Maintaining genetic connectivity is a central requirement for the long-term persistence of wide-ranging wildlife populations in increasingly human-modified landscapes. Population genetic approaches provide valuable tools for evaluating connectivity patterns and identifying early signs of genetic isolation. However, robust supraregional comparisons are often limited by differences in sampling design, marker systems, and analytical frameworks among studies. Here, we present the first comprehensive population-genetic assessment of red deer (Cervus elaphus) in Saxony-Anhalt, Germany, embedded within a standardized supraregional framework. We analysed multilocus microsatellite data from 698 individuals sampled across 14 management units and integrated these data with previously published datasets from Hesse and North Rhine-Westphalia, resulting in a comparative dataset comprising 3,188 genotyped individuals analysed using identical approaches. Across Saxony-Anhalt, red deer management units exhibited comparatively high levels of genetic connectivity and diversity relative to the more densely populated neighbouring federal states. Expected heterozygosity and allelic richness exceeded corresponding values observed in Hesse and North Rhine-Westphalia, while genetic clustering analyses consistently identified three major genetic clusters representing functional metapopulation complexes with substantial internal gene flow. At the same time, some peripheral AMUs, particularly Ziegelrodaer Forst and Duebener Heide, exhibited reduced connectivity, elevated differentiation, and demographic characteristics consistent with increasing functional isolation. Isolation-by-distance analyses further indicated that geographic distance alone did not fully account for the observed patterns of genetic differentiation among AMUs. Overall, the study demonstrates the value of standardized supraregional population-genetic frameworks for evaluating genetic connectivity across anthropogenically differentiated regions. The comparatively high connectivity observed in Saxony-Anhalt highlights the importance of maintaining existing exchange processes before local isolation results in substantial long-term genetic erosion.
Habitat loss and fragmentation expose small, isolated populations to genetic drift, inbreeding, and loss of adaptive potential. Ex situ breeding and reinforcement are increasingly used to mitigate these risks, yet their genetic outcomes often remain insufficiently evaluated. Here, we assessed the genetic status and conservation value of ex situ breeding populations of the endangered European ground squirrel (Spermophilus citellus) in the Czech Republic. We genotyped 198 individuals from eight populations, including four ex situ breeding colonies and four free-living or reinforced populations, using 12 microsatellite loci. Ex situ populations retained moderate to high levels of genetic diversity and showed no evidence of elevated inbreeding; the highest allelic richness and heterozygosity were observed in Zoo Brno, whereas the lowest diversity occurred in the free-living population Radouč. Bottleneck analyses revealed contrasting demographic histories, with the strongest recent signal detected in the Rescue Centre Rozovy and evidence of an older reduction in Zoo Praha. Bayesian clustering, PCoA, DAPC, pairwise differentiation, relatedness estimates, and AMOVA consistently showed that genetic structure was shaped primarily by locality, founder origin, and reinforcement history rather than by management category alone. In particular, RC Rozovy and Písečný vrch formed a distinct genetic cluster, while Hluboká and Karlovy Vary showed close genetic affinity consistent with documented reinforcement history. These findings indicate that well-managed ex situ populations can preserve valuable genetic variation for future conservation translocations. However, reinforcement and reintroduction should be guided by population-specific genetic information and integrated with long-term habitat management to support the viability of S. citellus populations in fragmented landscapes.
Understanding how genetic diversity is distributed within and between populations of rare species is critical for developing effective conservation strategies. The Miccosukee gooseberry (Ribes echinellum), a federally threatened shrub restricted to two known populations in South Carolina and Florida, faces ongoing ecological pressures and extremely limited regeneration. We used double-digest RAD sequencing to generate genome-wide SNP datasets to evaluate how genetic variation is distributed between and within populations. The two populations are genetically distinct, with similar levels of genetic diversity and high numbers of private alleles. Despite small effective population sizes, both populations maintained moderate heterozygosity, showed no evidence of inbreeding, and exhibited substantial fine-scale clonal spread and background relatedness. These patterns likely reflect historical connectivity and past reliance on sexual reproduction, since contemporary recruitment occurs almost exclusively via clonal stolons. We caution that a demographic time lag may be maintaining genetic diversity in the short term, but low regeneration poses a long-term risk to evolutionary potential. To safeguard this species, conservation strategies should prioritize capturing unique alleles through ex situ collections, protecting and managing both populations, and carefully evaluating gene flow interventions in light of potential local adaptation. These findings provide a rare case study of a clonally reproducing, range-restricted species where historical processes have preserved diversity, but contemporary demographic constraints threaten future adaptive capacity—insights that can inform management of other rare plants facing similar challenges.
The Japanese Archipelago, characterized by wide climatic variation and predominantly mountainous topography, exhibits a high diversity of endemic taxa. Among these, the Japanese serow is an endemic ungulate. To investigate the diversification history, genetic structure, and genetic diversity of the Japanese serow, and to inform conservation units, we conducted population genetic analyses using mtDNA and 12 microsatellite markers. Phylogenetic analysis of mtDNA identified five clades broadly corresponding to geographic regions. STRUCTURE analysis of microsatellite data revealed five major clusters with additional fine-scale subdivision into 13 local clusters. Distinct spatial genetic patterns were observed, including northward range expansion, genetic discontinuities associated with the uplift of the Japanese Alps, and genetic boundaries corresponding to peninsular and insular regions. Overall, the genetic structure of Japanese serow populations appeared to have been shaped by past climatic changes, geographic factors, and human activities, including historical poaching. The discordance between mtDNA and microsatellite patterns, along with observed admixture, may reflect recent gene flow driven by male-biased dispersal, as well as population expansion associated with conservation efforts and environmental changes. Based on these results, evolutionarily significant units and management units were provisionally delineated to inform conservation strategies.
Understanding how micro-geographic isolation and multi-layered drivers shape intraspecific genetic structure is critical for conserving narrow-range cliff endemics. Oreocharis guileana, an endangered cliff-restricted herb endemic to Hong Kong–Shenzhen coastal mountains, helps clarify combined influences of postglacial climate change and urban fragmentation on population genetics. Using chloroplast haplotypes and genome-wide SNPs from 106 individuals across six populations (subpopulations) at four distinct geographic sites, we detected extremely low nucleotide diversity: Hong Kong subpopulations (π ≈ 1.5 × 10⁻⁴) outperformed Shenzhen populations (π ≈ 1.2 × 10⁻⁴), and positive Tajima’s D across all samples indicated historical bottlenecks. Strong genetic differentiation existed between Hong Kong and Shenzhen groups (FST = 0.219–0.243), with moderate divergence among three Shenzhen populations (FST = 0.072–0.103), and no obvious isolation-by-distance pattern. Ancestral split of the two regional lineages happened 28,000 years ago owing to postglacial cliff habitat shrinkage, whereas population differentiation within Shenzhen arose the past two millennia alongside intensive human landscape alteration. Limited pollen and seed dispersal intrinsically restricts gene flow, and modern urbanization further strengthens isolation. We propose a hierarchical conservation framework: Hong Kong populations serve as core genetic reservoirs, the haplotype-unique SZ2 receives key protection, and improving connectivity among Shenzhen populations is superior to risky cross-border assisted gene flow. This study exposes urbanization-related genetic erosion risks for cliff-endemic plants and provides targeted conservation guidance for O. guileana.
Genetic diversity and its temporal-spatial distribution are key points for the adaptive potential of species. However, anthropogenic disturbances and ongoing climate change compromise the conservation of genetic resources, sessile organisms (e.g., plants) being the most affected. Arnica montana L. is a perennial Asteraceae species distributed across Europe, with important pharmaceutical, ecological and conservation value. However, genomic-level genetic studies are still lacking. To shed light on this gap, 12 locations distributed along the Iberian Peninsula, at the southern edge of the natural distribution of A. montana, were genomically assessed using restriction site-associated DNA sequencing (2bRADseq) to identify loci under selection (i.e., outliers) and to compare patterns of genetic diversity and population structure inferred from putatively adaptive loci with those obtained from neutral markers. After quality filtering, a total of 5,675 single nucleotide polymorphism (SNPs) were identified in 120 individuals. Genetic diversity levels were low and differed significantly among the five SNP datasets analysed, including panels composed of neutral loci and loci putatively under divergent selection. No significant correlations were detected between genetic diversity estimates and the geographical variables considered (latitude, longitude, elevation and location area). Significant population structure was found in all these datasets, with some differences among them, suggesting local adaptations and providing a finer and higher-resolution view of population structure. Based on these findings, conservation should focus on in situ strategies, genetic reinforcement within management units, potential reintroductions if required, and maintaining high ecological quality of habitats.
The hazel dormouse (Muscardinus avellanarius) is a locally endangered European glirid species with limited dispersal abilities. Genetic methods have been increasingly applied to measure the effects of habitat fragmentation on the genetic structure of hazel dormouse populations; however, standard collection methods require intensive sampling effort. Here, we present the results of a pilot study testing the feasibility of non-invasive hair and scat collection from nest tubes for dormouse genetic monitoring. In 2022, we collected samples at 73 sites distributed across an approximately 800 km2 area in a region of southern Germany comprising several isolated forest patches surrounded by agricultural land. Mitochondrial haplotype sequencing and microsatellite analysis resulted in 223 confirmed hazel dormouse detections from a total of 411 collected samples, with samples genetically assigned to 107 different individuals. Statistical testing for population structure was indicative of up to four genetically-differentiated populations corresponding to the main forest patches, suggesting inhibited dispersal between population clusters. The Aisch River valley was also found to be a major barrier to dispersal due to intense agricultural use and the existence of human settlements and traffic infrastructure. Our findings of strong population structuring and lower genetic diversity in isolated habitat patches highlights the greater risk of extirpation for isolated clusters of hazel dormice in Middle Franconia. Non-invasive genetic sampling is an effective tool for studying fragmentation effects on the hazel dormouse and other small mammals, and we provide recommendations for developing optimized sampling strategies that maximize efficiency while reducing researcher effort.
Widespread amphibians are often assumed to be demographically resilient, yet increasing habitat modification and intensive harvesting may erode genetic connectivity. In Nigeria, edible frogs such as the crowned bullfrog ( Hoplobatrachus occipitalis ) are subject to intense and largely unregulated exploitation, despite limited information on population demography, genetic diversity, or population connectivity. Here, we combine mitochondrial and genomic data to evaluate patterns of genetic structure and gene flow in H. occipitalis across Southwestern Nigeria and within a broader African biogeographic framework. Mitochondrial haplotype analyses revealed a dominant, widely distributed haplotype shared across West, Central, and East Africa, consistent with a recent late-Quaternary expansion and weak phylogeographic structure. Analyses based on genome-wide nuclear SNP data showed weak but detectable habitat-associated structuring among savanna, rainforest, and mangrove populations. Nigerian populations exhibited moderate and relatively homogeneous nucleotide diversity (π = 0.0006–0.0015). Pairwise genetic differentiation was low overall, with the highest differentiation observed between Derived Savanna and Guinea Savanna populations (FST = 0.021). Effective migration surface analyses identified localized reductions in gene flow, particularly near urban and coastal centers, indicating that anthropogenic modification may constrain connectivity at fine spatial scales. These results demonstrate that H. occipitalis remains genetically cohesive at regional scales, yet locally vulnerable to habitat fragmentation, urbanization, and exploitation. These findings highlight the importance of maintaining breeding habitat connectivity and regulating harvest in rapidly developing landscapes to preserve genetic diversity in widespread amphibians.
Habitat fragmentation is a key driver of reduced genetic connectivity and loss of genetic variation among populations, elevating the risk of inbreeding depression and reduced adaptive potential. The black-throated finch (Poephila cincta) is an endemic Australian finch with two recognised subspecies, a northern (P. c. atropygialis) and southern form (P. c. cincta) separated by a biogeographic barrier in northern Australia. The southern subspecies is nationally endangered and has experienced severe range contractions since the rise of pastoralism, with only two stronghold populations remaining (Townsville Coastal Plain and Desert Uplands Bioregion). Using a panel of more than 14,000 genome-wide single nucleotide polymorphisms for 107 individuals, we characterised spatial genetic structure for the Desert Uplands population. We mapped effective migration surfaces and tested for isolation by resistance to identify potential barriers to gene flow, estimated contemporary effective population sizes and reconstructed the demographic history of this population. We found evidence of restricted gene flow between localities only 16 km apart and strong isolation by geographic distance. Landscape resistance modelling identified areas of suitable woodland habitat that facilitated effective dispersal. More restricted gene flow in the southern range of this population is likely influenced by the fragmentation of suitable vegetation communities. Contemporary effective population sizes were near or below 1000, and we detected two historical population bottlenecks (> 50
Austrian dragonhead (Dracocephalum austriacum), a rare species of steppe and mountain steppe habitats, has a highly fragmented distribution across its entire range. Due to its narrow ecological requirements, it inhabits relict habitats that are increasingly threatened by climate change, human disturbance, and ongoing succession. Across Europe, the species persists in fewer than 90 small and spatially isolated populations. Despite legal protection, the species is threatened by habitat fragmentation and environmental change. We genotyped nearly all known populations across the species′ range using the DArTseq method to provide a genomic basis for conservation planning. We analysed key indices of genetic diversity, their spatial patterns, and phylogenetic relationships using genome-wide SNP data. To reconstruct the species’ phylogeographical history, we also conducted ecological niche modelling, demographic history inference and divergence time estimation. Our results reveal five geographically restricted genetic lineages that can be regarded as evolutionarily significant units. The most distinct lineage in the eastern Pyrenees exhibits signatures of long-term isolation and retention of ancestral polymorphism. In contrast, the remaining four lineages are of more recent origin and reflect a phylogeographic pattern consistent with gradual lineage diversification associated with Pleistocene habitat dynamics. The divergence between the two most distinct genetic lineages likely began during the Early Pleistocene, while a subsequent phase of range expansion and lineage diversification occurred during the Middle to Late Pleistocene. This pattern suggests that intraspecific differentiation was strongly influenced by Pleistocene climatic oscillations. Overall, genomic diversity is low and relatively uniform across the species′ range. Estimates of effective population size indicate that most populations are likely viable only in the short term, underscoring the need for coordinated conservation efforts across the species′ distribution.
Understanding genetic and biological diversity within a co-managed species complex can play an essential role in effective management strategies. This is particularly important in commercially and ecologically important stocks, such as the Vermilion/Sunset Rockfish complex. Vermilion (Sebastes miniatus) and Sunset (S. crocotulus/S. miniatus Type 1) Rockfish are part of a cryptic species complex with high value to the Southern California recreational fishery. Attempts to assess this complex have been complicated by an inability to easily distinguish these species visually. Here, we assessed the inter- and intraspecific genetic divergence within the Vermilion/Sunset cryptic species complex using genotyping-in-thousands by sequence (GT-seq) and low-coverage whole genome sequencing (lcWGS). We found that while Sunset Rockfish only exhibits subtle structure across its range, Vermilion Rockfish consists of three distinct cryptic lineages. The genetic divergence among these lineages (FST = 0.07–0.16) is higher than the divergence between many recognized species pairs, and there is little evidence for contemporary gene flow among them. Additionally, we found significant biological and ecological differentiation with all three groups found at significantly different depths. We found an extremely low rate of hybridization between the two species (0.27
Stocking native herbivores such as the Caribbean King Crab (Maguimithrax spinosissimus) is a promising strategy for controlling macroalgal proliferation and supporting coral reef restoration. In the Florida Keys, saltwater quarries have been proposed as semi-wild mariculture sites for producing crabs for large-scale stocking, but this approach requires understanding population dynamics to avoid genetic incompatibilities between wild and quarry sources. Here, we used population genomics to assess genetic diversity, structure, selection, connectivity, and effective population size in crab populations from the wild and quarries. Additionally, we applied ecological niche modeling to investigate whether M. spinosissimus is predicted to remain in the Florida Keys under different climate scenarios. Using 3,677 genome-wide SNPs from 82 individuals across 9 sites (6 wild, 4 quarry), we show that crabs in quarries retain genomic diversity comparable to crabs from wild locations, exhibit no detectable genomic structure among all populations, and have stable recent effective population sizes. Connectivity analyses reveal migration between all locations, including migrants from quarries into the wild. Migration patterns are mainly from the south to the north, consistent with regional oceanographic patterns. However, adaptive loci unique to crabs collected in one of the quarries, suggests potential local adaptation in at least one location. Ecological niche models indicate that the Florida Keys may persist as a suitable habitat for M. spinosissimus considering projections until 2100. These findings support the genetic viability of quarry-based mariculture as part of the large-scale stocking of M. spinosissimus for coral reef restoration that is consistent with guidelines for global conservation translocations.
Peripheral and disjunct populations are often the result of historic geological changes in the landscape and because of the long temporal span of colonization or vicariance, they are often genetically distinct and, when occupying small areas, vulnerable to population declines. In freshwater fishes, such populations are very susceptible to habitat destruction and environmental changes that could hasten extirpation. Because these populations are both geographically disjunct and genetically distinct from other populations, natural recolonization may be unlikely, and, because of the potential differences in the environment, human-mediated reintroductions may subsequently fail. Understanding the metapopulation genetic variation of those populations is critical for management efforts. Here, we assess the genomic variation and demographic history of the Ironcolor Shiner (Alburnops chalybaeus) with emphasis on the peripheral and disjunct populations. We find that the phylogeny of the species supports the hypothesis of an ancestral range in the southeast, while two independent lineages subsequently dispersed along the Atlantic coastal drainages and the Mississippi basin. We also inferred that genetically isolated, peripheral populations in Illinois and New Jersey have experienced geologically recent post-glacial population declines following glaciation consistent with their recent isolation. These findings imply the need for separate management of potential evolutionary significant units across the range of Ironcolor Shiner, as this broadly distributed species represents a series of isolated, disjunct populations. While many species may not be federally listed, extirpation of their peripheral populations is a key conservation issues requiring further attention.
Urban expansion and land development around the Greater Everglades Ecosystem have resulted in fragmentation and decline of Bletia purpurea populations, a terrestrial orchid native to South Florida. As habitat loss continues, assessment of genetic diversity and structure in remnant populations is critical for developing effective conservation strategies. Although differences in phenology, habitat preferences, and reproductive traits such as self-fertilization have been documented in Florida populations, comprehensive genetic data for this species had not been obtained prior to this study. In this work, a target capture sequencing approach utilizing the Orchidaceae963 bait set was applied to evaluate genetic diversity and structure across eight wild populations in Collier, Miami-Dade, and Palm Beach counties. Results indicate a northwest corridor of genetic connectivity among some populations, despite distances exceeding 95 km, likely reflecting a formerly continuous range prior to anthropogenic fragmentation. Three populations of conservation concern were identified: S1 formed a distinct genetic cluster suggestive of isolation; E3 exhibited elevated inbreeding that may compromise population viability; and E4 displayed emerging genetic differentiation despite otherwise moderate diversity metrics, particularly reflecting increasing isolation associated with urban fragmentation. These findings demonstrate the utility of targeted sequencing in conservation planning and provide essential baseline data to inform habitat restoration, population management, and preservation of genetic diversity in this state-threatened orchid.
Genetic monitoring plays a crucial role in the conservation and management of recovering protected species. The analysis of species-specific DNA fragments in environmental samples (eDNA), such as from water or soil, facilitates the molecular detection of elusive species. The Eurasian otter Lutra lutra experienced a dramatic decline in Europe during the 20th century. Reintroduction efforts have recently led to population recoveries across many parts of Europe, but these populations are difficult to monitor. Recently, eDNA data provided evidence of the presence of the species in central Italy where it disappeared three decades ago. We performed an eDNA survey in rivers of central Italy where the species has not been recorded. Filtered water samples were collected at five streams and analyzed by real-time quantitative polymerase chain reaction (qPCR). eDNA monitoring revealed the presence of the Eurasian otter in all rivers, even though not in all sampling points, suggesting the need to update the Eurasian otter monitoring combining traditional and molecular tools.
Hybridisation and introgression can significantly impact population structure in plants. The pedunculate (Quercus robur L.) and sessile (Quercus petraea (Matt.) Liebl.) oaks are interfertile, largely sympatric forest species making them suitable for studying how interspecific admixture affects range-wide genetic variation and structure. Focusing on the species’ western margin, 31 Irish stands were genotyped at 29 organelle and 412 nuclear loci before analysing with data from 4,780 trees spanning 438 stands across the entire distribution ranges. Haplotype variation was mapped and maximum likelihood inference of admixture was used to quantify hybridisation and introgression. Evidence for novel organelle haplotype evolution was found in Ireland and range-wide species integrity was high. In Ireland, the frequency of hybridisation and introgressed Q. petraea was very high. Irish Q. petraea had become differentiated from continental trees, whereas Q. robur trees were part of a single northwest European population. A high frequency of introgressed Q. petraea in Ireland is likely a consequence of thousands of years of asymmetric gene flow into Q. robur. Genetically pure bred Q. robur were found to be very rare in Ireland.
Narrow-range endemic species are often at the forefront of conservation efforts; however, a hybrid origin can significantly influence how they are classified and subsequently affect their conservation listings. The endangered narrow-range endemics, Callistemon forresterae and Callistemon nyallingensis from East Gippsland, Victoria, Australia, are both suspected to have arisen through hybridisation, and to reproduce clonally. We used 13,635 SNPs from DArTseq to assess their proposed hybrid origin and to quantify clonality and their genetic diversity. Collectively, principal coordinates analysis, STRUCTURE and NEWHYBRIDS provided strong support for the hybrid origin of C. forresterae. Varying levels of hybridisation were observed amongst all C. forresterae genotypes and are considered suggestive of a hybrid swarm. Conversely, no evidence of hybridisation was observed in C. nyallingensis, instead a strong genomic association with Callistemon subulatus was revealed. Pairwise relatedness estimates obtained using COANCESTRY revealed that C. forresterae and C. nyallingensis primarily reproduce asexually, with extreme clonality observed in all sampled populations of both taxa. From the three C. forresterae sub-populations (86 sampled stems) only nine genotypes were observed, and large genets comprised of many stems were found in each population. Only a single genotype was found amongst the C. nyallingensis population. Genetic diversity estimates were restricted by monoclonality in C. nyallingensis, while two of three C. forresterae populations exhibited heterozygote excess. The genomic data for C. forresterae and C. nyallingensis indicates that taxonomic revision may be necessary, however this would need to be underpinned by additional morphological studies supplemented with assessment of reproductive isolation and ploidy.
Hybridization of native species with introduced closely related taxa is of concern for nature conservation due to the risk of outbreeding depression and genetic swamping. Using mitochondrial DNA sequences and 13 microsatellite loci, we provide first genetic evidence that native grass snake (Natrix natrix natrix) populations in Berlin have been compromised by the introduction of at least one foreign subspecies (N. n. moreotica), originating from the southern Balkans and western Asia Minor. Genetic signatures of a third subspecies (N. n. vulgaris) in the same populations could result either from additional introductions or natural range expansion from the south. Dorsal stripes, absent in N. n. natrix but characteristic of the other two subspecies, have been documented in at least seven independent populations across Berlin, even where the genetic signal detected by the applied markers has been lost through backcrossing with native snakes. It remains unclear whether these hybrid populations will experience reduced fitness in the long term. We therefore recommend close monitoring of these populations and, wherever feasible, containing the dispersal of hybrid snakes.
Understanding how human-modified environments shape long-term genetic diversity is crucial for conservation, particularly in species experiencing declines. The House Sparrow Passer domesticus has declined markedly across Europe, yet its long-term genetic dynamics remain poorly understood in Mediterranean landscapes. We assessed spatiotemporal patterns of neutral genetic variation by integrating contemporary samples from 13 populations along an agricultural–urban gradient in Catalonia (NE Spain) with historical museum specimens (1919–1950). Using twelve microsatellite loci, we quantified changes in genetic diversity, population structure, and demographic signals. Historical populations were genetically homogeneous, reflecting an ancestral state of high regional connectivity. In contrast, contemporary populations exhibited increased genetic structuring, marginal increases in inbreeding coefficients, and heterozygote deficiencies, forming multiple clusters not associated with habitat categories. Isolation-by-distance was significant in contemporary populations (R2 = 11.1
Humans have long exploited the chondrichthyans, a lineage of jawed vertebrates characterized by a cartilaginous endoskeleton, and they remain an important fishery resource. However, fishing represents a major threat to cartilaginous fishes, especially given that their life history traits make them susceptible to fishing pressures. Indeed, oceanic shark populations have declined dramatically since the mid-twentieth century, with some chondrichthyans on the brink of extinction. While chondrichthyan-based pet food is prevalent in Taiwan, extensive food processing removes diagnostic morphological characters. This, combined with the use of generic product names, makes it difficult for customers to identify the species used in these products. Here, we authenticate through DNA barcoding 210 samples from 89 domestic and imported pet food products on the Taiwanese market. We successfully barcoded 207 of these samples, revealing sequences from chicken (Gallus gallus) and 28 chondrichthyan taxa (24 to species level and two each to genus and family level). Blue shark (Prionace glauca) was the most prevalent taxon, reflecting its highest catch biomass in Taiwan. None of the chondrichthyans we identified are on Taiwan’s Marine Protected Wildlife List, but some of them—Rhynchobatus palpebratus and Sphyrna lewini—are on CITES Appendix II and/or are threatened species according to the IUCN Red List. The use of generic names on pet food product labels likely results in a low mislabeling rate, but it also hinders customers from selecting products containing chondrichthyans of low conservation or health concern. Moreover, it creates a regulatory and or compliance issue for international trade, particularly for CITES listed taxa.
