scholarly journals Epinephelus Genus Groupers Population Structure and Length-Weight Relationships off Kenyan South Coast Indian Ocean Marine Waters

2016 ◽  
Vol 6 (1) ◽  
pp. 1-8
Author(s):  
B.O. Ogongo ◽  
E.C. Mwachiro ◽  
B.M. Fulanda
Keyword(s):  
Population Structure ◽  
Indian Ocean ◽  
South Coast ◽  
Marine Waters

Ostracods as Tsunami Tracers in Holocene Sequences

2010 ◽  
Vol 73 (1) ◽  
pp. 130-135 ◽  
Author(s):  
Francisco Ruiz ◽  
Manuel Abad ◽  
Luís Miguel Cáceres ◽  
Joaquín Rodríguez Vidal ◽  
María Isabel Carretero ◽  
...  
Keyword(s):  
Population Structure ◽  
Species Diversity ◽  
Indian Ocean ◽  
High Energy ◽  
Indian Ocean Tsunami ◽  
Tsunami Deposits ◽  
Shallow Marine ◽  
Juvenile Stages ◽  
Marine Areas ◽  
Age Population Structure

This review analyses the ostracod record in Holocene tsunami deposits, using an overview of the 2004 Indian Ocean tsunami impact on its recent populations and the associated tsunamigenic deposits, together with results from numerous investigations of other Holocene sequences. Different features such as the variability of the local assemblages, population density, species diversity, age population structure (e.g., percentages of adults and juvenile stages) or taphonomical signatures suggest that these microorganisms may be included amongst the most promising tracers of these high-energy events in marshes, lakes, lagoons or shallow marine areas.

Genetic population structure and connectivity in a commercially exploited and wide-ranging deepwater shark, the leafscale gulper (Centrophorus squamosus)

2012 ◽  
Vol 63 (6) ◽  
pp. 505 ◽  
Author(s):  
A. Veríssimo ◽  
J. R. McDowell ◽  
J. E. Graves
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
New Zealand ◽  
Indian Ocean ◽  
Genetic Homogeneity ◽  
Genetic Population Structure ◽  
Maturity Stage ◽  
Genetic Population ◽  
The Indian Ocean ◽  
Nuclear Loci

The leafscale gulper (Centrophorus squamosus) is a wide-ranging deepwater benthopelagic shark threatened by commercial fisheries in parts of its range. Despite concerns about resource sustainability, little is known about the population structure and connectivity between critical habitats of the leafscale gulper. This study investigates the genetic population structure and the migration patterns of C. squamosus using nuclear microsatellites and mitochondrial NADH dehydrogenase subunit 2 (ND2) gene sequences. Genetic diversity was estimated and compared among sample collections from off Ireland, Portugal, the Azores, South Africa and New Zealand. The null hypothesis of genetic homogeneity among all collections was not rejected by the nuclear loci (FST (the overall genetic differentiation among sample collections) = –0.002, P = 0.88), but we found long-term genetic divergence between New Zealand and the remaining collections at the mtDNA ND2 (FCT (genetic differentation among groups of sample collections) = 0.366, P = 0.000). Migration rate estimates indicated limited female dispersal across the Indian Ocean whereas males showed less restricted dispersal. Our results are consistent with a single genetic stock of C. squamosus and the existence of sex-biased dispersal across the Indian Ocean. Widespread genetic homogeneity at nuclear loci minimizes the loss of unique adaptive genetic diversity in the event of localised depletion. However, high local fishing mortality may have far reaching impacts given the marked sex- and maturity-stage-based habitat partitioning previously reported for C. squamosus.

INDIAN OCEAN TSUNAMI ON 26 DECEMBER 2004: NUMERICAL MODELING OF INUNDATION IN THREE CITIES ON THE SOUTH COAST OF SRI LANKA

2008 ◽  
Vol 02 (02) ◽  
pp. 133-155 ◽  
Author(s):  
J. J. WIJETUNGE ◽  
XIAOMING WANG ◽  
PHILIP L.-F. LIU
Keyword(s):  
Sri Lanka ◽  
Indian Ocean ◽  
Maximum Flow ◽  
South Coast ◽  
Indian Ocean Tsunami ◽  
The South ◽  
Tsunami Inundation ◽  
Inundation Maps ◽  
The Indian Ocean ◽  
2004 Tsunami

The 2004 Indian Ocean tsunami caused enormous loss of lives and damage to property in Sri Lanka and in several other countries bordering the Indian Ocean. One way of mitigating potential loss of lives from a similar event in the future is through early warning and quick evacuation of vulnerable coastal communities to safer areas, and such evacuation planning is usually carried out based on inundation maps. Accordingly, the present paper outlines the numerical modelling carried out to develop tsunami inundation maps on a grid of 10 m resolution for three cities on the south coast of Sri Lanka. The results give the tsunami arrival time contours and the spatial distribution of the extent of inundation, the maximum flow velocities as well as the hydrodynamic force in these three cities due to an event similar to the 2004 tsunami.

scholarly journals Genome Assembly of the Roundjaw Bonefish (Albula glossodonta), a Vulnerable Circumtropical Sportfish

2021 ◽  
Author(s):  
Brandon D. Pickett ◽  
Sheena Talma ◽  
Jessica R. Glass ◽  
Daniel Ence ◽  
Paul D. Cowley ◽  
...  
Keyword(s):  
Population Structure ◽  
Gene Flow ◽  
Indian Ocean ◽  
Genome Assembly ◽  
Anthropogenic Activities ◽  
Western Indian Ocean ◽  
Genetic Connectivity ◽  
High Quality ◽  
Widespread Species ◽  
High Quality Genome

ABSTRACTBackgroundBonefishes are cryptic species indiscriminately targeted by subsistence and recreational fisheries worldwide. The roundjaw bonefish, Albula glossodonta is the most widespread bonefish species in the Indo-Pacific and is listed as vulnerable to extinction by the IUCN’s Red List due to anthropogenic activities. Whole-genome datasets allow for improved population and species delimitation, which – prior to this study – were lacking for Albula species.ResultsWe generated a high-quality genome assembly of an A. glossodonta individual from Hawai‘i, USA. The assembled contigs had an NG50 of 4.75 Mbp and a maximum length of 28.2 Mbp. Scaffolding yielded an NG50 of 14.49 Mbp, with the longest scaffold reaching 42.29 Mbp. Half the genome was contained in 20 scaffolds. The genome was annotated with 28.3 K protein-coding genes. We then analyzed 66 A. glossodonta individuals and 38,355 SNP loci to evaluate population genetic connectivity between six atolls in Seychelles and Mauritius in the Western Indian Ocean. We observed genetic homogeneity between atolls in Seychelles and evidence of reduced gene flow between Seychelles and Mauritius. The South Equatorial Current could be one mechanism limiting gene flow of A. glossodonta populations between Seychelles and Mauritius.ConclusionsQuantifying the spatial population structure of widespread fishery species such as bonefishes is necessary for effective transboundary management and conservation. This population genomic dataset mapped to a high-quality genome assembly allowed us to discern shallow population structure in a widespread species in the Western Indian Ocean. The genome assembly will be useful for addressing the taxonomic uncertainties of bonefishes globally.

scholarly journals DNA barcoding of a tropical anguillid eel, Anguilla bicolor (Actinopterygii: Anguilliformes), in Indo-Pacific region and notes on its population structure

2021 ◽  
Vol 38 ◽  
pp. 1-7
Author(s):  
Ahmad Fathi Norarfan ◽  
Siti Shazwani Azreena Mokti ◽  
Hussein Taha ◽  
Muhamad Amin ◽  
Muhamad Ali ◽  
...  
Keyword(s):  
Population Structure ◽  
Indian Ocean ◽  
Dna Barcoding ◽  
Stock Assessment ◽  
Molecular Evidence ◽  
Pacific Region ◽  
Mitochondrial Cytochrome ◽  
The Indian Ocean ◽  
Different Populations ◽  
Important Fish

The tropical anguillid eel, Anguilla bicolor McCelland, 1844, includes two subspecies, Anguilla bicolor bicolor McCelland, 1844 and Anguilla bicolor pacifica Schmidt, 1928, and is distributed across the Indo-Pacific region. Although A. bicolor is widely distributed and recognized as an important fish resource in the Indo-Pacific region, few studies have been conducted on its genetic variation and population structure. DNA barcoding of A. bicolor specimens collected in the Indo-Pacific region was carried out in this study using mitochondrial cytochrome c oxidase subunit I. Anguilla bicolor was found to diverge genetically, which supported its classification into two different subspecies. In addition, our study showed that A. bicolor bicolor had two genetically distinct populations/groups, and these different populations co-occur geographically in Indonesia and Malaysia in the eastern Indian Ocean. Our findings suggest that the eel larvae might be transported from at least two geographically different spawning grounds in the Indian Ocean, and then recruited to and settled in the same habitats in Indonesian and Malaysian waters. The molecular evidence calls for further research on the life history, stock assessment and protection of the populations of A. bicolor bicolor in Indonesia and Malaysia.

scholarly journals Population structure and biology of shortfin mako, Isurus oxyrinchus, in the south-west Indian Ocean

2014 ◽  
Vol 65 (12) ◽  
pp. 1045 ◽  
Author(s):  
J. C. Groeneveld ◽  
G. Cliff ◽  
S. F. J. Dudley ◽  
A. J. Foulis ◽  
J. Santos ◽  
...  
Keyword(s):  
Population Structure ◽  
Indian Ocean ◽  
Fork Length ◽  
West Indian ◽  
Age And Growth ◽  
The South ◽  
South West Indian Ocean ◽  
South West ◽  
Shortfin Mako ◽  
West Indian Ocean

The population structure, reproductive biology, age and growth, and diet of shortfin makos caught by pelagic longliners (2005–10) and bather protection nets (1978–2010) in the south-west Indian Ocean were investigated. The mean fork length (FL) of makos measured by observers on longliners targeting tuna, swordfish and sharks was similar, and decreased from east to west, with the smallest individuals occurring near the Agulhas Bank edge, June to November. Nearly all makos caught by longliners were immature, with equal sex ratio. Makos caught by bather protection nets were significantly larger, males were more frequent, and 93% of males and 55% of females were mature. Age was assessed from band counts of sectioned vertebrae, and a von Bertalanffy growth model fitted to sex-pooled length-at-age data predicted a birth size (L0) of 90 cm, maximum FL (L∞) of 285 cm and growth coefficient (k) of 0.113 y–1. Males matured at 190 cm FL, aged 7 years, and females at 250 cm, aged 15 years. Litter sizes ranged from nine to 14 pups, and the presence of gravid females in bather protection nets suggested that some pupping occurred in shelf waters. Teleosts (mainly Trachurus capensis) occurred in 84% of stomachs collected on longliners, whereas elasmobranchs (63.5%) were most common in samples collected from bather protection nets, followed by teleosts (43.1%) and cephalopods (36.5%). Larger prey size may be a factor that attracts large makos to coastal waters.

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