Rhinoptera Javanica Research Articles

Microplastic occurrence in finfish and shellfish from the mangroves of the northern Gulf of Oman

This study was conducted to assess microplastic (MP) pollution in some aquatic animals inhabiting planted and natural mangrove swamps in the northern Gulf of Oman. The KOH-NaI solution was used to retrieve MPs from the gastrointestinal tracts of animals. The highest MP prevalence was recorded in crabs (41.65 %) followed by fish (33.89 %) and oysters (20.8 %). The abundance of MPs in examined animals varied from zero in Sphyraena putnamae to 11 particles in a Rhinoptera javanica specimen. When polluted-only animals were considered, the mean abundance of MPs significantly varied among species and between locations. The mean density of ingested MPs was higher in the planted mangrove animals (1.79 ± 2.89 vs. 1.21 ± 2.25 n/individual; mean ± SD). Among the examined fish species, R. javanica ingested the highest number of MPs (3.83 ± 3.93 n/individual; mean ± SD). The polyethylene/ polypropylene fragments or fibers of average 1900 μm size were recorded as predominant (>50 % occurrence) MP particles.

Effects of Urea Removal on the Stable Isotopes δ13C and δ15N in Rays from the Coastal Waters of Peninsular Malaysia

Highlight Research This is the first stable isotopes study of rays from Malaysian waters Urea extraction significantly enriched the δ15N values (‰) Urea removal is obliged for stable isotope studies on rays Such methodological information is critical for marine research in the region Abstract This is the first reported record of stable isotope values for elasmobranch rays within Malaysian waters, and serves as an important baseline methodological information for future studies investigating stable isotope values in both shark and ray species in the region. This study examined the effects of urea removal on the stable isotopes values of δ13C and δ15N in muscle tissues sampled from several elasmobranch rays species, namely Pastinachus atrus, Rhinoptera javanica, Himantura gerrardi, Himantura uarnak and Aetobatus ocellatus. Individual ray species were collected in July and August of 2018, from the coastal waters of Terengganu State, Malaysia. Urea removal was performed by soaking muscle tissue samples in deionised water for at least 24 hours before being dehydrated. The resulting stable isotope values of these samples were compared to samples that did not undergo the urea removal process. Stable isotope values were individual and species-specific, however, the effect of urea removal was significant for δ15N values but did not significantly affect the δ13C values. We conclude that removing urea from elasmobranch samples before stable isotope analysis is advisable to draw correct conclusions about the animal’s diets.

Rhinoptera javanica

This datasheet on Rhinoptera javanica covers Identity, Distribution.

First record of two Myliobatid Elasmobranchs from West Bengal, northern east coast of India

Two elasmobrach fish species Rhinoptera javanica Müller and Henle (1841) and Mobula kuhlii (Müller & Henle, 1841), of the order Myliobatiformes were reported for the first time from Digha, West Bengal coast. The morphometry and meristic characters of the species from West Bengal coast are provided based on collected materials.

Short Communication: The mitochondrial cytochrome c oxidase subunit I (COI) for identification of batoids collected from landed sites in Medan, Indonesia

Abstract. Lubis K, Sudibyo M, Farajallah A, Hanim N. 2020. Short Communication: The mitochondrial cytochrome c oxidase subunit I (COI) for identification of batoids collected from landing sites in Medan, Indonesia. Biodiversitas 21: 5414-5421. Batoids are member of Elsamoranch subclass which consist of many species. Most of batoids species are overexploited, especially in Medan Indonesia. Up to presents, the information about diversity of rays on the east coast of North Sumatra, Indonesia was very limited. Therefore, this research aimed to investigate the diversity of rays on the east coast of North Sumatra. We examined the morphological trait of 82 individuals of batoid from three landing sites on the east coast of North Sumatra, namely: Tanjung Balai, Belawan, and Percut, then identify its species based on determination key. After that, we collected pectoral muscle tissue from an individual in each species which successfully identified to extract its genomic DNA. Molecular based identification was carried out by using DNA fragment form COI gene. The successfully amplificated COI gene DNA fragment then was sequenced and analyzed. Based on morphological trait, we successfully identifying nine species of batoid, which is Maculabatis gerrardi, Gymnura poecilura, Dasyatis zugei, Brevitrygon heterura, Neotrygon kuhlii, Hemitrygon bennettii, Rhinobatos jimbaranensis, Rhinoptera javanica, and Taeniura lymma. The result of identification based on COI gene DNA fragment was in congruent with morphological-based identification based on data BLAST-N and genetic distance value within same species. The nucleotide diversity within same species ranged from 0-15 nucleotide variants.

First observation of mating behavior in three species of pelagic myliobatiform rays in the wild

Information on elasmobranch mating behavior is limited. For batoids, observations of mating behavior in the wild are available only for a few species. We present video documentation of new cases of mating behavior for three species of myliobatiform rays. On July 20, 2013, a group of six cownose rays (Rhinoptera bonasus) were observed mating in shallow coastal waters off New Jersey. On August 19, 2014, two whitespotted eagle rays (Aetobatus narinari) were observed mating in Harrington Sound, Bermuda. In both cases, all stages of the mating sequence described in the literature were observed: 1) close following, 2) pre-copulatory biting, 3) copulation/insertion, 4) resting, and 5) separation. This is consistent with observations of mating behavior for whitespotted eagle rays and Javanese cownose rays (Rhinoptera javanica) in captivity. This is the first time a complete mating sequence has been documented in the wild for either species. Additionally, on May 18, 2015, a group of four bentfin devil rays (Mobula thurstoni) were observed engaging in pre-mating behaviors at the Archipelago of Saint Peter and Saint Paul, Brazil and is the first documented account of mating behavior for this species. In all three cases, we noted that the female was considerably darker in color than the males, which may be evidence of a visual pre-copulation cue, as seen in other marine fishes. The similarity of the behaviors presented here and those observed in other species (e.g., M. birostris, Hypanus americanus, and Taeniurops meyeni) suggests mating behavior may be highly conserved among batoids.

Computational Model Construction and Analysis of the Hydrodynamics of a Rhinoptera Javanica

In this study, numerical simulations are employed to investigate the hydrodynamic performance and wake topology of a swimming Rhinoptera javanica. The study is motivated by the quest to understand the hydrodynamics of median and paired fin(MPF) mode with both spanwise and chordwise flexibility. The simulations employ an immersed boundary(IB)-simplified sphere function-based gas kinetic scheme(SGKS) method that allows us to simulate flows with complex moving boundaries on fixed Cartesian grids. A computational model is constructed based on biological data. The evolution of the hydrodynamic force and 3D vortex structures are presented. Besides, the effect of frequency and amplitude are also discussed to explain some behaviors of the actual Rhinoptera javanica. This work can provide a baseline for the design of a bio-inspired underwater vehicle.

DNA analysis of elasmobranch products originating from Bangladesh reveals unregulated elasmobranch fishery and trade on species of global conservation concern.

Trade involving elasmobranch products in Bangladesh is a four-decade-long practice in large scale and there is little understanding of its impact on species composition, population, and subsequent conservation. Capacity for monitoring and identification is lacking in landing and shark processing centres. A rapid survey and collection of tissue samples were performed in three landings and nine shark processing centres between 2016 and 2017 in the south-eastern coastal region of Bangladesh. Sequencing for a 707-bp fragment of the mitochondrial cytochrome c oxidase subunit I (COI) gene was used to assess the taxonomic status and species composition from 71 elasmobranch tissue samples collected from the shark processing centre only. Good quality COI sequences were obtained for 34 specimens representing 21 species—the majority of which are threatened with extinction. A total of ten species of sharks (Carcharhinus brevipinna, C. amboinensis, C. leucas, C. sorrah, C. amblyrhynchoides, Chiloscyllium burmensis, Galeocerdo cuvier, Rhincodon typus, Scoliodon laticaudus, and Sphyrna lewini), eleven species of rays (Aetomylaeus maculatus, Gymnura poecilura, Mobula mobular, M. kuhlii, Neotrygon indica, Pateobatis uarnacoides, Rhinoptera javanica, and R. jayakari), including three species of guitarfish (Glaucostegus granulatus, G. obtusus, and G. typus), were identified. Four species (14.7% of samples) were found to be listed in the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) in Appendix II. Sixteen species (59% of the specimens) were threatened with extinction according to IUCN Red List, whereas 41% were data deficient or not assessed. The results have important implications for the management of regional fisheries and the conservation of elasmobranchs as they 1) represent a preliminary understanding of elasmobranch diversity in trade; 2) depict a lack of awareness and monitoring; and 3) demonstrate a need for urgent monitoring and regulation of elasmobranch trade in Bangladesh.

Reef fish diversity of bottom set gillnet landings at Pamban, Tamil Nadu, India

The coral reef areas of Gulf of Mannar support a rich fauna of fishes and bottom set gill net is one of the important gears employed in this area. Reef fishes landed at Pamban fish landing centre by bottom-set gillnets operated in Gulf of Mannar, for a period of three years from January, 2009 to December, 2011 were studied based on fortnightly sampling. A total of 69 species belonging to 29 families were recorded during the study and as per IUCN, two species, Himantura uarnak and Rhinoptera javanica are included under the Vulnerable category. The landings amounted to 1761 tonnes during the period with a maximum contribution of 44% during 2011 and it was the minimum during 2010 with a share of 27%. Species-wise landings indicated the dominance of Lethrinus nebulosus (11.5%) followed by Neotrygon kuhlii (10.6%). The richness and diversity indices showed a gradual increase from 2009 to 2011 and all the year wise points in the funnel plot for variation in taxonomic distinctness (λ+) are within the expected limit. The qualitative and quantitative abundance along with different diversity measures are presented and discussed in this paper. The results of the present investigation suggest that the bottom set gill net fishery is in a healthy condition with respect to Pamban fish landing centre.

Exploited but Unevaluated: DNA Barcoding Reveals Skates and Stingrays (Chordata, Chondrichthyes) Species Landed in the Indonesian Fish Market

Reliable and precise species identification is important to fisheries management and conservation. However, many rays and skates in Indonesia are currently being exploited and landed into traditional fish market without a proper identification. Therefore, this study was conducted to identify species of skates and stingrays that were landed and traded in three fish markets in Indonesia (Palabuhanratu, Muara Saban, and Lampung) using molecular techniques and to determine the conservation status of the identified species based on IUCN (International Union for Conservation of Nature and Natural Resources) as well as defined by CITES (Convention on International Trade in Endangered Species). The mitochondrial cytochrome oxidase I (COI) gene was amplified by polymerase chain reaction (PCR) using a pair of primer, fish-BCL and fish-BCH. Of 29 tissue samples collected from the study sites, a total of five species were successfully identified: Dipturus chilensis (4), Himantura walga (1), Neotrygon kuhlii (11), Taeniura lymma (9) and Rhinoptera javanica (4). The Neighbor Joining phylogeny of mitochondrial lineages, based on partial COI gene sequences, the ingroup haplotypes were clustered into five main clades representing each species. The identified stingrays were being listed as vulnerable (D. chilensis and R. javanica), near threatened (H. walga and T. lymma), and data deficient (N. kuhlii) by IUCN, with two species (D. chilensis and H. walga) population were indicated decreased. Unfortunately, all of identified species have not been evaluated by CITES regarding their trade status. As a consequences, a valuable effort should be placed to create a scientific network for monitoring programmes not only on a local scale, and to make pressure on governments for adopting molecular techniques as tools for controlling and avoiding misidentification. Keywords: Mitochondrial DNA, Phylogeny, Coral Triangle, Taxonomy, Fisheries

Length-weight relationships for 10 elasmobranch species from the Oman Sea

Length–weight relationships (LWRs) were estimated for ten elasmobranch species from Iranian waters of the Oman Sea. All specimens were collected by bottom trawl (mesh size 80 mm in the cod end) between May and December 2014. A total of 509 individuals (107 Torpedo sinuspersici, 68 Rhinobatos punctifer, 63 Chaenogaleus macrostoma, 72 Himantura walga, 80 Himantura gerrardi, 58 Gymnura poecilura, 4 Himantura uarnak, 4 Rhinoptera javanica, 14 Aetobatus flagellum, and 39 Pastinachus sephen) were sampled and studied. Results showed that most species had positive allometric or isometric growth but that more studies were needed for final decisions on growth patterns. Both the disk length-body weight (DL/BW) and disk width-body weight (DW/BW) relationships also showed a good fit, reinforcing the credibility of the data in relation to the LWRs. This study is the first report of LWRs for these elasmobranchs in the northern Oman Sea.

Length-weight relationships for five stingray species from the Persian Gulf

Summary Length–weight relationships (LWR) of fishes are necessary for various purposes such as stock/ecological assessment, monitoring and management (Froese, 2006). In this study we report length–weight relationships for five species of stingrays found in the Persian Gulf, Iran. Only one LWR was previously reported in the scientific literature for Rhinoptera javanica (Raje, 2000).

Availability of vulnerable elasmobranches in the marine water of Bangladesh

A study was conducted about vulnerable shark and ray species availability and their percentage composition in two fish landing centers at Fishery ghat, Chittagong and BFDC fish harbor, Cox’s Bazar district during April 2006 through March 2012. A total of 35 species (11 shark and 24 ray species) was identified within these six years. Out of 35 species, only one vulnerable shark species, the silky shark Carcharhinus falciformis (Muller and Henle, 1839), was not abundant all the year round and three were vulnerable ray species, Javanese cow ray Rhinoptera javanica (Muller and Henle, 1841), banded eagle ray Aetomylaeus nichofii (Bloch and Schneider, 1801) and white spotted shovelnose ray Rhynchobatus laevis (Bloch and Schneider 1801) were found throughout the year during the study period. The average percentage composition by weight of C. falciformis was 1.38 and the availability of average number was 3202. The average percentage contribution and the landed average number of vulnerable R. javanica, A. nichofii and R. laevis species were 1.46% (948 numbers), 0.61% (554 numbers) and 0.54% (298 numbers), respectively of the total catch. DOI: http://dx.doi.org/10.3329/bjz.v40i2.14316 Bangladesh J. Zool. 40(2): 221-229, 2012

A Study of the Effects of 2-Phenoxyethanol as a Sedative and/or Anesthetic on Cow-Nosed Ray (<i>Rhinoptera javanica</i>)

A Study of the Effects of 2-Phenoxyethanol as a Sedative and/or Anesthetic on Cow-Nosed Ray (<i>Rhinoptera javanica</i>)