Genetic Diversity Resonates With Conservation Strategies: A Case Study of <scp><i>Labeo rohita</i></scp> Population

Conservation strategies often overlook genetic diversity, which is essential for biodiversity preservation and species adaptability. Efforts are minimal for low-income countries like Bangladesh. The current study assessed the population variances of <i>Labeo rohita</i>, a commercially important freshwater fish of Bangladesh, to find the impact of historical policy efforts in conserving diversity. Partial sequences of the mitochondrial <i>cytochrome b</i> gene (<i>cytb</i>) of 137 samples, originating from three major rivers (Padma, Jamuna, and Halda) and from randomly sampled cultured individuals, were analyzed. Significant differentiation was detected among the groups, with most genetic variation (90.35%) within groups. Eleven haplotypes were identified, including the most frequent haplotype (Hap1BD, 107/137). The geographically isolated Halda subpopulation, with earlier stronger conservation policy, displayed the highest haplotype (0.494) and nucleotide diversities (0.00133) compared to those of the Padma and Jamuna. The culture group also showed distinct diversity and haplotype patterns, which indicate an admixture of <i>L. rohita</i> fishes from different sources, including the Halda subpopulation. Pair-wise FST analysis indicated minimal genetic divergence between the Padma and Jamuna samples (FST = 0.00376), reflecting their geographical connections and moderate conservation strategies. Phylogenetic and haplotype network analyses revealed two distinct genetic clusters, with Jamuna and Padma clustering separately from the Halda subpopulation. Relatively lower effective population size estimation in both Padma and Jamuna could be a reflection of the loose conservation policy on these two rivers. This connection between conservation rules and genetic diversity in the Halda and other rivers indicates that conservation policy efforts, besides many other factors, might impact genetic variability, offering hope for future biodiversity conservation.