Genetic Variations in Populations from Farms and Natural Habitats of Asian Green Mussel,Perna viridis,in Singapore Inferred from Nine Microsatellite Markers

The Asian green mussel, Perna viridis, has been widely cultured in Southeast Asia as delicious seafood depending on natural spat. We analyzed the genetic diversity and population structure of three populations (two from Singapore and one from Malaysia) from natural habitats and two from Singapore farms, by genotyping a total of 262 adult individuals using nine polymorphic microsatellites. In all five populations, high allelic (number of alleles A = 11.0–14.4,allelic richness Ar = 10.4–13.9) and gene diversity (expected heterozygosity He = 0.73–0.77) were observed, whereas deficiency of heterozygosity (inbreeding index f = 0.08–0.12) was detected in all populations. Genetic differentiation among populations was low (pairwise fixation index ranged from 0.003 to 0.088), but statistically significant. The usefulness of the information about genetic variations for genetic resource management of the populations in wild habitats and farms to keep genetic variation and setting up a breeding program of Asian green mussel was discussed.     

Genetic structure of Irish freshwater pearl mussels (Margaritifera margaritifera and Margaritifera durrovensis): Validity of subspecies,roles of host fish,and conservation implications

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Colonization history and human translocations explain the population genetic structure of the noble crayfish (Astacus astacus) in Fennoscandia: Implications for the management of a critically endangered species

1. The noble crayfish (Astacus astacus) is an endangered freshwater species in Europe. The main threat is from lethal crayfish plague, caused by the oomycete Aphanomyces astaci that has been spread over Europe by introduced North American crayfish species, acting as chronic carriers of the disease.
2. Most of the remaining noble crayfish populations are found in the Baltic Sea area, and there is an urgent need to implement conservation actions to slow down or halt the extinction rate in this region. However, limited knowledge about the genetic structure of populations in this area has so far precluded the development of conservation strategies that take genetic aspects into consideration.
3. Key objectives of this large-scale genetic study, covering 77 locations mainly from northern Europe, were to describe the contemporary population genetic structure of the noble crayfish in the Fennoscandian peninsula (Sweden, Norway, and Finland), taking postglacial colonization history into account, and to evaluate how human activities such as stocking have affected the genetic structure of the populations.
4. Analyses of 15 microsatellite markers revealed three main genetic clusters corresponding to populations in northern, middle, and southern Fennoscandia, with measures of genetic diversity being markedly higher within populations in the southern cluster. The observed genetic structure probably mirrors two main colonizations of the Baltic Sea basin after the last glaciation period. At the same time, several deviations from this pattern were observed, reflecting past human translocations of noble crayfish.
5. The results are discussed in relation to the conservation and management of this critically endangered species. In particular, we recommend increased efforts to protect the few remaining noble crayfish populations in southern Fennoscandia and the use of genetic information when planning stocking activities, such as reintroductions following local extinctions.

     

利用微卫星荧光多重PCR技术分析壳白长牡蛎3代人工选育群体的遗传多样性

为了探讨壳白长牡蛎人工选育对群体遗传变异的影响,实验利用4个多重PCR组合共10个微卫星标记分析了连续3代壳白长牡蛎人工选育群体和野生群体及基础群体的遗传多样性。结果发现,6个群体的平均等位基因数量为7.2~12.6,等位基因丰度为6.8~11.0,期望和观测杂合度分别为0.672~0.769和0.486~0.542;与野生群体相比,3代选育群体的平均等位基因数显著降低,但平均期望杂合度并无显著差异。哈迪—温伯格平衡检验结果显示,在60个群体—位点组合中有39个群体—位点组合显著偏离哈迪—温伯格平衡,近交系数F_(is)范围为0.215~0.342。群体间遗传分化指数F_(st)范围为0.005~0.076,处于中—低等的遗传分化水平。研究表明,虽然连续选育对群体的遗传多样性和遗传分化造成了一定程度的影响,但人工选育群体依然表现为较高的遗传多样性,仍可以一定的选择压力对选育群体进行人工选育。     

Genetic variation of wild and cultured populations of the Kuruma prawn Marsupenaeus japonicus (Bate 1888) using microsatellites

The microsatellite DNA technique was used to detect the genetic variations between wild and cultured populations of Kuruma prawn Marsupenaeus japonicus Bate 1888. All the six microsatellite loci screened in this study showed high polymorphism for their PIC (0.6701–0.8989), which was much more than the standard value of 0.5. A total of 73 alleles were observed over six loci from 93 shrimps. The mean number of allele locus ranged from 9.83 (cultured) to 11.83 (wild). The number of effective alleles varied from 6.86 (cultured) to 8.58 (wild). The average of observed heterozygosity (H_o) of populations varied from 0.6935 (cultured) to 0.7370 (wild), and that of expected heterozygosity (He) was 0.8169 (wild) and 0.8209 (cultured). Tests of Hardy–Weinberg showed that these loci deviated significantly or highly significantly in one or both populations. Compared with the wild population, the cultured population showed little reduction in genetic variation. The total number of alleles (71, 59) was not significantly (P=0.296) different between wild and cultured populations. The paired‐samples t test of observed heterozygosity and expected heterozygosity implied that there was no significant difference (P=0.572 and 0.891 respectively) between wild and cultured populations. However, some rare allele loss might have occurred in the cultured population. A total of 14 unique alleles were found in the wild population, but only two unique alleles were observed in the cultured population. Therefore, there is a need to monitor genetic variability of cultured population, and to improve the hatchery program for the conservation of wild Kuruma prawn resources.     

Genetic Diversity and Population Structure in the Heavily Exploited Korean Rockfish,Sebastes schlegeli,in Korea

The Korean rockfish, Sebastes schlegeli, is a valuable and intensively exploited species in Korea. We discuss the genetic diversity and genetic structure of four Korean rockfish populations using eight microsatellite loci. In total, 161 different alleles from 138 individuals were observed. Average allele number per locus ranged from 2.5 to 23 and allelic richness varied from 13.38 to 14.63 within a population. Despite a long history of stocking practices, we found very high levels of polymorphism (mean heterozygosity = 0.810), which is comparable to other congeneric species. No significant difference in genetic diversity and molecular genetic variance (F_ST and R_ST) was observed among four local samples (P > 0.1). Little indication of contemporary inbreeding (F_IS= 0.051) or population structure (K = 1) was detected. This absence of differentiation may reflect high levels of gene flow along the coast of Korea. Our study demonstrates that rockfish in Korea should be managed as a single unit. Currently, the species does not appear to be genetically threatened, but the potential for a rapid loss of genetic diversity remains. This information on the genetic characteristics of Korean rockfish populations has important implications for fisheries management and conservation efforts, and will aid in the sustainable exploitation of the fishing resources and the preservation of biodiversity.     

Genetic structure of Orbicella faveolata population reveals high connectivity among a marine protected area and Varadero Reef in the Colombian Caribbean

1. The protection of ecosystems with high diversity, such as coral reefs, is not an approach that guarantees their conservation. Thus, maintaining connectivity among coral populations over the long term is a strategy that should be adopted in order to protect diversity and ecological processes. Although coral reefs in Colombia are highly diverse, the population genetics baseline data of keystone species such as Orbicella faveolata are limited.
2. To provide current information about the connectivity between populations of O. faveolata in the Colombian Caribbean, the genetic diversity and distribution of O. faveolata was evaluated with analysis of molecular variance (AMOVA), principal components, and migration estimations using 113 genets distributed in six populations. Also, a genetic structure analysis that included the available data for the Caribbean population was conducted, seeking to understand how the Colombian populations relate to the broader region.
3. According to the global fixation index (F_ST) for the Colombian Caribbean, there was no genetic structure (F_ST = 0.002). Discriminant analysis of principal components (DAPC) showed that Corales del Rosario Archipelago (CR), Este de Isla Fuerte (EIF), San Bernardo Archipelago (SB), and Varadero Reef (VR) were grouped with Oeste de Isla Fuerte (OIF), with Bushnell (BS) representing the most divergent cluster. Migration analysis showed relatively high migration from VR to CR and SB, highlighting the importance of VR as a genetic reservoir for the region. Structure analysis showed that the Colombian population presented a specific genetic identity (F_ST = 0.254), suggesting that the Colombian Caribbean population could be a peripheral population that contributes significantly to genetic variation and is connected through a complex connectivity process.
4. In conclusion, the estimated genetic connectivity reflects the influence of sea surface dynamics over the interpopulation exchange dynamics and the role of protected and nonprotected coral reef in the Colombian Caribbean. Thus, the Colombian Caribbean population of O. faveolata could be relevant to the conservation of genetic diversity on a larger scale.

     

Conservation genetic assessment of the paleback darter,Etheostoma pallididorsum,a narrowly distributed endemic in the Ouachita Highlands,Arkansas, USA

1. The paleback darter, Etheostoma pallididorsum, is considered imperilled and has recently been petitioned for listing under the Endangered Species Act. Previous allozyme-based studies found evidence of a small effective population size, warranting conservation concern. The objective of this study was to assess the population dynamics and the phylogeographical history of the paleback darter, using a multilocus microsatellite approach and mitochondrial DNA.
2. The predictions of this study were that: paleback darter populations will exhibit low genetic diversity and minimal gene flow; population structure will correspond to the river systems from which the samples are derived; reservoir dams impounding the reaches between the Caddo and Ouachita rivers would serve as effective barriers to gene flow; and the Caddo and Ouachita rivers are reciprocally monophyletic.
3. Microsatellite DNA loci revealed significant structure among sampled localities (global F_st = 0.17, P < 0.001), with evidence of two distinct populations representing the Caddo and Ouachita rivers. However, Bayesian phylogeographical analyses resulted in three distinct clades: Caddo River, Ouachita River, and Mazarn Creek. Divergence from the most recent ancestor shared among the river drainages was estimated at 60 Kya. Population genetic diversity was relatively low (H_e = 0.65; mean alleles per locus, A = 6.26), but was comparable with the population genetic diversity found in the close relatives slackwater darter, Etheostoma boschungi (H_e = 0.65; A = 6.74), and Tuscumbia darter, Etheostoma tuscumbia (H_e = 0.57; A = 5.53).
4. These results have conservation implications for paleback darter populations and can be informative for other headwater specialist species. Like other headwater species with population structuring and relatively low genetic diversity, the persistence of paleback darter populations is likely to be tied to the persistence and connectivity of local breeding and non-breeding habitat. These results do not raise conservation concern for a population decline; however, the restricted distribution and endemic status of the species still renders paleback darter populations vulnerable to extirpation or extinction.

     

福建牡蛎选育群体的遗传多样性

利用8个微卫星标记对福建牡蛎(Crassostrea angulata)基础群体、‘金蛎1号’选育系F6和野生群体进行遗传多样性分析。结果表明,每个位点在各群体的等位基因数为7~24个,各群体在所有位点的平均等位基因数为10.3~17.6个,平均等位基因丰度为9.8~16.8。平均观测杂合度和平均期望杂合度分别为0.655~0.662和0.788~0.872。经邦弗朗尼校正,哈迪–温伯格平衡检验结果显示,在24个群体–位点组合中18个群体–位点组合显著偏离平衡(P0.01)。群体内近交系数F_(is)值介于0.0095~0.2874,平均值为0.1992,遗传分化系数F_(st)介于0.0224~0.1627,平均值为0.0767,暗示选育群体中存在较低水平的非随机交配现象,属于中度偏低分化。研究表明,连续的选育对群体的遗传分化产生了一定的影响,但是,选育群体仍然具有较高水平的遗传多样性。     

菲律宾蛤仔人工选育群体与野生群体的遗传多样性分析

本研究利用10对微卫星标记对菲律宾蛤仔(Ruditapes philippinarum)人工选育群体与野生群体进行遗传多样性分析。结果表明,每个位点的等位基因数为3~12个,期望杂合度范围为0.307~0.757,观测杂合度范围0.208~0.583。等位基因丰富度AR的大小范围是3.0~10.7,PCR扩增产物片段大小在178~390 bp,共得到63个等位基因,平均等位基因数范围从4.4(白蛤)到5.1(龙王塘野生群体),野生群体等位基因丰富度最大(5.278),白蛤群体的等位基因丰富度最小(4.267)。哈迪–温伯格检验发现4个群体和10对微卫星的40个组合中,有21个组合显著偏离哈迪–温伯格平衡状态。Kruskal-Wallis检验表明各个群体间的平均等位基因丰富度无显著差异。4个群体遗传分化系数F_(st)在0.086~0.180,遗传分化最大的是白斑马蛤群体与龙王塘野生群体(F_(st)=0.180),遗传分化最小的是白蛤群体和海洋橙群体(F_(st)=0.086)。人工选育群体表现为中度分化水平(F_(st):0.086~0.113);龙王塘野生群体与人工选育群体表现为较大分化水平(F_(st):0.134~0.180)。结果表明,人工选育群体的遗传多样性仍然比较高,但连续的选育对群体的遗传多样性和遗传分化有一定程度的影响。     

Genetic divergence in Indian populations of M. rosenbergii using microsatellite markers

Macrobrachium rosenbergii, known as the giant freshwater prawn or Malaysian prawn, is the sixth largest aquaculture species in Asia. Knowledge of genetic diversity of M. rosenbergii is important to support management and conservation programmes, which will subsequently help in sustainable production of this economically important species. This study aimed to analyse the genetic diversity and population structure of five M. rosenbergii populations using 11 microsatellite loci. In analysing 240 samples, the number of alleles, observed heterozygosity (H_O) and expected heterozygosity (H_E) ranged from 3 to 20, from 0.250 to 0.978 and from 0.556 to 0.944 respectively. The five stocks of M. rosenbergii displayed high level of genetic diversity. Both the F_ST and amova analyses showed that there was significant genetic differentiation among all populations. The UPGMA dendrogram based on Nei's genetic distance matrix revealed that the Narmada and Mahi populations were in one cluster and Mahanadi and Subarnarekha populations in another single major branch, whereas the Kerala population clearly showed a separate cluster. This information on genetic variation will be useful for genetic improvement and conservation of Indian populations of giant freshwater prawn M. rosenbergii.     

Insights into population genetics,connectivity and demographic history of the longnosed skate Dipturus oxyrinchus (Linnaeus, 1758) in the western Mediterranean Sea

1. Genetic information is crucial for the conservation of Dipturus oxyrinchus (Linnaeus, 1758), a threatened large skate with declining populations over most of its geographical range. The main aim of the present study was to investigate the genetic structure, connectivity and demographic history of the longnosed skate in Sardinia (western Mediterranean Sea).
2. Patterns of population structure were assessed in 175 specimens from six sampling sites. Variation in two mitochondrial genes (cytochrome c oxidase subunit I (COI) and control region) highlighted high genetic diversity and low but significant genetic differentiation among sites, which clustered into three groups corresponding to the north‐west, north‐east and south Sardinian coasts.
3. The observed genetic structuring could presumably depend on a combination of past geological events, contemporary restrictions to dispersal and biological characteristics of the species (e.g. site‐fidelity, no pelagic larval stage, limited dispersal of juveniles and/or adults).
4. Demographic analyses showed signs of past population expansion, but substantial current stability of Sardinian populations. From a conservation perspective, these results are encouraging, and indicate that Sardinian populations are still large and stable, and seem not to have suffered negative side‐effects from the ever‐growing fishing pressure in the region.
5. The occurrence of genetic structuring strongly supported the close monitoring of populations to identify any erosion of their gene pool, and high genetic variability of the Sardinian D. oxyrinchus populations could thus represent priority populations for conservation purposes, providing potential sources for recolonization in cases of local extinctions in other areas of the distribution range of the species.
6. When the sequences from Sardinia were compared with those available from other areas, the data seem to exclude the possibility that the Atlantic and Mediterranean host totally isolated populations or even different species, as recently suggested. However, additional markers and a larger sampling sites are needed to confirm these findings.

     

High gene flow in two migratory Neotropical fish species,Salminus franciscanus and Brycon orthotaenia,and implications for conservation aquaculture

1. Two migratory and endangered freshwater fish species, Salminus franciscanus and Brycon orthotaenia, are endemic to one of the most important basins for hydropower capacity in South America. These two fish are target species of conservation aquaculture programmes along the São Francisco River system.
2. In order to implement effective strategies for the conservation of these species, microsatellite markers were developed and used to assess the genetic diversity and structure among wild groups. Fish were collected during the spawning season at four sampling sites, covering more than 1000 km.
3. Polymorphism loci were assessed, and a total of 133 and 107 alleles were found for S. franciscanus and B. orthotaenia, respectively. Despite the critical conservation status, B. orthotaenia showed high levels of genetic diversity, comparable with those of other closely related species.
4. Salminus franciscanus exhibited half of the genetic diversity of its sister species in terms of allelic diversity, indicating that this species will be more prone to genetic drift and inbreeding in conservation aquaculture programmes.
5. The results of an analysis of molecular variance for microsatellite markers in these species (F_ST = 0.007 for S. franciscanus and F_ST = 0.003 for B. orthotaenia) and the estimated recent migration rates (>40% among sampling sites) support panmixia in both species, despite the heterogeneities of the riverscape.
6. The results of this study and the microsatellites developed will play an important role in assisting agencies in making informed decisions on conservation aquaculture programmes.

     

Genetic diversity of two Philippine native freshwater goby species (Perciformes: Gobiidae): implications for conservation

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Global population genetic structure of the sequential hermaphrodite,dusky grouper (Epinephelus marginatus)

1. The dusky grouper Epinephelus marginatus is a large epinephelid species that occurs in the eastern and south-western Atlantic and western Indian Oceans. Late maturity, protogynous hermaphroditism, site fidelity, and overfishing have all contributed to its demographic decline.
2. Connectivity and demography within a broad sampling of dusky grouper populations throughout its distribution were assessed. To do so, genetic variation at 11 polymorphic microsatellite loci and a partial sequence of the mitochondrial control region (mtCR) were evaluated.
3. Two major mtCR lineages with a sequence divergence of 1.6% were found. The magnitude of genetic differentiation for mtCR among north and south Atlantic and Indian Ocean populations was high, with Φ_ST = 0.528.
4. D_EST and results of discriminant analysis of principal component revealed significant microsatellite genetic differentiation between all collection areas. Significant pairwise D_EST showed moderate (0.084) to very great (0.603) differentiation. The effective population size was low for all localities, ranging between 25 (Azores Archipelago) and 311 (Rio Grande do Sul). The overall effective population size was estimated as 299 (confidence interval = 215–412), and there was no evidence of strong or recent bottleneck effects.
5. Local and regional genetic structuring among dusky grouper populations is the consequence of the species' site fidelity, distribution across multiple oceanographic boundaries, and probably also of sequential hermaphroditism that contributes to the intensity of random genetic drift.
6. The spatial pattern of genetic structuring of dusky groupers is such that fisheries management and conservation of population genetic integrity will have to be pursued at the local and regional scales.

     

Population structure,genetic diversity,and colonization history of the eastern pondmussel,Sagittunio nasutus,in the Great Lakes drainage

1. The eastern pondmussel, Sagittunio nasutus (Bivalvia: Unionida), has declined in abundance and distribution in eastern North America over the last few decades. The declines are predominantly the result of infestation by invasive dreissenid mussels and changes in habitat. The species is now considered imperilled across large portions of its distribution, especially in the Laurentian Great Lakes region.
2. The genetic diversity and structure of the remnant populations in the Great Lakes region were assessed using 10 newly developed microsatellite DNA loci for S. nasutus. Understanding the remaining populations can inform future management projects and determine whether the remnant populations have experienced a genetic bottleneck or a founder effect. We hope that this will inform the conservation of other species in regions founded by, and isolated from, a more genetically diverse source population or with disjointed geographical distributions.
3. Focusing on the Great Lakes region, samples (n = 428) from 62 collection sites in 28 water bodies were collected. Across the locations sampled for S. nasutus 11 genetic populations were identified, with significant genetic differentiation among them. The genetic structure of the species was assessed, with genetic similarities among populations compared and with geographical routes of colonization and gene flow evaluated.
4. Initial colonization from the Atlantic coast into Lake Erie and Lake Ontario is evident, followed by colonization events into nearby inland rivers and lakes. Analyses found evidence of inbreeding in all but one population and evidence of past genetic bottlenecks or strong founder effects in all but four populations. This study deepens our understanding of the genetic past and present of this imperilled species, providing conservation suggestions for the future management of the species.

     

Genetic evaluation of translocation in artificially isolated populations of white-spotted charr (Salvelinus leucomaenis)

Genetic population structure of artificially isolated white-spotted charr (Salvelinus leucomaenis) populations before and after translocation were examined using polymorphic microsatellite loci. We released 20 migrant females of below-dam populations in the Kame and Hitozuminai rivers, Japan, into small above-dam sites of each river, and also collected juveniles (0+ fish) of the pre-translocation and the post-translocation cohorts for DNA analyses. Reduced genetic diversity, expressed as the number of alleles and expected heterozygosity, was observed in all above-dam populations before translocation relative to below-dam populations. Highly significant genetic differentiation was also found between above- and below-dam populations. After translocation, on the other hand, genetic diversity of above-dam populations was restored to the levels of below-dam populations. Differences in gene frequencies between above- and below-dam populations were not detected after translocation. These results, in turn, suggest that the translocations in our survey had an immediate effect on the restoration of genetic diversity, and that the translocated individuals strongly introgressed into above-dam populations.     

Genetic variation measured by microsatellites among three strains of domesticated rainbow trout (Oncorhynchus mykiss, Walbaum)

Genetic variation fuels selective change in natural and captive populations. In establishing a broodstock for selective improvement, the level of genetic diversity is an important consideration because it provides an indication of the scope for selective progress. Three domesticated strains of rainbow trout, Oncorhynchus mykiss (Walbaum), were examined at nine polymorphic microsatellite loci to assess detectable levels of allelic diversity and heterozygosity within and differentiation among the strains. A total of 126 alleles were observed to segregate into unique multilocus genotypes for each of the 152 individuals assayed. There was an average heterozygosity of 71.5% at these nine loci, and an average of 14 alleles at a locus. Each locus was represented by alleles unique to at least two of the three strains. Deviations from Hardy–Weinberg expectations of genotype frequencies were detected in each strain. Subsequent analysis indicated sub‐structuring within strains leading to Wahlund effects that caused these deviations. Significant differences in genotype frequencies and pairwise F_ST values demonstrated that all strains were unique. The overall F_ST of 0.089 provides additional evidence of unique genetic diversity present in each strain, and agrees well with the degree of genetic variation found in rainbow trout across broad geographical ranges. The genetic diversity contributed by each population suggests that there is greater scope for selective improvement of numerous traits within a synthetic strain combining these three strains than within any individual strain.     

Population genetic divergence of bonnethead sharks Sphyrna tiburo in the western North Atlantic: Implications for conservation

1. Sharks are a priority for conservation because numerous species, including small-sized coastal species, are being heavily exploited by commercial and recreational fisheries. Understanding the genetic population structure of sharks is key to effective management, maximizing their evolutionary potential in a rapidly changing environment and preventing population declines.
2. Limited dispersal is an important factor promoting population divergence for several coastal shark species. The genetic variation in 14 microsatellite loci and 21,006 single nucleotide polymorphisms genotyped using restriction-site-associated DNA sequencing was analysed to assess the genetic structure of the bonnethead shark, Sphyrna tiburo, in the western North Atlantic.
3. Genetic differences were identified among three well-defined regions: the western Florida coast, the south-eastern US Atlantic coast, and the southern Gulf of Mexico. Results support previous studies based on mitochondrial DNA sequences in defining differences among these regions and suggest limitations of bonnethead sharks in routinely performing long-distance migrations.
4. The limited connectivity among regions explains the pattern of genetic divergence but also reported divergence at the species/subspecies level. These genetically discrete bonnethead populations have independent evolutionary histories that may include local adaptations to specific areas.
5. Bonnethead sharks are currently managed as two stocks in the USA owing to recent genetic, tagging, and life history studies; however, no stock assessments or management plans exist for Mexico. These results not only serve to reinforce US management strategies and provide critical data about the extent of gene flow and sex dispersal among populations, but also begin the process of effective management in the waters of Mexico to ensure the long-term productivity and resilience of this species. With an absence of gene flow between populations from US waters and the southern Gulf of Mexico, there is a need for management plans based upon independent biological and population dynamics data since limited or no opportunities for populations to interchange individuals may occur to re-establish population viability.

     

Mitochondrial phylogeography reveals high haplotype diversity and unique genetic lineage in Indian dugongs (Dugong dugon)

1. India plays a significant role in dugong conservation by having the largest population within South Asia. The status of dugongs in India is largely unknown due to a paucity of reliable ecological data. This study generated mitochondrial control region sequences from ~10% of dugong individuals from existing populations within India. Furthermore, data generated in this study were compared with the global data to assess genetic lineages, population structure, and genetic diversity of Indian populations.
2. Multiple analyses suggest that the Indian dugong populations are part of a single genetic cluster, comprising South Asia, North-west Indian Ocean, and South-west Indian Ocean populations. Despite small population size, they retain high genetic diversity with unique mitochondrial DNA haplotypes within South Asia. Within India, novel haplotypes are observed from all dugong habitats sampled, with overall high haplotype diversity (0.85 ± 0.04) but low nucleotide diversity (0.005 ± 0.001). Indian populations exhibit genetic differentiation with higher within-population variance (63.41%) than among populations (36.59%). Two of the haplotypes observed in India are shared with Sri Lanka, implying genetic connectivity between these populations.
3. The genetic data from Indian dugong populations provide critical insights into the identification of dugong corridors and important dugong conservation zones in India. We suggest site-specific interventions, including the creation of new marine protected areas and boundary reorganization and expansion of other existing protected areas, to ensure population connectivity. In addition, simultaneous efforts towards seagrass meadow restoration, reduction of dugong mortalities, and community participation in dugong conservation are recommended for population recovery of this threatened marine herbivore.