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Pop-up Satellite Archival Tags (pop-up + satellite_archival_tag)
Selected AbstractsMovement and behaviour of large southern bluefin tuna (Thunnus maccoyii) in the Australian region determined using pop-up satellite archival tagsFISHERIES OCEANOGRAPHY, Issue 5 2008TOBY A. PATTERSON Abstract Pop-up satellite archival tags (PSATs) were deployed on 52 large (156,200 cm length to caudal fork) southern bluefin tuna (Thunnus maccoyii) in the western Tasman Sea during the austral winters of 2001,2005. Southern bluefin tuna (SBT) were resident in the Tasman Sea for up to 6 months with movements away from the tagging area occurring at highly variable rates. The data indicated a general tendency for SBT to move south from the tagging area in the Western Tasman Sea. Four individuals migrated west along the southern continental margin of Australia and into the Indian Ocean. Three individuals moved east into the central Tasman Sea, with one individual reaching New Zealand. We also describe the first observed migration of an SBT from the Tasman Sea to the Indian Ocean spawning grounds south of Indonesia. Individuals spent most of their time relatively close to the Australian coast, with an estimated 84% of time spent in the Australian Fishing Zone. SBT favored temperatures between 19 and 21°C, adjusting their depth to the vertical temperature distribution. Distinct diurnal diving patterns were observed and adjustment of depth to maintain constant ambient light levels over a 24-h period. The findings of this study are a significant advance toward greater understanding of the spatial dynamics of large SBT and understanding the connectivity between distant regions of their distribution. [source] Near real-time spatial management based on habitat predictions for a longline bycatch speciesFISHERIES MANAGEMENT & ECOLOGY, Issue 6 2006A. J. HOBDAY Abstract, Southern bluefin tuna (SBT), Thunnus maccoyii (Castelnau), is a quota-managed species that makes annual winter migrations to the Tasman Sea off south-eastern Australia. During this period it interacts with a year-round tropical tuna longline fishery (Eastern Tuna and Billfish Fishery, ETBF). ETBF managers seek to minimise the bycatch of SBT by commercial ETBF longline fishers with limited or no SBT quota through spatial restrictions. Access to areas where SBT are believed to be present is restricted to fishers holding SBT quota. A temperature-based SBT habitat model was developed to provide managers with an estimate of tuna distribution upon which to base their decisions about placement of management boundaries. Adult SBT temperature preferences were determined using pop-up satellite archival tags. The near real-time predicted location of SBT was determined by matching temperature preferences to satellite sea surface temperature data and vertical temperature data from an oceanographic model. Regular reports detailing the location of temperature-based SBT habitat were produced during the period of the ETBF fishing season when interactions with SBT occur. The SBT habitat model included: (i) predictions based on the current vertical structure of the ocean; (ii) seasonally adjusted temperature preference data for the 60 calendar days centred on the prediction date; and (iii) development of a temperature-based SBT habitat climatology that allowed visualisation of the expected change in the distribution of the SBT habitat zones throughout the season. At the conclusion of the fishing season an automated method for placing management boundaries was compared with the subjective approach used by managers. Applying this automated procedure to the habitat predictions enabled an investigation of the effects of setting management boundaries using old data and updating management boundaries infrequently. Direct comparison with the management boundaries allowed an evaluation of the efficiency and biases produced by this aspect of the fishery management process. Near real-time fishery management continues to be a realistic prospect that new scientific approaches using novel tools can support and advance. [source] Movement and behaviour of large southern bluefin tuna (Thunnus maccoyii) in the Australian region determined using pop-up satellite archival tagsFISHERIES OCEANOGRAPHY, Issue 5 2008TOBY A. PATTERSON Abstract Pop-up satellite archival tags (PSATs) were deployed on 52 large (156,200 cm length to caudal fork) southern bluefin tuna (Thunnus maccoyii) in the western Tasman Sea during the austral winters of 2001,2005. Southern bluefin tuna (SBT) were resident in the Tasman Sea for up to 6 months with movements away from the tagging area occurring at highly variable rates. The data indicated a general tendency for SBT to move south from the tagging area in the Western Tasman Sea. Four individuals migrated west along the southern continental margin of Australia and into the Indian Ocean. Three individuals moved east into the central Tasman Sea, with one individual reaching New Zealand. We also describe the first observed migration of an SBT from the Tasman Sea to the Indian Ocean spawning grounds south of Indonesia. Individuals spent most of their time relatively close to the Australian coast, with an estimated 84% of time spent in the Australian Fishing Zone. SBT favored temperatures between 19 and 21°C, adjusting their depth to the vertical temperature distribution. Distinct diurnal diving patterns were observed and adjustment of depth to maintain constant ambient light levels over a 24-h period. The findings of this study are a significant advance toward greater understanding of the spatial dynamics of large SBT and understanding the connectivity between distant regions of their distribution. [source] Bigeye tuna (Thunnus obesus) vertical movements in the Azores Islands determined with pop-up satellite archival tagsFISHERIES OCEANOGRAPHY, Issue 2 2008H. ARRIZABALAGA Abstract Movement patterns of 17 bigeye tuna (Thunnus obesus) near the Azores Islands were analyzed between April and May 2001 and 2002 using pop-up satellite archival tags. Despite short attachment durations (1 to 21 days, 8.2 days on average), their vertical movements revealed much shallower distribution of bigeye tuna in comparison with previous studies in the tropical Pacific and tropical Atlantic. Depth and temperature histograms were unimodal, although overall depth distribution during the day was deeper than during the night due to daily incursions in deeper waters. Although generalized additive models showed significant non-linear relationships with weight of the fish and sea level anomaly (as a proxy for variability of thermocline depth), the effect of these variables on bigeye depth appeared minor, suggesting that vertical movements of bigeye in the Azores during the spring migration may be influenced by food availability in upper water layers. [source] | ||||||||||