Hatchling short-necked turtles (Emydura macquarii) select aquatic vegetation habitats, but not after one month in captivity

Knowledge of turtle hatchling ecology is fundamental for managing wild populations. Information on habitat selection by turtle hatchlings is particularly important to ensure that conservation programmes that release hatchlings into the wild give them the best chances of surviving to adulthood. Currently, knowledge of the ecology of turtle hatchlings worldwide is limited, which restricts evidence-based management for threatened species. Here, we used laboratory and field experiments to test for effects of captivity on habitat selection, movement, and short-term survival of Murray River turtle hatchlings (Emydura macquarii). This species has declined > 60% since the 1970s, and a conservation plan is urgently needed to manage their recovery. In both the laboratory and field, we found that hatchlings select aquatic vegetation when it is available. Hatchlings raised in captivity for a month, however, were radio-tracked in habitats significantly further from vegetation after release, and over three times as many of these hatchlings were attacked by predators, compared to those released immediately after hatching. Aquatic vegetation is clearly an important habitat for hatchling E. macquarii, and therefore, (i) hatchling conservation should prioritise areas with appropriate aquatic vegetation, and (ii) aquatic vegetation restoration should be prioritised to ensure E. macquarii hatchling survival in the wild. Moreover, since captivity affects hatchling habitat selection, E. macquarii hatchlings should be released immediately upon hatching. Further research on soft release techniques and longer-term captivity is required to determine whether the impact of captivity can be reduced.