Mixed stock analyses indicate population-scale connectivity effects of active dispersal by surface-pelagic green turtles

2018 ◽  
Vol 601 ◽  
pp. 215-226 ◽  
Author(s):  
BM Shamblin ◽  
BE Witherington ◽  
S Hirama ◽  
RF Hardy ◽  
CJ Nairn
Keyword(s):  
Green Turtles ◽  
Active Dispersal ◽  
Population Scale ◽  
Mixed Stock ◽  
Mixed Stock Analyses

scholarly journals Mixed-stock analyses of migratory, non-native Chinook salmon at sea and assignment to natal sites in fresh water at their introduced range in South America

2020 ◽  
Vol 22 (11) ◽  
pp. 3175-3182
Author(s):  
Selim S. Musleh ◽  
Lisa W. Seeb ◽  
James E. Seeb ◽  
Billy Ernst ◽  
Sergio Neira ◽  
...  
Keyword(s):  
South America ◽  
Fresh Water ◽  
Chinook Salmon ◽  
Introduced Range ◽  
Mixed Stock ◽  
Mixed Stock Analyses

scholarly journals Closing the gap: mixed stock analysis of three foraging populations of green turtles (Chelonia mydas) on the Great Barrier Reef

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5651
Author(s):  
Karina Jones ◽  
Michael Jensen ◽  
Graham Burgess ◽  
Johanna Leonhardt ◽  
Lynne van Herwerden ◽  
...  
Keyword(s):  
Great Barrier Reef ◽  
Spatial Ecology ◽  
New Caledonia ◽  
Relative Proportion ◽  
Chelonia Mydas ◽  
Barrier Reef ◽  
Green Turtles ◽  
Mixed Stock Analysis ◽  
Stock Analysis ◽  
Mixed Stock

A solid understanding of the spatial ecology of green turtles (Chelonia mydas) is fundamental to their effective conservation. Yet this species, like many marine migratory species, is challenging to monitor and manage because they utilise a variety of habitats that span wide spatio-temporal scales. To further elucidate the connectivity between green turtle rookeries and foraging populations, we sequenced the mtDNA control region of 278 turtles across three foraging sites from the northern Great Barrier Reef (GBR) spanning more than 330 km: Cockle Bay, Green Island and Low Isles. This was performed with a newly developed assay, which targets a longer fragment of mtDNA than previous studies. We used a mixed stock analysis (MSA), which utilises genetic data to estimate the relative proportion of genetically distinct breeding populations found at a given foraging ground. Haplotype and nucleotide diversity was also assessed. A total of 35 haplotypes were identified across all sites, 13 of which had not been found previously in any rookery. The MSA showed that the northern GBR (nGBR), Coral Sea (CS), southern GBR (sGBR) and New Caledonia (NC) stocks supplied the bulk of the turtles at all three sites, with small contributions from other rookeries in the region. Stock contribution shifted gradually from north to south, although sGBR/CS stock dominated at all three sites. The major change in composition occured between Cockle Bay and Low Isles. Our findings, together with other recent studies in this field, show that stock composition shifts with latitude as a natural progression along a coastal gradient. This phenomenon is likely to be the result of ocean currents influencing both post-hatchling dispersal and subsequent juvenile recruitment to diverse coastal foraging sites.

scholarly journals Mixed-stock analysis in the age of genomics: Rapture genotyping enables evaluation of stock-specific exploitation in a freshwater fish population with weak genetic structure

2020 ◽  
Author(s):  
Peter T. Euclide ◽  
Tom MacDougall ◽  
Jason M. Robinson ◽  
Matthew D. Faust ◽  
Chris C. Wilson ◽  
...  
Keyword(s):  
Population Structure ◽  
Fishery Management ◽  
Spatial Scales ◽  
Genomic Data ◽  
Western Basin ◽  
Eastern Basin ◽  
Mixed Stock Analysis ◽  
Stock Analysis ◽  
Mixed Stock ◽  
Mixed Stock Analyses

AbstractMixed-stock analyses using genetic markers have informed fisheries management in cases where strong genetic differentiation occurs among local spawning populations, yet many fisheries are supported by multiple spawning stocks that are weakly differentiated. Freshwater fisheries exemplify this problem, with many harvested populations supported by multiple stocks of young evolutionary age that are isolated across small spatial scales. As a result, attempts to conduct genetic mixed-stock analyses of inland fisheries have often been unsuccessful. Advances in genomic sequencing now offer the ability to discriminate among populations with weak population structure by providing the necessary resolution to conduct mixed-stock assignment among previously indistinguishable stocks. We demonstrate the use of genomic data to conduct a mixed-stock analysis of Lake Erie’s commercial and recreational walleye (Sander vitreus) fisheries and estimate the relative harvest of weakly differentiated stocks (pairwise FST < 0.01). We used RAD-capture (Rapture) to sequence and genotype individuals at 12,081 loci that had been previously determined to be capable of discriminating between western and eastern basin stocks with 95% reassignment accuracy, which was not possible in the past with microsatellite markers. Genetic assignment of 1,075 fish harvested from recreational and commercial fisheries in the eastern basin indicated that western basin stocks constituted the majority of individuals harvested during peak walleye fishing season (July – September). Composition of harvest changed seasonally, with eastern basin fish comprising much of the early season harvest (May – June). Clear spatial structure in harvest composition existed; more easterly sites contained more individuals of east basin origin than did westerly sites. Our study provides important stock contribution estimates for Lake Erie fishery management and demonstrates the power of genomic data to facilitate mixed-stock analysis in exploited fish populations with weak population structure or limited existing genetic resources.

scholarly journals Lost at sea: genetic, oceanographic and meteorological evidence for storm-forced dispersal

2012 ◽  
Vol 9 (73) ◽  
pp. 1725-1732 ◽  
Author(s):  
C. Monzón-Argüello ◽  
F. Dell'Amico ◽  
P. Morinière ◽  
A. Marco ◽  
L. F. López-Jurado ◽  
...  
Keyword(s):  
Sea Turtles ◽  
Ocean Currents ◽  
Climate Change Scenarios ◽  
Storm Events ◽  
Long Distance ◽  
Stormy Weather ◽  
Juvenile Stages ◽  
Mixed Stock ◽  
Mixed Stock Analyses

For many species, there is broad-scale dispersal of juvenile stages and/or long-distance migration of individuals and hence the processes that drive these various wide-ranging movements have important life-history consequences. Sea turtles are one of these paradigmatic long-distance travellers, with hatchlings thought to be dispersed by ocean currents and adults often shuttling between distant breeding and foraging grounds. Here, we use multi-disciplinary oceanographic, atmospheric and genetic mixed stock analyses to show that juvenile turtles are encountered ‘downstream’ at sites predicted by currents. However, in some cases, unusual occurrences of juveniles are more readily explained by storm events and we show that juvenile turtles may be displaced thousands of kilometres from their expected dispersal based on prevailing ocean currents. As such, storms may be a route by which unexpected areas are encountered by juveniles which may in turn shape adult migrations. Increased stormy weather predicted under climate change scenarios suggests an increasing role of storms in dispersal of sea turtles and other marine groups with life-stages near the ocean surface.

scholarly journals Mixed-stock analyses among migratory, non-native Chinook salmon at-sea and assignment to natal sites in freshwater at their introduced range in South America

2019 ◽  
Author(s):  
Selim S. Musleh ◽  
Lisa W. Seeb ◽  
James E. Seeb ◽  
Billy Ernst ◽  
Sergio Neira ◽  
...  
Keyword(s):  
Genetic Structure ◽  
South America ◽  
Chinook Salmon ◽  
Complex Life Cycle ◽  
Small Contribution ◽  
Genetic Analyses ◽  
Introduced Range ◽  
Southern Patagonia ◽  
Mixed Stock ◽  
Mixed Stock Analyses

AbstractInvasive species with migratory behavior and complex life cycle represent a challenge for evaluating natal sites among individuals. Private and government-sponsored initiatives resulted in the successful introduction and naturalization of Chinook salmon (Oncorhynchus tshawytscha) throughout northern and southern Patagonia in South America. These migratory fish breed in freshwater, but spend most of their life at sea feeding, forming abundant populations in several watersheds draining into the southeast Pacific Ocean. We used single nucleotide polymorphisms (SNPs) combined with genetic structure and mixed-stock analyses to evaluate natal sites of Chinook salmon at-sea caught in one estuary and two coastal locations compared to reference populations from breeding sites in freshwater. Firstly, Bayesian individual-assignment analyses revealed no genetic structure among adults caught off the coast of the Toltén River and migrating (maturing) adults caught in Toltén River estuary, suggesting they likely belong to a single population. Secondly, mixed-stock genetic analyses revealed that most at-sea Chinook salmon caught in one estuary and two coastal locations likely originated from spawners from the nearest river (90-95%), with a small contribution from adjacent watersheds (5-10%). This appears consistent with Chinook salmon populations in their native range in which juveniles migrate short distances (100-200 km) from their river of origin to coastal feeding grounds, some of which became donor of propagules for non-native Chinook salmon populations under study. Mixed-stock genetic analyses provide considerable potential to identify the population of origin of Chinook salmon mixtures caught off the coast. They also seem an appropriate proof of concept to help identify potential immigrants from other watersheds as well as migration patterns and invasion pathways in a non-native species.

Mixed-stock analysis in green turtles Chelonia mydas: mtDNA decipher current connections among west Atlantic populations

2015 ◽  
Vol 28 (2) ◽  
pp. 197-207 ◽  
Author(s):  
Juliana Costa Jordao ◽  
Ana Cristina Vigliar Bondioli ◽  
Lurdes Foresti de Almeida-Toledo ◽  
Karin Bilo ◽  
Rachel Berzins ◽  
...  
Keyword(s):  
Chelonia Mydas ◽  
Green Turtles ◽  
Mixed Stock Analysis ◽  
Stock Analysis ◽  
Mixed Stock

No indications of Atlantic salmon (Salmo salar) shoaling with kin in the Baltic Sea

2008 ◽  
Vol 65 (8) ◽  
pp. 1738-1748 ◽  
Author(s):  
Stefan Palm ◽  
Johan Dannewitz ◽  
Torbjörn Järvi ◽  
Marja-Liisa Koljonen ◽  
Tore Prestegaard ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Baltic Sea ◽  
Salmo Salar ◽  
Genetic Relatedness ◽  
The Baltic Sea ◽  
Atlantic Salmon Salmo Salar ◽  
Related Individuals ◽  
The Baltic ◽  
Mixed Stock ◽  
Mixed Stock Analyses

Several studies have shown that fish shoals may consist of closely related individuals. It has been found, for example, that released out-migrating salmon smolts tend to aggregate with kin, including when sibling groups have been reared separately. We used genetic microsatellite markers to test whether “shoals” of adult Atlantic salmon ( Salmo salar ) during the marine phase (i.e., aggregations of fish caught in drift nets at offshore feeding areas in the Baltic Sea) consisted of closely related individuals (full-siblings, half-siblings). We found no evidence of kin cohesiveness related to shoals, however. Despite a weak overall tendency for individuals assigned to the same population (river or stock) to occur together, estimates of genetic relatedness in combination with consistent heterozygote deficiencies, and results from mixed-stock analyses and assignment tests collectively indicated that shoals consisted of unrelated fish from multiple populations.

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