Near real time satellite tracking of striped marlin ( Kajikia audax ) movements in the Pacific Ocean
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ORIGINAL PAPER
Near real time satellite tracking of striped marlin (Kajikia audax) movements in the PaciWc Ocean John C. Holdsworth · Tim J. Sippel · Barbara A. Block
Received: 14 March 2008 / Accepted: 28 November 2008 / Published online: 19 December 2008 © Springer-Verlag 2008
Abstract High-resolution satellite locations were obtained from striped marlin using Argos transmitters attached to the upper lobe of the caudal Wn. Twenty-six striped marlin were tagged oV New Zealand (2005–2007) and tracked as far as the central PaciWc Ocean. Caudal Wn mounted Argos tags generated 1,524 locations during a total of 659 tracking days [mean 25 (§21.24) days per Wsh and 2.3 (§2.30) locations per day]. 38% of locations have an estimated accuracy of §1 km or better. Displacement rates from high quality locations ranged from 2.9 to 170.8 km in a 24 h period, with a mode at 20–30 km and a mean of 45 km/day. The caudal Wn attachment methodology and antenna conWguration was adjusted each season to improve transmission life and data quality, with the best results obtained in the last year of deployments (2007). The longest track duration was 102 days, with a total displacement of 4,959 km and a total track distance from all locations received of 6,850 km. Tag shedding and antenna failure appear to have limited the duration of tracks from SPOT tags. The high temporal and spatial resolution data revealed behaviours not previously observed in striped marlin,
Communicated by M.I. Taylor. J. C. Holdsworth (&) · T. J. Sippel Blue Water Marine Research, PO Box 402081, Tutukaka, New Zealand e-mail: [email protected] T. J. Sippel School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand B. A. Block Tuna Research and Conservation Center, Hopkins Marine Station, Stanford University, PaciWc Grove, CA 93950, USA
including associations to subsurface bathymetric features. High resolution location data such as these are useful inputs for statistical models used to investigate habitat selection and switching between diVerent behavioural modes. The geolocations calculated using ukfsst estimates from PAT tag data had RMS errors of 1.01° latitude and 0.59° longitude when compared with SPOT tag Argos locations.
Introduction Striped marlin (Kajikia audax, Family Istiophoridae) (Collette et al. 2006) are a wide ranging pelagic Wsh found in the Indo-PaciWc Ocean. They are a high proWle recreational species in some countries such as New Zealand, and are also an important commercial species elsewhere in their range. Historically, movements of highly migratory species (HMS) including striped marlin were inferred from seasonal shifts in commercial catch per unit eVort (CPUE) data (Kume and Joseph 1969; Squire and Suzuki 1990) and from conventional mark and recapture techniques (Ortiz et al. 2003). These methods rely on an overlap between Wshing activity and striped marlin distribution so are Wsheries dependent. Striped marlin have a wide latitudinal distribution occurring from 45°N to 45°S latitude mainly in t
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