Resolving the genetic structure of striped marlin, Kajikia audax, in the Pacific Ocean through spatial and temporal sampling of adult and immature fish

2011 ◽  
Vol 68 (11) ◽  
pp. 1861-1875 ◽  
Author(s):  
Catherine M. Purcell ◽  
Suzanne Edmands

Spatial genetic structure in the highly migratory striped marlin ( Kajikia audax ) was examined using nuclear (microsatellite) and mitochondrial (control region sequences) DNA markers. While previous studies on striped marlin were limited by sampling design and sample size, this study employed a multiyear concurrent sampling scheme to collect tissue from seven locations representative of the species’ range in the Pacific: Japan, Hawaii, Southern California, Mexico, Central America, New Zealand, and Australia. Mature and immature specimens were analyzed separately to evaluate life-stage-specific population structure and movements. Microsatellite and sequence results revealed small but significant overall spatial subdivision (FST = 0.0145 and KST = 0.06995, respectively). Pairwise microsatellite analyses (n = 1199) revealed four groups: (1) Japan – Immature Hawaii – Southern California, (2) Mature Hawaii, (3) Mexico – Central America, and (4) Australia – New Zealand. Mitochondrial sequence analysis (n = 451) showed similar patterns; however, no significant differentiation was found between groups 1 and 2. This enhanced resolution of geographic genetic structure is important for understanding the complex migration patterns in this species. Moreover, the consistency among independent genetic studies on striped marlin provides strong support for management of at least three clearly delineated Pacific stocks.

2010 ◽  
Vol 88 (6) ◽  
pp. 553-566 ◽  
Author(s):  
Kaela B. Beauclerc ◽  
Bob Johnson ◽  
Bradley N. White

Peripheral populations of widespread species are often considered unworthy of conservation efforts; however, they may be adapted to the conditions found at the range edge and are therefore important to the future evolutionary potential of the species. Blanchard’s Cricket Frog (Acris blanchardi Harper, 1947) is widespread and abundant throughout the central United States, but is declining at the northern edge of its range. To assess the distinctiveness and conservation value of the northern populations, we investigated the spatial genetic structure and phylogeography of this anuran using mitochondrial control region sequences. Analysis of 479 individuals identified 101 haplotypes, with relatively low nucleotide diversity. Two moderately divergent clades were found. One was restricted to the southwest, which was probably a refugium during the Pleistocene, whereas the other occurred primarily across the north and is likely the result of postglacial colonization. The genetic distinctiveness of northern populations indicates the potential for adaptive differences of individuals in this region relative to those in the south. We therefore conclude that conservation efforts are justified for the declining northern populations of Blanchard’s Cricket Frog, and we use the spatial genetic structure described here to develop specific recommendations for this anuran.


2015 ◽  
Vol 24 (2) ◽  
pp. 296-309 ◽  
Author(s):  
Patrick M. A. James ◽  
Barry Cooke ◽  
Bryan M. T. Brunet ◽  
Lisa M. Lumley ◽  
Felix A. H. Sperling ◽  
...  

2014 ◽  
Vol 63 (1-6) ◽  
pp. 149-158 ◽  
Author(s):  
C. Z. Quiñones-Pérez ◽  
S. L. Simental-Rodríguez ◽  
C. Sáenz-Romero ◽  
J. P. Jaramillo-Correa ◽  
C. Wehenkel

Abstract In natural plant populations, the spatial genetic structure (SGS) is occasionally associated with evolutionary and ecological features such as the mating system, individual fitness, inbreeding depression and natural selection of the species of interest. The very rare Mexican P. chihuahuana tree community covers an area no more than 300 ha and has been the subject of several studies concerning its ecology and population genetics. The overall aim of most of these studies has been to obtain data to help design preservation and conservation strategies. However, analysis of the fine-scale SGS in this special forest tree community has not yet been conducted, which might help enrich the above mentioned conservation programs. In this study, we examined the SGS of this community, mostly formed by P. chihuahuana Martínez, Pinus strobiformis Ehrenberg ex Schlechtendah, Pseudotsuga menziesii (Mirb.) Franco, and Populus tremuloides Michx, in 14 localities at both the fine and large scales, with the aim of obtaining a better understanding of evolutionary processes. We observed a non-significant autocorrelation in fine-scale SGS, suggesting that the genetic variants of all four tree species are randomly distributed in space within each sampled plot of 50 x 50 m. At the larger scale, the autocorrelation was highly significant for P. chihuahuana and P. menziesii, probably as a result of insufficient gene flow due to the extreme population isolation and small sizes. For these two species our results provided strong support for the theory of isolation by distance.


2012 ◽  
Vol 93 (6) ◽  
pp. 1512-1524 ◽  
Author(s):  
Sarah A. Sonsthagen ◽  
Chadwick V. Jay ◽  
Anthony S. Fischbach ◽  
George K. Sage ◽  
Sandra L. Talbot

Abstract Pacific walruses (Odobenus rosmarus divergens) occupying shelf waters of Pacific Arctic seas migrate during spring and summer from 3 breeding areas in the Bering Sea to form sexually segregated nonbreeding aggregations. We assessed genetic relationships among 2 putative breeding populations and 6 nonbreeding aggregations. Analyses of mitochondrial DNA (mtDNA) control region sequence data suggest that males are distinct among breeding populations (ΦST = 0.051), and between the eastern Chukchi and other nonbreeding aggregations (ΦST = 0.336–0.449). Nonbreeding female aggregations were genetically distinct across marker types (microsatellite FST = 0.019; mtDNA ΦST = 0.313), as was eastern Chukchi and all other nonbreeding aggregations (microsatellite FST = 0.019–0.035; mtDNA ΦST = 0.386–0.389). Gene flow estimates are asymmetrical from St. Lawrence Island into the southeastern Bering breeding population for both sexes. Partitioning of haplotype frequencies among breeding populations suggests that individuals exhibit some degree of philopatry, although weak. High levels of genetic differentiation among eastern Chukchi and all other nonbreeding aggregations, but considerably lower genetic differentiation between breeding populations, suggest that at least 1 genetically distinct breeding population remained unsampled. Limited genetic structure at microsatellite loci between assayed breeding areas can emerge from several processes, including male-mediated gene flow, or population admixture following a decrease in census size (i.e., due to commercial harvest during 1880–1950s) and subsequent recovery. Nevertheless, high levels of genetic diversity in the Pacific walrus, which withstood prolonged decreases in census numbers with little impact on neutral genetic diversity, may reflect resiliency in the face of past environmental challenges.


2021 ◽  
Vol 7 ◽  
Author(s):  
Delphine B. H. Chabanne ◽  
Simon J. Allen ◽  
William Bruce Sherwin ◽  
Hugh Finn ◽  
Michael Krützen

Identifying population structure and boundaries among communities of wildlife exposed to anthropogenic threats is key to successful conservation management. Previous studies on the demography, social and spatial structure of Indo-Pacific bottlenose dolphins (Tursiops aduncus) suggested four nearly discrete behavioral communities in Perth metropolitan waters, Western Australia. We investigated the genetic structure of these four communities using highly polymorphic microsatellite markers and part of the hypervariable segment of the mitochondrial control region. Overall, there was no evidence of spatial genetic structure. We found significant, yet very small genetic differentiation between some communities, most likely due to the presence of highly related individuals within these communities. Our findings of high levels of contemporary migration and highly related individuals among communities point toward a panmictic genetic population with continuous gene flow among each of the communities. In species with slow life histories and fission-fusion dynamics, such as Tursiops spp., genetic and socio-spatial structures may reflect different timescales. Thus, despite genetic similarity, each social community should be considered as a distinct ecological unit to be conserved because they are exposed to different anthropogenic threats and occur in different ecological habitats, social structure being as important as genetic information for immediate conservation management. The estuarine community, in particular, is highly vulnerable and appropriate conservation measures are needed in order to maintain its connectivity with the adjacent, semi-enclosed coastal communities.


2014 ◽  
Vol 41 (1) ◽  
pp. 1-16 ◽  
Author(s):  
B. J. Gill

In December 1884 Charles Francis Adams (1857–1893) left Illinois, USA, by train for San Francisco and crossed the Pacific by ship to work as taxidermist at Auckland Museum, New Zealand, until February 1887. He then went to Borneo via several New Zealand ports, Melbourne and Batavia (Jakarta). This paper concerns a diary by Adams that gives a daily account of his trip to Auckland and the first six months of his employment (from January to July 1885). In this period Adams set up a workshop and diligently prepared specimens (at least 124 birds, fish, reptiles and marine invertebrates). The diary continues with three reports of trips Adams made from Auckland to Cuvier Island (November 1886), Karewa Island (December 1886) and White Island (date not stated), which are important early descriptive accounts of these small offshore islands. Events after leaving Auckland are covered discontinuously and the diary ends with part of the ship's passage through the Dutch East Indies (Indonesia), apparently in April 1887. Adams's diary is important in giving a detailed account of a taxidermist's working life, and in helping to document the early years of Auckland Museum's occupation of the Princes Street building.


2018 ◽  
Vol 21 (2) ◽  
pp. 89-95
Author(s):  
Vili Nosa ◽  
Kotalo Leau ◽  
Natalie Walker

ABSTRACT Introduction: Pacific people in New Zealand have one of the highest rates of smoking.  Cytisine is a plant-based alkaloid that has proven efficacy, effectiveness and safety compared to a placebo and nicotine replacement therapy (NRT) for smoking cessation.  Cytisine, like varenicline, is a partial agonist of nicotinic acetylcholine receptors, and blocks the rewarding effects of nicotine. Cytisine is naturally found in some plants in the Pacific region, and so may appeal to Pacific smokers wanting to quit. This paper investigates the acceptability of cytisine as a smoking cessation product for Pacific smokers in New Zealand, using a qualitative study design. Methods: In December 2015, advertisements and snowball sampling was used to recruit four Pacific smokers and three Pacific smoking cessation specialists in Auckland, New Zealand. Semi-structured interviews where undertaken, whereby participants were asked about motivations to quit and their views on smoking cessation products, including cytisine (which is currently unavailable in New Zealand). Interviews were recorded and transcribed verbatim, with thematic analysis conducted manually. Findings: Pacific smokers reported wanting to quit for loved ones and family, but did not find currently available smoking cessation products effective. Almost all participants had not previously heard of cytisine, but many of the Pacific smokers were keen to try it. Participants identified with cytisine on a cultural basis (given its natural status), but noted that their use would be determined by the efficacy of the medicine, its cost, side-effects, and accessibility. They were particularly interested in cytisine being made available in liquid form, which could be added to a “smoothie” or drunk as a “traditional tea”.  Participants thought cytisine should be promoted in a culturally-appropriate way, with packaging and advertising designed to appeal to Pacific smokers. Conclusions: Cytisine is more acceptable to Pacific smokers than other smoking cessation products, because of their cultural practices of traditional medicine and the natural product status of cytisine.


1986 ◽  
Vol 18 (11) ◽  
pp. 1-9 ◽  
Author(s):  
Willard Bascom

Southern California, with a coastal population of 12 million people, releases about 4.4 million cubic meters of treated waste water into the Pacific every day via outfalls that discharge three to six kilometers offshore at a depth of 60 meters. Diffusers cause each liter of waste to be diluted by 150 liters of deep cool water preventing it from reaching the surface except for short periods in winter. Data on the constituents of the four largest waste streams are presented and a brief account of the research done by the Southern California Coastal Water Research Project is given. Although the waste water now discharged meets rigorous state standards (with minor exceptions) and the steady improvement in sea conditions over a decade has been well documented, there is a continuing debate over whether our coastal waters are adequately protected. This is primarily because the damaging effects of DDT and PCBs that were discharged more than 14 years ago have been slow to go away. Although the amounts of DDT and PCB in sea animals are only one- tenth what they were a decade ago they tend to obscure the value of the improvements and the present discharge practices. The alternatives to sea disposal seem likely to cause greater damage to the overall environment.


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