Merino S.,CSIC - National Museum of Natural Sciences |
Hennicke J.,University of Hamburg |
Hennicke J.,CNRS Chizé Center for Biological Studies |
Martinez J.,University of Alcalá |
And 7 more authors.
Journal of Parasitology | Year: 2012
Among seabirds, the fregatids stand out with a high prevalence of blood parasites. Four of 5 species in this family have been found to be infected with Haemoproteus; however, complete species descriptions with molecular phylogeny are lacking. Seventy-five samples from 4 species of frigatebirds, i.e., Fregata andrewsi, Fregata minor, Fregata magnificens, and Fregata aquila, were screened for infections caused by species of Haemoproteus. Four different parasite haplotypes were found infecting frigatebirds based on the sequencing of a fragment of the cytochrome b gene. Two haplotypes belong to the subgenus Parahaemoproteus, and the other 2 correspond to haplotypes within the subgenus Haemoproteus. The more prevalent and cosmopolitan Parahaemoproteus haplotype (FregPHae1) was phylogenetically grouped with other Haemoproteus parasites infecting non-passerine birds, but it could not be detected from the single sample from F. aquila. The other Parahaemoproteus haplotype (FregPHae2) was not phylogenetically clustered with parasites infecting non-passerine birds, and it was sequenced from a single (1 each) F. andrewsi and F. minor. Blood smears from F. andrewsi infected only by FregPHae1 haplotype showed sufficient gametocytes to allow description of a new species, Haemoproteus valkiūnasi sp. nov. In contrast to Haemoproteus iwa, the only previously known blood parasite infecting frigatebirds and described from F. minor from Galapagos Islands, parasites from F. andrewsi (1) are shorter with no contact of gametocyte with host cell membrane, (2) have fewer pigment granules, and (3) have wider microgametocytes, with a smaller host nuclear displacement. In contrast, patent single infections corresponding to the cosmopolitan haplotype of the subgenus Haemoproteus (FregHae1) were also found in samples from 1 F. andrewsi, 1 F. minor, and 1 F. aquila. In all these cases, the number of microgametocytes was very low, resembling H. iwa, which lacks microgametocytes in the original description. Macrogametocytes of haplotype FregHae1 in F. andrewsi differ significantly from all the characteristics measured from H. valkiūnasi. In addition, it also differs from all characteristics of H. iwa despite being genetically identical in the analyzed fragment. © 2012 American Society of Parasitologists.
News Article | January 6, 2016
The British government, together with Blue Marine Foundation (BLUE) and Ascension Island Government (AIG) announced its plans of developing a marine reserve that is almost the same size as the UK's. The plan is to create a reserve that is about 234,291 square kilometers around Ascension Island in the Atlantic Ocean. Through the said project, authorities will close down 52.6 percent of Ascension's waters to fishing. They will monitor and strictly implement regulations in the closed section through satellite data and patrol boats. For the remaining 47.4 percent of the waters, officials will apply the gold standards in monitoring a tuna fishery and perform a scientific investigation to finalize the boundaries of a marine reserve, subject to local concurrence, by 2017. "With the creation of a marine reserve, Ascension will be performing a significant service for the biodiversity of the whole Atlantic," says Charles Clover, the Executive Chairman of BLUE. He also urges other UK and U.S. leaders to recognize the importance of this project and help Ascension Island in its new role as protector of a wide and less-exploited body of water. Bacon Foundation has pledged £300,000 or about $439,900 to create the marine reserve. BLUE said the grant will help enforce the boundary limits and ensure that the waters are protected entirely. UK Overseas Territories Minister James Duddridge said the government is thankful to Bacon Foundation for giving the said donation, which will also be used to perform interventions such as surveillance and overall management of the site for the next 18 months. Duddridge also said that the money can help the Ascension Island Government to determine and secure the future size and shape of the marine reserve. The authorities plan to implement the "belt and braces" strategy as the main protective measure for the area. Such intervention will help guarantee that the most efficient arrest of illegal unreported and unregulated vessels will take place. The satellite data that they intend to use as part of their monitoring program will come from Oxford University and satellite intelligence firm called Catapult. As for the patrol vessels, it will navigate throughout the island - both in the restricted and unrestricted areas - to closely monitor the waters. Amid the surge of protective plans, fishing in Ascension Island will not be completely banned. Authorities say they will still allow the tuna industry, which is mainly composed of Taiwanese longline vessels, to continue operations. Fishermen, however, must follow tight regulations. Tuna fishing will not be restricted simply because the Ascension Island Government lives on issuing tuna fishing licenses. A big chunk of its revenue comes from this industry and for this, they cannot just cancel one of its main monetary sources. Tuna is said to be very profitable. In fact, one tuna was sold for $118,000 in Japan on Monday, Jan. 4. The Japanese people are said to eat about 80 percent of all bluefin tuna caught in the world. The stocks have plummeted across the Pacific, Atlantic and Southern oceans in the last 15 years amid overfishing. Truly, the demand for this fish is on point. Despite allowing commercial fishing in the northern part of the island, authorities will still uphold complete ban on shark finning and other vulnerable sharks and other species. For this, they will necessitate vessels to carry on board de-hookers and dip nets to enable the live release of incidentally caught species such as turtles and seabirds, among others. Ascension Island has some of the largest marlin in the entire world. The island also houses the largest populations of green turtles, important groups of tropical seabirds and other endemic fish species such as the offensively-named "bastard cunningfish."
Morais R.A.,Federal University of Santa Catarina |
Brown J.,Ascension Island Government |
Bedard S.,California Academy of Sciences |
Ferreira C.E.L.,Federal University of Fluminense |
And 4 more authors.
Journal of the Marine Biological Association of the United Kingdom | Year: 2016
Isolated oceanic islands may give rise not only to new and endemic species, but also to unique behaviours and species interactions. Multi-species fish interactions, such as cleaning, following, mob-feeding and others are understudied in these ecosystems. Here we present qualitative and quantitative observations on cleaning and mob-feeding reef fish associations at the isolated Ascension Island, South Atlantic Ocean. Cleaning interactions were dominated by juveniles of the facultative fish cleaners Bodianus insularis and Pomacanthus paru, with lesser contributions of Chaetodon sanctaehelenae, Thalassoma ascensionis and the cleaner shrimp Lysmata grabhami. Two types of feeding mobs were consistently identified: less mobile mobs led by the surgeonfish Acanthurus bahianus and A. coeruleus and the more mobile mobs led by the African sergeant Abudefduf hoefleri. This is the first record of A. hoefleri from outside of the Eastern Atlantic and also the first report of this species displaying mob-feeding behaviour. The principal follower of both mob types was the extremely abundant Melichthys niger, but the main aggressor differed: Stegastes lubbocki, a highly territorial herbivore, was the main aggressor of Acanthurus mobs; and Chromis multilineata a territorial fish while engaged in egg parental care, was the principal aggressor towards Abudefduf mobs. Our study enhances the scarce information on reef fish feeding associations at the isolated Ascension Island and at oceanic islands in the Atlantic in general. Copyright © Marine Biological Association of the United Kingdom 2016
Baker K.,Royal Botanic Gardens |
Lambdon P.,Jamestown |
Jones E.,Royal Botanic Gardens |
Pellicer J.,Royal Botanic Gardens |
And 6 more authors.
Botanical Journal of the Linnean Society | Year: 2014
Last seen in 1958, the Ascension Island endemic fern, Anogramma ascensionis, was listed as extinct on the 2003 IUCN Red List. However, a 2009 survey rediscovered four plants on Green Mountain. Spores were collected and cultured invitro at the Royal Botanic Gardens, Kew, where a living collection of thousands of gametophytes and hundreds of sporophytes has been developed. To gain further insights into the biology of this species and the potential implications of invitro multiplication for conservation purposes, samples were characterized from the karyological point of view. Chromosome analysis of root tips has confirmed that the species is tetraploid, and flow cytometry assessments have revealed that haploid gametophytes produce diploid sporophytes, which confirms natural fertilization. In addition, an rbcL sequence from A.ascensionis has been generated and compared with those published for other Anogramma spp., suggesting a close relationship with A.chaerophylla from Brazil. Further surveys of Green Mountain have reported the presence of 40 A.ascensionis sporophytes in total. Vegetation community analyses have suggested that the present population may be confined to suboptimal habitats. We therefore propose that, prior to the dramatic transformation of the vegetation on the island as a result of the invasion of alien species (particularly Adiantum spp.), A.ascensionis may have flourished in more humid and shaded parts of the mountain. A multidisciplinary approach involving invitro culture, invasive species clearance and controlled translocation is discussed as the future roadmap for the conservation of this critically endangered fern. Our experiences have also highlighted lessons more broadly applicable to the conservation of extremely rare species elsewhere in the world, especially on remote island systems. © 2014 The Linnean Society of London.
Hartnoll R.G.,University of Liverpool |
Broderick A.C.,University of Exeter |
Godley B.J.,University of Exeter |
Musick S.,Ascension Island Government |
And 3 more authors.
Journal of Crustacean Biology | Year: 2010
Reproduction was studied in the land crab Johngarthia lagostoma on Ascension Island in the central South Atlantic from 2005 to 2008. Both sexes are mature by 60-70 mm carapace width (the sample > 4,000 crabs consisted almost entirely of mature specimens). Breeding occurs around the east and south shores of the island, but was studied predominantly at the only easily accessible site at North East Bay. The annual breeding migration extends from January to May, with peak migration in March in most years. The intensity of migration varies between years, and is not obviously related to rainfall. There is lunar entrainment, with increased numbers at the shore in the first quarter, but largest numbers in the last quarter. Both males and females migrate, but with females in greater numbers. At the shore 80 of the crabs are females. A few females mate and lay eggs in the upland residential areas, a greater number do so on the migration route, but the majority only after reaching the shore. Reproductive investment per brood averaged 5% on a dry weight basis, and fecundity averaged 72,000 eggs. © 2010 The Crustacean Society.
Weber S.B.,Ascension Island Government |
Weber S.B.,University of Exeter |
Weber N.,Ascension Island Government |
Weber N.,University of Exeter |
And 7 more authors.
Biodiversity and Conservation | Year: 2014
Although many species of marine mega-vertebrates are threatened as a result of human activity, some populations are showing promising signs of recovery following decades of protection. In this study, we report on the status of the South Atlantic’s largest green turtle (Chelonia mydas) nesting aggregation at Ascension Island, 70 years after legal protection and the cessation of commercial turtle harvesting that decimated the population. Using a monitoring dataset spanning 36 years, we modelled long-term trends in nesting activity at both a rookery level and across individual nesting beaches and beach clusters. Since monitoring began in 1977, the average number of green turtle clutches deposited annually at Ascension Island has increased sixfold, from approximately 3,700 to 23,700; a trend that has been accompanied by a significant decrease in the average size of nesting females. Interestingly, however, rates of increase in nesting activity have varied dramatically among nesting beaches, ranging from 0.4 to 6 % growth per annum. More than 97 % of this variation could be explained by distance from the main human settlement of Georgetown—the historic centre of turtle harvesting—with beaches closer to Georgetown experiencing the most rapid growth. More rapid population growth close to human centres seems counterintuitive, but may reflect the more intensive depletion of these accessible, local stocks during the harvesting era. Overall, the Ascension Island green turtle population appears to be recovering strongly, mirroring positive trends for this species across many parts of its geographic range. While not a cause for complacency, these trends are encouraging and demonstrate the capacity of marine megafauna to rebound when anthropogenic pressures are alleviated through conservation action. © 2014, Springer Science+Business Media Dordrecht.