scholarly journals Fibropapillomatosis infection in a population of green turtles at Watamu Bay, Kenya

2021 ◽  
Vol 20 (1) ◽  
pp. 111-123
Author(s):  
Sharon M. Jones ◽  
Itamar Caspi ◽  
Charles Lucas
Keyword(s):  
Indian Ocean ◽  
Horizontal Transmission ◽  
Western Indian Ocean ◽  
Chelonia Mydas ◽  
Infection Prevalence ◽  
Marine Biota ◽  
Community Factors ◽  
Green Turtles ◽  
Wide Range ◽  
Kenyan Coast

Anthropogenic stressors from onshore and offshore activities can act as driving factors of disease for a wide range of marine organisms. Green turtles (Chelonia mydas) are prominently afflicted with a tumour-causing disease known as fibropapillomatosis (FP) caused by the chelonid alphaherpesvirus ChHV5. Previous studies indicate that pathways of FP transmission may be genetic (vertical transmission) or linked to causal factors in a turtle’s environment (horizontal transmission). In this paper patterns of FP prevalence were examined in 10,896 records of green turtles caught or found stranded around Watamu Bay, Kenya, between 2003 – 2020. Findings were focused on locational and seasonal factors that may potentially influence infection. The findings show that FP prevalence varies significantly on an annual basis. Location significantly influenced infection prevalence, with prevalence higher in open ocean sites than sites located within the creek. Infection prevalence was highest at sites around the creek mouth and north of the creek mouth, with both regions exhibiting disparate annual patterns of infection. This paper is the first to examine long-term trends of FP prevalence in-depth in this region and has implications for the health of turtles and marine biota found along the Kenyan coast, and potentially within the wider Western Indian Ocean region. The findings emphasize the need to distinguish the infection pathways of causative agents via: i) further examination of the links between infection and environmental and/or biont community factors; and ii) the collection of data pertinent to the genetic diversity of green turtles and associated ChHV5 viral strains occurring in the Western Indian Ocean.

scholarly journals Species and Sex-Biased Predation on Hatchling Green Turtles by Frigatebirds on Europa Island, Western Indian Ocean

The Condor ◽  
2001 ◽  
Vol 103 (2) ◽  
pp. 405-408 ◽  
Author(s):  
Frédéric Lagarde ◽  
Matthieu Le Corre ◽  
Hervé Lormeé
Keyword(s):  
Indian Ocean ◽  
Feeding Behavior ◽  
Species Differences ◽  
Western Indian Ocean ◽  
Chelonia Mydas ◽  
Visual Observation ◽  
Male And Female ◽  
Green Turtles ◽  
Breeding Place

Abstract Europa Island is a major breeding place for green turtles (Chelonia mydas; 0.7 to 2.4 million juvenile turtles hatch there annually), Great Frigatebirds (Fregata minor; 700 to 1100 breeding pairs), and Lesser Frigatebirds (Fregata ariel; 1000 to 1200 pairs). By visual observation, we quantified the proportions of males, females, and juveniles of both frigatebird species prospecting over the hatching sites and preying on hatchling turtles. Of 1828 juveniles observed hatching at daytime (35 separate turtle emergences), 1632 were immediately eaten by male Great Frigatebirds. Only 10 hatchlings were preyed upon by female Great Frigatebirds; the remaining 186 were captured by juvenile Great Frigatebirds. Such feeding behavior was not observed in Lesser Frigatebirds. We suggest that the sexual and species differences in hatchling turtle predation are due to size differences between the two species and between male and female Great Frigatebirds.

scholarly journals Green turtle diet is dominated by seagrass in the Western Indian Ocean except amongst gravid females

2019 ◽  
Vol 166 (10) ◽  
Author(s):  
Holly J. Stokes ◽  
Jeanne A. Mortimer ◽  
Graeme C. Hays ◽  
Richard K. F. Unsworth ◽  
Jacques-Olivier Laloë ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Green Turtle ◽  
Western Indian Ocean ◽  
Chelonia Mydas ◽  
Breeding Habitat ◽  
Gut Contents ◽  
Seagrass Meadows ◽  
Green Turtles ◽  
The Republic ◽  
Gravid Females

Abstract Green turtles (Chelonia mydas) are key herbivores of tropical and subtropical neritic habitats and play a major role in structuring seagrass meadows. We present the first detailed assessment of green turtle diet in the Western Indian Ocean using the gut contents of salvaged animals from three atolls in the Republic of Seychelles separated from each other by 400–825 km: Cosmoledo (adults, n = 12), Farquhar (adults, n = 33; immature, n = 1) collected in 1982–1983; and Desroches (immatures, n = 8) in 2016–2018. We report the first comparison of the diets of gravid females (n = 17), males (n = 26) and non-breeding females (n = 2) at sites providing both foraging and breeding habitat. Seagrass (mostly Thalassodendron ciliatum) dominated the diet, accounting for 95% of the mean gut content biomass for males and non-breeding females but only 58% for gravid females, alongside relatively large amounts of substrate (14%) and macroalgae (13%). Satellite tracking of post-nesting green turtles from Chagos Archipelago in 2016 located foraging sites at Farquhar Atoll that coincided with capture locations of 26 of the 33 adult turtles sampled there in 1983. In situ surveys of those sites in 2018 revealed extensive nearly monospecific beds of T. ciliatum. The prominence of seagrass in the diet of green turtles and connectivity between foraging and nesting habitats throughout the region illustrate the need to conserve and monitor seagrass habitats of the Western Indian Ocean especially in the context of changing green turtle population densities.

scholarly journals Massive Infection of Seabird Ticks with Bacterial Species Related to Coxiella burnetii

2014 ◽  
Vol 80 (11) ◽  
pp. 3327-3333 ◽  
Author(s):  
David A. Wilkinson ◽  
Muriel Dietrich ◽  
Camille Lebarbenchon ◽  
Audrey Jaeger ◽  
Céline Le Rouzic ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Bacterial Community ◽  
Tick Species ◽  
New Caledonia ◽  
Bacterial Pathogens ◽  
Bacterial Species ◽  
Horizontal Transmission ◽  
Western Indian Ocean ◽  
Content Type ◽  
Medical Importance

ABSTRACTSeabird ticks are known reservoirs of bacterial pathogens of medical importance; however, ticks parasitizing tropical seabirds have received less attention than their counterparts from temperate and subpolar regions. Recently,Rickettsia africaewas described to infect seabird ticks of the western Indian Ocean and New Caledonia, constituting the only available data on bacterial pathogens associated with tropical seabird tick species. Here, we combined a pyrosequencing-based approach with a classical molecular analysis targeting bacteria of potential medical importance in order to describe the bacterial community in two tropical seabird ticks,Amblyomma loculosumandCarios(Ornithodoros)capensis. We also investigated the patterns of prevalence and host specificity within the biogeographical context of the western Indian Ocean islands. The bacterial community of the two tick species was characterized by a strong dominance ofCoxiellaandRickettsia. Our data support a strictCoxiella-host tick specificity, a pattern resembling the one found forRickettsiaspp. in the same two seabird tick species. Both the high prevalence and stringent host tick specificity suggest that these bacteria may be tick symbionts with probable vertical transmission. Detailed studies of the pathogenicity of these bacteria will now be required to determine whether horizontal transmission can occur and to clarify their status as potential human pathogens. More generally, our results show that the combination of next generation sequencing with targeted detection/genotyping approaches proves to be efficient in poorly investigated fields where research can be considered to be starting from scratch.

scholarly journals The value of long-term, community-based monitoring of marine turtle nesting: a study in the Lamu archipelago, Kenya

Oryx ◽  
2017 ◽  
Vol 53 (1) ◽  
pp. 71-80 ◽  
Author(s):  
Mike I. Olendo ◽  
Gladys M. Okemwa ◽  
Cosmas N. Munga ◽  
Lilian K. Mulupi ◽  
Lily D. Mwasi ◽  
...  
Keyword(s):  
Green Turtle ◽  
Low Cost ◽  
Western Indian Ocean ◽  
Chelonia Mydas ◽  
Sea Turtle ◽  
Marine Turtle ◽  
Olive Ridley ◽  
Community Based ◽  
Green Turtles ◽  
Incubation Duration

AbstractMonitoring of nesting beaches is often the only feasible and low-cost approach for assessing sea turtle populations. We investigated spatio-temporal patterns of sea turtle nesting activity monitored over 17 successive years in the Lamu archipelago, Kenya. Community-based patrols were conducted on 26 stretches of beach clustered in five major locations. A total of 2,021 nests were recorded: 1,971 (97.5%) green turtleChelonia mydasnests, 31 (1.5%) hawksbillEretmochelys imbricatanests, 8 (0.4%) olive ridleyLepidochelys olivaceanests and 11 (0.5%) unidentified nests. Nesting occurred year-round, increasing during March–July, when 74% of nests were recorded. A stable trend in mean annual nesting densities was observed in all locations. Mean clutch sizes were 117.7 ± SE 1 eggs (range 20–189) for green turtles, 103±SE 6 eggs (range 37–150) for hawksbill turtles, and 103±SE 6 eggs (range 80–133) for olive ridley turtles. Curved carapace length for green turtles was 65–125 cm, and mean annual incubation duration was 55.5±SE 0.05 days. The mean incubation duration for green turtle nests differed significantly between months and seasons but not locations. The hatching success (pooled data) was 81.3% (n = 1,841) and was higher for in situ nests (81.0±SE 1.5%) compared to relocated nests (77.8±SE 1.4%). The results highlight the important contribution of community-based monitoring in Kenya to sustaining the sea turtle populations of the Western Indian Ocean region.

scholarly journals Marine Turtles of the Western Indian Ocean

Oryx ◽  
1975 ◽  
Vol 13 (2) ◽  
pp. 164-175 ◽  
Author(s):  
Jack Frazier
Keyword(s):  
Indian Ocean ◽  
Western Indian Ocean ◽  
Valuable Resource ◽  
Nesting Habitat ◽  
Marine Turtles ◽  
Green Turtles ◽  
Two Factors ◽  
One Year ◽  
Over Exploitation

After seven years' study, visiting islands scattered over more than a million square miles of the western Indian Ocean, where once hundreds of thousands of green turtles nested every year, the author?'s “optimistic estimate” of the number of females nesting today is 5500. Only eighty years ago 12,000 were taken in one year on Aldabra alone. Over-exploitation by man for food – both of nesting females and eggs – and destruction of nesting habitat, i.e. disturbance of the beaches, are the two factors that are destroying this immensely valuable resource. The author's study was assisted by FPS.

Nematode Community Structure along the Continental Slope off the Kenyan Coast, Western Indian Ocean

2004 ◽  
Vol 89 (2) ◽  
pp. 188-205 ◽  
Author(s):  
Agnes W. Muthumbi ◽  
Ann Vanreusel ◽  
Gerard Duineveld ◽  
Karline Soetaert ◽  
Magda Vincx
Keyword(s):  
Community Structure ◽  
Indian Ocean ◽  
Continental Slope ◽  
Western Indian Ocean ◽  
Nematode Community ◽  
Kenyan Coast

scholarly journals UV-Indien network: ground-based measurements dedicated to the monitoring of UV radiation over the western Indian Ocean

2021 ◽  
Vol 13 (9) ◽  
pp. 4275-4301
Author(s):  
Kevin Lamy ◽  
Thierry Portafaix ◽  
Colette Brogniez ◽  
Kaisa Lakkala ◽  
Mikko R. A. Pitkänen ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Uv Radiation ◽  
Western Indian Ocean ◽  
Cloud Fraction ◽  
Monitoring Instrument ◽  
Clear Sky ◽  
Wide Range ◽  
Ozone Monitoring ◽  
Main Station

Abstract. Within the framework of the UV-Indien network, nine ground stations have been equipped with ultraviolet broadband radiometers, five of them have also been equipped with an all-sky camera, and the main station in Saint-Denis de la Réunion is also equipped with a spectroradiometer. These stations are spatially distributed to cover a wide range of latitudes, longitudes, altitudes, and environmental conditions in five countries of the western Indian Ocean region (Comoros, France, Madagascar, Mauritius, and Seychelles), a part of the world where almost no measurements have been made so far. The distribution of the stations is based on the scientific interest of studying ultraviolet radiation not only in relation to atmospheric processes but also in order to provide data relevant to fields such as biology, health (prevention of skin cancer), and agriculture. The main scientific objectives of this network are to study the annual and inter-annual variability in the ultraviolet (UV) radiation in this area, to validate the output of numerical models and satellite estimates of ground-based UV measurements, and to monitor UV radiation in the context of climate change and projected ozone depletion in this region. A calibration procedure including three types of calibrations responding to the various constraints of sustaining the network has been put in place, and a data processing chain has been set up to control the quality and the format of the files sent to the various data centres. A method of clear-sky filtering of the data is also applied. Here, we present an intercomparison with other datasets, as well as several daily or monthly representations of the UV index (UVI) and cloud fraction data, to discuss the quality of the data and their range of values for the older stations (Antananarivo, Anse Quitor, Mahé, and Saint-Denis). Ground-based measurements of the UVI are used to validate satellite estimates – Ozone Monitoring Instrument (OMI), the TROPOspheric Monitoring Instrument (TROPOMI), and the Global Ozone Monitoring Experiment (GOME) – and model forecasts of UVI – Tropospheric Emission Monitoring Internet Service (TEMIS) and Copernicus Atmospheric Monitoring Service (CAMS). The median relative differences between satellite or model estimates and ground-based measurements of clear-sky UVI range between −34.5 % and 15.8 %. Under clear skies, the smallest UVI median difference between the satellite or model estimates and the measurements made by ground-based instruments is found to be 0.02 (TROPOMI), 0.04 (OMI), −0.1 (CAMS), and −0.4 (CAMS) at Saint-Denis, Antananarivo, Anse Quitor, and Mahé, respectively. The diurnal variability in UVI and cloud fraction, as well as the monthly variability in UVI, is evaluated to ensure the quality of the dataset. The data used in this study are available at https://doi.org/10.5281/zenodo.4811488 (Lamy and Portafaix, 2021a).

Cadmium in tissues of green turtles (Chelonia mydas): A global perspective for marine biota

2018 ◽  
Vol 637-638 ◽  
pp. 389-397 ◽  
Author(s):  
Nairana Santos Fraga ◽  
Agnaldo Silva Martins ◽  
Derek R. Faust ◽  
Haruya Sakai ◽  
Adalto Bianchini ◽  
...  
Keyword(s):  
Chelonia Mydas ◽  
Global Perspective ◽  
Marine Biota ◽  
Green Turtles

scholarly journals Molecular Ecology of Coral Reef Microorganisms in the Western Indian Ocean coast of Kenya

2020 ◽  
Author(s):  
Sammy Wambua ◽  
Hadrien Gourlé ◽  
Etienne de Villiers ◽  
Oskar Karlsson ◽  
Nina Wambiji ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Coral Reefs ◽  
High Throughput Sequencing ◽  
Molecular Ecology ◽  
West Indian ◽  
Western Indian Ocean ◽  
Sediment Layer ◽  
The West ◽  
Kenyan Coast ◽  
West Indian Ocean

AbstractCoral reefs face increased environmental threats from anthropomorphic climate change and pollution, from agriculture, industries and tourism. They are economically vital for many people worldwide, and harbour a fantastically diverse ecosystem, being the home for many species of fish and algae. Surprisingly little is known about the microbial communities living in and in the surrounding of coral reefs. Here we employ high throughput sequencing for investigating the bacteria living in the water column and upper sediment layer in close proximity to coral reefs on the Kenyan coast of the West Indian Ocean. We show that while the read-level taxonomic distribution of bacteria is similar with ones obtained from 16S metabarcoding, whole metagenome sequencing provides valuable functional insights not available with 16S metabarcoding. We find evidence of pollution, marked by the presence of Vibrio and more importantly the presence of antibiotic resistance notably to vancomycin, that we attribute to the use of avoparcin in agriculture. Additionally, 175 bacterial genomes not previously sequenced were discovered.Our study is the first whole-metagenome study from the West Indian Ocean, provides a much-needed baseline to study microbes surrounding coral reefs under different conditions as well as the microbiome of coral reefs.

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