Conservation Genetics of Lake Superior Brook Trout: Issues, Questions, and Directions

Abstract

Parallel efforts by several genetic research groups have tackled common themes relating to management concerns about and recent rehabilitation opportunities for coaster brook trout Salvelinus fontinalis in Lake Superior. The questions that have been addressed include the evolutionary and genetic status of coaster brook trout, the degree of relatedness among coaster populations and their relationship to riverine tributary brook trout populations, and the role and effectiveness of stocking in maintaining and restoring coasters to Lake Superior. Congruent genetic results indicate that coasters are an ecotype (life history variant) rather than an evolutionarily significant unit or genetically distinct strain. Regional structure exists among brook trout stocks, coasters being produced from local populations. Introgression of hatchery genes into wild populations appears to vary regionally and may relate to local population size, habitat integrity, and anthropogenic pressures. Tracking the genetic diversity and integrity associated with captive breeding programs is helping to ensure that the fish used for stocking are representative of their source populations and appropriate for rehabilitation efforts. Comparative analysis of shared samples among collaborating laboratories is enabling standardization of genotype scoring and interpretation as well as the development of a common toolkit for assessing genetic structure and diversity. Incorporation of genetic data into rehabilitation projects will facilitate monitoring efforts and subsequent adaptive management. Together, these multifaceted efforts provide comprehensive insights into the biology of coaster brook trout and enhance restoration options.

Life histories and ecotype conservation in an adaptive vertebrate: Genetic constitution of piscivorous brown trout covaries with habitat stability

“…Genetically distinct ecotypes of fish are often documented between migratory and resident life histories (Lin, Quinn, Hilborn, & Hauser, ; Pearse et al., ; Taylor, ), but only sparsely so in brown trout, possibly in part as a result of sample bias (Hindar, Jonsson, Ryman, & Stahl, ; Krueger & May, ; Skaala & Naevdal, ). As in the present investigation, an ecotype signal may be less pronounced than genetic differentiation among geographically defined populations, and studies may give ambiguous results, often related to the different populations studied (Bernatchez et al., ; Docker & Heath, ; Heath, Bettles, Jamieson, Stasiak, & Docker, ; Marin et al., ; Olsen, Wuttig, Fleming, Kretschmer, & Wenburg, ; Wilson et al., ). Sympatric populations with different life history strategies are typically more similar to each other, than to geographically separated populations (Aykanat et al., ; Bernatchez et al., ; Docker & Heath, ; Hindar et al., ; Narum, Contor, Talbot, & Powell, ; Perreault‐Payette et al., ).…”

Comparison of growth physiology, morphology, and smolt indicators in juvenile Lake Superior brook trout (Salvelinus fontinalis) strains in reference to life history variation

“…The four strains of brook trout chosen, based on their life history strategies and availability, were two lacustrine coasters (NIP: Lake Nipigon, Ontario, Canada; TBH: Isle Royale, Michigan, USA), one adfluvial coaster (SIS: Siskiwit River, Isle Royale, Michigan, USA), and one stream-resident strain (IRV: Iron River, Michigan, USA). Recent studies have shown that there is genetic diversity within brook trout populations around Lake Superior, including the strains used in our study (Wilson et al 2008;Burnham-Curtis 2001). All strains used in this study are recognized as genetically distinct populations in the wild, and derived hatchery stocks are similarly distinct.…”

Spatial and Temporal Genetic Analysis of Walleyes in the Ohio River

“…Analyses of historical genetic data can provide information useful for evaluating the impacts of anthropogenic effects and generating population genetic baselines by which to measure genetic change and define management goals (Vähä et al 2008;Wilson et al 2008;. For this study, we developed historical genetic baselines for the Ohio River strain (museum specimens) and Great Lakes strain (contemporary Lake Erie basin) of Walleyes to compare against contemporary Ohio River populations.…”