Restoration of Native Biodiversity in Altered Environments: Reintroduction of Atlantic salmon into Lake Ontario

Less than a quarter of reintroduction programs have succeeded in re-establishing a self-sustaining population of an extirpated species. Optimal source population selection, based on an evolutionary perspective, could increase the fitness of translocated individuals, thereby improving the success rate of restoring extirpated populations. Here, using three source populations of Atlantic salmon, Salmo salar (LaHave River, Sebago Lake, and Lac Saint-Jean), that are being used for reintroduction efforts into Lake Ontario, I examined two optimal source population selection approaches: environment matching and adaptive potential. For environment matching, source populations from locations containing similar key environment features as the reintroduction location should contain adaptations to these features. For adaptive potential, source populations with high heritable genetic variation should have the potential to adapt to new selection pressures, such as the key environment features in the reintroduction location. I tested environment matching using experimental settings by exposing the three source populations to two key environment features that are likely impediments to a successful reintroduction of Atlantic salmon into Lake Ontario: the presence of non-native salmonids and a high thiaminase diet that can lead to a thiamine (vitamin B1) deficiency. I also quantified the amount of within-population heritable (additive) genetic variation for early-life history traits to assess the adaptive potential of the source populations. Although the average amount of heritable genetic variation was the highest for early-life history traits of the Sebago population, the amount was low, suggesting that the traits have a limited potential to adapt to any new selection pressures in Lake Ontario. Overall, the Sebago population (a match to both key environment features) had the highest performance, followed by the Saint-Jean population (match to a high thiaminase diet but not non-native salmonids), and finally the LaHave population (not a match to either feature). The pattern of overall performance and the low amount of heritable genetic variation of the three source populations generally supports environment matching over adaptive potential; however, further population comparisons are required over the entire life-cycle and in a fully natural setting to make more robust recommendations for large scale reintroduction efforts of Atlantic salmon into Lake Ontario

Transcriptome response of Atlantic salmon (Salmo salar) to competition with ecologically similar non-native species

Non-native species may be introduced either intentionally or unintentionally, and their impact can range from benign to highly disruptive. Non-native salmonids were introduced into Lake Ontario, Canada, to provide recreational fishing opportunities; however, the establishment of those species has been proposed as a significant barrier to the reintroduction of native Atlantic salmon (Salmo salar) due to intense interspecific competition. In this study, we compared population differences of Atlantic salmon in transcriptome response to interspecific competition. We reared Atlantic salmon from two populations (LaHave River and Sebago Lake) with fish of each of three non-native salmonids (Chinook salmon Oncorhynchus tshawytscha, rainbow trout O. mykiss, and brown trout S. trutta) in artificial streams. We used RNA-seq to assess transcriptome differences between the Atlantic salmon populations and the responses of these populations to the interspecific competition treatments after 10 months of competition in the stream tanks. We found that population differences in gene expression were generally greater than the effects of interspecific competition. Interestingly, we found that the two Atlantic salmon populations exhibited similar responses to interspecific competition based on functional gene ontologies, but the specific genes within those ontologies were different. Our transcriptome analyses suggest that the most stressful competitor (as measured by the highest number of differentially expressed genes) differs between the two study populations. Our transcriptome characterization highlights the importance of source population selection for conservation applications, as organisms with different evolutionary histories can possess different transcriptional responses to the same biotic stressors. The results also indicate that generalized predictions of the response of native species to interactions with introduced species may not be appropriate without incorporating potential population-specific response to introduced species

Integrating Problem Solving and Critical Reflection Opportunities in First- and Second-Year Science Courses.

The development of problem solving and critical reflection skills is neglected in early-level science courses; however, such skills are necessary in upper-year science courses and scientific careers (Gupta 2005). Early-year science teaching seems to be about memorization and recall (McDonald and Dominguez 2009) because teachers feel that they have insufficient time to integrate problem solving and critical reflection components into their courses while covering the subject matter (Kronberg and Griffin 2000). Yet, integrating problem solving and critical reflection opportunities into science courses does not have to take too much time and can cover the same curriculum subject matter (Kronberg and Griffin 2000; McDonald and Dominguez 2009); students usually learn more and have a greater understanding of concepts resulting in better grades (e.g., Chaplin 2009); and teachers have more frequent assessments of what their students are learning and can make instructional changes as required (McDonald and Dominguez 2009). This seminar will demonstrate methods (that are not greatly time consuming or drastically change the current curriculum) to integrate problem solving and critical reflection opportunities into lectures, laboratories, and tutorials of early-level science courses. Participants also have the opportunity to actively demonstrate the methods. The benefits of developing problem solving and critical reflection skills earlier in university science education are better grades, better integration of complex topics, and a better understanding of what students are actually learning

Genetic architecture and maternal contributions of early-life survival in lake trout Salvelinus namaycush

The influences of additive, non-additive and maternal effects on early survival (uneyed embryo survival, eyed embryo survival, alevin survival and overall survival to first feeding) were quantified in lake trout Salvelinus namaycush using a 7 × 7 full-factorial breeding design. Maternal effects followed by non-additive genetic effects explained around one third of the phenotypic variance of the survival traits. Although the amount of additive genetic effects were low

Data from: Genetic architecture of survival and fitness-related traits in two populations of Atlantic salmon

The additive genetic effects of traits can be used to predict evolutionary trajectories, such as responses to selection. Non-additive genetic and maternal environmental effects can also change evolutionary trajectories and influence phenotypes, but these later effects have received less attention by researchers. We partitioned the phenotypic variance of survival and fitness-related traits into additive genetic, non- additive genetic, and maternal environmental effects using a full-factorial breeding design within two allopatric populations of Atlantic salmon (Salmo salar). Maternal environmental effects were large at early life stages, but decreased during development, with non-additive genetic effects being most significant at later juvenile stages (alevin and fry). Non- additive genetic effects were also, on average, larger than additive genetic effects. The populations, generally, did not differ in the trait values or inferred genetic architecture of the traits. Any differences between the populations for trait values could be explained by maternal environmental effects. We discuss if the similarities in architectures of these populations is the result of natural selection across a common juvenile environment

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length, weight, family assignmen

Data from: Relative risks of inbreeding and outbreeding depression in the wild in endangered salmon

Conservation biologists routinely face the dilemma of keeping small, fragmented populations isolated, wherein inbreeding depression may ensue, or mixing such populations, which may exacerbate population declines via outbreeding depression. The joint evaluation of inbreeding and outbreeding risks in the wild cannot be readily conducted in endangered species, so a suggested 'safe' strategy is to mix ecologically and genetically similar populations. To evaluate this strategy, we carried out a reciprocal transplant experiment involving three neighbouring populations of endangered Atlantic salmon (Salmo salar) now bred in captivity and maintained in captive and wild environments. Pure, inbred, and outbred (first and second generation) cross types were released and recaptured in the wild to simultaneously test for local adaptation, inbreeding depression and outbreeding depression. We found little evidence of inbreeding depression after one generation of inbreeding and little evidence of either heterosis or outbreeding depression via genetic incompatibilities after one or two generations of outbreeding. A trend for outbreeding depression via the loss of local adaptation was documented in one of three populations. The effects of inbreeding were not significantly different from the effects of outbreeding. Hence, at the geographic scale evaluated (34-50 km), inbreeding for one generation and outbreeding over two generations may have similar effects on the persistence of small populations. The results further suggested that outbreeding outcomes may be highly variable or unpredictable at small genetic distances. Our work highlights the necessity of evaluating the relative costs of inbreeding and outbreeding in the conservation and management of endangered species on a case-by-case basis

Genetic architecture of gene transcription in two Atlantic salmon (Salmo salar) populations

Gene expression regulation has an important role in short-term acclimation and long-term adaptation to changing environments. However, the genetic architecture of gene expression has received much less attention than that of traditional phenotypic traits. In this study, we used a 5 × 5 full-factorial breeding design within each of two Atlantic salmon (Salmo salar) populations to characterize the genetic architecture of gene transcription. The two populations (LaHave and Sebago) are being used for reintroduction efforts into Lake Ontario, Canada. We used high-throughput quantitative real-time PCR to measure gene transcription levels for 22 genes in muscle tissue of Atlantic salmon fry. We tested for population differences in gene transcription and partitioned the transcription variance into additive genetic, non-additive genetic and maternal effects within each population. Interestingly, average additive genetic effects for gene transcription were smaller than those reported for traditional phenotypic traits in salmonids, suggesting that the evolutionary potential of gene transcription is lower than that of traditional traits. Contrary to expectations for early life stage traits, maternal effects were small. In general, the LaHave population had higher additive genetic effects for gene transcription than the Sebago population had, indicating that the LaHave fish have a higher adaptive potential to respond to the novel selection pressures associated with reintroduction into a novel environment. This study highlights not only the profound variation in gene transcription possible among salmonid populations but also the among-population variation in the underlying genetic architecture of such traits

Houde_heredity

Early life-history survival and fitness-related traits. Growing degree days information

Genetic and maternal effects on juvenile survival and fitness-related traits in three populations of Atlantic salmon

Although studies addressing natural selection have primarily focused on additive genetic effects because of their direct relationship with responses to selection, nonadditive genetic and maternal effects can also significantly influence phenotypes. We partitioned the phenotypic variance of survival and fitness-related traits in juvenile Atlantic salmon (Salmo salar) from three allopatric populations (LaHave, Sebago, and Saint-Jean) into additive genetic, nonadditive genetic, and maternal environmental effects using a full-factorial breeding design. We also modelled the potential increase in offspring performance if nonrandom mating (e.g., mate choice) is considered instead of random mating. The three populations exhibited significant differences in trait values as well as the genetic architecture of the traits. Nevertheless, nonadditive genetic and maternal environmental effects tended to be larger than the additive genetic effects. There was also a shift from maternal environmental to genetic effects during development in two of the populations. That is, maternal environmental effects were larger at early (egg and alevin) life stages, whereas nonadditive effects were larger at the later (fry) life stage. The amount of additive genetic effects was small, suggesting the traits will respond slowly to selection. We discuss how different maternal environmental effects across years may influence the genetic architecture of offspring traits