DIVE DATA FROM SATELLITE TAGS AND TIME-DEPTH RECORDERS - A COMPARISONIN WEDDELL SEAL PUPS

The diving behavior of juvenile Weddell seals, Leptonychotes weddellii , was monitored simultaneously with time-depth recorders (TDRs) and sa tellite-linked time-depth recorders (SLTDRs). Recovered TDRs provided a complete record of the depth and duration of all dives, while data r eceived from SLTDR tags via the ARGOS satellite system were compressed into the number of dives in each of six depth or duration bins. The d ive information from the two types of tags was compared to determine i f data compression, processing, and transmission influenced the data r eceived. While only half of the dive data collected by TDRs was also r eceived from the SLTDR tags, the chance of receiving SLTDR data was in dependent of when diving occurred, when data was transmitted, and the subsequent dive activity In addition, the number of dives in each dept h and duration bin was an accurate representation of the actual dive b ehavior. Therefore, SLTDR tags were judged to provide data qualitative ly similar to that provided by TDRs. The accuracy of seal locations pr ovided by Service ARGOS was estimated by comparison to Global Position ing System (GPS) locations, and the average position error found to be significantly greater than predicted by Service ARGOS or reported in other studies (LC0 locations +/-11.4 km, LC1 +/-5.0 km).