Use of Parentage Assignment and DNA Genotyping to Validate Scale Analysis for Estimating Steelhead Age and Spawning History

Seamons, Todd R.; Dauer, Michael B.; Sneva, John G.; Quinn, Thomas P.

doi:10.1577/m08-044.1

Cited by 20 publications

(31 citation statements)

References 28 publications

(36 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This problem becomes compounded if fish spawn multiple times. Resorption during the second spawning migration can obliterate annuli and previous spawn marks (White and Medcof 1968;Seamons et al 2009). The loss of a previous spawn check is more likely to occur if a fish spawns consecutively rather than spending a year in saltwater before the next spawning attempt because consecutive spawners will add less material to their scales between spawns.…”

Section: Discussionmentioning

confidence: 99%

Quantitative Assessment of Scale Resorption in Migrating and Spawning Steelhead of the Snake River Basin

Hernandez¹,

Copeland²,

Wright³

2014

Trans Am Fish Soc

View full text Add to dashboard Cite

Scales have been used for decades as a tool to interpret life histories in steelhead Oncorhynchus mykiss. Resorption can affect the accuracy of life history interpretations based on scale patterns, depending on the amount of material resorbed. For example, resorption can affect the distinctiveness and characteristics of spawn checks. Spawn checks have been reported in iteroparous salmonids, but no published experimental studies have established the precise relationship between reproduction and scale features. Our objectives were (1) to quantify scale resorption, and (2) to identify contributing factors to the observed resorption in migrating and spawning Snake River steelhead. Prespawn and postspawn scale samples from 72 fish were paired for analysis. We found considerable individual variability in the amount of material resorbed between prespawn and postspawn samples (mean, 26%; SD, 13.7%). Most resorption occurred during the winter as gonads matured and secondary sex characteristics were formed. In over half of the postspawn samples, resorption was sufficient to obscure or eliminate an annulus. In a few cases, resorption was minor enough that the eventual spawn check may be indistinct or absent. We recommend that ancillary marks be investigated as a means to help identify weak spawn checks and an index of resorption developed to determine if resorption was sufficient to cause loss of an annulus. Received March 27, 2014; accepted August 5, 2014

show abstract

Section: Discussionmentioning

confidence: 99%

Quantitative Assessment of Scale Resorption in Migrating and Spawning Steelhead of the Snake River Basin

Hernandez¹,

Copeland²,

Wright³

2014

Trans Am Fish Soc

View full text Add to dashboard Cite

show abstract

“…Scale‐pattern analysis is complicated in steelhead by their diverse life histories and iteroparity (Seamons et al. ; Copeland et al. ).…”

Section: Methodsmentioning

confidence: 99%

Interactions between Marine Growth and Life History Diversity of Steelhead from the Situk River, Alaska

Catterson

Sutton

McPhee

2020

N American J Fish Manag

View full text Add to dashboard Cite

Steelhead (the anadromous form of Rainbow Trout Oncorhynchus mykiss) exhibit a complex life history that is described by variable freshwater and ocean residency and maturation schedules. This diversity confers resilience but complicates their monitoring and management. The Situk River in Southeast Alaska has the longest running set of biological data and scale samples for steelhead in the state, and it is of particular interest because it supports the largest known population of steelhead in Alaska and is free of hatchery influence. We used a retrospective analysis of scales that were collected from 525 individuals over 11 years (1999–2012) to examine the relationships among freshwater growth, early ocean growth, and life history in a mixed‐effects modeling framework. Specifically, we examined the relationships among annual growth stanzas and adult length and we determined how age at maturity varied by sex and growth history while allowing these relationships to vary randomly among calendar years of growth. Within individuals, freshwater and first ocean‐year growth were positively correlated, while second ocean‐year growth was negatively correlated with earlier growth stanzas. Early‐maturing steelhead (returning after two ocean years) grew more quickly during their first ocean year, and they then grew more slowly during their second ocean year and attained smaller adult length than did later‐maturing steelhead (those that returned after three ocean years). Second ocean‐year growth was more variable than first ocean‐year growth and adult length were. Males tended to mature earlier than females did, and later‐maturing males attained larger freshwater growth than their earlier‐maturing male counterparts did and grew larger in overall length than did females. Our analyses identified divergent growth trajectories that were associated with age at maturity that began in freshwater periods but were most pronounced during early ocean residency. We found retrospective scale‐growth analysis to be a useful tool for better understanding the connections between ocean growth and demography in this important sport fish.

show abstract

“…Because there can be some error associated with the aging of scales, we also used hatchery fish ± 1 brood-year as putative offspring. Parentage analysis revealed that very few hatchery fish (o3%) had been assigned via scale ageing to the incorrect brood-year, which is not always the case with wild-born fish (for example, Seamons et al, 2009). We used Mendelian exclusion to assign hatchery fish to their broodstock parents (that is, each allele in an identified offspring matched at least one allele in both parents).…”

Section: Effective Number Of Broodstock Parentsmentioning

confidence: 99%

Effective size of a wild salmonid population is greatly reduced by hatchery supplementation

et al. 2012

View full text Add to dashboard Cite

Many declining and commercially important populations are supplemented with captive-born individuals that are intentionally released into the wild. These supplementation programs often create large numbers of offspring from relatively few breeding adults, which can have substantial population-level effects. We examined the genetic effects of supplementation on a wild population of steelhead (Oncorhynchus mykiss) from the Hood River, Oregon, by matching 12 run-years of hatchery steelhead back to their broodstock parents. We show that the effective number of breeders producing the hatchery fish (broodstock parents; N b ) was quite small (harmonic mean N b ¼ 25 fish per brood-year vs 373 for wild fish), and was exacerbated by a high variance in broodstock reproductive success among individuals within years. The low N b caused hatchery fish to have decreased allelic richness, increased average relatedness, more loci in linkage disequilibrium and substantial levels of genetic drift in comparison with their wild-born counterparts. We also documented a substantial Ryman-Laikre effect whereby the additional hatchery fish doubled the total number of adult fish on the spawning grounds each year, but cut the effective population size of the total population (wild and hatchery fish combined) by nearly two-thirds. We further demonstrate that the Ryman-Laikre effect is most severe in this population when (1) 410% of fish allowed onto spawning grounds are from hatcheries and (2) the hatchery fish have high reproductive success in the wild. These results emphasize the trade-offs that arise when supplementation programs attempt to balance disparate goals (increasing production while maintaining genetic diversity and fitness).

show abstract

Use of Parentage Assignment and DNA Genotyping to Validate Scale Analysis for Estimating Steelhead Age and Spawning History

Cited by 20 publications

References 28 publications

Quantitative Assessment of Scale Resorption in Migrating and Spawning Steelhead of the Snake River Basin

Quantitative Assessment of Scale Resorption in Migrating and Spawning Steelhead of the Snake River Basin

Interactions between Marine Growth and Life History Diversity of Steelhead from the Situk River, Alaska

Effective size of a wild salmonid population is greatly reduced by hatchery supplementation

Contact Info

Product

Resources

About