scholarly journals Wild Estonian and Russian sea trout (Salmo trutta) in Finnish coastal sea trout catches: results of genetic mixed-stock analysis

Hereditas ◽  
2014 ◽  
Vol 151 (6) ◽  
pp. 177-195 ◽  
Author(s):  
Marja-Liisa Koljonen ◽  
Riho Gross ◽  
Jarmo Koskiniemi
Keyword(s):  
Salmo Trutta ◽  
Sea Trout ◽  
Mixed Stock Analysis ◽  
Stock Analysis ◽  
Coastal Sea ◽  
Mixed Stock

Overwintering of sea trout (Salmo trutta) in freshwater: escaping salt and low temperature or an alternate life strategy?

2007 ◽  
Vol 64 (5) ◽  
pp. 793-802 ◽  
Author(s):  
Dennis S Thomsen ◽  
Anders Koed ◽  
Christian Nielsen ◽  
Steffen S Madsen
Keyword(s):  
Low Temperature ◽  
Water Temperature ◽  
Salmo Trutta ◽  
High Salinity ◽  
Life Strategy ◽  
Low Salinity ◽  
Sea Trout ◽  
Time Period ◽  
Coastal Sea ◽  
Brown Trout Salmo Trutta

Brown trout (Salmo trutta) show large phenotypic plasticity. Juveniles may reside in their native freshwater habitat until maturation or migrate into the ocean as 1- to 3-year-old smolts. Sea-going fish (sea trout) reside at sea for 2–3 years until migrating back to their native stream for reproduction. However, immature fish may leave the ocean during their first or second winter at sea and overwinter in freshwater. The question is why does this occur? We tested the hypothesis that hypo-osmoregulatory capacity is compromised by low temperature in two coastal sea trout populations, one representing high salinity and the other, low salinity. Immature sea-run trout were caught in lower parts of two rivers during winter and acclimated to laboratory conditions. Subgroups were challenged with high salinity or low water temperature or both, and their osmoregulatory performance was investigated. Low temperature compromised the hypo-osmoregulatory ability, as indicated by insufficient compensatory adjustments of ion-transport mechanisms. Tagging experiments revealed that descent of overwintering fish into the ocean occurred over a narrow time period coincident with increasing water temperature. We conclude that overwintering in freshwater is partly driven by compromised osmoregulatory physiology, but because not all fish in a population do so, the phenomenon may also reflect diverging life strategies.

Assigning origins in a potentially mixed-stock recreational sea trout (Salmo trutta) fishery

2012 ◽  
Vol 21 (4) ◽  
pp. 541-551 ◽  
Author(s):  
Geoff Veinott ◽  
Peter A. H. Westley ◽  
Lucas Warner ◽  
Craig F. Purchase
Keyword(s):  
Salmo Trutta ◽  
Sea Trout ◽  
Mixed Stock

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.

Mixed stock analysis of a resident green turtle, Chelonia mydas, population in New Caledonia links rookeries in the South Pacific

2015 ◽  
Vol 42 (6) ◽  
pp. 488 ◽  
Author(s):  
Tyffen C. Read ◽  
Nancy N. FitzSimmons ◽  
Laurent Wantiez ◽  
Michael P. Jensen ◽  
Florent Keller ◽  
...  
Keyword(s):  
New Caledonia ◽  
South Pacific ◽  
Chelonia Mydas ◽  
Marine Conservation ◽  
Published Data ◽  
The South ◽  
Mixed Stock Analysis ◽  
Coral Sea ◽  
Stock Analysis ◽  
Mixed Stock

Context Migratory species are known to pose a challenge for conservation because it is essential to understand their complex life history in order to implement efficient conservation actions. Aims In New Caledonia, large seagrass habitats in the Grand Lagon Sud (GLS) are home to resident green turtles (Chelonia mydas) of unknown origins. To assess the stock composition in the GLS, 164 foraging turtles were sampled for genetic analysis of ~770 base pairs of the mitochondrial DNA (mtDNA) control region. Methods Foraging turtles ranging in size from 48.0 to 108.4 cm curved carapace length were captured at five different sites within the GLS between September 2012 and December 2013. To provide baseline data for mixed stock analysis, published data from rookeries were used in addition to 105 samples collected at rookeries in the d’Entrecasteaux Islands and Chesterfield Islands in New Caledonia and at Malekula Island in Vanuatu. Exact tests of population differentiation and pairwise FST estimates were used to test for differences in mtDNA haplotype frequencies. Key results These analyses indicated that rookeries in the d’Entrecasteaux Islands and Vanuatu form unique management units and that the Chesterfield Islands rookeries are linked to the Coral Sea management unit. Mixed stock analysis indicated the highest proportion (mean = 0.63) of foraging turtles originate from the d’Entrecasteaux stock. Conclusions The larger contribution is estimated to be from a large rookery from New Caledonia, but smaller contributions are suggested from other rookeries in the South Pacific. Implications Marine conservation policies in New Caledonia need to consider the links between the foraging and nesting populations of C. mydas in New Caledonia and other rookeries and foraging grounds in the Coral Sea.

scholarly journals Genetic mixed stock analysis of an interceptory Atlantic salmon fishery in the Northwest Atlantic

2016 ◽  
Vol 174 ◽  
pp. 234-244 ◽  
Author(s):  
Ian R. Bradbury ◽  
Lorraine C. Hamilton ◽  
Gerald Chaput ◽  
Martha J. Robertson ◽  
Herlé Goraguer ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Northwest Atlantic ◽  
Mixed Stock Analysis ◽  
Stock Analysis ◽  
Mixed Stock ◽  
Salmon Fishery
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