Comparative biogeography and the evolution of population structure for bottlenose and common dolphins in the Indian Ocean

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.

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

Zoologia (Curitiba) ◽

10.3897/zoologia.38.e59332 ◽

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.

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POPULATION STRUCTURE AND BIOREPRODUCTION OF BIGEYE TUNA (Thunnus obesus) IN WESTERN PART OF SUMATERA AND SOUTHERN PART OF JAVA AND NUSA TENGGARA, INDIAN OCEAN

Indonesian Fisheries Research Journal ◽

10.15578/ifrj.21.2.2015.109-116 ◽

2015 ◽

Vol 21 (2) ◽

pp. 109

Author(s):

Ali Suman ◽

Hari Eko Irianto ◽

Khairul Amri ◽

Budi Nugraha ◽

Gatut Bintoro

Keyword(s):

Population Structure ◽

Indian Ocean ◽

Bigeye Tuna ◽

Spawning Ground ◽

Thunnus Obesus ◽

Tuna Fishing ◽

The Indian Ocean ◽

Mature Fish ◽

Immature Fish ◽

Important Fish

Bigeye tuna is an important fish resource in the Indian Ocean. This species like other tuna species needs to be managed properly in both national and international levels. Therefore some data and information on population structure and bioreproduction are required for management purpose. The current research was conducted to identify the population structure and bioreproduction of bigeye tuna (<em>Thunnus obesus</em>) in west off Sumatera and south off Java and Nusa Tenggara of Indian Ocean where tuna fishing spots are important. This research was based on catch landed by fishermen from the Indian Ocean during 2010. Analysis of population structure was done using DNA genetic analyses and bioreproduction by using histology technique. Results show that the population structure of the bigeye tuna in the Indian Ocean consisted of two different sub populations namely sub population of west off Sumatra and sub population of south of Java and Nusa Tenggara waters. Most of catch (about 39%) was categorized as immature fish (GI I). The immature fish was mostly found in west off Sumatera waters, meanwhile the catch in south off Java and Nusa Tenggara waters was mostly categorized as mature fish. This result may indicate that south off Java and Nusa Tenggara waters is a spawning ground of the bigeye tuna.

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Elver Invasion, Population Structure and Growth of Marbled eels Anguilla marmorata in a Tropical River on Réunion Island in the Indian Ocean

Environmental Biology of Fishes ◽

10.1023/b:ebfi.0000005761.51686.f7 ◽

2003 ◽

Vol 68 (4) ◽

pp. 339-348 ◽

Cited By ~ 6

Author(s):

Tony Robinet ◽

Sylvie Guyet ◽

Gérard Marquet ◽

Béatrice Mounaix ◽

Jean-Michel Olivier ◽

...

Keyword(s):

Population Structure ◽

Indian Ocean ◽

Reunion Island ◽

Tropical River ◽

Anguilla Marmorata ◽

Réunion Island ◽

The Indian Ocean

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Population structure and reproduction of the hermit crab Dardanus deformis (Anomura: Diogenidae) in the Indian Ocean

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315405011847 ◽

2005 ◽

Vol 85 (4) ◽

pp. 883-887 ◽

Cited By ~ 11

Author(s):

Carlos Litulo

Keyword(s):

Population Structure ◽

Indian Ocean ◽

Hermit Crab ◽

Reproductive Activity ◽

Female Size ◽

Frequency Distributions ◽

High Incidence ◽

Egg Number ◽

The Indian Ocean ◽

Continuous Reproduction

The population structure and fecundity of the hermit crab Dardanus deformis were studied. Monthly samples were obtained between January and December 2003 at Costa do Sol, Maputo Bay, southern Mozambique. A total of 604 individuals was analysed of which 273 were males, 164 non-ovigerous females and 167 ovigerous females. The overall size–frequency distributions were unimodal, with males reaching larger sizes than both ovigerous and non-ovigerous females. Females were slightly more abundant than males, but the overall sex ratio did not differ significantly from 1:1. Dardanus deformis showed continuous reproduction throughout the study period. A small number of juveniles was obtained, suggesting that recruitment may take place in a different habitat than that occupied by the adults. The egg number increased with female size, and the high incidence of ovigerous females, may suggest a higher reproductive activity probably as a result of the rapid embryonic development in the study area.

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