This study presents the first documented observations of a brachyuran crab's proactive fishing behaviour in conjunction with mangrove pneumatophores which are employed as prey-localization devices. All ecological data were recorded in situ using simple behavioural observations, visual census and field experiments. Field experiments were based on stimulus-response and ecological surveys on random displacement. Assemblages of Metopograpsus messor were observed daily performing a foraging/predatory tide-related cyclic behaviour pattern in an arid mangrove ecosystem which experiences challenging environmental conditions. Prey-localizing behaviour was observed during the flood tide when pneumatophore-borne vibrations were used to identify potential prey. The prey simulation field experiment (where a single pneumatophore was stimulated by knocking) showed that in >93% of instances a crab approached the exact pneumatophore being stimulated. As water levels increased during the tidal cycle M. messor was observed climbing pneumatophores. The crabs anchored themselves to the pneumatophore just above the water level with their pereiopods. The chelipeds were positioned in a pincher-like trap, and remained in a ‘capture-position’ waiting for prey to move within striking range. This characteristic fishing behaviour was performed daily by a population of M. messor. Ecological observations suggest that both these predatory behaviours are associated with the fish Aphanius dispar dispar in a direct prey–predator relation. Evidence suggests that these fishing behaviours evolved due to characteristics within the M. messor phylogeny (foraging in intertidal zones; daily displacement following tidal levels; high sensitivity to vibrations; and an opportunist diet) and its associated environment (presence of pneumatophores and high availability of a fish resource).

Where two species occupy the same habitat and similar niches, competition is likely to drive small-scale spatial niche separation or resource partitioning that may not be immediately apparent. A stable isotope approach was used to investigate potential trophic niche separation between co-existing rocky shore crabs in the North-West (NW) Arabian Gulf. Leptodius exaratus and Pilumnopeus convexus which occupy similar shore height on the same rocky intertidal habitats. We also investigated conspecific differences between males vs females and adults vs juveniles. δ15N results indicated that adults of both species occupy a high trophic level in the rocky shore community, suggesting similar functional roles and potential for competition for food resources, while significant differences in δ13C values indicated differences in dietary sources between the two species, and also changes in diet between juveniles and adults in both species. MixSIAR analysis of δ15N and δ13C data confirmed field observations that both species are generalist omnivores, with potential for direct competition including adult predation on juveniles, including conspecifics. Differentiation in isotopic niches (SIBER analysis) was mainly driven by the significant differences in δ13C values, suggesting that co-existence of the two crab species is at least in part mediated by trophic niche separation or dietary resource partitioning, with some (unquantified) potential for spatial resource partitioning at the microhabitat level.

Lead and lead minerals have been used for medical purposes throughout human history. For example, galena was used as an eye salve in pre-Dynastic Egypt and by the ancient Indian civilisations of Mohendro-Daro and Harappa some 3200 to 2800 B.C. (Nriagu, 1983). The use of lead and other heavy metals and their compounds in Ayurveda, the Hindu system of medicine, can be traced back to the first century A.D. when Jain and Buddhist healers began to encourage the use of these substances instead of animal products (Mukherjee, 1992).

The Arabian Gulf is one of the most heavily impacted water bodies raising serious concerns about the conservation status of many marine species. A limited coastal range and near-shore distribution make Indian Ocean humpback dolphins particularly vulnerable to mortality and traumatic injuries from heavy maritime traffic and gill-netting practices. Prior to the present study, no research had focused on the ecology of this species in the Arabian Gulf, despite the potential for human impacts. The mark–recapture method of photo-identification, undertaken during 55 boat-based surveys conducted between 2014 and 2015, was used to assess the occurrence, abundance and use of habitat of this endangered species along the coast of the Emirate of Abu Dhabi (UAE). In all, 368 h and 6703 km of observation were carried out over a period of 5 months, and 54 encounters were made with humpback dolphins. The group size ranged from 1 to 24 individuals and group composition showed that 79% of the observed dolphins were adults. Abundance estimates were calculated and fitted with open population models. A review of all available data indicates that the studied population is the largest reported in the world with 701 (95% CI = 473–845) individuals. While their occurrence within Abu Dhabi near-shore waters is frequent, the survey area appears to be only a part of a much larger home range for this humpback dolphin population. The observation of multiple threats derived from anthropogenic activities increases our concerns regarding the conservation of this important dolphin population.

Accurate sea-level reconstruction is critical in understanding the drivers of coastal evolution. Inliers of shallow marine limestone and aeolianite are exposed as zeugen (carbonate-capped erosional remnants) on the southern coast of the Arabian/Persian Gulf. These have generally been accepted as evidence of a eustatically driven, last-interglacial relative sea-level highstand preceded by a penultimate glacial-age lowstand. Instead, recent optically stimulated luminescence (OSL) dating suggests a last glacial age for these deposits, requiring >100 m of uplift since the last glacial maximum in order to keep pace with eustatic sea-level rise and implying the need for a wholesale revision of tectonic, stratigraphic and sea-level histories of the Gulf. These two hypotheses have radically different implications for regional neotectonics and land–sea distribution histories. Here we test these hypotheses using OSL dating of the zeugen formations. These new ages are remarkably consistent with earlier interpretations of the formations being last interglacial or older in age, showing that tectonic movements are negligible and eustatic sea-level variations are responsible for local sea-level changes in the Gulf. The cause of the large age differences between recent studies is unclear, although it appears related to large differences in the measured accumulated dose in different OSL samples.

Late Quaternary reflooding of the Persian Gulf climaxed with the mid-Holocene highstand previously variously dated between 6 and 3.4 ka. Examination of the stratigraphic and paleoenvironmental context of a mid-Holocene whale beaching allows us to accurately constrain the timing of the transgressive, highstand and regressive phases of the mid- to late Holocene sea-level highstand in the Persian Gulf. Mid-Holocene transgression of the Gulf surpassed today's sea level by 7100–6890 cal yr BP, attaining a highstand of > 1 m above current sea level shortly after 5290–4570 cal yr BP before falling back to current levels by 1440–1170 cal yr BP. The cetacean beached into an intertidal hardground pond during the transgressive phase (5300–4960 cal yr BP) with continued transgression interring the skeleton in shallow-subtidal sediments. Subsequent relative sea-level fall produced a forced regression with consequent progradation of the coastal system. These new ages refine previously reported timings for the mid- to late Holocene sea-level highstand published for other regions. By so doing, they allow us to constrain the timing of this correlatable global eustatic event more accurately.

Despite the wealth of archaeological sites and excellent conditions for preservation, few phytolith investigations have been undertaken from the Arabian Gulf region. The results from the Sasanian and Islamic archaeological tell of Kush, Ras al-Khaimah, United Arab Emirates, are presented. Kush is situated just inside the Gulf on an important trade route. The occupation sequence dates from the 4th century A.D. until the 13th century A.D., recording the development of the site in the Sasanian period, followed by the arrival of Islam in the 7th century A.D. and the final abandonment of the site in the late 13th century when the nearby site of al-Mataf (Julfar) began to develop closer to the present day coastline. All the samples analyzed contained abundant phytoliths (short cells, elongated cells, and groups of elongated cells) of various types. They included date palm (Phoenix dactylifera), papillae (possibly from barley (Hordeum)), and hair cells possibly from species of canary grass (Phalaris spp.). Some researchers have suggested that groups of elongated cells may indicate the presence of irrigation in semiarid environments. The present results for this class of phytoliths appeared to imply that intensive irrigation was unlikely to have taken place around Kush.

Historically cormorants have come into direct conflict with fisheries because of their feeding habits. The Socotra cormorant Phalacrocorax nigrogularis is a regionally endemic seabird restricted to the Arabian Gulf and coastal Oman, and is categorized as Vulnerable on the IUCN Red List. The species is perceived as being detrimental to local fisheries and is therefore persecuted. We studied the diet and estimated the number of Socotra cormorants breeding on Siniya Island, Umm Al Quwain, United Arab Emirates, to determine their impact on local fisheries. Regurgitated fish loads were collected during the breeding seasons of 2011–2012 and 2012–2013, and the biomass of fish consumed by the Socotra cormorant population was estimated. The diet comprised seven species of fish, with sailfin flying fish Parexocoetus mento and blue-stripe sardine Herklotsichthys quadrimaculatus dominating in 2011–2012 and anchovies (Encrasicholina spp.) dominating in 2012–2013. Biomass of fish loads was higher in 2011–2012 compared to 2012–2013, although mean biomass of fish loads did not differ. Dominant fish species in the cormorant's diet were either used as baitfish or were non-target species in the fisheries. The low overlap between the diet of the Socotra cormorant and the fish landed by the fisheries suggests that the cormorant's impact on fisheries is minimal. Conservation strategies to protect the birds and their feeding areas could safeguard populations of this species from further declines.

The presence of the fish species Monocentris japonica is reported from the Iraqi waters of the Arabian Gulf. One adult specimen (125 mm total length) was caught from the waters around the Khor Abdullah within the Iraqi marine territory, giving a new ichthyofaunal record for the area.

In marine turtles the selection of oviposition habitat is a key determinant of offspring success. I investigated which environmental features influenced the nesting activity and nest distribution of the hawksbill turtle Eretmochelys imbricata by daily monitoring of a rookery on the coast of the Arabian Gulf, in Qatar. I mapped the distribution of turtle nests and unsuccessful nesting attempts and measured key beach features. Data were analysed using autoregressive models, a specific regression technique dealing with spatial autocorrelation. Distribution of nests and unsuccessful nesting attempts were strongly spatially autocorrelated. In some areas almost all the turtles that approached the beach excavated a nest, whereas in other areas nesting was scarce but many unsuccessful attempts were observed. Turtle activity was lower in areas with a steep coastline and high rock cover. Nest density was higher on beaches with a low slope and little rock cover, and with soft soil and high vegetation cover. The density of unsuccessful nesting attempts was higher in areas with hard soil and low vegetation cover. These results are relevant for the management and restoration of nesting areas for this Critically Endangered species.