting at‐sea tracking of seals by satellite to rather gross movements. Fewer transmissions were detected and locations calculated when the seal was actively diving than when it was swimming near the surface as it departed from or returned to the haul‐out site. Consequently, average dive durations indicated by the PTT were substantially shorter than those calculated from TDR records. Documentation of foraging areas and detailed at‐sea movements using satellite technology may not be possible for pinnipeds unless PTT‐transmission rates are increased substantially from the 1 per 45 set maximum rate now permitted by Service Argos.