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Baited Remote Underwater Video Stations (BRUVS) are widely used for monitoring relative abundances of fishes, especially sharks, but only the maximum number of individuals seen at any one time (MaxN) is usually recorded. In both the Cayman Islands and the Amirante Islands, Seychelles, we used photo-ID to recognise individual sharks recorded on BRUVS videos. This revealed that for most species the actual numbers of separate individuals (IndN) visiting the BRUVS were significantly higher than MaxN, with, for example, ratios of IndN to MaxN being 1.17 and 1.24 for Caribbean reef, Carcharhinus perezi, and nurse, Ginglymostoma cirratum, sharks in the Cayman Islands, and 2.46 and 1.37 for blacktip reef, C. melanopterus, and grey reef, C. amblyrhynchos, sharks, respectively, in the Amirantes. Further, for most species, increasing the BRUVS deployment period beyond the 60 min normally used increased the observed IndN, with more than twice as many individuals in the Cayman Islands and &gt, 1.4 times as many individuals in the Amirantes being recorded after 120 min as after 60 min. For most species, MaxN and IndN rose exponentially with time, so data from different deployment periods cannot reliably be compared using catch-per-unit-effort (CPUE) calculated as catch-per-unit-time. In both study areas, the time of first arrival of individuals varied with species from &lt, 1 min to &gt, 2 h. Individually identifiable sharks were re-sighted after up to 429 days over 10 km away in the Cayman Islands and 814 days over 23 km away in the Amirantes, demonstrating that many individuals range over considerable distances. Analysis of Cayman re-sightings data yielded mean population estimates of 76 &plusmn, 23 (SE) and 199 &plusmn, 42 (SE) for C. perezi and G. cirratum, respectively. The results demonstrate that, for sharks, the application of both photo-identification and longer deployment periods to BRUVS can improve the precision of abundance estimates and provide knowledge of population size and ranging behaviour.

The global decline of coral reefs heightens the need to understand how corals respond to changing environmental conditions. Corals are metaorganisms, so-called holobionts, and restructuring of the associated bacterial community has been suggested as a means of holobiont adaptation. However, the potential for restructuring of bacterial communities across coral species in different environments has not been systematically investigated. Here we show that bacterial community structure responds in a coral host-specific manner upon cross-transplantation between reef sites with differing levels of anthropogenic impact. The coral Acropora hemprichii harbors a highly flexible microbiome that differs between each level of anthropogenic impact to which the corals had been transplanted. In contrast, the microbiome of the coral Pocillopora verrucosa remains remarkably stable. Interestingly, upon cross-transplantation to unaffected sites, we find that microbiomes become indistinguishable from back-transplanted controls, suggesting the ability of microbiomes to recover. It remains unclear whether differences to associate with bacteria flexibly reflects different holobiont adaptation mechanisms to respond to environmental change., The flexibility of corals to associate with different bacteria in different environments has not been systematically investigated. Here, the authors study bacterial community dynamics for two coral species and show that bacterial community structure responds to environmental changes in a host-specific manner.

Spinner dolphins, Stenella longirostris , are the primary target for marine mammal tourism in Egypt. The present study investigated the short‐term effects of tourist presence on the behaviour of spinner dolphins at Sha'ab Samadai (Samadai Reef), in the southern Egyptian Red Sea. The reef has a large central lagoon where a population of spinner dolphin regularly rest from mid‐morning to mid‐afternoon; visitors are permitted to snorkel in the southern part of the lagoon, but not in the northern closed zone that the dolphins mainly use. Dolphin behaviour was monitored both on days when tourist boats were present and on days when they were absent. In the presence of tourists the proportion of time that the dolphins spent resting was reduced by two‐thirds, whereas the times spent milling, travelling, and showing avoidance behaviour all increased. Furthermore, upon using Markov chain modelling to investigate the effect of tourist presence on the transition probabilities between dolphin activity states, significant changes were found in 10 of the 25 possible behavioural transitions, including increased probabilities of transitioning from resting to milling or travelling, from milling to travelling or avoiding, and from travelling to avoiding. These findings raise concerns that despite the management measures in place, tourist activities affect the dolphins’ behaviour to a greater extent than was previously apparent, with potential long‐term negative effects on their energy budget. The study led to proposals for amending the zoning of the site and for strengthening the regulations for tourist vessels.

Basking sharks Cetorhinus maximus tend to aggregate in summer at favoured locations along Britain and Ireland's west coast. Sharks have been described approaching and close-following one another, often to one side. This has been interpreted as putative pre-mating behaviour. At aggregation sites around the Inner Hebrides we used boat-based observation and in-water and overhead drone video-photography to document behaviour and to determine the sex of individuals. It was confirmed that a shark will frequently move purposely towards another from a distance and swim to maintain a position either directly behind or closely to one side of a conspecific for short periods. Contrary to expectation, we found no relationship between the sex of a shark or its size and close-following. This suggests that following behaviours are not mainly related to courtship. Further, abrasions on the nose suspected to be related to male behaviour were found to occur on both sexes, although abrasions on pectoral fins, similarly suggestive of mating-related behaviour, were predominantly on females. Breaching by basking sharks has also been proposed as a means of attracting the opposite sex. We observed breaching by solitary sharks but commonly by sharks within aggregations, and at other times by more than one shark on the same day at the same time; but there was not any clear evidence to indicate that breaching is primarily related to mating. More likely individuals show close following chiefly for feeding-related hydrodynamic advantage. It remains plausible however that mature sharks make use of feeding aggregations to initiate pre-courtship behaviour.

Background Sharks are in severe global decline due to human exploitation. The additional concern of emerging diseases for this ancient group of fish, however, remains poorly understood. While wild-caught and captive sharks may be susceptible to bacterial and transmissible diseases, recent reports suggest that shark skin may harbor properties that prevent infection, such as a specialized ultrastructure or innate immune properties, possibly related to associated microbial assemblages. To assess whether bacterial community composition differs between visibly healthy and insulted (injured) shark skin, we compared bacterial assemblages of skin covering the gills and the back from 44 wild-caught black-tip reef sharks (Carcharhinus melanopterus) from the Amirante Islands (Seychelles) via 16S rRNA gene amplicon sequencing. Results Shark skin-associated bacterial communities were diverse (5971 bacterial taxa from 375 families) and dominated by three families of the phylum Proteobacteria typical of marine organisms and environments (Rhodobacteraceae, Alteromonadaceae, Halomonadaceae). Significant differences in bacterial community composition of skin were observed for sharks collected from different sites, but not between healthy or injured skin samples or skin type (gills vs. back). The core microbiome (defined as bacterial taxa present in ≥50% of all samples) consisted of 12 bacterial taxa, which are commonly observed in marine organisms, some of which may be associated with animal host health. Conclusion The conserved bacterial community composition of healthy and injured shark skin samples suggests absence of severe bacterial infections or substantial pathogen propagation upon skin insult. While a mild bacterial infection may have gone undetected, the overall conserved bacterial community implies that bacterial function(s) may be maintained in injured skin. At present, the contribution of bacteria, besides intrinsic animal host factors, to counter skin infection and support rapid wound healing in sharks are unknown. This represents clear knowledge gaps that should be addressed in future work, e.g. by screening for antimicrobial properties of skin-associated bacterial isolates.

We assessed the distribution, diversity and abundance of corals in Pakistani waters. A total of 29 hard coral species (eight families and 14 genera), one black coral species and eight soft coral species (three families and seven genera) were recorded from 18 dive sites at nine locations along the coastline. Distribution of hard corals was extremely poor at Mubarak Village and Sandspit, and corals were not found at Goth Abdul Rehman, Gadani (Kuchiani) and Buleji. Moderately rich coral communities were recorded at Churna Island and at more exposed sites around Astola Island. By contrast highly diverse hard coral communities, with up to 80% cover, were found only at the northern sheltered side of Astola Island where Favites complanata, Favites pentagona, Coscinaraea monile and Porites nodifera were the most abundant species. Favites complanata was recorded from most dive sites at Astola Island. Porites nodifera and Pocillopora damicornis, and to a lesser extent Porites harrisoni, Leptastrea pruinosa and Psammocora obtusangulata formed large single species stands. No ‘true’ coral reef was found at any dive site; however, the formation of proto-reefs was evident around Astola Island. Soft corals were dominant at most exposed sites, particularly at Ormara (Roadrigues Shoals) and Jiwani. By comparing diversity with other locations in the region, corals distribution and growth appear to be fairly poor in Pakistan.

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 (

This study examined the stomach contents of 11 bottlenose dolphins (Tursiops sp.), five Indo-Pacific humpback dolphins (Sousa chinensis) and two spinner dolphins (Stenella longirostris) that were found stranded along the Omani coastline. Across the three species examined, a total of 4796 fish otoliths and 214 cephalopod beaks were found, representing at least 33 species in 22 families. Prey item importance was calculated using the percentage by number and percentage by frequency of occurrence methods, and a modified index of relative importance. The fish families Apogonidae, Carangidae and Scombridae were the most numerically important prey of the bottlenose dolphins. Sciaenidae was the most numerically important fish family for the Indo-Pacific humpback dolphins. The myctophid Benthosema pterotum formed the majority of the prey items of spinner dolphins. Cephalopod remains found in the stomach samples were represented by the families Sepiidae, Loliginidae and Onychoteuthidae. The known depth distribution of prey items of bottlenose dolphins indicated that the animals fed in a wide variety of habitats. Indo-Pacific humpback dolphin prey items indicated feeding in shallow coastal areas. Spinner dolphins appear to have exploited the upper 200 m of the water column for food, where their vertically migrating mesopelagic prey are found at night. Most prey species found in the stomach contents do not appear to be of current commercial importance in Oman. However, the findings here indicated that all three species of dolphins were feeding in areas where artisanal and/or commercial fishing occurs and has conservation implications.

1. To monitor any impacts to coral reefs related to the exponential growth of tourism in the South Sinai region of the Egyptian Red Sea, nine stations were established at key reef sites over 2002–2003. At each station coral cover was determined using a video survey method at depths of 3, 7 and 16 m, and fish abundance by underwater visual census at depths of 3 and 10 m. 2. Mean total coral cover (hard plus soft) ranged from 58% to 23% at 3 m, 50% to 14% at 7 m, and 52% to 13% at 16 m, and hard coral cover from 37.5% to 15.7% at 3 m, 32.8% to 7.0% at 7 m, and 17.8% to 2.2% at 16 m. Analyses confirmed differences in coral assemblage related to depth and wave exposure. 3. Fish abundances and assemblages also varied with depth and proximity of deep water. Also the one site subject to fishing had lower abundances of some commercial fish families and greater abundances of some herbivores. 4. Transects subject to greater tourist use did not segregate from those subject to less tourist use, despite evidence from other work of an effect from visitor damage to corals at some sites. This may be because visitors were more attracted to sites that had higher coral cover. 5. Comparison of the present data with that from past studies is difficult because of the differences in sites and method employed, but several observations suggest a moderate decline in coral cover during recent decades. Such a decline would be compatible with the recorded impact of an outbreak of crown-of-thorns starfish, Acanthaster planci, as well as with other evidence of accumulating damage by visitors. 6. Further monitoring using the same stations and consistent protocols is urgently required. Copyright © 2008 John Wiley & Sons, Ltd.

1. The effects of trampling by visitors walking over the reef flat to snorkel or swim along the reef edge were studied at Ras Um Sidd, a popular fringing reef site at Sharm El Sheikh, and in the Ras Mohammed National Park, South Sinai, Egypt. Twelve stations showed a sequence of events linked to increased frequency and extent of trampling, with the intensities of trampling ranging from 0.1 to 324 tramplers m−2 yr−1. 2. Heavily trampled stations had a reduced coral cover (in particular branching corals), higher amounts of coral damage, less old dead coral, less obligate corallivorous fishes and more herbivores. 3. Wave exposure was crucial in determining the susceptibility of coral communities to trampling. Exposed communities were dominated by branching corals and were mechanically more resistant, since wave stress had favoured stockier growth forms. 4. The applicability of the ‘carrying capacity concept’ was investigated as a management tool for determining how much use is sustainable. Examination of the relationship between hard coral cover and intensity of trampling suggested that carrying capacity could be set at approximately 50 tramplers m−2 yr−1. The actual amount of damage caused by trampling showed a linear increase with increasing trampling intensities, so that the carrying capacity concept, as defined in this study, was not applicable to the relationship since no threshold existed. Instead, the ‘limits of acceptable change’ approach would be more practicable, with managers deciding what amount of coral damage they permit before limiting access. To establish meaningful limits of change, more knowledge is required about ecological as well as social consequences (e.g. visitor satisfaction) of such limits. Copyright © 2007 John Wiley & Sons, Ltd.

Reef walking on the shallow reef flats of fringing reefs is an activity commonly observed on Red Sea coral reefs. Of the 137 in-water observations of reef walkers made at Ras Um Sidd, Sharm El Sheikh, South Sinai, 12.4% caused coral damage. Eighteen incidents of coral damage were recorded, 44.4% being breakages of branching corals, 39.8% abrasions of various growth forms and 16.7% detachments of soft coral colonies. Sediment was stirred-up on 31.4% of observations. Tramplers broke 0.1 branches per minute and raised 1.5 sediment clouds, thereby causing more damage than reported from divers. Damage caused depended on coral community structure and past trampling history, with communities dominated by fragile branching corals being most susceptible to mechanical damage and communities heavily trampled in the past being less susceptible. Given that main motives for reef walking included crossing the reef flat, adjusting gear or communicating, management interventions, such as the construction of a walkway combined with a public awareness campaign, could reduce the numbers of reef walkers by up to 39%.

Following centuries of exploitation, basking sharks (Cetorhinus maximus) are considered by IUCN as Endangered in the Northeast Atlantic, where they have now been substantially protected for over two decades. However, the present size of this population remains unknown. We investigated the use of photo-identification of individuals’ dorsal fins, combined with mark-recapture methodology, to investigate the size of populations of basking shark within the west coast of Scotland. From a total of 921 encounters photographed between 2004 and 2011, 710 sharks were found to be individually identifiable based on dorsal fin damage and natural features. Of these, only 41 individuals were re-sighted, most commonly both within days of, and close to the site of, the initial encounter. A smaller number were re-sighted after longer periods of up to two years. A comparison of the distinguishing features of individuals on first recording and subsequent re-sighting showed that in almost all cases these features remained little changed, suggesting the low re-sighting rate was not due to a loss of distinguishing features. Because of the low number of re-sighting we were not able to produce reliable estimates for the long-term regional population. However, for one 50 km diameter study area between the islands of Mull, Coll and Tiree, we were able to generate closed-population estimates for 6–9 day periods in 2010 of 985 (95% CI = 494–1683), and in 2011 of 201 (95% CI = 143–340). For the same 2011 period an open-population model generated a similar estimate of 213 (95% CI = 111–317). Otherwise the low rate and temporal patterning of re-sightings support the view that such local basking shark populations are temporary, dynamic groupings of individuals drawn from a much larger regional population than previously supposed. The study demonstrated the feasibility and limitations of photo-identification as a non-invasive technique for identifying individual basking sharks.

Six commonly used coral reef survey methods, mapping of 1 m × 1 m quadrats (MAP), line-point transect (LPT), line-intercept transect (LIT), video sampling (VIDEO) and 1 m × 1 m photo-quadrats analysed by point-sampling (PHOTP) or by outlining coral colonies (PHOTS), were compared for their accuracy and precision in recording benthic substrate cover, and for their time-and cost-efficiency. Sampling was carried out along a 50 m transect at Ras Um Sidd, South Sinai, Egypt. For abundant substrate categories (> 10% cover) few significant differences were recorded between the results obtained by the different methods. Detailed mapping of quadrats (MAP) along the entire length of the transect served as the baseline against which the results of other methods were evaluated. Compared to this, VIDEO provided the most accurate cover estimates of major benthic substrate categories. Both line-transect methods, LIT and LPT, overestimated the cover of some categories, while PHOTP and PHOTS underestimated them. A series of factors seemed to be responsible for the differences in the substrate cover values obtained using different methods, including contour effects, proportion of substrate sampled, view angle, image resolution and observer bias. Power analysis indicated that the sample sizes required to yield an 80% chance of detecting even a 20% relative difference in total hard coral cover (e.g. between sites or times) were 27 mapped quadrats, or 1200 points for LPT, or 135 m of LIT, or 116 frames with 15 points for VIDEO, or 38 photo-quadrats for PHOTP and 33 for PHOTS; these are sample sizes considerably in excess of those commonly used by most reef workers. Much greater sample sizes are required to detect similar differences in cover of individual coral growth forms or taxa. When the time taken to record and analyse these data is considered, relative cost-efficiency in terms of time required by the different methods to detect this level of change was found to be VIDEO > PHOTP > PHOTS > LPT > MAP > LIT. Where, in more detailed studies, information is also required on numbers and sizes of colonies or on processes causing change, use of photo-quadrats may be preferred. A new protocol, recording 0.25 m × 0.25 m mini-quadrats with modern underwater digital still camera, is proposed, as combining this advantage of photo-quadrats with the sampling power of VIDEO.

The finding of neonatal whale sharks from Northern Indian Ocean waters off of Pakistan and Bangladesh and the description of several very small whale sharks from around Seychelles during the last few years are reported. These findings are discussed in relation to published reports of growth rates, the areas of occurrence and segregation by sex, and the behaviour of very young whale sharks, which are key factors in their conservation management.

To investigate how the perceptions and behaviour of visitors to coral reefs are influenced by their prior experience and knowledge of marine life, a questionnaire-based study was undertaken at sites in the Ras Mohammed National Park and at Sharm El Sheikh, South Sinai, Egypt. It was evident that over the 10-20 years during which these reefs have deteriorated (mainly due to reef-flat trampling), there have been interrelated shifts in the nature of visitors making use of them. First, there has been a shift from experienced divers and snorkellers to inexperienced snorkellers and non-snorkellers with a poorer knowledge of reef biology. Second, there has been a shift in the predominant nationalities of visitors, from German and British, through Italian, to Russian. More recent user groups both stated and showed that they had less experience of snorkelling; they also showed less knowledge of marine life and less interest in learning about it. Visitor perceptions of both the state of the marine life on the reefs and the acceptability of current visitor numbers also varied between groups. More recent visitor groups and visitors with less knowledge were more satisfied with reef health. In general, however, visitor perceptions of reef health did not correlate well with actual reef conditions, probably because more experienced visitors preferred less impacted sites with which they were nevertheless less satisfied than inexperienced visitors at heavily impacted sites. More recent visitor groups were also less bothered by crowding on the shore or in the water. Consequently, the apparent "social carrying capacity" of sites seems to be increasing to a level well above the likely "ecological carrying capacity".

Coral-associated bacteria play an increasingly recognized part in coral health. We investigated the effect of local anthropogenic impacts on coral microbial communities on reefs near Jeddah, the largest city on the Saudi Arabian coast of the central Red Sea. We analyzed the bacterial community structure of water and corals (Pocillopora verrucosa and Acropora hemprichii) at sites that were relatively unimpacted, exposed to sedimentation & local sewage, or in the discharge area of municipal wastewaters. Coral microbial communities were significantly different at impacted sites: in both corals the main symbiotic taxon decreased in abundance. In contrast, opportunistic bacterial families, such as e.g. Vibrionaceae and Rhodobacteraceae, were more abundant in corals at impacted sites. In conclusion, microbial community response revealed a measurable footprint of anthropogenic impacts to coral ecosystems close to Jeddah, even though the corals appeared visually healthy. published

We investigated factors influencing fish abundance and emigration across the boundaries of a no-take zone (NTZ), and its adjacent fished zones, within the Nabq Managed Resource Protected Area, South Sinai, Egyptian Red Sea. Underwater visual census of eight families of reef fish was undertaken at three depths across the whole NTZ (1.2 km), and for a similar distance into the adjacent fished zones. Because most fishing occurs in shallow water, the effect of the NTZ changed with depth. On reef flat transects (1 m depth), seven families showed significantly higher abundance in the NTZ, whereas at 10 m depth only two herbivorous families, Acanthuridae (surgeonfishes) and Siganidae (rabbitfishes) showed a significant difference, both being more abundant in the fished zones, an effect most likely due to reduced competition or predation. To look for evidence of emigration (spillover) of fish from the NTZ, data were also tested for evidence of gradients in abundance extending from within the NTZ to within the fished zones. In shallow water six families showed significant declines in abundance moving away from the centre of the NTZ, whereas at 10 m, the only significant gradients were for acanthurids and siganids, both becoming more abundant moving further into the fished zones. Comparisons of estimated fish length between areas also showed significant differences. The results indicate that at Nabq, while fishing reduces the abundance of most families, especially predators, abundance of some families and species, especially herbivores, may increase under light fishing pressure. Thus, spillover may occur to an extent and in a direction depending on trophic group and fishing intensity.

Gathering of molluscs on the reef-top, largely by women, is part of the traditional fishery practised by Bedouin in South Sinai, Egypt. The catch is dominated by Tridacna spp. and Octopus spp. Within the Nabq Managed Resource Protected Area, on the southern Gulf of Aqaba coast, a network of no-take zones (NTZs) was established (in 1995) to promote sustainable management of finfish stocks. Since this zoning also applied to exploitation of invertebrates, surveys of large species of molluscs and echinoderms across selected NTZs and adjacent fished areas were conducted (over 2000–2002) to assess any effects of gathering. Pooled data from all three years showed significantly higher abundances of Tridacna and Tectus dentatus in the NTZs, with greater abundances occurring at the reef edge zone. Size–frequency distributions revealed both a greater size range of Tridacna and a greater mean size of both Tridacna and Te. dentatus , within the NTZs, as compared to the fished areas. The size–frequency distribution of gleaned Tridacna , determined from discarded shells, also showed a smaller size range than did live Tridacna within the NTZs. By contrast, holothurians, which are not currently exploited by the local Bedouin, showed greater abundance in fished areas than in NTZs. Large diadematid sea urchins, along with the non-commercial strombs, Strombus gibberulus and Strombus fasciatus , were also significantly more abundant within fished areas, an effect presumed due to reduced predation pressure from fish as a result of fishing. Within the fished areas, there was a positive relationship between local abundance of Tridacna and of diadematids, thought to be due to high densities of the urchins acting as a deterrent against gathering. The establishment of NTZs has led to significant differences in invertebrate populations between take zones (TZ) and no-take zones. However, since there can be little or no spillover of adults of less mobile or sedentary invertebrates from NTZs to fished areas, any benefit to the fishery will depend largely on the greater larval production and export from protected populations.

Using an observational approach, the territorial behaviour of the coral feeding butterflyfish Chaetodon austriacus was investigated on three fringing reefs in the northern Red Sea. C. austriacus pairs defended exclusive feeding territories against conspecifics. Territories varied in area between 10 m 2 and 300 m 2 . Territory holders defended intrusions of territory borders by means of aggressive displays and chases, but rate of aggression was not related to either territory area or perimeter. However, movement rate and feeding rate were related to territory perimeter and area and may therefore be indicators of cost and benefit when considering the economics of territory defence.

The Red Sea is a large marine ecosystem in which biological research has been considerable but integrated environmental assessment insubstantial. Approximately 1400 coastal and offshore (i.e. island) sites in the Saudi Arabian Red Sea were examined and an analysis of ordinal data on the abundance of ecosystems and magnitude of human uses/environmental impacts was conducted. Mangroves, seagrasses, other floral groups and terrestrial mammals were significantly more abundant at the coastal sites than offshore. The coastal sites were also impacted most heavily, while reefs, birds, turtles and marine mammals were significantly more abundant in offshore areas. Latitudinal trends include significantly increased abundance of mangroves and seagrasses (and other flora) towards the southern Red Sea, and a decrease in abundance of reefs. Significantly higher levels of beach oil were encountered towards the northern Red Sea, probably reflecting its greater proximity to the Gulf of Suez. Cluster analysis using all biological data revealed distinctive groupings which separated according to latitude. The biogeographic patterns are comparable to those observed in previous studies for seagrasses and other communities.Using a relational database, applications of the findings to coastal management include creation of environmental profiles for particular sites or sectors, identification of resource-use conflict areas, and selection of representative sites for protected areas. Comparison with data from a complementary investigation in the Arabian Gulf indicates that the Red Sea is less perturbed by human activities than the Arabian Gulf. However, it is also evident that the Red Sea is no longer a pristine environment.

Observations were carried out in the Ras Mohammed National Park (Sharm el Sheikh, Sinai, Egypt) both to determine the rates of damage to corals by SCUBA divers and to assess the effectiveness of environmental education in reducing these. A single environmental awareness briefing reduced the rate of divers' contact with reef substrates from 1·4 to 0·4 contacts per diver per 7 min observation period. At the same time, the proportion of contacts that were voluntary, and so mainly directed at non-living substrate, increased to 63·8%. As a result, the rates of contact with living corals (as opposed to non-living substrates) decreased from 0·9 to 0·15 instances per diver per 7 min. This rate of contact prior to briefings is estimated to correspond to c. 500 potentionally damaging contacts per day at the most heavily used dive sites, equivalent to c. 15 incidents m −2 year −1 .

There is considerable overlap in use of some resources among species within guilds of coral reef fish. Here, however, we describe two studies indicating behavioural differences in microhabitat use between species of damselfish (Pomacentridae). Differential association with different microhabitats during normal foraging was investigated on fringing reefs in the Egyptian Red Sea. Species present in reef quadrats were tested for an association with features such as substrate cover, coral growth forms and extent of vertical faces. For 9 damselfish species discriminant functions were derived predicting their presence or absence with success rates of 77 to 100%, implying marked association between each fish species and a particular combinaton of substrates. The number of damselfish species present was found to be highly correlated with various reef characteristics, especially the number of coral growth forms present. Differences in reef zone and substrate use for spawning and nesting by 12 non-territorial damselfish species were investigated in the Maldives. Overlap indices between each species pair for zone and for substrate both showed a predominance of zero values. A combined overlap index was also calculated; 83% had values lower than 0.5, confirming a high degree of resource partitioning between species. These observations support the suggestion that behavioural differences in habitat use between species may be significant in sustaining diversity among coral reef fish.

The effect of artisanal fishing on the abundance and diversity of coral reef fish assemblages was investigated in the Kisite Marine National Park and Mpunguti Marine National Reserve at Shimoni, Kenya. Fishing is prohibited within the Park whereas in the Reserve artisanal fishing using traditional methods is practised. Visual censuses of six representative reef fish families (Chaetodontidae, Lethrinidae, Lutjanidae and Serranidae in 1992 and 1994, and Labridae and Pomacentridae in 1994 only) were undertaken along 250×10 m band transects on two similar pairs of reefs subject to differing fishing pressure. The abundance of commercial species (Lethrinidae, Lutjanidae and Serranidae) was depressed in the Reserve. The unfished butterflyfishes (Chaetodontidae) and damselfishes (Pomacentridae) also showed a greater abundance in the Park than in the Reserve. However, neither species number nor Shannon diversity (H′) of any of these families was affected by fishing pressure. Possible reasons for these findings are discussed. The abundance of commercial species, though not of non-commercial unfished species, increased significantly in the Reserve between 1992 and 1994, suggesting that the unfished Park may be acting as a source of larvae or supply of emigrating adults for the depleted Reserve. The results are comparable with other recent studies describing the effects of fishing pressure and also with those studies detailing the effects of habitat refugia in coral reef areas.

The impact of leisure scuba diving on coral reefs is described for the resort of Sharm el Sheikh on the Red Sea. It is established that significant damage is caused by this activity and presents a serious problem in environmental management. Sources of damage are investigated; the main problem is shown to be connected with the use of cameras. Some immediate control measures are discussed but it is recognised that total control may be difficult given the economic importance of the activity to the resort.

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.

A combination of photography and subsequent image analysis of the photographs has been used to measure maximum length, perimeter length and total area of fronds of tagged Fucus serratus L. as part of a study of the growth of this species on the Yorkshire coast. Maximum mean growth rate of 0·26 cm d-1 was observed during June–July. Minimum mean growth rate of 0·01 cm d-1 was observed during October-March. The method is relatively quick and convenient, and has the advantage that in addition to apical growth of the longest and/or other branches, lateral growth and total growth in surface area can all be recorded, while loss of tissue can also be determined. A further advantage is that a photographic record is obtained of the history of each individual plant.

The ranging and feeding behaviour of the butterflyfishChaetodon austriacus (Chaetodontidae) was studied at eight sites along the Red Sea coast of Saudi Arabia. This species was strongly paired and was found to defend territories intraspecifically, predominantly by display and non-aggressive ‘advertisement’. Frequencies of overt aggression were relatively low. Two other species of butterflyfish were aggressed against occasionally, but this did not appear to be space-related.C. austriacus fed entirely on scleractinian corals, primarilyAcropora, but included a variety of other genera in the diet. Territories appeared to be defended primarily for feeding and were significantly larger (1.6 times) at 10–15 m on the fore-reef slope than at the 1–2 m deep reef-edge. The availability of coral differed by a similar amount between depths, cover being 1.7 times greater in shallow water. Feeding rates did not differ significantly between depths.

Despite being the second largest fish, basking sharks ( Cetorhinus maximus ) have been assumed to remain in discrete populations. Their known distribution encompasses temperate continental shelf areas, yet until now there has been no evidence for migration across oceans or between hemispheres. Here we present results on the tracks and behaviour of two basking sharks tagged off the British Isles, one of which released its tag off Newfoundland, Canada. During the shark's transit of the North Atlantic, she travelled a horizontal distance of 9589 km and reached a record depth of 1264 m. This result provides the first evidence for a link between European and American populations and indicates that basking sharks make use of deep-water habitats beyond the shelf edge.

Beaked whales are not a commonly encountered species, but Cuvier's beaked whale, Ziphiuscavirostris, is the most cosmopolitan. Nonetheless, little is known of its distribution in the north-eastern Indian Ocean, particularly along the coasts of India, Pakistan and Iran. Here we present the first confirmed record of the species for Pakistan from a stranded specimen that was found during a routine beach survey. None have been seen during inshore boat surveys to date. Considering the level of naval activity and seismic surveys in the waters off Pakistan, incorporation of mitigating measures and monitoring surveys are suggested to avoid potential beaked whale mortality. This is the first confirmed record of Z. cavirostris on the Pakistani coast and is an important finding for the Pakistan Biodiversity Action Plan and their National Conservation Strategy for marine mammals.

During the global coral bleaching event of 1997/1998 Kenyan reefs experienced between 50% and 90% coral mortality, with coral cover at Malindi being reduced from 35–45% (pre-bleaching) to 10–20%. Even before this event there was concern that these reefs were being impacted by increased sediment loads from the nearby Sabaki River. Here we report that since 1998 coral cover has declined yet further with, in 2004, means of 5.1% being recorded at North Reef (within the non-fished Malindi Marine National Park) and 2.3% on Leopard Reef (within the fished Marine Reserve). Prior to bleaching 55 coral genera were recorded from the area, currently we find only 23. Meanwhile algal cover, especially the calcareous green alga Halimeda, has increased, and on Leopard Reef is twice that on North Reef. Taken with the evidence of previous studies, these data suggest a combined impact of coral bleaching with sedimentation and fishing.

Decomposition of Rhizophora apiculata, Rhizophora mucronata, Bruguiera parviflora and Sonneratia alba leaves was studied in situ using litter bags in both Cleared and Virgin Jungle Reserve (VJR) mangrove forests in Peninsular Malaysia. A single exponential model best described the rate of decomposition for each species. All leaf species decomposed faster in the VJR site than in the Cleared site (R. apiculata P

Sperm whales (Physeter macrocephalus) occur frequently in stranding records worldwide. However, none have been reported along the Pakistani coastline to date. This paper documents the first reported stranding of a sperm whale on the Pakistani coast. Ultimately, this finding is important in the planning of Pakistan's Biodiversity Action Plan and its National Conservation Strategy for marine mammals.

The biodiversity of many ecosystems is under threat and although seas cover the majority of our planet's surface, far less is known about the biodiversity of marine environments than that of terrestrial systems. It is also not clear whether many of the patterns known to occur on land also occur in the sea. Until we have a firmer idea of the diversity of a wide range of marine habitats and what controls it, we have little hope of conserving biodiversity, or determining the impact of human activities such as mariculture, fishing, dumping of waste and pollution. This book brings together key studies from the deep sea and open ocean, to tropical shores and polar regions to consider how comparable the patterns and processes underlying diversity are in these different ecosystems. Marine Biodiversity will be a major resource for all those interested in biodiversity and its conservation.

Whale sharks, Rhincodon typus, are known to aggregate to feed in a small number of locations in tropical and subtropical waters. Here we document a newly discovered major aggregation site for whale sharks within the Al Shaheen oil field, 90 km off the coast of Qatar in the Arabian Gulf. Whale sharks were observed between April and September, with peak numbers observed between May and August. Density estimates of up to 100 sharks within an area of 1 km(2) were recorded. Sharks ranged between four and eight metres' estimated total length (mean 6.92 ± 1.53 m). Most animals observed were actively feeding on surface zooplankton, consisting primarily of mackerel tuna, Euthynnus affinis, eggs.

There is a lack of studies on how provisioning may influence shark numbers and behaviour. The effects of long-term provisioning were investigated at a Red Sea reef, where both grey reef shark (Carcharhinus amblyrhynchos) and silky shark (Carcharhinus falciformis) occurred. Initially, grey reef sharks outnumbered silky sharks, but over 6 years, silky shark numbers increased almost 20-fold, whereas grey-reef sightings decreased >90%. Following this, silky-shark sightings also declined considerably (>80%). It is suggested that these declines could relate to local overfishing. Many silky sharks were identified individually through distinctive markings or conventional tagging. Some individual silky sharks were recorded regularly over 2 years or more, but most appeared to be transient visitors. Sighting records indicated that provisioning extended the residency of transient individuals. If visiting silky sharks were drawn from a larger regional population, this would explain both their initial accumulation and why, to begin with, sightings were sustained despite local fishing pressure. Conversely, the site fidelity typical of grey reef sharks would have made them more susceptible to local depletion. Silky sharks were recorded as behaving more boldly when present in greater numbers, but the decline in grey reef sharks appears to be unrelated to the initial increase in the numbers of silky shark.

Many shark populations are experiencing critical declines from overfishing, triggering potentially detrimental cascade effects on marine ecosystems. Silky sharks, Carcharhinus falciformis, have experienced some of the most severe declines, yet little information exists on their behavioural ecology to inform management decisions. In the present study, the movement patterns of a sexually segregated subpopulation of female silky sharks on reefs in the Central Red Sea were investigated using acoustic telemetry to characterise habitat-use and residency patterns. Frequent baiting of sharks at a particular reef-site significantly increased time spent in the vicinity, although no increases in use of other reef areas 5–10 and 50–60 km away were recorded, and regular use of all three reef areas persisted in the absence of bait. Observed residency patterns varied considerably, from being present almost year-round to visiting only intermittently. The sharks spent significantly longer times at study reefs during daylight hours, even within bait-free regions, suggesting the diel bias is normal. This pattern became less distinct nearer the full moon when there is more ambient light. The regular, perennial use of these reefs by mature and near-mature female silky sharks highlights the importance of this habitat in the Red Sea for recruitment into the local shark population.

Stable limit cycles at the scale of individual reefs and hydrodynamic connections between reefs for larval transport are together sufficient to account qualitatively for the large scale dynamics of the phenomenon. Several different factors may generate the stable limit cycles, and these need not be mutually exclusive, but rather reinforcing. An important factor in the limit cycle dynamics in other areas is fish predator pressure on the starfish; increased pressure can suppress limit cycle behaviour. There is some evidence that the same factor may have been coercive on the GBR. Fish predator pressure may have been reduced through the intensification of fishing in the 1960s, leading to the two waves of outbreaks experienced on the GBR since then. There is a possibility that successive waves of outbreaks could degrade the system.

Both a population dynamic model and simplified calculations of the numbers of fish predators that would be required to control heavy recruitment of the coral-eating crown-of-thorns starfish (Acanthaster planci L.) predict threshold densities of fish predators below which starfish population outbreaks may occur. This prediction has been tested through comparable surveys of putative fish predators in the Red Sea, where no major outbreaks of A. planci were found or are known to have occurred, and on the Great Barrier Reef, where two major series of outbreaks have occurred during the last 25 years. In the Red Sea densities of presumed fish predators were found to be well above the predicted threshold. By contrast on the Great Barrier Reef mean densities both of proposed fish predators of juvenile and subadult A. planci, and of know fish predators of adult A. planci, were below the predicted threshold. Moreover the densities of fish predators on four mid-shelf reefs that are believed to have escaped major outbreaks of A. planci were found to be significantly higher than those on otherwise similar but impacted reefs. These data are compatible with the hypothesis that current and recent outbreaks of the crown-of-thorns starfish on the Great Barrier Reef have been facilitated by the presence of only relatively low numbers of fish predators, the numbers of which may have been decreased as a result of the intensification of fishing pressure that has occurred from the 1960s onwards.