Stingray Species Research Articles

Diversity and ecological relationships of Cestoda and Monogenoidea parasites of freshwater stingrays (Myliobatiformes, Potamotrygonidae), in the upper Paraná River, Brazil

The Neotropical freshwater stingrays of Potamotrygon genus present a unique and complex natural history and biogeographical pattern that can be traced to a marine origin and the colonization of the continental environment during the Miocene. During the evolution of potamotrygonids, several species of the parasitic fauna coevolved and co-opted concomitantly to their hosts during the colonization of the new environments. One striking example can be observed during the colonization of the upper Paraná River region. However, few studies explored the ecological and taxonomic aspects of potamotrygonid parasites. In this work, we investigate aspects of the ecology and taxonomy of the species of Monogenea and Cestoda that are parasites the species of freshwater stingrays of the genus Potamotrygon in the upper Paraná River. Our results indicate that at least six species of parasites are present in potamotrygonids in the region. Two of the observed parasites are putative new species and three of the parasitic species were identified for the first time in the region, hence expanding their geographic distributions. We quantified ecological aspects at different levels of communities for the collected parasite species. We compared the diversity in different locations and hosts and performed an exploratory analysis to investigate the differences in parasite abundance. Additionally, an identification key for the Monogenea and Cestoda species of the sampled region is provided.

Conservation status of sharks and rays caught in Indonesian Fisheries Management Area 712

Abstract. Lelono TD, Bintoro G, Setyanto A, Setyahadi D, Sutjipto DO, Adhihapsari W, Aliviyanti D, Isdianto A. 2024. Conservation status of sharks and rays caught in Indonesian Fisheries Management Area 712. Biodiversitas 25: 2603-2614. Elasmobranchs, including sharks and rays, are some of the most vulnerable marine fish and are particularly at risk from fishing pressure. Sharks and rays landing data that listed in the Convention on International Trade in Endangered Species (CITES) appendices and/or assessed as in The International Union for Conservation of Nature (IUCN) Red List threatened categories were collected from July to October 2023 at two sites in Indonesian Fisheries Management Area (FMA) 712, East Java, Indonesia, namely Pelabuhan Perikanan Nusantara (PPN) Brondong at Lamongan District and Pelabuhan Perikanan Pantai (PPP) Muncar at Banyuwangi. Stingray species designated as Critically Endangered (CR), Endangered (EN), or Vulnerable (VU) were recorded at both landing sites. More IUCN Red List threatened ray species were recorded at Brondong than at Muncar. Based on Brondong's international trade status, ray species landed at Brondong are at higher risk of extinction than those landed at PPP Muncar. Six shark species are currently listed in CITES Appendix II: A pelagicus, A. superciliosus, S. lewini, S. zygaena, C. falciformis, and I. oxyrinchus. At PPP Muncar, two of these species were traded. Sharks landing at Muncar included species in IUCN Red List categories, while those landing at Brondong were in four categories. Two CITES categories regulate the capture of sharks landed at PPP Muncar and PPN Brondong. At both sites, numerous species with conservation statuses of CR, EN, VU, and NT are still caught. In conclusion, exploitation and insufficient control threaten the shark and ray populations in PPP Muncar and PPN Brondong. To save these species, conservation efforts should prioritize trade monitoring, habitat protection, and stricter laws.

Hematological and plasma biochemical profile of two species of freshwater stingrays from the Amazon.

The evaluation of hematological and plasma biochemical parameters and the subsequent establishment of reference intervals facilitate the diagnosis of the health status of animals. This work aimed to determine the blood parameters of wild specimens of the stingrays Potamotrygon motoro and Potamotrygon orbignyi from the lower Solimões River region, Amazonas, Brazil. One hundred forty-one stingrays were captured, 92 specimens of P. motoro and 49 of P. orbignyi, of both sexes and at different stages of development. No effect of sex was observed on the blood parameters of juvenile animals for both species. P. motoro neonates presented a distinct hematological and biochemical profile, with significantly lower hematocrit values, hemoglobina, number of erythrocytes, mean corpuscular hemoglobin concentration, monocytes, plasma glucose, total proteins, albumin, and globulin. On the other hand, total cholesterol and urea levels were significantly higher in this same group compared to juveniles of the same species. Comparison between species revealed lower values of triglycerides and total cholesterol in P. orbignyi of both sexes. The results obtained are pioneering for these Amazonian species in white water environments and will serve as a basis for evaluating the health status of wild stingrays. Thus, from the analysis of the blood of the P. motoro and P. orbignyi stingrays, it was possible to observe good health conditions.

Occurrence of Four Freshwater Stingrays (Chondrichthyes: Potamotrygoninae) in the Uatumã River Basin, Amazon Region: A Field Study

The Amazon region has the largest diversity of freshwater stingrays; however, there are still places where information about this group is scarce. The present work aims to record the occurrence of freshwater stingrays in the Uatumã river basin, Amazonas, Brazil. For this, collections were carried out in three municipalities bathed by the Uatumã River, Presidente Figueiredo, Itapiranga, and São Sebastião do Uatumã. The rays were collected through fishing using a hand net and, after capture, were identified through the pattern of the dorsal and ventral color of the disc, the absence or presence of the labial groove, and the organization of the row of spines on the tail, and were also measured, weighed, and sexed. In total, 69 specimens of Potamotrygonines were captured, 59 of which were from the genus Potamotrygon and ten individuals from the genus Paratrygon. The present study provides preliminary information on the characteristics of freshwater stingray species that may occur in the Uatumã River. Furthermore, new research is necessary to improve the identification of specimens to determine the diversity and elucidate aspects related to the biology of elasmobranchs in the Uatumã River Basin, Brazil.

First Karyotypic Insights into Potamotrygon schroederi Fernández-Yépez, 1958: Association of Different Classes of Repetitive DNA

Introduction: Currently, there are 38 valid species of freshwater stingrays, and these belong to the subfamily Potamotrygoninae. However, cytogenetic information about this group is limited, with studies mainly using classical techniques, Giemsa, and C-banding. Methods: In this study, we used classical and molecular cytogenetic techniques – mapping of 18S and 5S rDNA and simple sequence repeats (SSRs) – in order to investigate the karyotypic composition of Potamotrygon schroederi and reveal the karyoevolutionary trends of this group. Results: The species presented 2n = 66 chromosomes with 18m + 12sm + 16st + 20a, heterochromatic blocks distributed in the centromeric regions of all the chromosomes, and terminal blocks in the q arm of pairs 2 and 3. Mapping of 18S rDNA regions revealed multiple clusters on pairs 2 and 7 and a homolog of pair 24. The 5S rDNA region was found in the pericentromeric portion of the subtelocentric pair 16. Furthermore, dinucleotide SSRs sequences were found in the centromeric and terminal regions of different chromosomal pairs, with preferential accumulation in pair 17. In addition, we identified conspicuous blocks of (GATA)n and (GACA)n sequences colocalized with the 5S rDNA (pair 16). Conclusion: In general, this study corroborates the general trend of a reduction in 2n in the species of Potamotrygoninae subfamily. Moreover, we found that the location of rDNA regions is very similar among Potamotrygon species, and the SSRs accumulation in the second subtelocentric pair (17) seems to be a common trait in this genus.

BETWEEN BUCCAL PUMPING AND BITING - EVIDENCE OF INTRAUTERINE MOUTH MOVEMENTS AND REPRODUCTIVE ASPECTS OF NEOTROPICAL FRESHWATER STINGRAYS (Elasmobranchii: Potamotrygoninae)

Preliminary findings regarding the reproduction of three neotropical freshwater stingray species, Potamotrygon henlei, P. motoro, and P. orbignyi, are presented herein. These species are characterized by the presence of a singular functional left ovary and two operational uteri. Two distinct fertility models have been identified: fecundity dependent, and fecundity independent of maternal size. Furthermore, this study briefly outlines the process of capture-induced parturition and its implications for the fate of the litter. Additionally, it sheds light on novel embryonic behavioral patterns, particularly highlighting the active swimming exhibited by embryos within the uterine environment, notably during the latter stages of development. Consequently, it is suggested that these movements, coupled with oral activities and active biting, facilitate branchial ventilation and potentially intrauterine foraging - a phenomenon previously documented only in sharks belonging to the order Lamniformes. Keywords: Abortion, Histotroph, Capture stress, Embryonic nutrition.

Progesterone receptors in extratesticular ducts of the Amazonian stingray Potamotrygon wallacei: A potential role in sperm maturation and aggregate formation

In cururu stingray (Potamotrygon wallacei Carvalho, Rosa and Araújo 2016) males, plasma progesterone (P4) levels appear to be associated with spermiation events. However, the specific contribution of P4 in sperm maturation via extratesticular ducts in this stingray species is unknown. With the aim of filling this knowledge gap, this study examined the morphology and the presence of progesterone receptors (PR) in the ducts, and analyzed the relationship of progesterone (P4) with sperm maturation and formation of aggregates. Morphological analysis showed that a columnar pseudostratified epithelium with stereocilia lined all the attached ducts. In active males, the secretory cells of the epididymis and the Leydig glands presented PR; however, these receptors were not found in the distal region of the epididymis (essential for nurturing and capacitation events) of regressing males. In the seminal vesicles of active males, the spermatozoa are parallelly aligned and embedded in a matrix to form the spermatozeugmata. The matrixes are formed by proteins secreted by the ducts and Sertoli cell cytoplasts. These structures presented PR, which suggests that P4 engages in sperm metabolism during storage. Our findings allude to the potential role of P4 in regulating the development and function of the attached ducts in different reproductive phases. Furthermore, P4 seems to be an essential component for regulating sperm progress, protein secretion, aggregate formation, and maintenance of sperm during storage in this freshwater stingray.

Dots in the dark: dorsal polychromatism in the endemic Xingu Freshwater Stingray

AbstractPolychromatism refers to the presence of two or more color patterns within a species. Several species exhibit polychromatic patterns, including some elasmobranchs such as the Xingu Freshwater Stingray (Potamotrygon leopoldi), a threatened, endemic freshwater stingray species that is exploited in the international aquarium trade. Analysis of polychromatic patterns can provide insight into evolutionary mechanisms and be a useful tool for monitoring international trade. In this context, the present study analyzed intraspecific color variation in P. leopoldi. A total of 241 individuals collected in two areas along the Xingu River in Brazil were used for the study. Four dorsal color patterns of P. leopoldi were described. Size differences between color classes were statistically significant, suggesting that these color variations are associated with ontogenetic color changes. In addition, two color morphs specific to each locality were identified and described. Moreover, the occurrence of polychromatic forms in a Potamotrygoninae species may contribute to the understanding of diversification in this group, since some mechanisms of speciation are associated with polychromatism. Analysis of color variation in P. leopoldi is expected to help improve trade monitoring, especially given the existence of look‐alike species.

A Review of the Conservation Status and Ecology of the Giant Freshwater Whipray (Urogymnus polylepis) across Its Known Distribution

The giant freshwater whipray is a large-bodied stingray species that is listed as endangered across its known range from India through Southeast Asia. However, little is known about the species’ ecology, biology, and conservation status. We reviewed all available literature, articles, and reports on the species found through database and internet searches in order to consolidate and update information on the giant freshwater whipray. We found that remarkably little research has been done, and most existing information on the species is derived from fisher catch reports. Whiprays of 300 kg or more have been reported in most countries where it occurs. The available evidence suggests that this species is endangered across its range by numerous threats, including fishing, bycatch, bottom trawls, pollution, and habitat destruction and fragmentation. Various reports indicate declines in population size, genetic diversity, and body size. Relatively stable populations may persist in the Maeklong River, Thailand, the Mekong River in Cambodia, and insular Southeast Asia. More work is needed to understand the species’ spatio-temporal distribution, reproductive behavior, migration patterns, and general ecological and biological characteristics in order to inform effective management and conservation plans. Due to difficulties in sampling this rare species and monitoring fisher catches, partnership and collaboration with all stakeholders, including local fishers, government officials, and researchers, is essential to produce conservation gains for the giant freshwater whipray.

Life history (length-weight relationship, conditional factors, reproductive aspects), stomach contents and nursery ground of stingray in the Arafura Sea

Stingrays are a resource that is vulnerable to overfishing and habitat degradation. The research was conducted to obtain data and information that is still lacking and much needed for the utilization and protection of stingrays, including; life history, stomach contents, and nursery ground. The study was conducted in October - November 2018 by exploratory, including taking stingrays by trawling and measuring habitat conditions with Conductivity, Temperature, and Depth. The results showed a total stingrays are 744 individuals, weighing 2,986.6 kg and 24 species. Individual stingrays have a width disc range of 9-134 cm and a weight of 20-67000 g. The growth pattern of stingrays is generally allometric, except for Gymnura zonura. The average value of the relative condition factors is generally >1, except for Aetomylaeus maculatus and Brevitrygon walga. Stingrays have an unbalanced sex ratio, gonads consist of 43% adolescent and 57% mature, and the number of neonates is 1-6 /parent. The correlation between clasper length and disc width is generally positive, except for Hemitrygon longicauda. Of the stomach contents of all stingray species, 64 % is shrimp, Himantura leoparda which have various prey. The area east of Aru and west of Papua are the locations used as nursery grounds by most various stingrays. Nursery grounds of Stingray is generally shallow coastal areas with low oxygen, eutrophic and high turbidity. The results of this study are expected to be used as a basis for managing stingray resources in the Arafura Sea and further research is recommended to be carried out in four different seasons.

DNA contamination and taxonomic diversity hinder eDNA research on freshwater stingray species: Comment on Lim & Then (2022)

Recently, Lim & Then (2022; Endang Species Res 48:43-50) used an environmental DNA (eDNA) PCR-based method for detecting the presence of an endangered species of freshwater stingray, Fluvitrygon kittipongi (Dasyatidae), in the Pahang River basin, east Peninsular Malaysia. For that, they designed a species-specific pair of primers to amplify a 196 base pair (bp) fragment of the cytochrome c oxidase I (COI) gene. Lim & Then (2022) reported positive detection of this species along an upstream stretch of the Pahang River during the inter-monsoon and the southwest monsoon seasons, with the PCR-amplified eDNA sequences identical to the reference COI sequences of F. kittipongi collected from the Perak River basin, west Peninsular Malaysia. Here, we argue that such positive results are likely the consequence of a DNA contamination because the 196 bp COI fragments of F. kittipongi from the Pahang River and the Perak River differ from each other by 4 nucleotide substitutions. The source of contamination in Lim & Then (2022) could have been the Perak samples the authors handled to develop the primers. We also briefly discuss the potential impact of the presumed co-occurrence of freshwater stingrays of the genus Fluvitrygon in the Pahang River on the specificity of the F. kittipongi-specific primers designed by Lim & Then (2022).

Morphological aspects and germ cells of male reproductive tract of river stingray, Potamotrygon amandae

The family Potamotrygonidae are the only species of stingrays restricted to fresh water and located exclusively in South America. The objective of this research was to analyze the morphological aspects and germ cells of the male reproductive tract of Potamotrygon amandae. The samples were fixed in 10% formalin, and then dehydrated in an ascending ethanol series (70 to 100%). To carry out light microscopy analyses, they were embedded in paraffin, cut and stained; as for scanning electron microscopy analyses, the samples were dried, glued in metallic bases and metalized. The gross morphology consisted of the following paired organs: testis, epididymis, deferent duct, Leydig gland, seminal vesicle, clasper, and the clasper gland. Microscopically, several stages of spermatogenesis were observed in the testis, occurring in spherical follicles, similar to other stingrays. The epididymis was formed by one duct subdivided in various tubules. The deferent ducts were continuous with the epididymis, and the lumen was full of spermatozoa. The Leydig glands consisted of glandular units with eosinophilic content in the lumen of some, and the deferent ducts ran parallel to the ventral portion. The seminal vesicles possessed numerous compartments to store the sperm, with a wall similar to a hive, and the lumen was full of spermatozoa. Alcian Blue (AB) and Periodic Schiff-Acid (PAS) performed in the Leydig Gland, deferens ducts and seminal vesicle was positive only in the connective tissue, the cilia were PAS+ and the nuclei stained weakly for AB. The clasper gland was composed of unit glands and was covered with striated muscle externally. It stained very well with Periodic Schiff-Acid. The morphological aspects of the male reproductive tract of Potamotrygon amandae were similar to other stingrays.

MORPHOLOGICAL CHARACTERS OF FRESHWATER STINGRAYS (CHONDRICHTHYES: DASYATIDAE) IN MUSI RIVER, PALEMBANG CITY, SOUTH SUMATERA PROVINCE

A study to determine morphological characets of freshwater stingray in Musi River of South Sumatra Province has been conducted from June to December 2020. The fishes were collected in Musi River where located at middle of Palembang city. Collected specimens were preserved to Animal Ecology Laboratory, Department of Biology, Faculty of Mathematic and Natural Science of Sriwijaya University. There are four species of freshwater stingrays collected, Fluvitrygon oxyrhyncha. Fluvitrygon kittipongi. Fluvitrygon signifer, and Fluvitrygon sp ‘musi’ 2. The results of the measurement of morphometric and morphological characteristics showed that there were differences in size and morphological characteristics of the types of fish found, indicating that stingray had different size ranges.

First record of mating behaviour and induced parturition of the Brazilian endemic Lutz's stingray Hypanus berthalutzae.

The recently described Lutz's stingray Hypanus berthalutzae is endemic to the Brazilian Province, including oceanic islands. Although it is expected to have life-history traits similar to the southern stingray H. americanus, little is known about its reproductive biology. Here we present the first observations of courtship behaviour (n=4), copulation (n=3) and an induced parturition of H. berthalutzae at the Fernando de Noronha Archipelago, an insular Marine Protected Area from the Equatorial Atlantic Ocean. The mating event records included (1) 'chasing/close following', (2) 'biting/precopulatory biting', (3) 'insertion/copulation' and (4) 'separation'. These results are especially relevant considering that records of reproductive behaviour in the wild are rare for elasmobranchs in general. Mating events occurred in different months, suggesting that the reproductive cycle of H. berthalutzae in this insular system is asynchronous, as observed for other stingray species in regions with favourable environmental conditions and abundant food throughout the year. The opportunistic documentation of the induced parturition allowed for direct nonlethal observation of the two pups at or near full term in late May. Although preliminary, these observations should be considered in future management plans as they provide relevant data about the life-history traits and mating behaviour of this endemic and threatened species.

Identification of stingrays species and exploitation rate of blue-spotted maskray (Neotrygon kuhlii) landed at TPI tanjung beringin, Serdang Bedagai Regency, North Sumatera Province

Serdang Bedagai Regency has fisheries and marine potential demersal species of stingray in TPI Tanjung Beringin. The current study used a survey and descriptive method, accompanied by sample collection and morphology identification, as well as determining the rate explotation of fish landed in TPI Tanjung Beringin. A total of five species were successfully identified: Neotrygon kuhlii, Brevitrygon heterura, Aetoplatea zonura, Maculabatis macrura and Rhynchobatus australiae. The most dominant stingray species landed in TPI Tanjung Beringin namely of Neotrygon kuhlii, so that condition was an analysis of Neotrygon kuhlii weight length relationship of fish and body weight is negative allometric growth is more dominant than weight gain. The growth rate Von Bertalanffy is L ∞ (infinity) value is 300.30 mm, K value is 0.42 and t0 value is -0.68, the fish growth can be influenced by internal and external factors. Mortality and exploitation rate of Neotrygon kuhlii total mortality (Z) value is 1.01, natural mortality (M) value is 0.59408, fishing mortality (F) value is 0.4192 and exploitation rate is 0.7105 as long as indicators high fishing mortality and decreasing natural mortality indicate a state of growth overfishing.

A new elasmobranch fauna from the early Miocene of Sharbithat (Sultanate of Oman) reveals the teeth of an ancient fantail stingray

Here we describe a new elasmobranch assemblage consisting of isolated dental material from the Aquitanian near-shore marine deposits of the Shuwayr and Warak formations at Sharbithat, in eastern Sultanate of Oman. The faunal composition clearly indicates affinities to other early Miocene elasmobranch-bearing localities worldwide. This assemblage is predominantly composed of large and common pelagic sharks as well as teeth attributable to a new species of fantail stingray, Taeniurops tosii, as old as the oldest undisputable fossil records of Taeniurops. The study of this fossil assemblage presented here improves the knowledge of the ancient elasmobranchs that frequented the eastern Arabian coasts during the closure of the Neotethys and the birth of the Arabian Sea. DOI: 10.1344/GeologicaActa2022.20.2

A synergistic, global approach to revising the trypanorhynch tapeworm family Rhinoptericolidae (Trypanobatoida).

Since 2010, the trypanorhynch tapeworm family Rhinoptericolidae Carvajal & Campbell, 1975 has housed just two distinctive, monotypic genera (Rhinoptericola Carvajal & Campbell, 1975 and Nataliella Palm, 2010). However, global collections of tapeworms from sharks and rays over the last more than three decades brought to light the need for major revision of the family by suggesting a much greater species-level diversity for the nominal genus Rhinoptericola. Through synonymy and the description of new species, the number of species in the genus is increased from one to eight. A phylogenetic analysis of the D1–D3 gene region of 28S rRNA (28S), including seven of the now nine species of rhinoptericolids, and a broad sampling of the other Trypanobatoida is the first to recover a monophyletic Rhinoptericolidae. In addition to systematic revision, this study allowed for the first evaluation of the degree of intraspecific vs interspecific variation in 28S for adult trypanorhynchs across the various hosts and geographic localities from which they have been reported, suggesting a relatively consistent boundary for Rhinoptericola. It is further suggested that detailed scanning electron microscopy (SEM) images of both the basal and metabasal armatures greatly aid in the interpretation of hook arrangement and shape. A schematic to streamline determination of the tentacular surface presented in scanning electron micrographs and line drawings of trypanorhynchs is presented for species with both two and four bothria. In combination, these methodological refinements can now be used as a model to resolve issues of classification and non-monophyly within both major lineages of the Trypanorhyncha. As a result of the taxonomic work, Rhinoptericola megacantha Carvajal & Campbell, 1975 (previously only known from the American cownose ray from the Chesapeake Bay and the Ticon cownose ray from the Gulf of Mexico, Venezuela, and Brazil) is now known from an additional species of cownose ray and a species of stingray, and is revealed to have a transatlantic distribution. Data from SEM suggest a simpler interpretation of hook arrangement in the metabasal armature for Rhinoptercola and—in combination with 28S sequence data—support Shirleyrhynchus Beveridge & Campbell, 1988 (a former rhinoptericolid) as its junior synonym. The three species formerly assigned to Shirleyrhynchus are thus transferred to Rhinoptericola. Data from light microscopy on whole-mounted specimens and histological sections, SEM, and 28S showed the eutetrarhynchid Prochristianella jensenae Schaeffner & Beveridge, 2012b to be morphologically consistent with species of Rhinoptericola and it is thus transferred to the genus. The type series of P. jensenae was determined to be mixed, representing two distinct species which are here redescribed and described as new, respectively. Two additional novel species of Rhinoptericola are described from cownose rays from off Mozambique and the Gulf of California.

Trophic ecology of sympatric juvenile stingrays within a nursery area

Nursery areas are crucial for many elasmobranch species, providing advantages such as increased access to prey and reduced predation risk. This study investigated the trophic interactions of two juvenile stingray species within a coastal communal nursery using stable isotope analysis. Muscle, plasma and red blood cells samples were taken from the mangrove whipray Urogymnus granulatus and the cowtail stingray Pastinachus ater, and δ15N, δ13C and δ34S measured. Urogymnus granulatus had higher mean δ13C, δ15N and δ34S than P. ater. General linear models showed no significant trends between δ13C, δ15N or δ34S and body size or sex. Low isotopic niche overlap, combined with previous data on movement patterns, provided evidence of niche partitioning between stingrays that likely reflect differences in feeding grounds and prey selection. Despite the differences in feeding grounds and prey selection, previous studies showed that U. granulatus and P. ater share sand and reef flat areas for most of the day (~20 h). δ13C and δ34S values suggested that mangrove-derived carbon had little importance to stingrays’ diets in the study area. Results presented in this study bring new insights to the feeding ecology of two sympatric stingray species and their trophic interactions within a communal nursery area.

Environmental DNA approach complements social media reports to detect an endangered freshwater stingray species in the wild

Environmental DNA (eDNA) barcoding has emerged as an important non-invasive sampling technique for the detection of rare and endangered species that can be difficult to sample. Our objective was to develop a low-cost eDNA barcoding approach for the detection of an Endangered freshwater stingray species Fluvitrygon kittipongi in a tropical river system in Peninsular Malaysia. We designed a species-specific primer for a fragment of F. kittipongi cytochrome oxidase subunit I mtDNA (244 bp). The effectiveness of this primer to detect the stingray was evaluated using water samples taken from the upper and middle reaches of the Pahang River coupled with social media reports on sightings of F. kittipongi. Five of 14 water samples tested showed positive PCR amplification for the targeted species. These results represent the first successful application of eDNA to detect freshwater stingrays in Malaysia. Using a combination of freshly obtained carcass samples, social media reporting and target species eDNA detection, this study provides formal occurrence records of F. kittipongi in Malaysia in 3 major watersheds: the Perak, Pahang and Kelantan Rivers.

Intensive Commercialization of Endangered Sharks and Rays (Elasmobranchii) Along the Coastal Amazon as Revealed by DNA Barcode

Elasmobranchs represent a well-defined group, composed of about 1,150 species inhabiting diverse aquatic environments. Currently, several of these species have been classified as threaten due to overexploitation. Therefore, we used DNA barcode to identify traded species of sharks and stingrays in the municipality of Bragança (Amazon coastal region), a major fishery landing site in northern Brazil. We collected a total of 127 samples labeled into 24 commercial nomenclatures over 1-year period. Twenty species were discriminated and 13 of them are recognized under some threatening status. In relation to sharks, Carcharhinidae showed the highest number of species, half of them classified as endangered, followed by hammerhead sharks (Sphyrnidae), with four species also regarded as threatened with extinction. The Rhinopteridae and Dasyatidae rays were the most abundant groups, with trade records of the following threatened species: Rhinoptera brasiliensis, Rhinoptera bonasus, Hypanus berthalutzae, and Fontitrygon geijskesi. It is noteworthy that threatened species of elasmobranchs have been frequently and regularly exploited because of inefficient fishery management policies. Therefore, effective inspection practices need to be incorporated in fisheries, including the use of DNA barcode to enable a reliable method of species authentication and to assure the proper commercialization.