Monitoring social behaviour as an assessment of translocation success in a reintroduced population of the endangered Leon Springs pupfish (Cyprinodon bovinus)

1. Translocation of endangered species fromcaptivity into thewild is a common conservation practice used to bolster populations, expand natural ranges, and restore species that have been extirpated. 2. Often little is known of the fate of organisms after they are released, and extended monitoring of reintroduced populations is necessary for understanding the efficacy of this method. 3. Thought to have become extinct, the endangered Leon Springs pupfish (Cyprinodon bovinus) was rediscovered in 1965. Recently, conservation efforts have focused on renovating their natural habitat and reintroducing C. bovinus from a captive colony established in 1976 back into the ancestral habitat. 4. A reintroduction was performed in 2015, and the population was monitored over the next 14 months to ascertain whether territorial males were behaving typically for the species, and whether there were any changes in social behaviour over time. 5. An established population in nearby Diamond Y Spring was used as a benchmark for typical social behaviour, and as an indicator for any expected seasonal differences in behaviour. 6. The development of a typical social system at Monsanto Deep Pool was evident almost immediately, as males started to establish breeding territories, defend them from intruders, and participate in reproductive activities, such as courtship and spawning. The presence of juveniles within a year indicated that individuals were successfully reproducing. 7. It appears that the translocated C. bovinus are developing into a stable and reproductively successful population.