Genetic Variation and Fitness: A Test in a Naturalized Population of Brook Trout (Salvelinus fontinalis)

Abstract

Liskauskas, A. I>., and M. M. Ferguson. 1991. Genetic variation and fitness: a test in a naturalized population of brook trout (Saiveliwus dontina%is). Can. 1. Fish. Aquat. Sci. 48: 21 52-21 62.The relationship between enzyme heterozygosity and several components sf fitness (sine and survival) was examined in a naturalized popeslation of brook trsut (Salvelinus dontinalis) from Algonquin Provincial Park, Ontario. Significant differences in allele frequency and the number of heterozygous loci per individual were Pound among five age classes spanning most of the life history stages sf brook trsut in this population. A young sf the year (YOY) cohort sampled after a period of high natural mortality had significantly greater numbers of heterozygous loci per individual than YOY sampled shortly after emergence from redd sites. A positive association between heterszygasity and size was only found in YOY sampled in June and not in the other age classes in which sexual maturity was not a complicating factor. The association between heterozygssity and size was affected by the onset of sexual maturity. Significant negative regressions between rnultilocus or single lscus heterozygosity and size were found in mature males whereas heterozygosity was positively associated with size in females. These dissimilarities may Re the result sf differences in growth rates prim to sexual maturation and differential allocation of energy towards gametic and somatic tissue.On a &$lie la relation entre 11h6t6rog6nie des enzymes et plusieurs cornposantes de la condition physique (taille et taux de survie) dans une population acclirnat6e d'omble de fontaine (Salvelinus fmtinalis) d e e parc provincial Algsnquin (Ontario). O n a releve des differences significatives de la frbquence allelique et der nsmbre de loci hetersaygotes par poisson chez cinq classes dt3ges englobant la presque totalit6 du cycle vital de I'ornble de fontaine csmposant cette population. L16chantillonnage d'une c~h o r t e d'ombles de rnsins d'un an aprPs une periode de mortalit6 naturelle etev6e a revel6 un nsmbre laettement plus &lev$ de loci h6terozygetes par poisson comparativement aux ornbles du mGme 2ge echantillonnks peu apr6s avoir quitt6 les sillons. Une association positive entre Ith6tersgt5nie et la taille n'a et6 relevee que chez ies ambles de rnoins d'un an echantillsnn6s en juin et non chez les autres classes d'dges oO la maturite sexuelle nt6tait pas un facteur coniplexant. L'approche de la maturit6 sexuelle infiuait sur l'association eotre 11h6t6rsg6nie et la taille. On a aussi relev6 des r6gressions negatives significatives entre, d'une part, Bth6t6rog6nie A plusieurs loci et Ith6t6rsgt5saie A un seui lscus et, d'autre part, la taille des rn2les matures, tandis que 11h6t6rog6nie msntrait une association positive avec la taiile des femelles. Ces differences peuvent Gtre le resultat de variations du taux de croissance avant la rnaturite sexuelle et une repartition differentielle de I'energie pour Itelaboration de tissus ssmatiques et de gamPtes.

Anthropogenic and habitat correlates of hybridization between hatchery and wild brook trout

“…The mean (±SE) admixture across all stocked lakes after correcting for microsatellite uncertainty (Vähä and Primmer 2006) was 0.38 ± 0.013 for STRUCTURE and 0.36 ± 0.015 for BAPS, yet few lakes displayed intermediate admixture; roughly half of the lakes had mean admixture above 0.57 or 0.52 for the STRUCTURE and BAPS methods, respectively, while the other half demonstrated admixture levels below 0.22 or 0.13, respectively (Table 1). Within-lake variance in admixture was generally low (0.0016 to 0.016 for STRUCTURE and 0.0006 to 0.050 for BAPS), which is to be expected because in most cases at least seven generations have passed (Liskauskas and Ferguson 1991) since stocking ceased.…”

Enzyme heterozygosity and growth in rainbow trout: genetic and physiological explanations

“…However, studies with another species of salmonid fish, indicate that sexspecific associations between heterozygosity and body size are not an artifact of laboratory rearing. Mature male brook trout, Salvelinus fontinalis, from Mykiss Lake, Algonquin Provincial Park, Ontario show significant negative associations between multilocus heterozygosity and fork length whereas heterozygosity was positively associated with fork length in females (Liskauskas & Ferguson, 1991). Differences in growth rates prior to sexual maturation and differential allocation of energy towards gametic and somatic tissue have been proposed as mechanisms for the different relationships between body size and heterozygosity in male and female brook trout.…”

The independence of enzyme heterozygosity and life-history traits in natural populations of Salvelinus fontinalis (brook trout)

“…Allozyme variation at six of 42 enzyme-coding loci examined has also been documented within and among these populations (Ferguson et al, 1991 Hutchings, 1990, for stream characteristics). Collections were made 7-10 days prior to reproduction (i.e.…”

“…The products of six loci were polymorphic within and among populations (Ferguson et a!., 1991). These enzymes, specific loci and their respective alleles were alcohol dehydrogenase (ADH: -29, -100), glycerol-3-phosphate dehydrogenase (G3P-1: 100, 167), isocitrate dehydrogenase (IDH-4: 65, 80, 100), lactate dehydrogenase (LDH-3: 72, 100), malic enzyme (ME-i: 0, 50, 100), and phosphoglucomutase (PGM-1: 0, 100).…”