Detailed kinship estimation for detecting bias among breeding families in a reintroduced population of the endangered bagrid catfish 𝘛𝘢𝘤𝘩𝘺𝘴𝘶𝘳𝘶𝘴 𝘪𝘤𝘩𝘪𝘬𝘢𝘸𝘢𝘪

Abstract

In the context of initiatives focused on captive breeding and reintroduction of endangered animal species, it is crucial to minimize any bias in reproductive success during the reintroduction phase in order to preserve genetic diversity. One population of 𝘛𝘢𝘤𝘩𝘺𝘴𝘶𝘳𝘶𝘴 𝘪𝘤𝘩𝘪𝘬𝘢𝘸𝘢𝘪, a critically endangered bagrid catfish endemic to Japan, faces a threat from the construction of a dam. To address this, a captive breeding program followed by translocation is being implemented. Multiple breeding families are involved in this process; however, if there is a bias in reproductive success among them after release, it will result in a decline in genetic diversity. To ascertain potential biases of reproductive success among released individuals, we attempted to identify the familial lineage of individuals born at the release site. Due to the unavailability of samples from the released individuals themselves, we reconstructed the pedigree of three generations using distant kinship relationships, such as grandparent–grandchild and uncle–aunt–nephew–niece relationships, with data of 2230–5674 single-nucleotide polymorphisms obtained from whole genome re-sequence, and three different software. Our findings indicate no bias between lineages in the first year after reintroduction, but a significant bias in the second year, emphasizing the need for continuous management and monitoring of reintroduced populations. This study demonstrates that monitoring kinship after reintroduction can correct lineage bias, which is critical for the prompt restoration of genetic diversity.