Genetic changes in an Atlantic salmon population resulting from escaped juvenile farm salmon

A study was made of rivers in Northwest Ireland where escapes of adult Atlantic salmon (Salmo salar) are known to have occurred from adjacent sea cages. Two markers that showed substantial frequency differences between these farm and wild populations were used: an Ava II-B mtDNA haplotype and allele E at minisatellite locus Ssa-A45/2/1. Farmed populations also showed a significant reduction in mean heterozygosity over the three minisatellite loci examined. Independent occurrence of mtDNA and minisatellite DNA markers in several juvenile samples indicated interbreeding of escaped farm salmon with wild salmon. The proportion of juveniles of maternal farm parentage in two rivers ranged from 18% in 1993 to 2% in 1995 with an average of 7% in both rivers (1993-1995) and a maximum frequency of 70% in an individual sample. Only a small proportion of 29 000 adult farm salmon that escaped in spring 1992 appear to have bred successfully in the rivers studied. Juveniles of farmed parentage survived to at least the 1+ summer stage, but the subsequent fate of these fish could not be determined in the time period of the study.

Download Full-text

Genetic history of the population of Atlantic salmon, Salmo salar L., under restoration in the Connecticut River, USA

ICES Journal of Marine Science ◽

10.1016/j.icesjms.2006.04.003 ◽

2006 ◽

Vol 63 (7) ◽

pp. 1286-1289 ◽

Cited By ~ 3

Author(s):

Fernando Ayllon ◽

Jose L. Martinez ◽

Francis Juanes ◽

Stephen Gephard ◽

Eva Garcia-Vazquez

Keyword(s):

Atlantic Salmon ◽

Connecticut River ◽

River Population ◽

Tissue Samples ◽

Genetic Changes ◽

Penobscot River ◽

Salmon Population ◽

Donor Population ◽

History Of ◽

Locus Number

Abstract The Connecticut River lost its Atlantic salmon population as a result of human activity 200 years ago. Cultured stocks, derived mainly from the Penobscot River, were employed to restore the population, and an annual run of salmon has been successfully re-established, although the population is not yet self-sustaining. We examined variation at microsatellite loci in historical scale and modern tissue samples to evaluate the degree and direction of any genetic changes that have occurred in the introduced population. The current genetic pattern of the Connecticut River population is very similar to that of its Penobscot River donor population. We found no differences in heterozygosity, mean number of alleles per locus, number of migrants, or FST values between the two populations, suggesting that no genetic bottlenecks had occurred during the restoration programme.

Download Full-text

Rapid sex-specific evolution of age at maturity is shaped by genetic architecture in Atlantic salmon

10.1101/317255 ◽

2018 ◽

Author(s):

Y. Czorlich ◽

T. Aykanat ◽

J. Erkinaro ◽

P. Orell ◽

CR. Primmer

Keyword(s):

Atlantic Salmon ◽

Adaptive Evolution ◽

Genetic Architecture ◽

Phenotypic Diversity ◽

Age At Maturity ◽

Evolutionary Patterns ◽

Genetic Changes ◽

Evolutionary Response ◽

Fitness Trait ◽

Salmon Population

AbstractUnderstanding the mechanisms by which populations adapt to their environments is a fundamental aim in biology. However, it remains challenging to identify the genetic basis of traits, provide evidence of genetic changes and quantify phenotypic responses. Age at maturity in Atlantic salmon represents an ideal trait to study contemporary adaptive evolution as it has been associated with a single locus in the vgll3 region, and has also strongly changed in recent decades. Here, we provide an empirical example of contemporary adaptive evolution of a large effect locus driving contrasting sex-specific evolutionary responses at the phenotypic level. We identified an 18% decrease in the vgll3 allele associated with late maturity (L) in a large and diverse salmon population over 36 years, induced by sex-specific selection during the sea migration. Those genetic changes resulted in a significant evolutionary response in males only, due to sex-specific dominance patterns and vgll3 allelic effects. The vgll3 allelic and dominance effects differed greatly in a second population and were likely to generate different selection and evolutionary patterns. Our study highlights the importance of knowledge of genetic architecture to better understand fitness trait evolution and phenotypic diversity. It also emphasizes the potential role of adaptive evolution in the trend toward earlier maturation observed in numerous Atlantic salmon populations worldwide.

Download Full-text

Size selection from fishways and potential evolutionary responses in a threatened Atlantic salmon population

River Research and Applications ◽

10.1002/rra.3155 ◽

2017 ◽

Vol 33 (7) ◽

pp. 1004-1015 ◽

Cited By ~ 8

Author(s):

G. A. Maynard ◽

M. T. Kinnison ◽

J. D. Zydlewski

Keyword(s):

Atlantic Salmon ◽

Size Selection ◽

Salmon Population

Download Full-text

Variation in Male Parr Maturation Within and Among Populations of Atlantic Salmon, Salmo salar

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f86-154 ◽

1986 ◽

Vol 43 (6) ◽

pp. 1242-1248 ◽

Cited By ~ 111

Author(s):

Ransom A. Myers ◽

Jeffrey A. Hutchings ◽

R. John Gibson

Keyword(s):

Atlantic Salmon ◽

Salmo Salar ◽

Fork Length ◽

Detectable Effect ◽

Genetic Changes ◽

Mature Parr ◽

Total Proportion ◽

Second Year ◽

Size Threshold ◽

Atlantic Salmon Parr

The covariation of growth and maturation in male Atlantic salmon parr, Salmo salar, produces a relationship characterized by a size threshold below which individuals generally do not mature. The threshold of 70–72 mm fork length is evident both within and among populations. Parr maturation can reduce growth during the second year of life by an average of 4.0%. Among-year variation in growth rate affects the yearly incidence of maturation for males at age 1 + but has no detectable effect on the total proportion of male parr maturing in a population. Increases in the proportion of mature parr in the Matamek River, Quebec, can be explained by variation in growth alone; there is no evidence for genetic changes in this population.

Download Full-text

Advances in Fish Tagging and Marking Technology

Advances in Fish Tagging and Marking Technology ◽

10.47886/9781934874271.ch6 ◽

2012 ◽

Keyword(s):

Atlantic Salmon ◽

Salmo Salar ◽

Release Time ◽

Tag Identification ◽

Penobscot River ◽

Salmon Population ◽

Declining Populations ◽

Simple Change ◽

Using Data ◽

Made In

<i>Abstract</i>.—Atlantic salmon <i>Salmo salar </i>smolts are stocked in the Penobscot River, Maine to supplement declining populations. Since 2000, approximately 550,000 hatchery smolts are annually released into the river, of which 32% of these (175,000) were marked with visual implant elastomer (VIE) tags indicating release time and location. Our study found that tag colors of adult returns were often misread due to confusion between green and yellow marks and between red and pink marks. Using data collected on mark readings in a controlled hatchery environment, we corrected for tag identification errors made in the field, thereby allowing adjustments to be made in the marked returns to accurately assess the number of returns from multiple stocking groups. When adult returns from multiple stocking groups were compared, significant differences were detected between stocking groups, including a three-fold difference between two of the stocking groups. Hence, a simple change in smolt stocking locations and times may be of value in the recovery of the Penobscot River salmon population.

Download Full-text

Stable isotopes suggest the location of marine feeding grounds of South European Atlantic salmon in Greenland

ICES Journal of Marine Science ◽

10.1093/icesjms/fsz258 ◽

2020 ◽

Vol 77 (2) ◽

pp. 593-603 ◽

Cited By ~ 1

Author(s):

Ana Almodóvar ◽

Graciela G Nicola ◽

Daniel Ayllón ◽

Clive N Trueman ◽

Ian Davidson ◽

...

Keyword(s):

Atlantic Salmon ◽

Population Decline ◽

Migration Route ◽

North Atlantic Current ◽

Migration Routes ◽

Δ13c And Δ15n ◽

Δ13c Values ◽

The North ◽

Salmon Population ◽

And Migration

Abstract Historical data on the oceanic distribution and migration routes of southernmost Atlantic salmon Salmo salar populations from Europe are almost non-existent, as no rigorous tagging initiatives have been conducted. Here, we used stable isotope data (δ13C and δ15N) of historic scale collections to identify the potential marine feeding areas of the largest salmon population in the Iberian Peninsula. Data were compared with published datasets from Northern Ireland, Wales, south England, and northeast UK coast, which correspond to series between 15- and 33-year long within the time period from 1958 to 2009. Temporal covariation in sea surface temperature, primary productivity, and δ13C values suggests that feeding areas of Iberian salmon are located around Greenland, both in the Labrador and the Irminger seas. Furthermore, δ13C values of Atlantic salmon from Canadian rivers reported in the literature are similar to those found in individuals from Spanish rivers. Our results suggest that Iberian salmon follow a westerly migration route towards Greenland instead of following the easterly branch of the North Atlantic current into the Norwegian Sea. Characterization of feeding patterns and migration routes might help to understand the causes of ongoing population decline and establish targeted conservation programmes for threatened Iberian salmon.

Download Full-text