Husbandry of Newly Born Endangered White's Seahorse, <i>Hippocampus whitei</i> , for Conservation Stocking

ABSTRACT Conservation stocking programmes have been increasingly used to reverse wildlife population declines; however, the success of such programmes can often depend on the number and fitness of animals translocated or released. The White's seahorse Hippocampus whitei is an endangered seahorse species endemic to eastern Australia, where a conservation stocking programme has been used to reinforce wild populations, with some success. A lack of research into the husbandry of newly born H. whitei limited the potential success of such a programme. Here, we determine the optimal husbandry methods for the rearing of newly born H. whitei through a series of controlled‐aquaria experiments, aiming to improve growth rates and ex situ survivorship, for the purpose of conservation stocking. We demonstrate that newly born H. whitei can feed upon Artemia nauplii from day of birth, whilst optimising husbandry methods, including water temperature (22–25°C), food provision (SELCO‐enriched Artemia at density 1 Art mL −1 ), stocking densities (up to 0.75 L −1 ) and weaning age (28 days), significantly improved the growth and survival (&gt;85%) of newly born H. whitei . Using the methods described here, seahorses attained a mean height of 68.15 ± 4.6 mm SD 102 days after birth, a size considered suitable for release. These results provide guidance for improving captive breeding programme for an endangered species and will help improve conservation stocking outcomes.