Prospects for a genetic management strategy to control Gyrodactylus salaris infection in wild Atlantic salmon (Salmo salar) stocks

2010 ◽  
Vol 67 (1) ◽  
pp. 121-129 ◽  
Author(s):  
Ragnar Salte ◽  
Hans Bernhard Bentsen ◽  
Thomas Moen ◽  
Smita Tripathy ◽  
Tor Andreas Bakke ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Management Strategy ◽  
Control Measure ◽  
Survival Rates ◽  
Challenge Test ◽  
Genetic Management ◽  
Genetic Trait ◽  
Atlantic Salmon Salmo Salar ◽  
Sib Families

We estimated additive genetic variation and heritability of survival after Gyrodactylus salaris infection from survival records in a pedigreed family material of wild Atlantic salmon ( Salmo salar ) in a controlled challenge test. We used a statistical model that distinguishes between survival time for the fish that died and the ability to survive the entire test as two separate traits. Eleven of the 49 full-sib families suffered 100% mortality, 15 families had between 10% and 25% survival, and the four least affected families had survival rates between 36% and 48%. Estimated heritability of survival on the liability scale was 0.32 ± 0.10. Time until death for fish that died during the test and the ability to survive the entire test were not expressions of the same genetic trait. Simply selecting survivors as parents for the next generation is expected to more than double the overall survival rate in only one generation, given similar exposure to the parasite. Improving the genetic capacity to survive the infection will probably not eradicate the parasite, but when used as a disease control measure, such improvement may contain the infection at a level where the parasite ceases to be a major problem.

Estimated Escapement of Atlantic Salmon (Salmo salar) for Maximum Smolt Production in Rivers of Different Productivity

1979 ◽  
Vol 36 (2) ◽  
pp. 132-140 ◽  
Author(s):  
Philip E. K. Symons
Keyword(s):  
Atlantic Salmon ◽  
Water Temperature ◽  
Salmo Salar ◽  
Fishery Management ◽  
Survival Rates ◽  
Atlantic Salmon Salmo Salar ◽  
Egg Deposition ◽  
Average Maximum ◽  
Game Fish ◽  
Space Requirements

Smolt production at different egg deposition densities is estimated from data on survival rates and space requirements of juvenile Atlantic salmon (Salmo salar) reported in the literature. Average maximum production of smolts is estimated to be approximately 5/100 m2 for 2+ smolts, 2/100 m2 for 3+ smolts, and 1/100 m2 for 4+ smolts. Minimum egg depositions recommended for production of these numbers of smolts are 220/100 m2, 165–220/100 m2, and 80/100 m2 for each age of smolts, respectively. The escapement of adults required to produce these depositions must be estimated from observed average weights of returning females and a reported fecundity of Atlantic salmon between 1650 and 1760 eggs/kg of female. With the exception of Ungava rivers, average smolt age in any particular river can be estimated from the number of days per year on which water temperature reaches or exceeds 7 °C. Key words: fishery resources, fishery management, production (biological), escapement, survival, game fish, freshwater fish, rivers

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.

scholarly journals Interannual changes in recruitment of the Atlantic salmon (Salmo salar) population in the River Oir (Lower Normandy, France): relationships with spawners and in-stream habitat

2005 ◽  
Vol 62 (4) ◽  
pp. 695-707 ◽  
Author(s):  
Jean-Luc Baglinière ◽  
Frédéric Marchand ◽  
Vincent Vauclin
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Survival Rates ◽  
Stream Habitat ◽  
Juvenile Salmon ◽  
Strongly Correlated ◽  
Data Set ◽  
Atlantic Salmon Salmo Salar ◽  
Salmon Population ◽  
The Mean

Abstract Since 1985, the dynamics of the Atlantic salmon (Salmo salar) population in the River Oir, a spawning tributary of the River Sélune (Lower Normandy, France), have been studied from a data set of parr density and the number and the age structure of migrating fish (smolts and adults). Parr densities (1.5–17.4 per 100 m2) and smolt production (0.25–9.2 per 100 m2) varied considerably from year to year. Migrating juveniles were mainly 1 year old. Abundance of parr and smolts was strongly correlated with 0+ densities. Egg-to-smolt survival rates were highly variable year on year (0.044–1.07%). During the juvenile freshwater phase, mortality was highest between the egg and the 0+ stage (97.5–99.9%). The fluctuations in abundance of juvenile salmon appear to be linked to the number and distribution of spawners within the stream during spawning, and also to the amount of silt deposition on the spawning beds. As a result, mortality was highest during the under-gravel phase, and the mean survival rate from egg to smolt was much lower than in rivers less impacted by human activities. Therefore, during the study period, the low production of smolts during some years might lead to a low renewal rate of the salmon population.

Performance of farmed, hybrid, and wild Atlantic salmon (Salmo salar) families in a natural river environment

2012 ◽  
Vol 69 (12) ◽  
pp. 1994-2006 ◽  
Author(s):  
Øystein Skaala ◽  
Kevin A. Glover ◽  
Bjørn T. Barlaup ◽  
Terje Svåsand ◽  
Francois Besnier ◽  
...  
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Growth Rates ◽  
Egg Size ◽  
Relative Survival ◽  
Hybrid Progeny ◽  
Wild Salmon ◽  
Farmed Salmon ◽  
Atlantic Salmon Salmo Salar ◽  
Sib Families

Survival, growth, and diet were compared for farmed, hybrid, and wild Atlantic salmon (Salmo salar) families from the eyed egg to the smolt stage in River Guddalselva, Hardangerfjord, Norway. All individuals that survived until the smolt stage were captured in a Wolf trap and identified to one of the 69 experimental families using microsatellite markers. Survival of farmed salmon progeny was significantly lower than that of hybrids and wild progeny. However, survival varied considerably, from 0.17% to 6.4%, among farmed families. Egg size had an important influence on survival. Half-sib hybrid families with a farmed mother had higher survival when fathered by wild salmon than by farmed salmon. The overall relative survival of farmed families compared with that of their hybrid half-sib families fell from 0.86 in the second cohort to 0.62 in the last cohort with increasing fish density. Smolts of farmed parents showed significantly higher growth rates than wild and hybrid smolts. The overlap in diet among types of crosses demonstrates competition, and farm and hybrid progeny therefore will reduce the river’s capacity for production of wild salmon.

Relative Rates of Utilization by Commercial and Sport Fisheries of Atlantic Salmon (Salmo salar) from the Miramichi River, New Brunswick

1971 ◽  
Vol 28 (3) ◽  
pp. 351-363 ◽  
Author(s):  
C. J. Kerswill
Keyword(s):  
Atlantic Salmon ◽  
New Brunswick ◽  
Salmo Salar ◽  
Considerable Increase ◽  
Survival Rates ◽  
Maritime Provinces ◽  
Average Ratio ◽  
Atlantic Salmon Salmo Salar ◽  
Total Utilization ◽  
Made In

Studies of naturally produced Atlantic salmon (Salmo salar) smolts, marked from 1950 to 1961 on tributaries of the Miramichi River by differential finclipping, indicated that commercial fisheries accounted for over 60% of their total utilization as adults. The bulk of commercial recoveries was about equally divided among Newfoundland traps, Miramichi drift nets, and Miramichi trapnets; the remainder came from various commercial catches in the Maritime Provinces and Quebec. The percentages of grilse (1 sea-year fish) in commercial catches were low, 20% for Northwest Miramichi and 17% for Southwest Miramichi fish.Anglers reported 10 and 7%, respectively, of all the recaptures of Northwest and Southwest fish. All these angling recoveries were made in freshwater sections of the Miramichi River. Grilse comprised over 70% of angling recaptures.Spawning escapement accounted for 25% of the Northwest returns, of which 60% were grilse; and 19% of the Southwest returns, of which 85% were grilse.For the total of 174,509 smolts marked on the Northwest Miramichi the minimum survival rate to fisheries and spawning escapement was 2.7%. For 78,117 Southwest smolts, the corresponding value was 2.0%. These survival rates, except for the Newfoundland commercial catches, were not adjusted for completeness of search and other factors.The average ratio of grilse to larger salmon in the adult recoveries, about 0.6:1, was much lower than in more recent smolt-tagging experiments by another worker (about 2:1) and indicated a considerable increase in the ratio for Miramichi stock between 1950 and 1968.

Phylogeographic lineages and differentiation pattern of Atlantic salmon (Salmo salar) in the Baltic Sea with management implications

1999 ◽  
Vol 56 (10) ◽  
pp. 1766-1780 ◽  
Author(s):  
Marja-Liisa Koljonen ◽  
Håkan Jansson ◽  
Tiit Paaver ◽  
Oleg Vasin ◽  
Jarmo Koskiniemi
Keyword(s):  
Atlantic Salmon ◽  
Baltic Sea ◽  
Salmo Salar ◽  
Isolation By Distance ◽  
Conservation Strategy ◽  
The Baltic Sea ◽  
Genetic Management ◽  
Atlantic Salmon Salmo Salar ◽  
Starting Point ◽  
The Baltic

The genetic structure and isolation pattern of the Atlantic salmon (Salmo salar) throughout its range in the Baltic Sea were examined as a starting point for a conservation strategy for the species in this area. The allozyme variation in seven polymorphic loci was studied in 5125 salmon from 24 rivers in four countries. A clear dichotomy was observed between stock groups from southeastern (Russia, Estonia, Latvia, southern Sweden) and northwestern (northern Finland, northern Sweden) drainage regions, corresponding to the postglacial colonisation of the Baltic Sea by two phylogeographic lineages, one from the east (the Ice Lake lineage) and one from the west (the Atlantic lineage). The geographical and genetic distances between stocks fit the one-dimensional "isolation-by-distance" model (p < 0.001). The estimated gene flow ranged from 0 to10 migrants per generation. The total diversity of hatchery stocks was 72% of that of the wild stocks. Genetically similar stock groups, phylogeographic lineages, and drainage regions are recommended for use as genetic management units in addition to stock level.

Modeling the impacts of dams and stocking practices on an endangered Atlantic salmon (Salmo salar) population in the Penobscot River, Maine, USA

2019 ◽  
Vol 76 (10) ◽  
pp. 1795-1807
Author(s):  
Justin R. Stevens ◽  
John F. Kocik ◽  
Timothy F. Sheehan
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Survival Rates ◽  
Scenario Planning ◽  
Accurate Estimate ◽  
Survival Model ◽  
Spatially Explicit ◽  
Atlantic Salmon Salmo Salar ◽  
Penobscot River ◽  
Flow Dependency

Dams challenge Atlantic salmon (Salmo salar) conservation, while hatcheries are a common but poorly evaluated recovery tool. We developed a spatially explicit smolt survival model for the Penobscot River, Maine, USA, population. By partitioning survival through dams (with flow dependency), free-flowing river reaches, and the estuary (with dam dependency), the model quantified how these factors influenced the number of fish entering the ocean. Given historical impounded conditions, 74%–22% of hatchery smolts released entered the ocean annually from 1970 to 2012. Of 19.7 million smolts stocked, 7.7 million entered the ocean (39%). Survival was most variable at dams (range 95% to 63%), followed by in-river (range 98% to 70%) and estuary (range 88% to 82%). Overall, lower-river stocking sites resulted in significantly higher numbers at ocean entry because of fewer dam encounters and shorter migrations. Higher flows also resulted in reduced losses. By reconstructing these freshwater and estuary dynamics, the model provides a more accurate estimate of ocean recruitment annually and can be used for scenario planning of future stocking locations relative to predicted flows while being adaptable to new survival rates.

Analysis of Growth of Atlantic Salmon (Salmo salar) in a Small Newfoundland River

1978 ◽  
Vol 35 (1) ◽  
pp. 60-68 ◽  
Author(s):  
E. M. P. Chadwick ◽  
T. R. Porter ◽  
P. Downton
Keyword(s):  
Atlantic Salmon ◽  
Salmo Salar ◽  
Survival Rates ◽  
River System ◽  
First Year ◽  
Commercial Fishery ◽  
Atlantic Salmon Salmo Salar ◽  
Dependent Relationship ◽  
Survival Density ◽  
Sea Survival

Growth and sea survival rates decreased with increasing smolt age, with survival being 12, 6, and 3% for 3+, 4+, and 5+ smolt, respectively. All spawning fish were grilse, which suggests that older smolt became large salmon and were thus more vulnerable to the commercial fishery. A density-dependent relationship was observed for 3+ smolt in their 1st yr of growth, but not for older smolt; younger smolt probably spend their juvenile life in a more productive but space-limiting part of the river. Variation between river-system environments may be responsible for the opposing results of studies on Atlantic salmon (Salmo salar) life history. Key words: Salmo salar, growth, sea survival, density dependence, first-year growth, age at smoltification

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