Observations of mesoscale movements in the short-tailed stingray, Dasyatis brevicaudata from New Zealand using a novel PSAT tag attachment method

Short-tailed stingrays (Dasyatis brevicaudata) are the largest stingrays in the world. They are common in New Zealand waters and aggregate seasonally in large numbers at the Poor Knights Islands Marine Reserve (PKMR), where they are a major attraction. Pop-up satellite archival tags (PSAT) were attached to two female short-tailed stingrays at two New Zealand offshore islands (within and nearby the PKMR) to investigate patterns of movement. These are the first PSAT data published for a stingray species. The rays were tagged for 62 and 151 days using a novel method of tag attachment developed specifically for ray species. Analyses of geolocation, depth and behavioural data indicate neither ray moved large distances (≤ 25 km) from the tagging locations. However, they showed a seasonal shift to deeper waters, progressively increasing time spent at greater depths and decreasing time spent at shallow depths towards winter. In addition, one ray displayed strong diel vertical movements. The method developed for PSAT attachment to stingrays proved successful and can be applied for long-term (> 6 months) movement and behavioural studies.