Genetic dynamics of a 11-year ex situ managed Itasenpara bitterling population

EX situ conservation management is an effective method that conserves endangered species that are on the decline owing to anthropogenic alteration of natural habitats. This entails the management of a captive population while maintaining its genetic variability and preventing its adaptation to the captive environment. However, implementation of such efforts is largely limited to experimental animals and zoo-managed animals with pedigree information. In this study, ex situ management of endangered Itasenpara bitterling (Acheilognathus longipinnis) was conducted, while practicing recommended conservation procedures, for the purpose of conserving this species. In this 11 year long study, we conducted multi-locus microsatellite DNA analyses to evaluate the genetic dynamics of an ex situ captive population of A. longipinnis, as well as the wild A. longipinnis population of the Kiso River. Genetic diversity generally varied between yearly cohorts in each of the captive sub-populations, and some showed a stable increasing trend with generations. When all sub-populations were considered as one population, genetic diversity was maintained at a high value, while effective population size generally reached target values, thereby preventing inbreeding. These results were achieved by maintaining multiple captive sub-populations and exchanging individuals between them. Simultaneously, the introduction of additional individuals from the wild population produced genetic variability in the captive population. These fluctuating patterns of genetic diversity in the captive A. longipinnis population were desirable compared to previously predicted values. Consequently, these findings show that the current ex situ conservation program is suitable for maintaining the genetic composition of the captive population of A. longipinnis.