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Fish and Fisheries of Saint Helena Island

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... The movements of both the surface and subsurface currents over many years has resulted in a mixed marine fauna in the waters of St Helena including western Atlantic, eastern Atlantic and circumtropical species. and Edwards & Glass (1987a & b) provided the first lists of fish records for St Helena Island which were summarised in a book by Edwards (1990). He described 138 species from 61 families from St Helena Island. ...
... Ichthyapus ophioneus (Evermann & Marsh, 1900)-Surf eel , Sand eel (St H) References: in part as Sphagebranchus sp. vel S. acutirostris, Blache & Bauchot (1972) as Rhinechelys ophioneus, , Edwards (1990:70), McCosker (2004 , , Edwards (1990) and Wirtz et al. (2014) should thus be referred to I. insularis. St. Helena BMNH specimens of I. ophioneus were checked by E. Boehlke and apparently do not belong to the Ascension endemic species I. insularis McCosker, 2004 (McCosker pers. ...
... Ichthyapus ophioneus (Evermann & Marsh, 1900)-Surf eel , Sand eel (St H) References: in part as Sphagebranchus sp. vel S. acutirostris, Blache & Bauchot (1972) as Rhinechelys ophioneus, , Edwards (1990:70), McCosker (2004 , , Edwards (1990) and Wirtz et al. (2014) should thus be referred to I. insularis. St. Helena BMNH specimens of I. ophioneus were checked by E. Boehlke and apparently do not belong to the Ascension endemic species I. insularis McCosker, 2004 (McCosker pers. ...
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A check-list of the fishes of St Helena Island is presented. The following species are recorded for the first time from St. Helena Island: Rhincodon typus, Mobula tarapacana, Muraena melanotis, Caranx latus, Seriola rivoliana, Balistes capriscus, Lutjanus jocu, Centropyge aurantonotus, Acanthurus coeruleus, Lepidocybium flavobrunneum, Tetrapturus pfluegeri, Coelorinchus geronimo, Pentaceros richardsoni, Gephyroberyx darwinii, Brotula cf multibarbata, Poromitra crassiceps, Echiostoma barbatum, Malacosteus niger, Pachystomias microdon. Including these nineteen new records there are 189 fish species currently known from St Helena. Three of them appear to be undescribed. Eight species and two subspecies are currently considered endemic to St. Helena Island.
... Cadenat & Marchal, 1963;Lubbock, 1980;Bingeman & Bingeman, 2005, p. 51. Lubbock, 1980;Edwards & Glass, 1987a;Edwards, 1990, p. 133. Melichthys niger (Bloch, 1786 Black triggerfish References: Cadenat & Marchal, 1963 as Mellichthys buniva;Lubbock, 1980;Edwards & Glass, 1987a;Edwards, 1990, pp. 133 -134;Bingeman & Bingeman, 2005, p. 51. ...
... Finally and surprisingly, a small fraction of the Ascension (and St Helena) marine fauna is of Indian Ocean origin. In the Atlantic Ocean, the Indo-Pacific carangid Uraspis helvola is only known from Ascension and St Helena Islands (Edwards, 1990) and the endemic Helcogramma ascensionis is the only Atlantic member of this otherwise Indo-Pacific genus (Holleman, 2007). The link with the Indo-Pacific is confirmed by the presence on Ascension Island of the crab Percnon abbreviatum, not know from any other Atlantic locality (Manning & Chace, 1990). ...
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The species Rhincodon typus, Alopias superciliosus, Isurus oxyrinchus, Carcharhinus obscurus, Galeocerdo cuvier, Sphyrna lewini, Hexanchus griseus, Manta birostris, Gymnothorax vicinus, Hippocampus sp., Epinephelus itajara, Cookeolus japonicus, Apogon pseudomaculatus, Phaeoptyx pigmentaria, Remora albescens, Caranx bartholomaei, Carangoides ruber, Decapterus tabl, Seriola dumerili, Thalassoma sanctaehelenae, Cryptotomus sp., Ruvettus pretiosus, Acanthocybium solandri, Auxis rochei, Auxis thazard, Euthynnus alletteratus, Katsuwonus pelamis, Thunnus alalunga, Thunnus obesus, Xiphias gladius, Istiophorus platypterus, Kajikia albida, Makaira nigricans, Tetrapturus pfluegeri, Hyperoglyphe perciformis, Schedophilus sp., Cantherhines macrocerus, Sphoeroides pachygaster and Diodon eydouxii are recorded for the first time from Ascension Island. We have recognized two previous records as identification errors and indicate 11 other records as doubtful. Including the 40 new records, we now list 173 fish species from Ascension Island, of which 133 might be considered ‘coastal fish species’. Eleven of these (8.3%) appear to be endemic to the island and a further 16 species (12%) appear to be shared endemics with St Helena Island.
... Interface 19: 20210859 observations of turtles in unusual locations. For example, during the green turtle breeding season at Ascension Island, some turtle mating pairs are also seen on the island of St Helena, 1100 km to the south, even though that island has no nesting beaches [48]. The implication is that these mating turtles at St Helena were likely trying to find Ascension Island but became lost. ...
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How animals navigate across the ocean to isolated targets remains perplexing greater than 150 years since this question was considered by Charles Darwin. To help solve this long-standing enigma, we considered the likely resolution of any map sense used in migration, based on the navigational performance across different scales (tens to thousands of kilometres). We assessed navigational performance using a unique high-resolution Fastloc-GPS tracking dataset for post-breeding hawksbill turtles ( Eretmochelys imbricata ) migrating relatively short distances to remote, isolated targets on submerged banks in the Indian Ocean. Individuals often followed circuitous paths (mean straightness index = 0.54, range 0.14–0.93, s.d. = 0.23, n = 22), when migrating short distances (mean beeline distance to target = 106 km, range 68.7–178.2 km). For example, one turtle travelled 1306.2 km when the beeline distance to the target was only 176.4 km. When off the beeline to their target, turtles sometimes corrected their course both in the open ocean and when encountering shallow water. Our results provide compelling evidence that hawksbill turtles only have a relatively crude map sense in the open ocean. The existence of widespread foraging and breeding areas on isolated oceanic sites points to target searching in the final stages of migration being common in sea turtles.
... Por su parte, A. rochei, la cachorreta alicorta, ha sido colectada junto con su congénere, en febrero y comienzos de marzo, cuando la surgencia costera samaria está en su pico más elevado (Bernal y Zea, 2000). Vale la pena tener en cuenta que de pocas localidades aisladas en el Atlántico hay registros de ambas especies; por ejemplo, Edwards (1990) las lista para la isla de Santa Helena en el Atlántico central. Un camino de investigación interesante sería la comparación detallada de las poblaciones atlánticas de A. rochei, incluyendo al menos material de EE. ...
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The marine environment of the Santa Marta region (Colombian Caribbean) is unique in many ways. The coexistence there of both species of Auxis is herewith reported and discussed. Auxis thazard, the frigate tuna or frigate mackerel, has been reported several times from Santa Marta; however, the occurrence of A. rochei, the bullet tuna or bullet mackerel, is reported for the first time. Some inter and intraspecific differences are discussed; fishery aspects are commented as well.
... Profundidad: 60 a 600 m (Edwards, 1990). ...
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Between October and August 1999 five cruises were made on board of R/V Ancón, across the Colombian Caribbean slope, from Punta Estrella (Guajira), near the Venezuelan border, to Cabo Tiburón (Chocó), near the Panamá border. Eighty trawls were made between 200 and 500 m depth with a semi-balloon net. Twelve new records of fishes for the Colombian Caribbean in the orders Beryciformes, Zeiformes, Perciformes and Tetraodontiformes were collected. Plectranthias garrupellus (Serranidae), Benthodesmus tenuis and B. simonyi (Trichiuridae) are new records for the Caribbean; Diplospinnus multistriatus (family Gempylidae) is a new record for the southern Caribbean.
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Data from 369 sightings of mobulid rays from St Helena Island, Cardno and Bonaparte seamounts in the South Atlantic are summarised. 50 % (183) of sightings were observed from a boat, 48 % (176) of sightings were encountered in water, of which 95 % (168) were whilst actively scuba diving. 2 % (10) of mobulid ray sightings were observed from land. Sightings data indicate that the Chilean devil ray Mobula tarapacana (Philippi, 1892) is a frequent visitor to St Helena and is present all year. We document the first photographic evidence of the presence of oceanic manta, Mobula birostris (Walbaum, 1792) at St Helena. Two solitary individuals were photographed off the north coast of St Helena in June 2018. These sightings confirm previous unverified reports on the species occurrence and extend the known distribution range of M. birostris in the open South Atlantic Ocean to 16°S.
Article
Yellowfin tuna are the mainstay of the traditional tuna fisheries in St Helena waters, but there is limited knowledge of their ecology and feeding behaviour in the area. In this study yellowfin tuna stomach contents were used to assess spatio‐temporal changes in feeding strategy and consider the role of tuna in the local ecosystem. Comparisons of the feeding spectra of yellowfin tuna between inshore regions of St Helena and oceanic seamounts demonstrated that in both areas the species was largely piscivorous. In inshore waters yellowfin consumed more neritic fauna, including significant numbers of crab megalopa, whereas around seamounts the diet included a greater diversity of epi‐ and mesopelagic fish and squids. The most important fish prey species in inshore waters was the St Helena butterflyfish Chaetodon sanctahelenae, and around seamounts was the pufferfish Lagocephalus lagocephalus. Results indicate that the diet spectrum of yellowfin tuna in St Helena waters is relatively similar to those of conspecifics living in waters with relatively low productivity, with strategies indicative of food‐poor ecosystems. The availability of coastal fauna may make areas around islands and seamounts more attractive for feeding aggregations of yellowfin tuna, compared to the open ocean. The relatively unselective feeding of yellowfin tuna means that stomachs can provide valuable data on the species diversity, particularly in remote areas with limited opportunities for dedicated research expeditions.
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• In 2016, the UK government announced plans for a large‐scale Marine Protected Area around Ascension Island, a UK Overseas Territory in the South Atlantic. • To improve baselines for marine life to support ambitious conservation and assess change over time, archives were searched for historical accounts of wildlife from Ascension's discovery in 1501 to the present. For more recent changes, 139 interviews with past and present inhabitants were conducted. • Ascension's marine life has, from first discovery to the present, been consistently remarked upon for its exceptional abundance. Historical sources indicate declines in seabird and turtle populations from human exploitation and introduction of rats and cats. They are recovering with good management, although still below pre‐settlement abundance. • Interviews with residents indicate more recent changes, notably declines in catch per unit of fishing effort at popular shore angling sites, a decline in yellowfin tuna (Thunnus albacares ) and increase in Galapagos sharks (Carcharhinus galapagensis ). • What is very notable, however, based on the interviews, was that there was no temporal signal suggestive of recent systemic decline, in marked contrast to many parts of the world where recent wildlife declines have been pervasive and steep. Ascension represents a remarkable and immensely important centre of abundance in a sea of depletion and change, warranting full protection for all the island's waters.
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A synthetic model is presented to enlarge the evolutionary framework of the General Dynamic Model (GDM) and of the Glacial Sensitive Model (GSM) of oceanic island biogeography from the terrestrial to the marine realm. The proposed “Sea-Level Sensitive” dynamic model (SLS) of marine island biogeography integrates historical and ecological biogeography with patterns of glacio-eustasy, merging concepts from areas as diverse as taxonomy, biogeography, marine biology, volcanology, sedimentology, stratigraphy, palaeontology, geochronology and geomorphology. Fundamental to the SLS model is the dynamic variation of the littoral area of volcanic oceanic islands (defined as the area between the intertidal and the 50-m isobath) in response to sea-level oscillations driven by glacial–interglacial cycles. The following questions are considered by means of this revision: 1) What was the impact of (global) glacio-eustatic sea-level oscillations, particularly those of the Pleistocene glacial-interglacial episodes, on the littoral marine fauna and flora of volcanic oceanic islands? 2) What are the main factors that explain the present littoral marine biodiversity on volcanic oceanic islands? 3) How can differences in historical and ecological biogeography be reconciled, from a marine point of view? These questions are addressed by compiling the bathymetry of eleven Atlantic archipelagos/islands to obtain quantitative data regarding changes in the littoral area based on Pleistocene sea-level oscillations, from 150 ka to the present time. Within the framework of a model sensitive to changing sea levels, we discuss the principal factors affecting the geographical range of marine species; the relationships between modes of larval development, dispersal strategies and geographical range; the relationships between times of speciation, modes of larval development, ecological zonation and geographical range; the influence of sea-surface temperatures and latitude on littoral marine species diversity; the effect of eustatic sea-level changes and their impact on the littoral marine biota; Island Marine Species–Area Relationships; and finally, the physical effects of island ontogeny and its associated submarine topography and marine substrate on littoral biota. Based on the SLS dynamic model, we offer a number of predictions for tropical, subtropical and temperate volcanic oceanic islands on how rates of immigration, colonization, in-situ speciation, local disappearance, and extinction interact and affect the marine biodiversity around islands during glacials and interglacials, thus allowing future testing of the theory.
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The pantropical sea urchin genus Eucidaris contains four currently recognized species, all of them allopatric: E. metularia in the Indo-West Pacific, E. thouarsi in the eastern Pacific, E. tribuloides in both the western and eastern Atlantic, and E. clavata at the central Atlantic islands of Ascension and St. Helena. We sequenced a 640-bp region of the cytochrome oxidase I (COI) gene of mitochondrial DNA to determine whether this division of the genus into species was confirmed by molecular markers, to ascertain their phylogenetic relations, and to reconstruct the history of possible dispersal and vicariance events that led to present-day patterns of species distribution. We found that E. metularia split first from the rest of the extant species of the genus. If COI divergence is calibrated by the emergence of the Isthmus of Panama, the estimated date of the separation of the Indo-West Pacific species is 4.7-6.4 million years ago. This date suggests that the last available route of genetic contact between the Indo-Pacific and the rest of the tropics was from west to east through the Eastern Pacific Barrier, rather than through the Tethyan Sea or around the southern tip of Africa. The second cladogenic event was the separation of eastern Pacific and Atlantic populations by the Isthmus of Panama. Eucidaris at the outer eastern Pacific islands (Galapagos, Isla del Coco, Clipperton Atoll) belong to a separate clade, so distinct from mainland E. thouarsi as to suggest that this is a different species, for which the name E. galapagensis is revived from the older taxonomic literature. Complete lack of shared alleles in three allozyme loci between island and mainland populations support their separate specific status. Eucidaris galapagensis and E. thouarsi are estimated from their COI divergence to have split at about the same time that E. thouarsi and E. tribuloides were being separated by the Isthmus of Panama. Even though currents could easily convey larvae between the eastern Pacific islands and the American mainland, the two species do not appear to have invaded each other's ranges. Conversely, the central Atlantic E. clavata at St. Helena and Ascension is genetically similar to E. tribuloides from the American and African coasts. Populations on these islands are either genetically connected to the coasts of the Atlantic or have been colonized by extant mitochondrial DNA lineages of Eucidaris within the last 200,000 years. Although it is hard to explain how larvae can cross the entire width of the Atlantic within their competent lifetimes, COI sequences of Eucidaris from the west coast of Africa are very similar to those of E. tribuloides from the Caribbean. FST statistics indicate that gene flow between E. metularia from the Indian Ocean and from the western and central Pacific is restricted. Low gene flow is also evident between populations of E. clavata from Ascension and St. Helena. Rates of intraspecific exchange of genes in E. thouarsi, E. galapagensis, and E. tribuloides, on the other hand, are high. The phylogeny of Eucidaris confirms Ernst Mayr's conclusions that major barriers to the dispersal of tropical echinoids have been the wide stretch of deep water between central and eastern Pacific, the cold water off the southwest coast of Africa, and the Isthmus of Panama. It also suggests that a colonization event in the eastern Pacific has led to speciation between mainland and island populations.
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The shore fishes of St. Helena Island, South Atlantic Ocean (15°58′S 5°43′W), are reviewed. A checklist of 81 species of shore fish with notes on the ecology and geographical distribution of each species is presented. Sixteen of the species have not before been recorded at St. Helena and seven other species have previously been identified incorrectly. Two new species, Chromis sanctaehelenae Edwards (Pomacentridae) and Quisquilius ascensionis Dawson and Edwards (Gobiidae), are described and the pomacentrid Stegastes sanctaehelenae (Sauvage) is redescribed and a neotype designated. In addition, hitherto unreported records of the cephalochordate Epigonichthys lucayanus, and of an Eleotris species (Eleotrididae) found in a freshwater pool near the coast, are included. The ecology and zoogeography of the shore fishes is discussed.34·2% of the shore fishes are widespread amphi-Atlantic warm-water species. 15·2% are western Atlantic species which have the central Atlantic islands as their eastern limit, whilst 13·9% are eastern Atlantic species which reach their western limit in the central Atlantic. 20·3% are essentially known only from Ascension and St. Helena (although two of these species have also reached St. Paul's Rocks and one is known also at the Azores). 13·9% are endemic to St. Helena and two species are known otherwise only in the Indo-West Pacific.The shore-fish fauna has a predominantly central Atlantic character and cannot be considered as an integral part of the fish faunas of either the Western or the Eastern Atlantic Regions.
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Myroconger compressus Günther is redescribed on the basis of the holotype and a second specimen from Dakar, west Africa. The latter specimen was cleared and stained, and the osteology is described and figured. Myroconger belongs to a monotypic family, the Myrocongridae, whose closest relatives are the Xenocongridae and Muraenidae. A phylogenetic analysis of the three families indicates that the Myrocongridae is the primitive sister group of the other two. The type locality is supposed to be St. Helena, but there is no subsequent evidence that the species occurs there. The specimen reported by Osorio from São Thomé cannot be located today, and the record is considered unconfirmed. The meager evidence suggests that west Africa is the most likely place to find the species.
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Gadella Lowe, widespread in warm temperate and tropical seas is represented by eight nominal species, of which one is new. The genus is distinguished from other morid genera with light organs by the absence of a barbel. Thirty-one species of Physiculus Kaup are recognised, including six which are newly described. Physiculus is found in tropical and temperate waters of all oceans and is distinguished from other morid genera with light organs by the presence of a barbel and absence of vomerine teeth. Salilota Günther is represented by a single species found only in cool temperate waters of South America and is distinguished from other morid genera with light organs by the presence of a barbel and vomerine teeth.
Article
The pelagic fishes of St Helena Island, South Atlantic Ocean (15°58′S 5°43′W) are reviewed. A checklist of 53 taxa of pelagic fishes, with notes on fisheries significance, ecology and geographical distribution, is presented. Twelve of the taxa have not before been recorded at St Helena. Of particular interest are records of three primarily Indo-Pacific species: Decapterus muroadsi (Temminck and Schlegel), Uraspis helvola (Forster) and Scomberomorus commerson (Lacepède). Apart from U. helvola, which is known also from Ascension Island, these species are not otherwise recorded in the Atlantic Ocean.Of the 49 pelagic fishes whose identities are clear, 81·6% are wide-ranging species known from both the Atlantic and Indo-Pacific regions, 12·2% are pan-Atlantic warm-water species and 4·1% are eastern Atlantic species which reach their western limit in the central Atlantic. In addition, the subspecies Platybelone argalus trachura is found only at St Helena and Ascension.The principal pelagic species caught by St Helena fisheries are Katsuwonus pelamis, Thunnus albacares, T. obesus, T. alalunga, Scomber japonicus, Acanthocybium solandri and Pseudocaranx dentex, which together accounted for almost 95% of fish landings in 1982–1983 fiscal year.
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IN my paper ``On the `Manatee' of St. Helena''1. I brought forward evidence that the so-called `manatee' formerly found at St. Helena was a sea-lion, probably the Cape sea-lion, Arctocephalus antarcticus, not a sea-cow, natural conditions at St. Helena being quite unsuitable for sea-cows.
Article
The spotted dolphin exploited at St Helena is of the same species as that exploited In the eastern tropical Pacific and referred to Stenella attenuala. Take is now illegal, but former catches were about 50-300 annually. A few bottlenose dolphins. Tursiops truncaiw, were also taken. Impacts on the population arc uncertain, because of poor documentation of catches and lack of good estimates of current population sizes. The fishery apparently originated in 'porpoise' harpooning by 19th-century whalers. The population of spotted dolphins is apparently isolated and offers a good opportunity for observation of what happens in a dolphin population when exploitation is halted.