Horizontal and vertical movements of white marlin, Kajikia albida, tagged off the Yucatán Peninsula

The white marlin, Kajikia albida, is a highly migratory, prized sport fish of conservation concern. Improved understanding of white marlin ecology, including habitat use, will inform management measures. To improve white marlin movement knowledge in a region with limited information, we tagged 18 individuals off the eastern Yucatan Peninsula, Mexico with pop-up satellite archival transmitters. Tracks lasting 9–328 d, yielded data across 1277 d, and covered distances of 891–10 579 km. Horizontal movements varied greatly with ten individuals remaining in the Gulf of Mexico/northwestern Caribbean and eight individuals entering the western North Atlantic. Although white marlin experienced a temperature range of 10.0–33.6 °C, the majority of time was spent in waters >24 °C. Marlin displayed diel diving patterns with deeper dives occurring more frequently during the daytime. As water columns warmed, dive duration, maximum daily depth, and dive depth all increased. As a result, 18% of the time was spent at depths >100 m in the warmest water columns compared with <1% in the coldest water columns. Although the thermal characteristics of the water column greatly influence white marlin diving behaviour, the generally shallow distributions provide a way of separating white marlin from important fishery species.