scholarly journals RESULTS OF ATLANTIC SALMON INVESTIGATIONS IN NORTHERN DVINA RIVER DURING FISHING FOR RESEARCH PURPOSES

Fisheries ◽  
2020 ◽  
Vol 2020 (3) ◽  
pp. 64-70
Author(s):  
Igor Studenov ◽  
Dmitriy Chupov ◽  
Gennadiy Ustyuzhinskiy ◽  
Alexey Tortsev
Keyword(s):  
Atlantic Salmon ◽  
Age Structure ◽  
Innovative Development ◽  
Financing System ◽  
Fishery Research ◽  
Migration Dynamics

Since 2008, due to the change in the fishery research financing system, a decrease in research variety was noticed. After changes in fisheries legislation, the use of the "quasi-budget" financing through the implementation of "scientific" quotas was discontinued. Obvious enough, that the destruction of valuable living resources caught during research fishing led to inability of fisheries research to ensure innovative development of the branch, as well as to preserve the scope of research achieved by 2008. Despite this, the studies carried out in 1994-2014 have significantly expanded the understanding of the Atlantic salmon biology in the Northern Dvina River. The observations produced extensive material on migration dynamics, catch on effort in fishing gear, length and weight indicators, sex and age structure of spawning herds of Atlantic salmon of the Northern Dvina River.

scholarly journals Atlantic salmon (Salmo salar) smolt and early post-smolt migration and survival inferred from multi-year and multi-stock acoustic telemetry studies in the Gulf of St. Lawrence, northwest Atlantic

2018 ◽  
Vol 76 (4) ◽  
pp. 1107-1121 ◽  
Author(s):  
Gérald Chaput ◽  
Jonathan Carr ◽  
Jason Daniels ◽  
Steve Tinker ◽  
Ian Jonsen ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Survival Rates ◽  
Fork Length ◽  
Probability Of Survival ◽  
Size Dependent ◽  
Atlantic Salmon Salmo Salar ◽  
Key Points ◽  
Migration Dynamics

Abstract The migration dynamics and inter-annual variation in early at-sea survival of Atlantic salmon (Salmo salar) smolts over 14 years of study are reported for four river populations located in the Gulf of St. Lawrence (Canada). Acoustically tagged smolts were monitored at three points along their migration from freshwater to the Labrador Sea, a migration extending more than 800 km at sea and a period of 2 months. A hierarchical state-space version of the Cormack–Jolly–Seber model was used to estimate apparent survival rates from incomplete acoustic detections at key points. There was a positive size-dependent probability of survival through the freshwater and estuary areas; the odds of survival of a 16 cm smolt were 1.5–1.7 times higher than for a 13.5 cm smolt, length at tagging. Length adjusted (centred to the mean fork length of smolts during the study of 14.6 cm) survivals through the estuary and nearshore waters were estimated to range between 67 and 90% for the two river populations migrating through Chaleur Bay in contrast to lower survival estimates of 28–82% for the two populations from the neighbouring Miramichi Bay. Across the 14 years of study, survival estimates varied without trend for the populations of Chaleur Bay, but declined for the populations migrating through Miramichi Bay. Survival through the Gulf of St. Lawrence was variable but generally high among years and rivers, ranging from 96% day−1 to 99% day−1. Long term, replicated studies at multiple sites using acoustically tagged smolts can provide empirical data to examine hypotheses of the location and timing of factors contributing to smolt and post-smolt mortality of salmon at sea.

Assessment of Early Migration Dynamics of River-Specific Hatchery Atlantic Salmon Smolts

2017 ◽  
Vol 146 (6) ◽  
pp. 1279-1290 ◽  
Author(s):  
James P. Hawkes ◽  
Timothy F. Sheehan ◽  
Daniel S. Stich
Keyword(s):  
Atlantic Salmon ◽  
Early Migration ◽  
Migration Dynamics

scholarly journals Phenological and phenotypic changes in Atlantic salmon populations in response to a changing climate

2012 ◽  
Vol 69 (9) ◽  
pp. 1686-1698 ◽  
Author(s):  
Christopher D. Todd ◽  
Kevin D. Friedland ◽  
Julian C. MacLean ◽  
Bryce D. Whyte ◽  
Ian C. Russell ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Age Structure ◽  
Condition Factor ◽  
Temporal Trends ◽  
Maternal Influence ◽  
Phenotypic Changes ◽  
Changing Climate ◽  
The North ◽  
Age Related ◽  
Run Timing

Abstract Todd, C. D., Friedland, K. D., MacLean, J. C., Whyte, B. D., Russell, I. C., Lonergan, M. E., and Morrissey, M. B. 2012. Phenological and phenotypic changes in Atlantic salmon populations in response to a changing climate. – ICES Journal of Marine Science, 69: 1686–1698. Atlantic salmon (Salmo salar) of southern European origin migrating to the Norwegian Sea currently encounter anomalously high sea-surface temperatures, and returning adults are of low mean condition factor. For the River North Esk (Scotland), time-series changes in river age-structure of emigrant smolts and returning one- and two-sea-winter (1SW and 2SW) adults are assessed. A comparison of the river age-structure of returning adults (1977–1999) with that of their respective annual emigrant smolt cohorts shows no evidence of river age-related bias in survivorship at sea. Evidence is presented of a possible transgenerational, or maternal, influence (poor somatic condition of spawners) driving reduced quality of emigrant S2 smolts in the North Esk. This effect is concurrent with an influence of freshwater climate as indicated by the North Atlantic Oscillation Index (NAOI). The maternal influence and NAOI variation in the winter immediately prior to smolt migration jointly explain approximately 29 (S2) and 17% (S3), respectively, of the variation in the mean size of smolts over the period 1975–2010. Run-timing of 1SW adult cohorts returning to Scotland shows recent delays. Variation in river flow did influence mean return date for the River Tweed, but adult condition factor, which itself shows temporal trends likely to be associated with ocean climate change, was the primary significant explanatory variable for run-timing in the rivers North Esk and Tweed. Overall, in years of poorer adult condition, 1SW salmon stay at sea longer.

Life-history transitions among Atlantic salmon (Salmo salar) morphotypes

1996 ◽  
Vol 76 (1) ◽  
pp. 35-40 ◽  
Author(s):  
P. Presa ◽  
G. Blanco ◽  
E. Vázquez ◽  
J. A. Sánchez
Keyword(s):  
Atlantic Salmon ◽  
Bimodal Size Distribution ◽  
Critical Determinant ◽  
Threshold Size ◽  
Precocious Males ◽  
Migration Dynamics ◽  
River Sample ◽  
The Individual ◽  
Tagging System ◽  
Population Threshold

Morphotype distribution in Atlantic salmon populations is a critical determinant in the migration dynamics and rearing success of this species. The achievement of smolting status depends on the individual opportunities to reach the upper mode of the bimodal size distribution in the first winter. Growth of the morphotypes between 10 and 20 mo post-hatch was investigated. For this, an individual tagging system was applied on two replicates of parr from a Sella River sample (northem Spain). The smolt-like parr of the first winter (37%) became smolts in the first spring. Meanwhile, dwarf parr (25%) and precocious males (6%) did not smolt and became precocious males in the second winter. Medium-sized parr of the first winter (32%) became smolt-like parr (19%) or precocious males (13%) in the second winter. The average smolt-like sizes in the first and the second winters were 11.39 cm and 14.97 cm, respectively. These results indicate that for the Sella River sample (i) only upper modal fish smolt in the first spring, (ii) 1 + smolts are mainly females (77%), and (iii) smolting does not depend upon a population threshold size. Key words:Salmo salar, hatchery, morphotypes, smolting

scholarly journals Quantifying the Effects of Post-surgery Recovery Time on the Migration Dynamics and Survival Rates in the Wild of Acoustically Tagged Atlantic Salmon Salmo Salar Smolts

2020 ◽  
Author(s):  
Jason Daniels ◽  
Eric B. Brunsdon ◽  
Gerald Chaput ◽  
Heather Dixon ◽  
Holly Labadie ◽  
...  
Keyword(s):  
Treatment Group ◽  
Atlantic Salmon ◽  
Salmo Salar ◽  
Recovery Time ◽  
Migration Rate ◽  
Survival Rates ◽  
Negative Effects ◽  
Post Surgery ◽  
In The Wild ◽  
Migration Dynamics

Abstract Background: The experimental effects of surgically implanting fish with acoustic transmitters is likely to have negative effects on survival and behavior. Measuring the extent of these negative effects is important if we wish to extrapolate inferences from tagged animals to unmanipulated animals. In this study, we examine the effect of surgery and post-tagging recovery time on the survival and migration rate of acoustically tagged wild Atlantic Salmon (Salmo salar) smolts through freshwater, estuarine and ocean phases of migration. Four treatment groups were used: pre-smolt captured in the fall that overwintered in a hatchery and were tagged either 75 days prior to release (winter hatchery) or within 24 hours prior to release (spring hatchery) and smolt captured during the spring smolt run, tagged 24 hours prior to release and released during the day (day-released) or night (night-released).Results: The spring hatchery treatment group served as a reference treatment group such that surgical (comparison to winter hatchery treatment) and hatchery effects (comparison to day-released and night-released treatments) could both be discerned. The hatchery effect increased migration rate whereas short recovery times and captivity in a hatchery negatively affected survival. These effects were most pronounced within the first 5 days and/or 48 km downstream post-release, however, the residual surgical effects appeared to persist during the transition from the estuary into salt water.Conclusions: Even with smolts originating from the wild and spending relatively little time within the hatchery environment, post-release survival was still negatively affected. Migration speed was faster for hatchery smolts but is likely only due to their larger size. Surgical effects were most prominent during the initial migration period in freshwater and again in the transition from the estuary to saltwater which may be due to added stress during these transitional zones. As surgery related bias will likely never be completely removed from telemetry studies it is important to quantify and account for these effects in situ when making inferences on the unmanipulated component of the population.

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