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Years of unregulated fishing activity have resulted in low abundances of elasmobranch species in the Saudi Arabian Red Sea. Coastal populations of sharks and rays in the region remain largely understudied and may be at risk from large-scale coastal development projects. Here we aim to address this pressing need for information by using fish market, unmanned aerial vehicle and baited remote underwater video surveys to quantify the abundance and diversity of sharks and rays in coastal habitats in the Saudi Arabian central Red Sea. Our analysis showed that the majority of observed individuals were batoids, specifically blue-spotted ribbontail stingrays (Taeniura lymma) and reticulate whiprays (Himantura sp.). Aerial surveys observed a catch per unit effort two orders of magnitude greater than underwater video surveys, yet did not detect any shark species. In contrast, baited camera surveys observed both lemon sharks (Negaprion acutidens) and tawny nurse sharks (Nebrius ferrugineus), but in very low quantities (one individual of each species). The combination of survey techniques revealed a higher diversity of elasmobranch presence than using either method alone, however many species of elasmobranch known to exist in the Red Sea were not detected. Our results suggest that aerial surveys are a more accurate tool for elasmobranch abundance estimates in low densities over mangrove-associated habitats. The importance of inshore habitats, particularly for batoids, calls for a deeper understanding of habitat use in order to protect these environments in the face of unregulated fishing, mangrove removal, and anticipated developments along the coastline of the Saudi Arabian Red Sea.

In light of the extirpation of a number of elasmobranch species commonly encountered in fresh and estuarine waters elsewhere in the world, 39 river systems were sampled throughout northern Australia to determine the species present. A total of 502 elasmobranchs representing 36 species, in addition to 1531 teleosts representing 46 species, were captured. In regard to elasmobranch species known to frequent riverine habitats, the bull shark Carcharhinus leucas was captured in the highest number, followed by the freshwater sawfish Pristis microdon, the freshwater whipray Himantura chaophraya and the dwarf sawfish Pristis clavata. Although these species were generally captured in low numbers, all were widely distributed throughout the region. Furthermore, the waters of King Sound, Western Australia, and the rivers entering it, i.e. the Fitzroy, May and Robinson rivers, were found to contain far higher numbers of P. microdon and P. clavata than any of the other rivers sampled, as well as the northern river shark Glyphis sp. C, and which subsequently provided an ideal locality to study the biology of these species. The Fitzroy River was shown to act as a nursery for P. microdon and P. clavata, where immature individuals remain for a maximum of four or five years before migrating to marine waters. Investigations of the rostra and rostral tooth morphology of P. microdon indicated their usefulness as a diagnostic tool in differentiating this species from other members of the genus, including P. clavata, and for differentiating between the sexes, i.e. female P. microdon generally possess 17-21 teeth cf. 19-23 teeth in males. However, no significant difference in the number of rostral teeth was found between female and male P. clavata, with both sexes possessing an average of 42. Furthermore, the facts that P. clavata was captured up to 2332 mm in total length and all of the individuals were immature, indicates that the description of this species as a ‘dwarf’ sawfish is erroneous. The use of rivers of northern Australia as nurseries was also apparent for C. leucas, with none of the 111 individuals dissected (ranging in length from 681 to 1365 mm TL) being mature. Furthermore, this species appeared to remain within the rivers for approximately four years. Stomach content analysis and field observations confirmed an opportunistic, and often aggressive, feeding nature, and thus the species may pose some risk to bathers utilising inland waters far upstream (i.e. over 300 km). Morphometrics and radiographs of 10 Glyphis sp. C captured from the macrotidal waters of King Sound (the first capture of this species in Western Australia) indicated that these specimens possessed both a wider range in total vertebral count (i.e. 140-151 cf. 147-148) and number of diplospondylous caudal centra (i.e. 64-70 cf. 65-68) than that previously reported and lent support for its synonymisation with Glyphis gangeticus. Radiographs also revealed the spinal deformation and fusing of vertebrae in three of the ten individuals, which may be attributable to a genetic abnormality indicative of inbreeding within a small gene pool. Analyses of stomach content and stable carbon (ä13C) and nitrogen (ä15N) isotope ratios of fishes occurring in the Fitzroy River indicated that the diets of a majority of the species present are broad, and greatly influenced by the seasonal availability of different prey types. While stomach content analysis suggested that aquatic insects, and to a lesser extent filamentous algae, represent vitally important food sources for many of the species present, stable isotope analysis strongly suggested that this latter food source may not be an important direct energy source, and that prey types which persist throughout the year (e.g. fish, molluscs and Macrobrachium rosenbergii) may in fact be more important sources of the energy than dietary data revealed. Dietary overlap was found to be the highest during the wet season when prey availability was high, decreased in the early dry season as fishes became more specialised in their feeding, before increasing again in the late wet when food became very limited. These analyses also supported the views that juvenile fishes may target high energy food items to attain higher growth rates and a large size rapidly, in order to achieve competitive feeding advantages and reduce the risk of predation, and that many species will maximise their energy intake in response to changes in resource availability.

Orientador: Otto Bismarck Fazzano Gabig / Resumo: O presente estudo apresenta descrição da anatomia do coração de 9 espécies de raias, pertencentes a 3 ordens, como se segue: Rhinobatiformes (Pseudobatos percellens, Pseudobatos horkelii e Zapteryx brevirostris), Rajiformes (Rioraja agassizi, Atlantoraja cyclophora e Gurgesiella dorsalifera) e Myliobatiformes (Dasyatis hypostigma, Rhinoptera bonasus e Mobula thurstoni), todas ocorrendo na plataforma continental e talude do Sudeste e Sul do Brasil. Como objetivos, pretendeu-se verificar a existência de padrão evolutivo nas válvulas cardíacas destes animais. No total foram utilizados 92 animais, onde foram tomadas medidas morfométricas e contagem das válvulas do coração. O número de fileiras de válvulas variou de 2 a 6, com variação interespecífica. Em sua maioria as primeiras válvulas do cone arterioso são maiores e apresentam a extremidade anterior tricúspide. A análise estatística indicou diferenças morfométricas no coração entre as ordens, assim como diferença significativa no número de válvulas entre as espécies, porém algumas medidas não são significativas e portando não adequadas para uso com fins taxonômicos. Para a ordem Myliobatiforme, o número de válvulas condiz com a posição evolutiva, onde os animais apresentaram a maior quantidade de válvulas. / Mestre

Submitted by Italo Rafael Bini Junior null (italobini@hotmail.com) on 2018-03-05T16:41:11Z No. of bitstreams: 1 Análise comparativa do cone arterioso em três grupos de raias.pdf: 2164859 bytes, checksum: 32d326ace9f1ad2f6fc40c39d7b3561d (MD5) / Rejected by Disleide Silvia Valerio Gounella null (disleide@clp.unesp.br), reason: Boa tarde. Favor corrigir o Nome do primeiro Orientador. abs. Disleide on 2018-03-05T17:45:27Z (GMT) / Submitted by Italo Rafael Bini Junior null (italobini@hotmail.com) on 2018-03-05T17:51:17Z No. of bitstreams: 1 Análise comparativa do cone arterioso em três grupos de raias.pdf: 2164859 bytes, checksum: 32d326ace9f1ad2f6fc40c39d7b3561d (MD5) / Rejected by Disleide Silvia Valerio Gounella null (disleide@clp.unesp.br), reason: Bom dia. Faltou uma palavra chave em ingles. abs. Disleide on 2018-03-06T13:36:09Z (GMT) / Submitted by Italo Rafael Bini Junior null (italobini@hotmail.com) on 2018-03-06T13:38:30Z No. of bitstreams: 1 Análise comparativa do cone arterioso em três grupos de raias.pdf: 2164859 bytes, checksum: 32d326ace9f1ad2f6fc40c39d7b3561d (MD5) / Approved for entry into archive by Disleide Silvia Valerio Gounella null (disleide@clp.unesp.br) on 2018-03-06T15:00:25Z (GMT) No. of bitstreams: 1 binijunior_ir_me_svic.pdf: 2164859 bytes, checksum: 32d326ace9f1ad2f6fc40c39d7b3561d (MD5) / Made available in DSpace on 2018-03-06T15:00:25Z (GMT). No. of bitstreams: 1 binijunior_ir_me_svic.pdf: 2164859 bytes, checksum: 32d326ace9f1ad2f6fc40c39d7b3561d (MD5) Previous issue date: 2018-01-30 / O presente estudo apresenta descrição da anatomia do coração de 9 espécies de raias, pertencentes a 3 ordens, como se segue: Rhinobatiformes (Pseudobatos percellens, Pseudobatos horkelii e Zapteryx brevirostris), Rajiformes (Rioraja agassizi, Atlantoraja cyclophora e Gurgesiella dorsalifera) e Myliobatiformes (Dasyatis hypostigma, Rhinoptera bonasus e Mobula thurstoni), todas ocorrendo na plataforma continental e talude do Sudeste e Sul do Brasil. Como objetivos, pretendeu-se verificar a existência de padrão evolutivo nas válvulas cardíacas destes animais. No total foram utilizados 92 animais, onde foram tomadas medidas morfométricas e contagem das válvulas do coração. O número de fileiras de válvulas variou de 2 a 6, com variação interespecífica. Em sua maioria as primeiras válvulas do cone arterioso são maiores e apresentam a extremidade anterior tricúspide. A análise estatística indicou diferenças morfométricas no coração entre as ordens, assim como diferença significativa no número de válvulas entre as espécies, porém algumas medidas não são significativas e portando não adequadas para uso com fins taxonômicos. Para a ordem Myliobatiforme, o número de válvulas condiz com a posição evolutiva, onde os animais apresentaram a maior quantidade de válvulas. / The present study presents a description of the anatomy of the heart in 9 species of rays belonging to 3 orders, as follows: Rhinobatiformes (Pseudobatos percellens, Pseudobatos horkelii and Zapteryx brevirostris), Rajiformes (Rioraja agassizi, Atlantoraja cyclophora and Gurgesiella dorsalifera) and Myliobatiformes (Dasyatis hypostigma, Rhinoptera bonasus and Mobula thurstoni), all occurring on the continental shelf and slope of Southeastern and Southern Brazil. As objectives, it was intended to verify the existence of an evolutionary pattern in the cardiac valves of these animals. In total, 92 animals were used, where morphometric measurements and heart valve counts were taken. The number of valve ranks ranged from 2 to 6, with interspecific variation. In most cases the first valves of the arterial cone are larger and present a tricuspid anterior extremity. Statistical analysis indicated morphometric differences in the heart between the orders, as well as a significant difference in the number of valves between the species, however some measures are not significant and carrying not suitable for use with taxonomic purposes. For the Myliobatiform order, the number of valves corresponds to the evolutionary position, where the animals presented the largest number of valves.

The pelagic stingray, Pteroplatytrygon violacea, is a bycatch species in the global pelagic longline fishery. However, little research has been conducted on its basic biology, including prey composition, trophic positioning, and habitat utilization. Descriptions of the habitat utilization have largely been through indirect analyses of catch rates in commercial fisheries, which also provided no information on actual behaviors. The first chapter of this thesis will describe the habitat utilization and behavior of four individual pelagic stingrays using electronic tagging technology. Prior diet descriptions were hampered, in part, by low sample sizes and accordingly provided little information on the ecological interactions of these animals. Similarly, the second chapter of this thesis will therefore provide a new diet description for the pelagic stingray using a combined analysis of traditional stomach contents with stable isotope values, thereby addressing both ingestion and assimilation. A more robust study of the trophic dynamics of the pelagic stingray, in conjunction with the description of its habitat utilization, will provide a better understanding of its role within the pelagic ecosystem. Ultimately, the goal is to obtain knowledge of the less economic species with good science so when management approaches shift from species-specific to ecosystem based, the transition will already have known information to change efficiently.

The goal of this dissertation was to further examine the visual system and its importance to the bonnethead shark (Sphyrna tiburo). This species of hammerhead shark possesses the least amount of lateral cephalofoil expansion. Better understanding of their visual system and potential visually-mediated behaviors may increase understanding regarding adaptive benefits of their unique head shape. The dissertation revealed four factors regarding this species' visual system: 1) the extent of their optical visual fields span between 68-72 degrees laterally and cover their visual horizon, 2) they possess a fairly large (approximately 112 degree) blind spot directly in front of their cephalofoil, 3) they possess an average of 35 degrees of lateral head movement during sinusoidal swimming which likely increase the lateral extents of their optical visual fields, and 4) they can detect and show interest in small visual stimuli resembling their preferred prey species, the blue crab.

Despite being the world’s largest batoid fish, manta rays have been the focus of very little research in the last century. Almost nothing is currently known about their ecology or distribution throughout the world’s oceans. Manta rays are considered to be near-threatened to vulnerable by the World Conservation Union’s Redlist of endangered species, yet many populations still face threats from target fishing for their fin cartilage, branchial filaments and meat. The taxonomic history of the genus Manta has been questionable and convoluted,with Manta having one of the most extensive generic and species synonymies of any living genus of cartilaginous fish. Currently this genus is considered to be monotypicwith a single recognized species, Manta birostris. Behavioural and morphological data collected during this study showed that there are two distinct, sympatric species of manta ray in Mozambique. This discovery has led to an examination of manta ray distribution worldwide, with the two species hypothesis receiving further support from study sites in the Indian and Pacific Oceans. This thesis examined large populations of both putative species in Mozambique. Development and application of a photographic-identification methodology allowed identification of individuals based on their unique ventral surface markings (spots). The ability to recognise individuals enabled many aspects of both populations to be examined. A total of 449 individual rays were identified of Manta birostris variant A and 101 individual rays were identified of Manta birostris variant B. Both populations exhibited a highly significant female bias in observed sex ratios of 1:3.5 and 1:7.4 respectively. The photographic identification approach was used in studies of population size and structure and to examine the reproductive ecology of these two distinct populations. Population estimates incorporating four years of re-sighting data on Manta birostris variant A and five years of data on Manta birostris variant B were conducted using the program MARK resulting in super population estimates of 890 and 600 individuals respectively. The region encompassing the study site was identified as a mating ground for Manta birostris variant A based on observations of mating events and fresh pectoral fin tip scars on female rays produced when the male rays bite onto the fins during copulation. The distribution of scars was highly biased, with 99% on the left pectoral fin, indicative of a strong lateralised behavioural trait in this species. No other elasmobranch has been reported to display behavioural lateralisation. The study region also acts as a birthing ground, with individuals giving birth in the summer after a gestation period of approximately one year. Reproductive periodicity in M. birostris variant A was most commonly biennial, but a few individuals were seen to be pregnant in consecutive years, confirming an annual ovulatory cycle. The production of a single pup appears to be the normal situation, although observations in the wild as well as during opportunistic dissections of individuals killed in fisheries revealed that two pups are conceived on occasion. Morphometric analysis of late-term foetus (M. birostris variant A) was contrasted with measurements taken from adult rays. These are the only detailed measurements on M. birostris variant A from the western Indian Ocean. Predatory scarring and bite injuries on individuals of both variant A and B were consistent with attacks from sharks of various sizes. The frequency and effect of these predatory injuries on the two populations were examined over a three-year period. Acoustic tags were attached to fourteen rays and their presence/absence at sites around the major inshore reefs was explored to evaluate how the rays utilised their environment on a temporal scale. Cleaning activity of both putative species of manta rays by small fishes occurred on these reefs and was considered to be the main reason why the rays were present at these sites. Parasite removal and wound healing were implicated as the benefits received. Host cleaner fish species partition the manta ray body to avoid interspecific competition while the two putative species appear to partition cleaning habitats, with very little overlap apparent. This research on manta rays is the first of its kind in African waters. Many aspects of the study have contributed to the limited baseline data currently available for this genus. The study additionally provided sufficient empirical evidence to warrant the separation of these two putative species of Manta and a full revision of the genus with the systematic examination of specimens throughout Manta’s range. The results of this study may be useful in this endeavour as diagnostic characteristics have been isolated that may help to differentiate members of this genus. The results of this research study are directly applicable to management strategies for both putative species of manta rays off the East Coast of Africa as well as populations worldwide and have highlighted the potential need for different conservation strategies

Despite being the world’s largest batoid fish, manta rays have been the focus of very little research in the last century. Almost nothing is currently known about their ecology or distribution throughout the world’s oceans. Manta rays are considered to be near-threatened to vulnerable by the World Conservation Union’s Redlist of endangered species, yet many populations still face threats from target fishing for their fin cartilage, branchial filaments and meat. The taxonomic history of the genus Manta has been questionable and convoluted,with Manta having one of the most extensive generic and species synonymies of any living genus of cartilaginous fish. Currently this genus is considered to be monotypicwith a single recognized species, Manta birostris. Behavioural and morphological data collected during this study showed that there are two distinct, sympatric species of manta ray in Mozambique. This discovery has led to an examination of manta ray distribution worldwide, with the two species hypothesis receiving further support from study sites in the Indian and Pacific Oceans. This thesis examined large populations of both putative species in Mozambique. Development and application of a photographic-identification methodology allowed identification of individuals based on their unique ventral surface markings (spots). The ability to recognise individuals enabled many aspects of both populations to be examined. A total of 449 individual rays were identified of Manta birostris variant A and 101 individual rays were identified of Manta birostris variant B. Both populations exhibited a highly significant female bias in observed sex ratios of 1:3.5 and 1:7.4 respectively. The photographic identification approach was used in studies of population size and structure and to examine the reproductive ecology of these two distinct populations. Population estimates incorporating four years of re-sighting data on Manta birostris variant A and five years of data on Manta birostris variant B were conducted using the program MARK resulting in super population estimates of 890 and 600 individuals respectively. The region encompassing the study site was identified as a mating ground for Manta birostris variant A based on observations of mating events and fresh pectoral fin tip scars on female rays produced when the male rays bite onto the fins during copulation. The distribution of scars was highly biased, with 99% on the left pectoral fin, indicative of a strong lateralised behavioural trait in this species. No other elasmobranch has been reported to display behavioural lateralisation. The study region also acts as a birthing ground, with individuals giving birth in the summer after a gestation period of approximately one year. Reproductive periodicity in M. birostris variant A was most commonly biennial, but a few individuals were seen to be pregnant in consecutive years, confirming an annual ovulatory cycle. The production of a single pup appears to be the normal situation, although observations in the wild as well as during opportunistic dissections of individuals killed in fisheries revealed that two pups are conceived on occasion. Morphometric analysis of late-term foetus (M. birostris variant A) was contrasted with measurements taken from adult rays. These are the only detailed measurements on M. birostris variant A from the western Indian Ocean. Predatory scarring and bite injuries on individuals of both variant A and B were consistent with attacks from sharks of various sizes. The frequency and effect of these predatory injuries on the two populations were examined over a three-year period. Acoustic tags were attached to fourteen rays and their presence/absence at sites around the major inshore reefs was explored to evaluate how the rays utilised their environment on a temporal scale. Cleaning activity of both putative species of manta rays by small fishes occurred on these reefs and was considered to be the main reason why the rays were present at these sites. Parasite removal and wound healing were implicated as the benefits received. Host cleaner fish species partition the manta ray body to avoid interspecific competition while the two putative species appear to partition cleaning habitats, with very little overlap apparent. This research on manta rays is the first of its kind in African waters. Many aspects of the study have contributed to the limited baseline data currently available for this genus. The study additionally provided sufficient empirical evidence to warrant the separation of these two putative species of Manta and a full revision of the genus with the systematic examination of specimens throughout Manta’s range. The results of this study may be useful in this endeavour as diagnostic characteristics have been isolated that may help to differentiate members of this genus. The results of this research study are directly applicable to management strategies for both putative species of manta rays off the East Coast of Africa as well as populations worldwide and have highlighted the potential need for different conservation strategies

Despite being the world’s largest batoid fish, manta rays have been the focus of very little research in the last century. Almost nothing is currently known about their ecology or distribution throughout the world’s oceans. Manta rays are considered to be near-threatened to vulnerable by the World Conservation Union’s Redlist of endangered species, yet many populations still face threats from target fishing for their fin cartilage, branchial filaments and meat. The taxonomic history of the genus Manta has been questionable and convoluted,with Manta having one of the most extensive generic and species synonymies of any living genus of cartilaginous fish. Currently this genus is considered to be monotypicwith a single recognized species, Manta birostris. Behavioural and morphological data collected during this study showed that there are two distinct, sympatric species of manta ray in Mozambique. This discovery has led to an examination of manta ray distribution worldwide, with the two species hypothesis receiving further support from study sites in the Indian and Pacific Oceans. This thesis examined large populations of both putative species in Mozambique. Development and application of a photographic-identification methodology allowed identification of individuals based on their unique ventral surface markings (spots). The ability to recognise individuals enabled many aspects of both populations to be examined. A total of 449 individual rays were identified of Manta birostris variant A and 101 individual rays were identified of Manta birostris variant B. Both populations exhibited a highly significant female bias in observed sex ratios of 1:3.5 and 1:7.4 respectively. The photographic identification approach was used in studies of population size and structure and to examine the reproductive ecology of these two distinct populations. Population estimates incorporating four years of re-sighting data on Manta birostris variant A and five years of data on Manta birostris variant B were conducted using the program MARK resulting in super population estimates of 890 and 600 individuals respectively. The region encompassing the study site was identified as a mating ground for Manta birostris variant A based on observations of mating events and fresh pectoral fin tip scars on female rays produced when the male rays bite onto the fins during copulation. The distribution of scars was highly biased, with 99% on the left pectoral fin, indicative of a strong lateralised behavioural trait in this species. No other elasmobranch has been reported to display behavioural lateralisation. The study region also acts as a birthing ground, with individuals giving birth in the summer after a gestation period of approximately one year. Reproductive periodicity in M. birostris variant A was most commonly biennial, but a few individuals were seen to be pregnant in consecutive years, confirming an annual ovulatory cycle. The production of a single pup appears to be the normal situation, although observations in the wild as well as during opportunistic dissections of individuals killed in fisheries revealed that two pups are conceived on occasion. Morphometric analysis of late-term foetus (M. birostris variant A) was contrasted with measurements taken from adult rays. These are the only detailed measurements on M. birostris variant A from the western Indian Ocean. Predatory scarring and bite injuries on individuals of both variant A and B were consistent with attacks from sharks of various sizes. The frequency and effect of these predatory injuries on the two populations were examined over a three-year period. Acoustic tags were attached to fourteen rays and their presence/absence at sites around the major inshore reefs was explored to evaluate how the rays utilised their environment on a temporal scale. Cleaning activity of both putative species of manta rays by small fishes occurred on these reefs and was considered to be the main reason why the rays were present at these sites. Parasite removal and wound healing were implicated as the benefits received. Host cleaner fish species partition the manta ray body to avoid interspecific competition while the two putative species appear to partition cleaning habitats, with very little overlap apparent. This research on manta rays is the first of its kind in African waters. Many aspects of the study have contributed to the limited baseline data currently available for this genus. The study additionally provided sufficient empirical evidence to warrant the separation of these two putative species of Manta and a full revision of the genus with the systematic examination of specimens throughout Manta’s range. The results of this study may be useful in this endeavour as diagnostic characteristics have been isolated that may help to differentiate members of this genus. The results of this research study are directly applicable to management strategies for both putative species of manta rays off the East Coast of Africa as well as populations worldwide and have highlighted the potential need for different conservation strategies