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Marine traffic is increasing globally yet collisions with endangered megafauna such as whales, sea turtles, and planktivorous sharks go largely undetected or unreported. Collisions leading to mortality can have population-level consequences for endangered species. Hence, identifying simultaneous space use of megafauna and shipping throughout ranges may reveal as-yet-unknown spatial targets requiring conservation. However, global studies tracking megafauna and shipping occurrences are lacking. Here we combine satellite-tracked movements of the whale shark, Rhincodon typus, and vessel activity to show that 92% of sharks’ horizontal space use and nearly 50% of vertical space use overlap with persistent large vessel (>300 gross tons) traffic. Collision-risk estimates correlated with reported whale shark mortality from ship strikes, indicating higher mortality in areas with greatest overlap. Hotspots of potential collision risk were evident in all major oceans, predominantly from overlap with cargo and tanker vessels, and were concentrated in gulf regions, where dense traffic co-occurred with seasonal shark movements. Nearly a third of whale shark hotspots overlapped with the highest collision-risk areas, with the last known locations of tracked sharks coinciding with busier shipping routes more often than expected. Depth-recording tags provided evidence for sinking, likely dead, whale sharks, suggesting substantial “cryptic” lethal ship strikes are possible, which could explain why whale shark population declines continue despite international protection and low fishing-induced mortality. Mitigation measures to reduce ship-strike risk should be considered to conserve this species and other ocean giants that are likely experiencing similar impacts from growing global vessel traffic., [Significance] Global vessel traffic is increasing alongside world economic growth. The potential for rising lethal ship strikes on endangered species of marine megafauna, such as the plankton-feeding whale shark, remains poorly understood since areas of highest overlap are seldom determined across an entire species range. Here we show how satellite tracking whale sharks and large vessel movements globally provides a means to localize high-overlap areas and to determine how collision risk changes in time. Our results point to potential high levels of undetected or unreported ship strikes, which may explain why whale shark populations continue to decline despite protection and low fishing-induced mortality. Collision mitigations in high-collision-risk areas appear necessary to help conserve this iconic species., Funding for data analysis was provided by the UK Natural Environment Research Council (NERC) through a University of Southampton INSPIRE DTP PhD Studentship to F.C.W. Additional funding for data analysis was provided by NERC Discovery Science (NE/R00997/X/1) and the European Research Council (ERC-AdG-2019 883583 OCEAN DEOXYFISH) to D.W.S., Fundação para a Ciência e a Tecnologia (FCT) under PTDC/BIA/28855/2017 and COMPETE POCI-01–0145-FEDER-028855, and MARINFO–NORTE-01–0145-FEDER-000031 (funded by Norte Portugal Regional Operational Program [NORTE2020] under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund–ERDF) to N.Q. FCT also supported N.Q. (CEECIND/02857/2018) and M.V. (PTDC/BIA-COM/28855/2017). D.W.S. was supported by a Marine Biological Association Senior Research Fellowship.

Oil and gas platforms act as artificial habitats for a myriad of marine organisms. In this study, we used opportunistic remotely operated vehicle (ROV) data to describe fouling assemblages through the characterization of functional groups in the Al Shaheen oil field, situated in Qatari waters. The surveys showed a strong vertical stratification, with the number of functional groups increasing from the surface to the bottom. In addition, the majority of functional groups had their highest frequency of occurrence in the 35-60 m interval. In turn, multivariate analyses showed a slight structure among platforms with different ages. The lowest number of functional groups occurred in the early ages (2-3 years old), and some groups either increased or decreased their frequency and abundance along the years. A step further is now required to determine whether these platform foundations should be converted to reefs after their decommissioning (i.e., Rigs to Reefs approach).

Environmental DNA (eDNA) provides a promising supplement to traditional sampling methods for population genetic inferences, but current studies have almost entirely focused on short mitochondrial markers. Here, we develop one mitochondrial and one nuclear set of target capture probes for the whale shark (Rhincodon typus) and test them on seawater samples collected in Qatar to investigate the potential of target capture for eDNA-based population studies. The mitochondrial target capture successfully retrieved similar to 235x (90x - 352x per base position) coverage of the whale shark mitogenome. Using a minor allele frequency of 5%, we find 29 variable sites throughout the mitogenome, indicative of at least five contributing individuals. We also retrieved numerous mitochondrial reads from an abundant nontarget species, mackerel tuna (Euthynnus affinis), showing a clear relationship between sequence similarity to the capture probes and the number of captured reads. The nuclear target capture probes retrieved only a few reads and polymorphic variants from the whale shark, but we successfully obtained millions of reads and thousands of polymorphic variants with different allele frequencies from E. affinis. We demonstrate that target capture of complete mitochondrial genomes and thousands of nuclear loci is possible from aquatic eDNA samples. Our results highlight that careful probe design, taking into account the range of divergence between target and nontarget sequences as well as presence of nontarget species at the sampling site, is crucial to consider. eDNA sampling coupled with target capture approaches provide an efficient means with which to retrieve population genomic data from aggregating and spawning aquatic species.

The whale shark is an ideal flagship species for citizen science projects because of its charismatic nature, its size, and the associated ecotourism ventures focusing on the species at numerous coastal aggregation sites. An online database of whale shark encounters, identifying individuals on the basis of their unique skin patterning, captured almost 30,000 whale shark encounter reports from 1992 to 2014, with more than 6000 individuals identified from 54 countries. During this time, the number of known whale shark aggregation sites (hotspots) increased from 13 to 20. Examination of photo-identification data at a global scale revealed a skewed sex-ratio bias toward males (overall, more than 66%) and high site fidelity among individuals, with limited movements of sharks between neighboring countries but no records confirming large, ocean basin-scale migrations. Citizen science has been vital in amassing large spatial and temporal data sets to elucidate key aspects of whale shark life history and demographics and will continue to provide substantial long-term value.

An assessment of vertical distribution, diel migration, taxonomic and functional diversity of fishes was carried out at offshore platforms in The (Arabian–Iranian–Persian) Gulf. Video footage was recorded at the Al Shaheen oil field between 2007 and 2014 using a remotely operated vehicle (ROV). A total of 12 822 individual fishes, from 83 taxonomic groups were recorded around the platforms. All the species identified are considered native to The Gulf, although Cyclichthys orbicularis and Lutjanus indicus were recorded for the first time in Qatari waters. Several trends were uncovered in the vertical distribution of the fish community; most species were observed between 20 and 50 m depth and fish abundance decreased towards the bottom, with the highest abundances recorded in the upper layers, i.e. down to 40 m depth. Vertical variation in fish diversity, however, was generally not accompanied by differences in vertical movements. Carnivores and invertivores were the dominant trophic groups, being found at each depth range from surface to seabed. The functional indices showed no significant differences between water depths or diel cycles. The study demonstrates that oil platforms represent a hotspot of fish diversity and interesting sites for studying fish communities, abundance and behaviour.

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., Article impact statement: Environmental DNA provides habitat‐characteristic molecular signatures and can be used efficiently to map marine biodiversity at large spatial scales.

The Gulf was contaminated with a large quantity of crude oil during the Gulf War in 1991. Some of the oil beached on the shorelines of the Northwest coast of Qatar. It was discovered, during a sampling campaign in 2015, that the shorelines were contaminated with both fresh oil and heavily weathered oil that could be originating from the Gulf War. A total of 38 oil spill samples were collected during two sampling campaigns and analysed with gas chromatography - mass spectrometry (GC–MS). The chemical fingerprints of petroleum biomarkers and C0-C4 alkyl-substituted polycyclic aromatic compounds for these spill samples were compared to those of more than 250 crude oils from around the world applying the CHEMSIC method (chemometric analysis of selected ion chromatograms). The weathering degree varied significantly between samples, and relatively unweathered oil from the Gulf War oil spill is still found in the Al Zubarah area together with oil from more recent spills. The spill samples were found to originate from at least two sources with most resemblance to oils from Kuwait and Saudi Arabia.

Assessing the movements and connectivity of whale sharks Rhincodon typus through their range is difficult due to high individual mobility and limited knowledge of their behaviour following dispersal from coastal aggregation sites. Here, we use a large set of photo-identification and stable isotope data (δ15N and δ13C) to test the assumption that sharks frequenting aggregation sites in Mozambique, Tanzania, and Qatar are a mixed stock, as inferred by genetic data. Photo-identification revealed negligible connectivity among aggregation sites and none between the southern and central areas of the Western Indian Ocean (Mozambique and Tanzania) and the Arabian Gulf (Qatar). Sight−resight data indicated that shark movements at each site could be best represented by a model that included emigration, re-immigration, and some mortality or permanent emigration. Although there was high individual variation in the isotope profiles of sharks from each location, comparison with latitudinal isotope data suggests that sharks had shown site fidelity to within a few hundred kilometres of each study area over the period of isotopic integration. Given the Endangered status of whale sharks and regional differences in anthropogenic threat profiles, further studies — and conservation assessment efforts — should consider the possibility that whale shark subpopulations exist over smaller geographical scales than previously documented.

The Arabian Gulf countries’ marine environment has been subjected to increasing industrial development and anthropogenic pressure, leading to the growing introduction of contaminants into the marine environment, with a large percentage of those consisting of potentially genotoxic substances. In this study, we performed the first integrated assessment of some of the genotoxic contaminants present in the Qatari marine environment and their biological effect, by the evaluation of the aneuploidy levels on the native pearl oyster Pinctada radiata. The aneuploidy levels varied significantly between sampling sites but not between sampling seasons. However, an important spatial and temporal variability of the bioaccumulated contaminants in the P. radiata tissues was observed, leading us to suggest that the high levels of aneuploidy found in the two harbor sampling sites could be a consequence of a local chronical contamination and not a direct response to the temporal fluctuations of the bioavailable contaminants to P. radiata.

The Arabian Gulf is the warmest sea in the world and is host to a globally significant population of the whale shark Rhincodon typus. To investigate regional whale shark behaviour and movements, 59 satellite-linked tags were deployed on whale sharks in the Al Shaheen area off Qatar from 2011–14. Four different models of tag were used throughout the study, each model able to collect differing data or quantities of data. Retention varied from one to 227 days. While all tagged sharks crossed international maritime boundaries, they typically stayed within the Arabian Gulf. Only nine sharks dispersed through the narrow Strait of Hormuz into the Gulf of Oman. Most sharks stayed close to known or suspected feeding aggregation sites over summer months, but dispersed throughout the Arabian Gulf in winter. Sharks rarely ventured into shallow areas (

Population genetics is essential for understanding and managing marine ecosystems, but sampling remains challenging. We demonstrate that high-throughput sequencing of seawater environmental DNA can provide useful estimates of genetic diversity in a whale shark (Rhincodon typus) aggregation. We recover similar mitochondrial haplotype frequencies in seawater compared to tissue samples, reliably placing the studied aggregation in a global genetic context and expanding the applications of environmental DNA to encompass population genetics of aquatic organisms.

Over the years there have been several reports of oil spills affecting particularly the northern coast of Qatar. In most cases, the source of oil spills is not identified. The spilled oils are very resistant to degradation and can affect the coastal ecosystem over many years. Even today, after 24 years, some of the oil that was spilled during the 1991 Gulf War can be found in sand, close to the Al Zubahra UNESCO site.The Maersk Oil Research and Technology Center in Doha (MO-RTC) has established the Oil Fingerprint project in collaboration with the University of Qatar and the University of Copenhagen. One of the objectives of the collaboration is to identify the potential source and origin of oil spills based on their chemical composition.A total of 38 samples were collected. During the sampling campaign it was discovered that the coast was contaminated with highly weathered oil that could originate from the Gulf War era but also with more fresh oil that most likely originates from recent oil spills in the Arabian Gulf. We therefore collected polluted soil samples and contaminated sediments from two main areas along the beach in North-western Qatar. The samples were analysed using gas chromatography – mass spectrometry in selected ion monitoring mode (GC-MS/SIM) and the oil composition was characterized. The likely source of the beached oil was identified by a comparison of diagnostic source ratios by comparing petroleum hydrocarbon fingerprints of steranes and hopanes of the spills against an oil database. The initial chemical fingerprinting based on selected ion chromatograms (SICs) of steranes (m/z 217) and hopanes (m/z 191), were remarkable similar as were the C29-/C30-Hopane ratios between sampling sites. However, a more detailed pixel-based analysis showed significant differences between samples.The process also included an assessment of the physical and biological weathering effects on the oil spills. Petroleum biomarker patterns (steranes and hopanes) are identical for all 14 samples included in this pilot study. The only differences observed were in the relative concentration of LMW and HMW steranes. This could be due to real source oil differences, however, the general weathering patterns indicate that these differences are more likely due to extensive weathering of especially two samples (9-02, 3-02) but also 8-01 and 10-01 shows severe weathering effects. Analysis of alkyl-PAHs provided an overall evaporative weathering degree for the samples. Distinct differences in the isomer patterns were observed for 3- to 4-ring alkyl-PAHs and this cannot be immediately explained as biodegradation. The largest fraction of the samples seems to originate from the same source but other sources are clearly present. A more detailed analysis with normalization to Euclidean norms within six selected SICs revealed more source specific information. In conclusion, the results indicate at least 2-3 different sources on the basis of differences in PAH isomer patterns. This was confirmed by visual inspection of SICs of C1-C3 alkyl-substituted phenanthrene, dibenzothophene, chrysene and pyrene isomers. Apart from the finding that the spills originate from several sources, the evaporation profiles indicated that not all of the spills are crude oils but that some are also heavy fuels. This suggests ongoing bunker flush off the coast of Qatar.These findings are of importance in further bioremediation processes in which, different approaches should be investigated to achieve high efficiency strategies if removal of oil pollutants from AlZubaraa area.

Aquatic ecosystems across the globe are under significant threat, suffering from various forms of anthropogenic disturbances, which is greatly impacting global biodiversity, economy and human health. Reliable monitoring of species is crucial for data-driven management actions in this context, but remains a challenge owing to non-standardized and selective methods relaying on physical identification of species by visual surveys and counting of individuals. However, traditional monitoring techniques remain problematic due to difficulties associated with correct identification of cryptic species or juvenile life stages, These traditional methods depend on practical and taxonomic expertise, which is steadily declining. In an attempt to come up with new objective solutions for monitoring biodiversity, recent and ongoing studies in Qatari waters, uses and further develops novel environmental DNA (eDNA) methods for Monitoring aquatic biodiversity in the Gulf and elsewhere.Previous studies have shown that diversity of rare and threatened European freshwater animals - representing amphibians, fish, mammals, insects and crustaceans - can be detected and quantified based on environmental DNA (eDNA) obtained directly from small water samples of lakes, ponds and streams (Thomsen et al. 2012a).Subsequently, for the first time, we investigated the potential of using metabarcoding of eDNA obtained directly from seawater samples to account for marine fish and mammal biodiversity. We show that such marine eDNA can account for fish biodiversity using high-throughput sequencing. Promisingly, eDNA covered the fish diversity better than any of 9 methods, conventionally used in marine fish surveys. Additionally, we show that even short fish eDNA sequences in seawater degrades beyond detectable levels within days, in accordance with results obtained from freshwater eDNA (Thomsen et al. 2012b). Controlled mesocosm experiments have also shown that eDNA becomes undetectable within 2 weeks after removal of animals, indicating that eDNA traces are near contemporary with species presence. Our findings underpin the ubiquitous nature of eDNA traces in the environment and support the use of eDNA as a tool for monitoring rare, threatened and economically important species across a wide range of taxonomic groups.A particularly interesting study focuses on the large whale shark aggregation at the Al Shaheen Oil Field, located in the offshore area called “Block 5”, in the NE of the Exclusive Economic Zone (EEZ) of Qatar. Maersk Oil Qatar is currently operating several oil and gas production platforms within this field, and also take active part in a large whale shark research project studying many aspect about the aggregation. Quantitative PCR (qPCR) and high-throughput sequencing of sea water from the area have successfully been employed to gain new information about the occurrence, abundance and biology of the aggregation. More specifically, data from 2013 and 2014 showed that whale shark eDNA concentrations follows visual observations of abundance, and that degradation of eDNA occur rapidly, supporting that the obtained genetic material is of local origin. Our findings confirm that seawater samples can contain key information on populations of oceanic species, and demonstrate a general potential of eDNA for studying populations of marine organisms.Although further studies are needed to validate the eDNA approach under varying environmental conditions, our findings provide a strong proof-of-concept with great perspectives for future monitoring of aquatic biodiversity and resources in the Gulf.ReferencesThomsen PF, Kielgast J, Iversen LL, Wiuf C, Rasmussen M, Gilbert MTP, Orlando L, Willerslev E (2012a). Monitoring Endangered Freshwater Biodiversity using Environmental DNA. Molecular Ecology 21, 2565–2573.Thomsen PF, Kielgast J, Iversen LL, Møller PR, Rasmussen M, Willerslev E (2012b). Detection of a Diverse Marine Fish Fauna using Environmental DNA from Seawater Samples. PLOS ONE 7(8), e41732.

The Arabian Gulf is a semi-enclosed sea with very high evaporation and low discharge rates resulting in extreme saline and thermal conditions. Additionally the system is characterized by a weak hydrodynamic flushing resulting in pollutant build-up over time. As a result, compared to open marine systems, added stress imposed by pollutants is likely to have severe consequences.Qatar has witnessed a rapid expansion in coastal development, linked to its industrial and population growth in recent decades. While economically and socially valuable, the growth comes with an associated environmental cost and Qatar's marine environment now faces many pressures including eutrophication, inputs of domestic sewage, discharge of industrial waste and the resuspension of sediment due to coastal construction. Although the threats pose to biota inhabiting Qatar's marine environment are evident, their extent has yet to be fully assessed.A large percentage of contaminants in the aquatic environment consist of potentially (directly or indirectly) genotoxic, carcinogenic and mutagenic substances. A genotoxin can modify the genetic material at non lethal and non cytotoxic concentrations and has often belated effects which are significantly important at the population and community levels. Genotoxins have particularly high ecotoxicological relevance in situations of chronic exposure to low doses and to multiple contaminants (e.g. in case of PAHs rich tarballs arriving in the shorelines), raising he need to establish genotoxicological profiles of the ecosystems.Indeed several regulatory developments such as: EU – Marine Strategy Framework Directive, the or US – Environmental Protection Agency – Integrated Risk Information System have stressed explicitly on the need of the detection and assessment of potential carcinogenic and mutagenic toxicants using genotoxicity endpoints.The analysis of cytogenetic endpoints in organisms exposed to contaminants in their natural environment contributes significantly to the early detection of genotoxic damage. The relevance of cytogenetic parameters and atypical cytogenetic features, such as numerical chromosomal abnormalities, i.e. aneuploidy, have largely proven their relevance as alerting indicators of poor environmental health and relevant biomarkers for the early detection of environmental stressors.The use of marine invertebrates for in situ environmental assessment is a widely accepted method for identifying risks to the ecosystems. Moreover, at the DNA and chromosome levels they express qualitatively similar types of induced damage to that found in higher organism (e.g. numerical and structural chromosomal aberrations).In this study, we aimed to take a step towards Qatar's marine sustainability by assessing the health status of the marine environment, and providing early alerting symptoms of degradation, by having as specific objectives: i) to measure the levels, in abiotic (water, sediments) and a marine invertebrate model species, of various anthropogenic contaminants (metals, polycyclic aromatic hydrocarbons, (PAHs) and Total polyaromatic hydrocarbons (TPH) at 3 selected sites around the Qatari coast, ii) measure the biological response at the chromosome level, and iii) determine the main drivers of genotoxicity through a multivariate analysis in order to establish a first partial genotoxicological profile of the Qatar Marine Zone.The 3 selected sampling sites, with expected different levels and sources of pollution were: South of Al Khor, Al Wakra harbor and South of Doha harbor. Two sampling campaigns were performed, one in summer and one in winter, to evaluate the role of the abiotic parameters, among others, on the bioavailability of the studied contaminants.The native pearl oyster Pinctada radiata was selected as model and surrogate species due to, its wide distribution along the Qatari coast, filter feeder and sessile mode of life and to its ability as a bivalve to bioaccumulate pollutants. Chemical analyses of the main trace metals and hydrocarbons were performed in water, sediment and P. radiata samples.The evaluation of the aneuploidy levels in P. radiata was estimated in 25–30 animals from each sampling site and season, by counting the total number of aneuploid metaphases over 30 metaphases counted per individual.The evaluation of the aneuploidy level on Pinctada radiata from the three sampling sites revealed an occurrence of significantly higher levels in Al-Wakra harbor (17% in summer and 20% in winter) and South of Doha harbor (19% in summer and 17% in winter), when compared to Al Khor (5% in summer cand 7% in winter). No statistically significant differences were observed between seasons in each location.In order to investigate the discrepancy between sampling sites and seasons with respect to all estimated descriptors and to evaluate the relationship between all the studied parameters, a principal component analysis (PCA) was performed. Aneuploidy levels were highly correlated to mercury and PAHs levels in the bivalve tissue. Moreover, the higher aneuploidy levels registered at Al Wakra harbor (both seasons) and Doha harbor (summer) showed a high correlation with the contaminants levels in P. radiata tissues. South of Al Khor (in both sampling seasons) was highly positively correlated with Cadmium (Cd), although this contamination was not responsible for a significant increase of the aneuploidy levels.The studied genotoxic contaminants were found to be highly variable among considered locations and between sampling seasons. Indeed, the 6 observations (contaminants levels among three sampling sites at two sampling seasons) differ substantially, no site or sampling season grouping being observed, which suggests an important spatial and temporal variability of the bioaccumulation of pollutants into P. radiata tissues.The aneuploidy levels, however, were consistently different among sampled locations, but did not differ between the two sampling seasons, suggesting that aneuploidy is the consequence of a local chronic contamination, and not a direct response to the temporal variability of the contaminants in P. radiata tissues.The results of this study confirm the suitability of the cytogenetic endpoints to discriminate, categorize the studied sites as regards to their level of contamination, underlining the added value of the detection of the genotoxicity levels in the marine environment to environmental health assessment and mitigation research programs. Further studies should be developed, under the specific hydrological and toxicological conditions of the Qatar Marine Zone (QMZ), to better explain the underlining mechanisms of such genotoxicity in the local filter feeders.The establishment of a Genotoxicological profile of the QMZ would be a valuable contribution to a wider approach on environmental diagnosis or prognosis, contributing to the protection and sustainability of the QMZ natural habitats and resources.

Background Gathering data on the life of enigmatic animals remains a challenge, despite its important role in biodiversity conservation and management. For many species, biogeographic investigations are largely the result of information that is generated from multiple sources, often over long time-scales, because measuring biogeographic and biological data over large geographic areas is simply not feasible by a single team of researchers. But in the current age of a well-educated public and accessible and mobile digital technology, scientists are now able to harness the observations of many, thus infinitely increasing their power of observation. Despite its status as the world's largest fish, there remains a paucity of information on the biology and ecology of whale sharks (Rhincodon typus). This species is however a prime target for ‘citizen science’ monitoring because of its charismatic nature, presence at many coastal aggregation sites and the growth of ecotourism around this species. Approach Information on whale shark sightings worldwide can be gathered by various stakeholders and stored in the Wildbook for Whale Sharks (www.whaleshark.org) database. Whale shark identification images are collected when a swimmer photographs the individual's unique spot pattern immediately behind the gill slits, which is distinct and long-lasting, and this image (with associated sighting data and information on shark size and sex) is then submitted to the online database. Computer-assisted scanning technology is then employed to determine whether the individual whale shark in question is a ‘new’ shark or a ‘resight’ of a previously reported whale shark within the database. Wildbook can then be queried to gain insights on various aspects of whale shark biology and ecology from data available at the various global hotspots. Results Members of the public and researchers alike contributed in this collaborative citizen science project enabling (as of 31 December 2014) almost 30000 whale shark encounter reports, comprising 6300+ individuals from 54 countries, to be identified. The number of recognized global aggregation sites (constellations) has increased from 13 to 20. The majority of these (14 out of 20) show a marked sex-ratio bias towards males (>66%). Site fidelity is relatively high, with an overall mean percentage of sharks returning to the 20 hotspots in two or more years of 35.7% (to a maximum of 21 years). Despite photo-identification revealing movements of sharks between a number of neighbouring countries/regions, there are no records confirming large, ocean basin-scale migrations. Strong seasonality in sightings is evident at many locations, suggesting that in general, that these aggregations are frequently exploiting known coastal feeding opportunities. Conclusions This study demonstrates the utility of citizen science in amassing large datasets and their utility in elucidating key aspects of whale shark life-history and demographics.

Background A large aggregation of whale sharks in the central part of the Arabian/Persian Gulf has recently been documented by the Qatar Whale Shark Research project. Observations made by offshore workers have indicated a continuous presence of whale sharks close to platforms in the Al Shaheen oil field during the summer months. It has been established that the sharks come here to feed on fish eggs of the Mackerel tuna, Euthynnus affinis. The Al Shaheen location is characterized by numerous offshore platforms that could attract the spawning Mackerel tuna and thereby influence the numbers and distribution of whale sharks in the area. Understanding the movement and residency patterns of whale sharks is critical for their management, particularly in an offshore oil field. Approach In the period from 2012–2015 a total of 104 whale sharks were fitted with acoustic V16 tags. The sharks were all tagged in the Al Shaheen oil field during the aggregation period from May to September and ranged in size from 4 to 10 meters TL. The movement pattern of sharks within the Al Shaheen field was monitored using an array of up to 15 VR2W receivers placed a minimum of 4 km apart. The receivers were placed on the seabed at different distances from selected offshore installations and recovered using remotely activated releases. Results Of the 104 tagged sharks, 102 were detected by the deployed receivers during the study period. The maximum detection distance was estimated to be between 500–1000 m from the receiver. More than 99% of the detections occurred between the months of April–September. Average annual residence time in the Al Shaheen area was 38.5 days (±27.5 SD) with some sharks showing a continued presence during the entire April–September period. Conclusions The results indicate that the whale sharks are almost only present in the Al Shaheen area during the April–September period, confirming the visual observations made by workers on the offshore installations. Aggregations, sometimes numbering more than 100 individuals, have only been observed while the whale sharks were feeding on Mackerel tuna spawn. The long residence time indicates that the Al Shaheen area is a highly important feeding ground. The sharks showed a high affinity for the same platforms throughout the study period, while their presence was only rarely recorded at other platform locations. This could indicate that the Mackerel tuna are spawning in a confined location within the study area and that the whale shark distribution within Al Shaheen is strongly associated to the spawning site and the prevailing currents. The platforms themselves may concentrate whale shark presence in the spawning area, but their full importance for the behavior of whale sharks is still to be determined. Mitigating measures have been established in order to minimize potential impacts on whale sharks related to offshore activities.

The Al Shaheen oil field is located approximately 80 km north-east off the coast of Qatar in the Arabian Gulf. It is the largest offshore oil field in Qatar and it is operated by Maersk Oil on behalf of its partner Qatar Petroleum. The Al Shaheen area is a highly productive marine environment due to a combination of complex nutrient rich currents and high temperatures. The diverse marine ecosystem is exemplified by one of the world's largest aggregations of whale sharks (Rhincodon typus) that return to this area every summer. The whale shark is listed as vulnerable on the IUCN Red List of Threatened Species and is the largest fish in the world. Having to operate in an area that hosts such a unique natural event poses a challenge to the parties involved but after years of dedicated research the secret behind the annual aggregation of the whale sharks in the Al Shaheen field is now better understood. The knowledge that has been gleaned is currently being used to help prevent significant disturbance to these majestic species and at the same time, maintain an efficient operation. Seismic operations have been scheduled for periods outside of the known aggregation season, and vessel traffic has been restricted in certain areas of the field. These initiatives have revealed that cost effective environmental risk management is achieved by gaining the best possible understanding of the ecosystem that is being impacted. Unless substantial published information is available for the area of concern this will most often require dedicated and continued research efforts. The reward in taking an "Ecosystem Approach", however, is an opportunity to establish collaboration between the industry, regulators and academia, resulting in effective and well-documented mitigation measures.

Background: The Qatar Whale Shark Research Project is a collaboration of government, industry and academia founded in 2010 to investigate anecdotal reports by Maersk Oil platform workers of large numbers of whale sharks seen in the Al Shaheen Oil field, Qatar. Methods: Photo-ID records have been collected from 2011 to present. Satellite-linked and acoustic tags have both been deployed, and biochemical 'biological tags' are being collected through tissue sampling. Plankton samples and environmental information are routinely being recorded. Fixed-station platform observations are being reported daily by gas industry workers to establish seasonality and sighting trends. Results: Aggregations of 100+ whale sharks have been regularly reported in offshore Qatari waters between May and September. Molecular barcoding of plankton samples has shown that the sharks are feeding specifically on tuna spawn from the species Euthynnus affinis. The tuna are thought to gather and spawn in the area due to both the unintentional protection offered by oil and gas platforms and the artificial habitat created by the structures. Preliminary satellite and acoustic tagging results indicates that the sharks aggregate during the summer months and disperse in the winter, in conjunction with the tuna. None of the satellite-tagged sharks have left the Arabian Gulf, although photo-ID has matched sharks between Qatar and the Strait of Hormuz and northern Gulf of Oman. During the 2012 season, 226 left-side shark identities were recorded, with 24% of sexed sharks (n = 144) identified as female and 76% being male. Mean estimated length was 6.88 ± 1.37 m (n = 156; range 4-10 m). Conclusion: The Al Shaheen Oil Field off Qatar is host to a globally significant aggregation of whale sharks, driven by the presence of high densities of E. affinis tuna spawn. Preliminary tracking data suggests that the sharks stay in the Arabian Gulf throughout the year.

Data on the occurrence of whale sharks, Rhincodon typus, in the Arabian Gulf and Gulf of Oman were collected by dedicated boat surveys and via a public-sightings scheme during the period from 2011 to 2014. A total of 422 individual whale sharks were photo-identified from the Arabian Gulf and the northern Gulf of Oman during that period. The majority of sharks (81%, n = 341) were encountered at the Al Shaheen area of Qatar, 90 km off the coast, with the Musandam region of Oman a secondary area of interest. At Al Shaheen, there were significantly more male sharks (n = 171) than females (n = 78; X2 = 17.52, P < 0.05). Mean estimated total length (TL) for sharks was 6.90 m ± 1.24 (median = 7 m; n = 296). Males (7.25 m ± 1.34; median = 8 m, n = 171) were larger than females (6.44 m ±1.09; median = 7 m, n = 78; Mann-Whitney U test, p < 0.01). Of the male sharks assessed for maturity 63% were mature (n = 81), with 50% attaining maturity by 7.29 m and 100% by 9.00 m. Two female sharks of >9 m individuals were visually assessed as pregnant. Connectivity among sharks sighted in Qatari, Omani and UAE waters was confirmed by individual spot pattern matches. A total of 13 identified sharks were re-sighted at locations other than that at which they were first sighted, including movements into and out of the Arabian Gulf through the Strait of Hormuz. Maximum likelihood techniques were used to model an estimated combined population for the Arabian Gulf and Gulf of Oman of 2837 sharks ± 1243.91 S.E. (95% C.I. 1720-6295). The Al Shaheen aggregation is thus the first site described as being dominated by mature males while the free-swimming pregnant females are the first reported from the Indian Ocean.

Acoustic monitoring of small cetaceans (harbour porpoises and dolphins) has been conducted around two platforms in the central North Sea. At one platform, there was continuous drilling activity while at the other platform, drilling did not occur during the monitoring period. The objective was to assess activity of harbour porpoises, Phocoena phocoena, around the platforms and assess the behavioural effects from sound emissions related to drilling activities.Passive acoustic monitoring devices (PAMs – T-POD ver. 5) were deployed at both locations for a period of more than two years. The PAMs are able to detect high frequency sound from small cetaceans and thereby assess the activity of animals in the immediate area surrounding the platforms.The results indicate that there is a relatively high activity of harbour porpoises around both the observed offshore platforms throughout the year. Clear seasonal trends in acoustic activities were not observed aside from increased activity levels during the fall of 2007 and in the late fall of 2008 at both locations. It is possible that these events are the results of a movement of harbour porpoises away from the calving grounds to the offshore areas. The offshore structures are known to attract fish and could function as feeding stations for the harbour porpoises, i.e. the platforms most likely function as artificial reefs. Hydrographic conditions at the platform locations that could influence the availability of prey in the area will naturally influence the activity level of the harbour porpoises. The study indicates that offshore platforms and drilling activities do not pose a significant threat to small cetaceans. However, the results show that short-term behavioural effects must be expected during activities that result in high sound intensity levels, e.g. during the ramming of conductors.The study confirms that PAMs are a useful tool for monitoring behavioural changes of small cetaceans in offshore environments. However, rough weather conditions and the risk of collision with vessels present a challenge. Loss of equipment and consequently loss of data is very likely to happen. In addition, the costs of maintaining the equipment and retrieving the data are significant due to the remote location. Consequently, the use of PAMs should be carefully considered when assessing the purpose of the monitoring.

Este artículo contiene 10 páginas, 6 figuras, 1 tabla., The response of mixed Southeast Asian seagrass beds to siltation was analyzed based on field data, a transplantation experiment and experimental manipulation of light availability in seagrass populations along a silt gradient at Cape Bolinao, The Philippines. Seagrass species diversity, shoot density and depth penetration declined with increasing amounts of suspended material and increasing water column light attenuation along the silt gradient. The seagrass species could be ranked according to decreasing tolerance to siltation as: Enhalus acoroides > Cymodocea serrulata > Halodule uninervis > Thalassia hernprichii > Halophila ovalis > Cymodocea rotundata > Syringodium isoetifoliurn. A gradual decline in shoot density and depth penetration of the different species along the silt gradient suggested that changes in the vertical light attenuation coefficient in the water column, primarily caused by differences in suspended inorganic solids, was the most important factor affecting seagrass performance. However, inconsistency among the species in response to Increasing water depth, artificial shading and transplantation indicated that other factors, such as siltat~on-derivedc hanges in sediment conditions, contribute to the sequential loss of seagrass species along the silt gradient., his study was funded by the STD-I11 program of the Commission of the European Union (Project TS3'-CT94-0301) and by the Faculty of Natural Sciences, University of Copenhagen.