Explore the vast range of titles available.

The southern Persian/Arabian Gulf experiences extreme seasonal temperature variation (> 20 °C) making it among the most hostile reef environments on Earth. Previous anecdotal evidence has suggested that seasonal temperature changes may influence regional reef fish assemblages, but to date research has been limited. To examine the influence of temperature on reef fish abundance and composition, we performed visual surveys in summer and in winter over three years at three reefs in the southern Gulf (Dhabiya, Saadiyat and Ras Ghanada). Overall abundance of fishes was 40% higher in summer than in winter, and multivariate analyses showed strong and significant differences in overall seasonal community structure, consistent at all sites and across all years. Seasonal differences were largely driven by nine of the 30 observed species, which together accounted for 70% of the divergence in community structure between summer and winter. Of these nine species, Lutjanus ehrenbergii, Lutjanus fulviflamma, Plectorhinchus sordidus and Abudefduf vaigiensis were significantly more abundant in summer, Parupeneus margaritatus and Acanthopagrus bifasciatus, were significantly more common on reefs in winter. We discuss these changes in terms of seasonal physiological and ecological constraints, and explore the implications of these changes on the functional ecology of reef fishes in this thermally variable and extreme environment.

Marine fish may become contaminated as a result of environmental pollution including hazardous metals. Due to the presence of metalloids and toxic metals such as cadmium, lead, copper, and zinc in fish tissue, it may endanger health, considering the countless benefits of consuming fish, which can harm the human body if consumed in toxic amounts. Therefore, it is vital to monitor the concentration of metals in fish meat to ensure compliance with food safety regulations and protect the consumer. We considered the levels of Ni, Zn, Cu, Pb, and Cd in 60 marine fish samples (3 species) collected from coastal areas of the northwestern coast of the Persian Gulf and estimated their health risk. Mean concentrations of Ni, Zn, Cu, Pb, and Cd were 1.88 ± 0.07 µg/g, 27.16 ± 8.11 µg/g, 11.55 ± 4.12 µg/g, 14 ± 0.06 µg/g, and 0.19 ± 0.03 µg/g wet weight. Estimated average daily intakes (EDIs) for adults and children of Ni, Zn, Cu, Pb, and Cd were 0.89–4.15 μg/kg bw/day, 12.89–60.02 μg/kg bw/day, 5.47–25.53 μg/kg bw/day, 0.54–2.51 μg/kg bw/day, and 0.09–0.42 μg/kg bw/day. Our analysis revealed elevated levels of Ni and Pb in the fish samples, raising concerns about potential health hazards associated with their consumption. This study provides critical insights into heavy metal contamination in marine fish, highlighting the need for ongoing monitoring and proactive measures to ensure safe seafood consumption in the northwest Persian Gulf.

The Arabian/Persian Gulf (‘Gulf’ hereafter) is bordered by eight countries that consider fishery as their most important renewable resource. This includes artisanal fisheries, which are a major contributor to seafood production and fishers’ livelihoods. Despite the importance of the artisanal sector, in-depth studies examining aspects—like total and country-specific production trends, used fishing gears and main threats—remain limited. Inadequate knowledge about such fundamental aspects could jeopardize the sustainability of fisheries and muddle policymaking. Here, we provide a comprehensive account of artisanal fisheries in the Gulf. Specifically, we examined: (i) magnitude of the artisanal sector, (ii) types of fishing gears used, (iii) exploited functional groups, and (iv) threats to and opportunities for sustainable artisanal fisheries. We show that around 71% of the Gulf total catch is produced by artisanal fisheries, and this trend is growing. The dominating fishing gears are gillnets, traps, and lines—collectively accounting for 72% of the total catch. Among these fishing gears, gillnets alone account for a third of the production. Most of the artisanal catch comprises medium to large fish that are demersal, pelagic, and reef-associated. Fisheries are primarily based on gear restrictions, minimum size of capture, seasonal closures, and spatial restrictions. However, weak enforcement is a core issue for the effectiveness of management regulations. Mismanaged fisheries, coastal development, and climate change are primary threats facing fish abundance and essential fish habitats. Engaging artisanal fishers in management and preserving habitats can contribute toward sustainable artisanal fisheries in the Gulf.

AIM: The Red Sea is characterised by a unique fauna and historical periods of desiccation, hypersalinity and intermittent isolation. The origin and contemporary composition of reef‐associated taxa in this region can illuminate biogeographical principles about vicariance and the establishment (or local extirpation) of existing species. Here we aim to: (1) outline the distribution of shallow water fauna between the Red Sea and adjacent regions, (2) explore mechanisms for maintaining these distributions and (3) propose hypotheses to test these mechanisms. LOCATION: Red Sea, Gulf of Aden, Arabian Sea, Arabian Gulf and Indian Ocean. METHODS: Updated checklists for scleractinian corals, fishes and non‐coral invertebrates were used to determine species richness in the Red Sea and the rest of the Arabian Peninsula and assess levels of endemism. Fine‐scale diversity and abundance of reef fishes within the Red Sea were explored using ecological survey data. RESULTS: Within the Red Sea, we recorded 346 zooxanthellate and azooxanthellate scleractinian coral species of which 19 are endemic (5.5%). Currently 635 species of polychaetes, 211 echinoderms and 79 ascidians have been documented, with endemism rates of 12.6%, 8.1% and 16.5% respectively. A preliminary compilation of 231 species of crustaceans and 137 species of molluscs include 10.0% and 6.6% endemism respectively. We documented 1071 shallow fish species, with 12.9% endemic in the entire Red Sea and 14.1% endemic in the Red Sea and Gulf of Aden. Based on ecological survey data of endemic fishes, there were no major changes in species richness or abundance across 1100 km of Saudi Arabian coastline. MAIN CONCLUSIONS: The Red Sea biota appears resilient to major environmental fluctuations and is characterized by high rates of endemism with variable degrees of incursion into the Gulf of Aden. The nearby Omani and Arabian Gulfs also have variable environments and high levels of endemism, but these are not consistently distinct across taxa. The presence of physical barriers does not appear to explain species distributions, which are more likely determined by ecological plasticity and genetic diversity.

Conservation and management of marine biodiversity depends on biomonitoring of marine habitats, but current approaches are resource-intensive and require different approaches for different organisms. Environmental DNA (eDNA) extracted from water samples is an efficient and versatile approach to detecting aquatic animals. In the ocean, eDNA composition reflects local fauna at fine spatial scales, but little is known about the effectiveness of eDNA-based monitoring of marine communities at larger scales. We investigated the potential of eDNA to characterize and distinguish marine communities at large spatial scales by comparing vertebrate species composition among marine habitats in Qatar, the Arabian Gulf (also known as the Persian Gulf), based on eDNA metabarcoding of seawater samples. We conducted species accumulation analyses to estimate how much of the vertebrate diversity we detected. We obtained eDNA sequences from a diverse assemblage of marine vertebrates, spanning 191 taxa in 73 families. These included rare and endangered species and covered 36% of the bony fish genera previously recorded in the Gulf. Sites of similar habitat type were also similar in eDNA composition. The species accumulation analyses showed that the number of sample replicates was insufficient for some sampling sites but suggested that a few hundred eDNA samples could potentially capture >90% of the marine vertebrate diversity in the study area. Our results confirm that seawater samples contain habitat-characteristic molecular signatures and that eDNA monitoring can efficiently cover vertebrate diversity at scales relevant to national and regional conservation and management. La conservación y el manejo de la biodiversidad marina depende del biomonitoreo de los hábitats marinos, pero las estrategias actuales requieren de muchos recursos y de diferentes estrategias para diferentes organismos. El ADN ambiental (ADNa) extraído de muestras de agua es una estrategia eficiente y versátil para detectar animales acuáticos. En el océano, la composición del ADNa refleja la fauna local a escalas espaciales finas, pero se sabe poco sobre la efectividad del monitoreo basado en el ADNa de las comunidades marinas a grandes escalas. Investigamos el potencial del ADNa para caracterizar y distinguir las comunidades marinas a escalas espaciales grandes mediante una comparación de la composición de especies de vertebrados entre los hábitats marinos de Qatar, en el Golfo Arábigo (también conocido como el Golfo Persa), con base en el meta-código de barras del ADNa extraído de muestras de agua de mar. Realizamos análisis de acumulación de especies para estimar cuánta de la diversidad de vertebrados logramos detectar. Obtuvimos secuencias de ADNa de diversos ensamblajes de vertebrados marinos, los cuales abarcaron 191 taxones de 73 familias. Estos taxones incluyeron a especies raras y en peligro de extinción y cubrieron el 36% de los géneros de peces óseos previamente registrados en el golfo. Los sitios con tipos similares de hábitat también fueron similares en cuanto a la composición del ADNa. Los análisis de acumulación de especies mostraron que el número de réplicas de muestras fue insuficiente para algunos sitios de muestreo, pero sugieren que unos cientos de muestras de ADNa podrían capturar potencialmente >90% de la diversidad de vertebrados marinos en el área de estudio. Nuestros resultados confirman que las muestras de agua marina contienen firmas moleculares características del hábitat y que el monitoreo de ADNa puede cubrir eficientemente la diversidad de vertebrados a escalas relevantes para la conservación y el manejo nacional y regional. 海洋生物多样性的保护和管理依赖于对海洋生境的生物监测，而目前的监测方法都属于资源密集型，且对 不同生物需要采取不同的方法。 从水样中提取环境 DNA (eDNA) 是一种调查水生动物高效通用的方法。 在海 洋中，eDNA 的组成反映了区域精细空间尺度上动物群的情况, 但对于 eDNA 在更大尺度上调查海洋生物群落的 有效性尚有待探究。 本研究基于 eDNA 条形码技术在海水样品中的应用，比较了卡塔尔和阿拉伯湾（又称波斯 湾）海洋生境的脊椎动物组成，以分析 eDNA 在大空间尺度上描述和分辨海洋生物群落的能力。 我们通过物种 累积分析估计了我们检测到的脊椎动物多样性。 结果显示，我们获得的 eDNA 序列来自包含 73 个科 191 个类 群的海洋脊椎动物群集。 这些动物中包括稀有物种和濒危物种，覆盖了该海湾现有记录中 36% 的硬骨鱼属。 生 境类型相近的位点检测到的 eDNA 组成也相似。 物种累积分析还表明一些采样位点的样品重复个数不足，但几 百个 eDNA 样本可能足够捕获该研究地区 90% 以上的海洋脊椎动物多样性。 我们的研究结果证实了海水样本 中含有具有生境特点的分子信号，且 eDNA 检测可以在与国家和区域保护管理所涉及的尺度上有效覆盖脊椎动 物多样性。

Elasmobranch population declines due to human impacts have been documented at a global scale, having impacts on the functioning and structure of marine ecosystems. This situation leads to an international focus on the conservation of their populations and a key step in the management and conservation of elasmobranch populations is to understand their trophic ecology. Here, by using stable isotopes analysis, we investigated the trophic relationships, trophic niche breadth, and trophic redundancy among 21 batoids and 12 sharks inhabiting the Persian Gulf and Gulf of Oman, two productive areas of the Arabian Sea considered global elasmobranch hotspots. Isotopic results revealed differences in the trophic niche and trophic position among the elasmobranch sampled at species and at family level. For example, the batoids of the family Torpedinidae and the sharks of the family Triakidae occupied higher trophic positions and the family Glaucostegidae showed a lower trophic niche width, whereas the batoids of the family Myliobatidae or Gymnuridae, in overall, showed lower higher trophic niche width, reflecting the trophic habits described for most of the sampled species. We also provided some insights into the ecology of poorly known species, especially relevant for those that are endangered at a global or regional scale. In conclusion, we provide new information about the trophic ecology among batoids and sharks inhabiting the Persian Gulf and Gulf of Oman. This information is highly useful to study the consequences of future changes on their feeding preferences due to natural or human-related factors.

The Persian Gulf consider as the fundamental biological marine condition between the seas. There is a different assortment of marine life forms including corals, wipes, and fish in this marine condition. Mangrove timberlands are found all through this sea-going biological system. Sullying of the Persian Gulf to oil-based goods is the principle of danger to this marine condition and this contamination can effectively affect this differing marine condition. Numerous specialists examined the result of oil contamination on Persian Gulf marine creatures including corals sponges, bivalves, and fishes. These analysts affirmed this oil contamination on the Persian Gulf significantly diminished biodiversity. Diverse microorganisms fit to consume oil-based commodities detailed by various scientists from the Persian Gulf and their capacity to the debasement of unrefined petroleum has been examined. There has additionally been little exploration of cyanobacteria, yeast, and unrefined petroleum debasing organisms in this sea-going environment. Biosurfactants are amphipathic molecules that upgrade the disintegration of oil and increment their bioavailability to corrupt microscopic organisms. Additionally, biosurfactant-producing bacteria were discovered from the Persian Gulf, and the capability to degradation of crude oil in microscale was evaluated. The current review article aims to collect the finding of various researches performed in the Persian Gulf on oil pollution and crude-oil biodegradation. It is expected that by applying biological methods in combination with mechanical and chemical methods, the hazard consequences of crude-oil contamination on this important aquatic ecosystem at the world will be mitigated and a step towards preserving this diverse marine environment.

Otolith shape variation in the Ornate goby, Istigobius ornatus (Teleostei: Gobiidae), collected along the intertidal coasts of the Persian Gulf and Oman Sea, was analysed using Wavelet transform technique in the ShapeR package to determine population differentiation and structure. There were significant differences (P < 0.001, ANOVA) among geographically distant populations based on the variation in the anterior and posterior otolith rims. However, otolith shapes of neighbouring populations were more similar to each other (P > 0.01). Mantel test showed a positive correlation between the Euclidean distance of otolith shape and geographical distances among populations (r = 0.93, P < 0.002). This indicates that levels in otolith shape resemblance between populations are dependent on geographic distance. Different scenarios are discussed to explain the pattern of otolith shape variation and population structure. Among possible key mechanisms responsible for population differentiations are isolation by distance, Late Pleistocene sea level fluctuations, and ecological and geographical differences between the studied locations. This study highlights otolith shape efficiency as an exceptionally convenient morphological marker to study intraspecific-level evolutionary and contemporary phenomena in marine fish.

The smoothnose wedgefish Rhynchobatus laevis, a shark-like ray classified as Critically Endangered by the International Union for Conservation of Nature, has received limited research attention. To address the knowledge gaps in its spatial behaviour, this study utilised satellite monitoring of a fortuitously captured female over a 51-day period in the Arabian Gulf. Based on the resulting movement track, the individual covered a minimum distance of 712 km, traversing the exclusive economic zones of three different countries. Its track began in the United Arab Emirates, from where it headed north, entering Iranian waters, where it spent most of its time, before continuing westward across the Gulf and eventually reaching Qatari waters. Novel insights into its behaviour revealed an observation of rapid ascents over the study period. Although both diurnal and nocturnal ascents were observed, they occurred predominantly during nocturnal periods. Contrary to the prevailing belief that wedgefish are bottom-associated, the study animal spent a considerable amount of time in the water column. The use of various depths in both nearshore and offshore waters highlights elevated susceptibility to multiple types of fishing gear. This underscores the need for an international cooperative approach to the management and conservation of shark-like rays in the Arabian Gulf.