Omani Waters Research Articles

Identification of Sparidae species based on COI and 16S rRNA DNA barcoding along the coast of Oman

Fish species belonging to the Sparidae family hold significant commercial value for Oman’s fisheries. Although 18 out of 132 known sparid species have been reported in Omani waters, accurate morphological identification remains challenging for many species. We used DNA barcoding based on cytochrome oxidase subunit І (COI) and 16S ribosomal RNA (16S rRNA) to identify commercially important sparid species. Sixty-three specimens were collected from three major Omani fisheries landings, namely Khasab, Suhar, and Salalah, spanning over 3165 km of coastline. Sequences of 16 S rRNA (521 bp) and COI (506 bp) identified 16 species by 16S rRNA, ten species by COI. Notably, Dentex gibbosus was reported for the first time in Omani waters. The identified 16 species, phylogenetically, belong to two genetically distinct groups. The interspecific genetic distances among species ranged from 0.011 to 0.279 based on 16S rRNA and 0.104–0.259 based on COI, indicating different groups within Omani waters. DNA barcoding provided high taxonomic resolution of sparid biodiversity in Oman and the surrounding region. Additionally, the study contributes to establishing a reference database for the Sparidae family of species from Oman.

Testing osteometric species determination on zooarchaeological dolphin remains from Late Neolithic and Early Bronze Age sites in Ash-Sharqiyyah, Sultanate of Oman

Different Late Neolithic and Early Bronze Age sites located in the Ras al-Hadd cape and Ras al-Jinz Bay area (Ash-Sharqiyyah South Governorate, Sultanate of Oman) have provided thousands of zooarchaeological dolphin remains suggesting a strong reliance on the exploitation of these animals. Dolphins are hard to identify to the species level due to a highly comparable interspecies osteological morphology as well as a general lack of extensive osteological reference collections. As a result, such remains are frequently identified as “dolphin”, without any further species identification being undertaken. In this study, we assess whether an osteometric method for distinguishing the nine dolphin species that are present in Omani waters can be used to identify the zooarchaeological specimens. Zooarchaeology by Mass-Spectrometry (ZooMS) was also undertaken on a subset of the specimens but proved ineffective due to the poor preservation of the material in an arid climate. This evidence strengthens the need for effective species identification methods based on traditional zooarchaeological methods. This research is based on our ongoing analysis of the thousands of dolphin remains from the Omani zooarchaeological assemblages.

Sailfin velifer, Velifer hypselopterus Bleeker, 1879 (Perciformes, Veliferidae) in Oman waters: a new substantiated record from the Arabian Sea coast of Oman

The first substantiated records of Sailfin velifer, Velifer hypselopterus Bleeker, 1879 in Omani waters are reported based on 10 specimens ranging in total length 300-430 mm, which have been collected by gill net on the coast of Al-Ashkharah City, 319 km south of Muscat City, Arabian Sea, Oman. Morphometric and meristic data are provided and compared with those of several specimens of this species from other parts of the world. This study reports on the largest specimen of this species ever being collected.

Otobothrium muscatense n. sp. (Trypanorhyncha: Otobothriidae) from Rhabdosargus sarba (Forsskål) (Sparidae), with new locality records of larval trypanorhynchs off the Sultanate of Oman.

In the evaluation of the larval trypanorhynch fauna off the Sultanate of Oman, a total of 188 bony fishes belonging to 16 species were studied, which led to the description of a new species with the establishment of new host and locality records. A new otobothriid species, Otobothrium muscatense n. sp., is described from Rhabdosargus sarba (Forsskål). Based on scolex morphology and tentacular armature, the new species closely resembles the small-sized Otobothrium Linton, 1890 species described as Otobothrium cysticum (Mayer, 1842) and O. crenacolle Linton, 1890. However, it differs from them in the basal armature by a more robust shape of the first principal and the triangular shape of the billhooks as well as by the retractor muscle originating inthe posterior part of the tentacle sheath, attaching to a thickening of thetentacle sheath wall,with a muscular branch continuing and attaching atfrontpart of the bulb. It differs from the other species of Otobothrium by size, the combination of six principal hooksand a single intercalary hook in the metabasal armature, and the plane of reflection through the tentacle surfaces. New locality records of the tentaculariids Nybelinia indica Chandra, 1986, Heteronybelinia yamagutii (Dollfus, 1960), Tentacularia coryphaenae Bosc, 1797, and Mixonybelinia lepturi Palm, 2004, together with the lacistorhynchids Pseudogrillotia multiminacantha Palm, 2004 and Callitetrarhynchus gracilis (Rudolphi, 1819), and the pseudotobothriid Parotobothrium balli (Southwell, 1929) off the Muscat region are established. Of the reported species, especially P. multiminacantha and M. lepturi occurring in Trichiurus lepturus L. further demonstrate the relatedness between the Indonesian and the northwestern Indian Ocean fauna, increasing the number of joint records between Indonesia and Omani waters to 14 species.

The Horseface Unicornfish Naso fageni Morrow, 1954 in Omani Waters: a Verification of a Prior Visual Sighting from the Sea of Oman

The first confirmed record of the horseface unicornfish, Naso fageni Morrow, 1954, in Omani waters is reported here, based on a specimen of 550 mm total length which has been collected by gill nets on the coast of Quriat City, 120 km south of Muscat, the capital of Oman. Morphometric and meristic data are provided and compared with those of several specimens of this species from other parts of the world.

Age, growth, population dynamics and stock status of Perna perna in Omani waters

Age, growth, population dynamics and stock status of Perna perna in Omani waters

A New Fishery Area for the Swordfish Xiphias gladius Linnaeus, 1758 (Teleostei: Xiphiidae) in the Sea of Oman

The first record of the swordfish Xiphias gladius Linnaeus, 1758, in Omani waters is based on a specimen of 1756 mm total length, which has been collected by gill net on the coast of Sur City, 151 Km south of Muscat City, Oman. Morphometric and meristic data are provided and compared with those from other sea basins.

The moonfish, Mene maculata (Perciformes: Menidae), and the crimson snapper, Lutjanus erythropterus (Perciformes: Lutjanidae), in Omani waters: a questioned occurrence and possible presence of self-sustaining populations

The first confirmed record of the moonfish, Mene maculata (Bloch & Schneider, 1801) (Perciformes: Menidae), and the crimson snapper, Lutjanus erythropterus Bloch, 1790 (Perciformes: Lutjanidae), in Omani waters is reported on the basis of 10 (M. maculata) and 7 (L. erythropterus) specimens, ranging in total length 290–410mm and 300–720mm respectively, which were collected using gill-net on the coast of Muscat City, Oman. Morphometric and meristic data are provided and compared with those of several specimens of these species from other parts of the world. The present study reports on the largest recorded specimen of M. maculata. It also reports on the presence of a sustainable population of both species in the Oman Sea, Sultanate of Oman.

Mortality of the abalone Haliotis mariae (Haliotidae: Mollusca) in aquaculture

The Omani abalone, Haliotis mariae, is the only species of abalone found in Omani waters. Given the rarity of this species and the high price it can fetch on the market (US$ 150 kg-1 dry weight), the wild abalone fishery in the Dhofar region has been regarded as a valuable income source for the past decade. The present study was undertaken set to investigate the mortality of abalone held at the Mirbat Research Center, through bacteriological and histopathological based investigations and challenge tests. Only the adult wild abalone that had been kept for a year in the hatchery, visually, appeared to be clear of disease symptoms. Infected individuals typically were swollen around the mouth, had fluid tinged with blood, bubbles in the intestines, and, very weak adhesive strength. The foot area (muscle) of diseased animals was noticeably very soft and individuals that were seen lying upside down on the bottom of the tank subsequently died. On dissection, the intestinal organs released bubbles and a foul smelling odour. Identification of the isolated bacteria using various identification methods indicated that individuals were infected with Staphylococcus sciuri. Histopathology of infected individuals revealed spongiosis of the tissues with evident bacterial infection. Neither of these histopathological conditions were seen in healthy abalone. The study concludes that the bacterium Staphylococcus sciuri may be the likely cause of abalone mortalities.

Gill monogenean communities on three commercially important sparid fish in Omani waters

The prevalence and intensity of polyopisthocotylean monogeneans on the gills of three commercially important species of sparid caught in Omani coastal waters close to the city port of Muscat were determined and compared. Throughout May 2012 to April 2013, infections on bi-weekly samples of the soldier seabream, Argyrops filamentosus (Valenciennes, 1830), the king soldier seabream, Argyrops spinifer (Forsskål, 1775), and, the silver seabream, Rhabdosargus sabra were evaluated. From a total of 200 specimens (standard length of 26–52 cm), caught by line angling or by traps, at least three species of gill monogenean, namely Omanicotyle [Bivagina] heterospina, Heteromicrocotyla sp. and Microcotyle sp., were commonly encountered. Silver bream, which was infected by all three monogeneans, bore the highest infections (100% prevalence; mean intensity of 20.14 ± 0.92 parasites fish-1), whilst the soldier bream, which was infected only by O. heterospina had the lowest levels of infection (of the three sparids with 63.8% prevalence; mean intensity 5.8 ± 0.17 parasites fish-1). Comments on the distribution of monogeneans on each host are provided but to what extent this is influenced by water current speeds passing through the buccal and opercular cavities, gill morphology, parasite size, and / or the morphology and efficiency of the parasite’s attachment apparatus requires establishing and forms the basis of ongoing investigations.

Marine Parasites of Omani Waters: State of knowledge

Parasitological studies of marine fish inhabiting the Sultanate of Oman began in the late sixties of the twentieth century and continued through ‘82. These studies revealed a total of 154 marine parasite species belonging to ten taxonomic groups.These included myxosporeans, microsporidia, helminths, parasitic crustaceans and leeches. New species were described, some of which were categorized as harmful to public health and some were found to have an impact on the quality and marketability of their hosts. The geographical distribution of the recorded parasites will be pointed out in the current paper. In addittion, the distribution patterns of the reported parasites will be analyzed and discussed according to the ecology of the perspective hosts of each parasite. Six groups of parasites can be suggested; Pelagic (3,1%), Demersal (58,4%), Benthic (23%), Pelagic-Demersal (7,5%, Demersal-Benthic (5,6%) and Pelagic- Demersal-Benthic (2,5%). Demersal parasites were the most abundant and least abundant were Pelagic-Demersal- Benthic and Pelagic ecological groups of parasites. In addition, some parasites were categorized as potential threats to future development of aquaculture industry in the country.

Reproductive Biology of the Indian Oil Sardine Sardinella longiceps From Al-Seeb Waters off Oman

The objective of this study is to examine the reproductive biology of the Omani-Indian oil sardine Sardinella longiceps from Al-Seeb area off the Omani waters. During the period January 2004–December 2008, a total of 1592 sardines were sampled. The lengths of the sampled fish ranged from 11.9 to 22 cm with a mean length of 16.5 ± 1.84 cm and modal length of 15.5 cm. Their weights ranged from 14 to 94.6 g with a mean weight of 42.43 ±15.19 g and modal weight of 43.7 g. The length–weight relationship equations analyzed for the combined sex, female, and male sardines were 2.99 W ? 0.009? L , 2.94 W ? 0.011?L , and 2.94 W ? 0.001?L , respectively. The length at 50% maturity for combined sex, female, and male sardines was 16.35, 16.46, and 16.28 cm, respectively. During the study, the Omani sardines were observed to spawn in October, June, and July, September, June, and January and September during the years 2004, 2005, 2006, 2007, and 2008, respectively. During the sampling period, the relative condition factor Kn varied from one year to another and ranged from 0.36 to 1.46 with a mean of 0.9 ± 0.08. An overall mean sex ratio of 0.68 ± 0.02 proved to be significantly different from the expected theoretical sex ratio of 0.5 (?2 = 200; df = 1; P ? 0.05).

Population Dynamics and Management of Goldlined Seabream Rhabdosargus sarba (Sparidae) from the Oman Coast of Arabian Sea

Rhabdosargus sarba is one of the most important coastal demersal species inhabiting Omani waters. An estimate of the age and growth of R. sarba ranging from 15 to 43.2 cm total length collected from the Omani waters is made by examining the growth increment of their whole otoliths. The growth rings showed that R. sarba rarely attain more than six years. The von Bertalanffy growth parameters were K = 0.33 yr-1, L∞ = 46.97 cm and to = -0.83 yr. The mean total mortality coefficient Z estimated by two different methods was 1.8 yr-1. The geometric mean of natural mortality coefficient M was 0.6 yr-1. Exploitation rate E was computed as 0.67, while the length at first capture was 22.9 cm. The yield per recruit analysis showed that the stock of R. sarba in the Arabian Sea is overexploited and the exploitation rate should be reduced by about 47% to maintain a sufficient stock biomass for spawning and recruitment as well as the length at first capture should be raised to about 30 cm.

First record of Mola ramsayi from the Sea of Oman, Sultanate of Oman

The first record of the southern ocean sunfish Mola ramsayi in Omani waters is reported based on a single 916 mm total length specimen found stranded on the coasts of Sur City 193 km south of the Omani capital Muscat, 22835′10.22′′N 59830′18.91′′E. This account also represents the third northernmost record of a south ocean sunfish in the Indian Ocean. Morphometric and meristic data are provided and compared with those of 5 specimens caught off United Arab Emirates, Brazil and India. The southern ocean distribution of M. ramsayi is corrected in this report.

Spatial-Temporal Distribution of the Palinurid and Scyllarid Phyllosoma Larvae in Oman Coastal Waters

The Bongo Net samples collected between 2005 and 2008 in the Sea of Oman and in the north-western part of the Arabian Sea (near Massirah Island) were analyzed, for a pilot assessment of seasonal and spatial distribution of the phyllosoma larvae. In the samples collected, 84% of all phyllosoma larvae were from the family Palinuridae, while the others were contributed by family Scyllaridae. All larvae of Panulirus homarus were in the first development stage and had a mean body length of 1.30±0.89mm. The phyllosoma larvae of the less abundant family Scyllaridae were in the second, third, and fourth development stages, which had a mean length of 2.3mm, 3.3mm and 4.63mm, respectively. In terms of seasonal changes, the phyllosoma larvae tend to appear in Omani waters in February, reaching their maximum numbers in April. The abundance of phyllosoma P. homarus was as much as twofold higher in the Arabian Sea compared to the Sea of Oman.

Fish Kill Incidents and Harmful Algal Blooms in Omani Waters

Red tide, one of the harmful algal blooms (HABs) is a natural ecological phenomenon and often this event is accompanied by severe impacts on coastal resources, local economies, and public health. The occurrence of red tides has become more frequent in Omani waters in recent years. Some of them caused fish kill, damaged fishery resources and mariculture, threatened the marine environment and the osmosis membranes of desalination plants. However, a number of them have been harmless. The most common dinoflagellate Noctiluca scintillans is associated with the red tide events in Omani waters. Toxic species like Karenia selliformis, Prorocentrum arabianum, and Trichodesmium erythraeum have also been reported recently. Although red tides in Oman have been considered a consequence of upwelling in the summer season (May to September), recent phytoplankton outbreaks in Oman are not restricted to summer. Frequent algal blooms have been reported during winter (December to March). HABs may have contributed to hypoxia and/or other negative ecological impacts.

First record of Antennarius coccineus from the Gulf of Oman and second record of Antennarius indicus from the Arabian Sea coast of Oman

The present paper reports the first record of one antennarid species from the Gulf of Oman and the second record of another frogfish from the Arabian Sea coasts of Oman. The record of Antennarius coccineus is a north-eastern extension of its distribution in Omani waters. Antennarius indicus was recorded for the second time from the Arabian Sea coasts of Oman.

Noteworthy elasmobranch records from Oman

Records of 11 elasmobranch species previously unreported from, or uncommon in, Omani waters are presented. Records new to Oman include Carcharhinus altimus, C. leiodon, Centrophorus isodon, Ctenacis fehlmanni, Himantura fai, Mobula eregoodootenke and Sphyrna zygaena, whereas noteworthy records of uncommon species include Himantura imbricata, Paragaleus randalii, Rhinobatos salalah and Taeniura meyeni – some of which are confirmed from the Gulf of Oman for the first time. These records bring to 57, the number of elasmobranch species confirmed in Omani waters.