Jefferson T.A.,Clymene Enterprises |
Weir C.R.,Ketos Ecology |
Anderson R.C.,Manta Marine Pvt Ltd |
Ballance L.T.,Southwest Fisheries Science Center |
And 2 more authors.
Mammal Review | Year: 2014
The global range of Risso's dolphin Grampus griseus is not well known, and there has been confusion in the literature as to whether the species has a broad, circumglobal range or only occurs along continental margins. To clarify the species' distribution and habitat preferences, we compiled and reviewed all available (published and unpublished) records of sightings and captures of this species for the past 62 years (1950-2012, n=8068 records). Stranding records were not included. The results showed that the species has a range that extends across ocean basins and spans between at least 64°N and 46°S, and is apparently absent from high-latitude polar waters. Although Risso's dolphins occur in all habitats from coastal to oceanic, they show a strong range-wide preference for mid-temperate waters of the continental shelf and slope between 30° and 45° latitude. Although a number of misconceptions about the distributional ecology of Risso's dolphin have existed, this analysis showed that it is a widespread species. It strongly favours temperate waters and prefers continental shelf and slope waters to oceanic depths. These habitat preferences appear to hold throughout much or all of the species' range. © 2013 The Mammal Society and John Wiley & Sons Ltd.
Woodland D.J.,University of New England of Australia |
Anderson R.C.,Manta Marine Pvt Ltd
Zootaxa | Year: 2014
Siganus insomnis sp. nov. is described from the Maldives, Sri Lanka and southern India. It most closely resembles S. lineatus (Valenciennes) from the Western Pacific but differs in coloration, principally in that most if not all of the bronze bands on its mid and upper sides continue horizontally and unbroken through to the nape and opercular slit. By contrast, in S. lineatus, typically the anterior area below the spinous dorsal fin down to the mid-sides is irregularly marked with golden bronze spots, commas, or a maze of contorted lines. S. guttatus (Bloch) is the third member of this group of sibling species; its sides are covered with orange to bronze-gold spots. It is distributed throughout S.E. Asia, i.e., it occupies a geographic position between the areas inhabited by S. lineatus and S. insomnis. Thus the gene pools of S. lineatus and S. insomnis are quarantined from one another by distance and the intervening presence of S. guttatus in S.E. Asia. The geographical separation of the populations of S. lineatus and S. insomnis from one another is reinforced by the absence of suitable, coralline habitats for these species in the western half of the Bay of Bengal. Copyright © 2014 Magnolia Press.
Dalebout M.L.,University of New South Wales |
Scott Baker C.,University of Auckland |
Scott Baker C.,Oregon State University |
Steel D.,University of Auckland |
And 11 more authors.
Marine Mammal Science | Year: 2014
We present genetic and morphological evidence supporting the recognition of a previously synonymized species of Mesoplodon beaked whale in the tropical Indo-Pacific, Mesoplodon hotaula. Although the new species is closely-related to the rare ginkgo-toothed beaked whale M. ginkgodens, we show that these two lineages can be differentiated by maternally (mitochondrial DNA), biparentally (autosomal), and paternally (Y chromosome) inherited DNA sequences, as well as by morphological features. The reciprocal monophyly of the mtDNA genealogies and the largely parapatric distribution of these lineages is consistent with reproductive isolation. The new lineage is currently known from at least seven specimens: Sri Lanka (1), Gilbert Islands, Republic of Kiribati (1+), Palmyra Atoll, Northern Line Islands, U.S.A. (3), Maldives (1), and Seychelles (1). The type specimen (Sri Lanka) was described as a new species, M. hotaula, in 1963, but later synonymized with M. ginkgodens. This discovery brings the total number of Mesoplodon species to 15, making it, by far, the most speciose yet least known genus of cetaceans. © 2014 Society for Marine Mammalogy.
Hobson K.A.,Environment Canada |
Anderson R.C.,Manta Marine Pvt Ltd |
Soto D.X.,Environment Canada |
Soto D.X.,University of New Brunswick |
Wassenaar L.I.,Environment Canada
PLoS ONE | Year: 2012
Large numbers of the Globe Skimmer dragonfly (Pantala flavescens) appear in the Maldives every October-December. Since they cannot breed on these largely waterless islands, it has recently been suggested that they are "falling out" during a trans-oceanic flight from India to East Africa. In addition, it has been suggested that this trans-oceanic crossing is just one leg of a multi-generational migratory circuit covering about 14,000-18,000 km. The dragonflies are presumed to accomplish this remarkable feat by riding high-altitude winds associated with the Inter-tropical Convergence Zone (ITCZ). While there is considerable evidence for this migratory circuit, much of that evidence is circumstantial. Recent developments in the application of stable isotope analyses to track migratory dragonflies include the establishment of direct associations between dragonfly wing chitin δ2H values with those derived from long-term δ2H precipitation isoscapes. We applied this approach by measuring wing chitin δ2H values in 49 individual Pantala flavescens from the November-December migration through the Maldives. Using a previously established spatial calibration algorithm for dragonflies, the mean wing δ2H value of -117±16 ‰ corresponded to a predicted mean natal ambient water source of -81 ‰, which resulted in a probabilistic origin of northern India, and possibly further north and east. This strongly suggests that the migratory circuit of this species in this region is longer than previously suspected, and could possibly involve a remarkable trans-Himalayan high-altitude traverse. © 2012 Hobson et al.
Romanov E.V.,PROSPER Project PROSpection et habitat des grands PElagiques de la ZEE de La Reunion |
Potier M.,French National Center for Scientific Research |
Anderson R.C.,Manta Marine Pvt. Ltd |
Quod J.P.,Agence pour la Recherche et la Valorisation Marines ARVAM Pareto |
And 3 more authors.
Journal of the Marine Biological Association of the United Kingdom | Year: 2015
Recent observations of unusual mass stranding and mortality of two Indian Ocean crustacean species, the swimming crab Charybdis smithii and the mantis shrimp Natosquilla investigatoris, are documented and analysed. Strandings of C. smithii were observed for the first time in the equatorial Indian Ocean, the main area of its pelagic distribution. Strandings of mantis shrimps are reported from throughout the western Indian Ocean; occurrences of mass stranding in the Maldives Archipelago mark an extension of the known range of N. investigatoris into the central Indian Ocean. Mortality of crabs probably represents a ‘catastrophic event’. In contrast, mantis shrimp strandings, which were always associated with a sudden increase of its biomass (‘blooms’), are apparently post-reproduction mortalities indicating potential semelparity for this species. Copyright © Marine Biological Association of the United Kingdom 2015
Kershaw F.,Columbia University |
Kershaw F.,American Museum of Natural History |
Leslie M.S.,American Museum of Natural History |
Leslie M.S.,National Oceanic and Atmospheric Administration |
And 14 more authors.
Journal of Heredity | Year: 2013
Accurate identification of units for conservation is particularly challenging for marine species as obvious barriers to gene flow are generally lacking. Bryde's whales (Balaenoptera spp.) are subject to multiple human-mediated stressors, including fisheries bycatch, ship strikes, and scientific whaling by Japan. For effective management, a clear understanding of how populations of each Bryde's whale species/subspecies are genetically structured across their range is required. We conducted a population-level analysis of mtDNA control region sequences with 56 new samples from Oman, Maldives, and Bangladesh, plus published sequences from off Java and the Northwest Pacific. Nine diagnostic characters in the mitochondrial control region and a maximum parsimony phylogenetic analysis identified 2 genetically recognized subspecies of Bryde's whale: the larger, offshore form, Balaenoptera edeni brydei, and the smaller, coastal form, Balaenoptera edeni edeni. Genetic diversity and differentiation indices, combined with a reconstructed maximum parsimony haplotype network, indicate strong differences in the genetic diversity and population structure within each subspecies. Discrete population units are identified for B. e. brydei in the Maldives, Java, and the Northwest Pacific and for B. e. edeni between the Northern Indian Ocean (Oman and Bangladesh) and the coastal waters of Japan. © The American Genetic Association 2013. All rights reserved.
PubMed | University of New South Wales and Manta Marine Pvt Ltd
Type: | Journal: Zootaxa | Year: 2014
Siganus insomnis sp. nov. is described from the Maldives, Sri Lanka and southern India. It most closely resembles S. lineatus (Valenciennes) from the Western Pacific but differs in coloration, principally in that most if not all of the bronze bands on its mid and upper sides continue horizontally and unbroken through to the nape and opercular slit. By contrast, in S. lineatus, typically the anterior area below the spinous dorsal fin down to the mid-sides is irregularly marked with golden bronze spots, commas, or a maze of contorted lines. S. guttatus (Bloch) is the third member of this group of sibling species; its sides are covered with orange to bronze-gold spots. It is distributed throughout S.E. Asia, i.e., it occupies a geographic position between the areas inhabited by S. lineatus and S. insomnis. Thus the gene pools of S. lineatus and S. insomnis are quarantined from one another by distance and the intervening presence of S. guttatus in S.E. Asia. The geographical separation of the populations of S. lineatus and S. insomnis from one another is reinforced by the absence of suitable, coralline habitats for these species in the western half of the Bay of Bengal.
Sattar S.A.,Marine Research Center |
Andrefouet S.,Institute Of Recherche Pour Le Developpement |
Ahsan M.,Marine Research Center |
Shiham Adam M.,Marine Research Center |
And 2 more authors.
Atoll Research Bulletin | Year: 2012
Fishing trips made in Central Maldives in 2006-2007 provided fresh insights on the status of the Republic of Maldives coral reef fishery. Previous assessments had been made nearly two decades prior and an update on the resource status was needed. Indeed, tourist resorts have multiplied in Maldives in the past 20 years, resulting in an increased demand for local fresh fish that resorts routinely purchase directly from local fishermen. To assess the impacts of tourism demand on fishery and fish populations, fishing locations, fishing gears, catch compositions and catch lengths are reported here for atolls of the Central Maldives. Data from the 2006-2007 fishing trips are compared to data available from Malé fish markets and to historical 1989/1991 fishing campaign data to assess potential changes in fish population structures and catches. Despite different sampling strategies, comparisons of catch data do not suggest any alarming trend. Catch composition is similar, and the most frequent species captured remain of similar sizes. Yields per square kilometre of fished reefs (1.7-3.5 tonnes/km 2) remain below published thresholds for unsustainable fisheries. Nevertheless, signs of changes should be taken seriously in the perspective of increased demand from the local tourism industry and increased value of fresh and processed fish for export markets.
Anderson R.C.,Manta Marine Pvt Ltd. |
Adam M.S.,Marine Research Center |
Goes J.I.,Bigelow Laboratory for Ocean Sciences
Fisheries Oceanography | Year: 2011
The Republic of Maldives in the central Indian Ocean is home to large numbers of manta rays, Manta alfredi. They are known to undertake seasonal migrations within the Maldives, but these movements have not been well documented. The aims of this study were to map the seasonal distribution of manta rays within the Maldives, and to provide some indications of the physical and biological oceanographic processes affecting their distribution. The seasonal distribution of mantas was determined from a national survey of fishermen, interviews with experienced divers and personal observations. The data demonstrate that the distribution of mantas is strongly influenced by the seasonally reversing monsoon currents. Mantas occur on the downstream sides of the atolls, and are rare on the upstream sides, switching sides biannually as the monsoon currents change direction. These seasonally alternating currents are driven by monsoon winds which also alternate according to the season, and bring clear oceanic water to the upstream sides of the atolls. As the currents pass over the Maldives ridge, nutrient-rich waters are lifted to the surface, promoting phytoplankton blooms (as demonstrated by the distribution of chlorophyll-a) on the downstream sides of the atolls. This manifestation of the island mass effect supports an abundance of zooplankton, which in turn supports the manta rays. © 2011 Blackwell Publishing Ltd.