Striped marlin (Tetrapturus audax) movements and habitat utilization during a summer and autumn in the Southwest Pacific Ocean

Six striped marlin (Tetrapturus audax) were caught on hook and line from recreational fishing boats near northern New Zealand (34oS 174oE) and tagged and released with pop-off satellite archival tags. For periods ranging from 22-60 days over the geographic range 168oE-170oW and 13-34oS, five tags collected a total of 202 days (range of 21-60 days) of data. These data permit the investigation of striped marlin geographic and vertical movements and water temperatures occupied from February to June 2003. One hundred and one days of geoposition data showed a preliminary view of their movements in and around New Zealand waters. Transmitted temperature and depth data indicated striped marlin spent 80% (±2%) of their time in the mixed layer including 72% (±2%) of their time in the top 5 metres. Temperature data indicated 75% (±10%) of the striped marlin's time was spent in water temperatures between 20.1°C and 24.0°C. Tagged striped marlin moved faster during periods of directed movement away from New Zealand versus periods of passive movements when the fish were proximal to New Zealand or not moving in any specific direction. These data support some existing hypothesis about striped marlin physiological ecology and provides preliminary suggestions about how striped marlin bycatch might be reduced.