Introduced, invaded and forgotten: allopatric and sympatric native snow trout life-histories indicate brown trout invasion effects in the Himalayan hinterlands

2021 ◽  
Author(s):  
Aashna Sharma ◽  
Vineet Kumar Dubey ◽  
Jeyaraj Antony Johnson ◽  
Yogesh Kumar Rawal ◽  
Kuppusamy Sivakumar
Keyword(s):  
Brown Trout ◽  
Life Histories ◽  
Snow Trout

scholarly journals Genome-wide divergence patterns support fine-scaled genetic structuring associated with migration tendency in brown trout

2018 ◽  
Vol 75 (10) ◽  
pp. 1680-1692 ◽  
Author(s):  
Alexandre Lemopoulos ◽  
Silva Uusi-Heikkilä ◽  
Anti Vasemägi ◽  
Ari Huusko ◽  
Harri Kokko ◽  
...  
Keyword(s):  
Brown Trout ◽  
Life Histories ◽  
Salmo Trutta ◽  
Life History Variation ◽  
Isolated Populations ◽  
Genetic Structuring ◽  
Migration Barriers ◽  
Brown Trout Salmo Trutta ◽  
Russian River ◽  
High Level

Brown trout (Salmo trutta) exhibit highly diverse life histories varying from resident, slow-growing, and early maturing to migratory, fast-growing, and late maturing, even within single watersheds. We sampled 11 locations within the transboundary Finnish–Russian River Koutajoki watershed to evaluate genomic differences among mainstem and headwater sites, of which some are isolated by migration barriers. Restriction site associated sequencing (RADSeq) revealed that the most headwater localities supported unique, isolated populations with generally lower heterozygosity compared with the mainstem populations. The sampled migratory adults in the three main stems showed signals of admixture despite small but statistically significant genetic divergence, while the headwater populations, except for two, showed a high level of divergence and a lack of admixture. These results suggest that most of the headwater populations consist of resident brown trout and that the population genetic structuring is often maintained even in the absence of migration barriers. Our results have clear implications for fisheries management and conservation; each brown trout subpopulation represents an evolutionarily important unit with unique genetic makeup and life history variation.

scholarly journals Life on the Edge: The Long-Term Persistence and Contrasting Spatial Genetic Structure of Distinct Brown Trout Life Histories at Their Ecological Limits

2006 ◽  
Vol 97 (3) ◽  
pp. 193-205 ◽  
Author(s):  
Agostinho Antunes ◽  
Rui Faria ◽  
Warren E. Johnson ◽  
René Guyomard ◽  
Paulo Alexandrino
Keyword(s):  
Genetic Structure ◽  
Brown Trout ◽  
Life Histories ◽  
Spatial Genetic Structure

scholarly journals Alternative migratory tactics in brown trout (Salmo trutta) are underpinned by divergent regulation of metabolic but not neurological genes

2021 ◽  
Author(s):  
Robert Wynne ◽  
Louise Archer ◽  
Stephen Hutton ◽  
Luke Harman ◽  
Patrick Gargan ◽  
...  
Keyword(s):  
Gene Expression ◽  
Brown Trout ◽  
Life Histories ◽  
Salmo Trutta ◽  
Molecular Mechanisms ◽  
Molecular Genetic ◽  
Specific Gene ◽  
Metabolic Processes ◽  
Tissue Specific ◽  
The Brain

The occurrence of alternative morphs within populations is common but the underlying molecular mechanisms remain poorly understood. Many animals, for example, exhibit facultative migration, where two or more alternative migratory tactics (AMTs) coexist within populations. In certain salmonid species, some individuals remain in natal rivers all their lives, whilst others (in particular, females) migrate to sea for a period of marine growth. Here we performed transcriptional profiling (“RNA-seq”) of the brain and liver of male and female brown trout to understand the genes and processes that differentiate migratory and residency morphs (AMT-associated genes) and how they may differ in expression between the sexes. We found tissue-specific differences with greater number of genes expressed differentially in the liver (n = 867 genes) compared to the brain (n = 10) between the morphs. Genes with increased expression in resident livers were enriched for Gene Ontology terms associated with metabolic processes, highlighting key molecular-genetic pathways underlying the energetic requirements associated with divergent migratory tactics. In contrast, smolt-biased genes were enriched for biological processes such as response to cytokines, suggestive of possible immune function differences between smolts and residents. Finally, we identified evidence of sex-biased gene expression for AMT-associated genes in the liver (n = 18) but not the brain. Collectively, our results provide insights into tissue-specific gene expression underlying the production of alternative life-histories within and between the sexes, and point towards a key role for metabolic processes in the liver in mediating divergent physiological trajectories of migrants versus residents.

scholarly journals Spatial assemblage and interference competition of introduced Brown Trout (Salmo trutta) in a Himalayan river network: Implications for native fish conservation

2021 ◽  
Vol 24 (2) ◽  
pp. 33-42
Author(s):  
Aashna Sharma ◽  
Vineet Kumar Dubey ◽  
Jeyaraj Antony Johnson ◽  
Yogesh Kumar Rawal ◽  
Kuppusamy Sivakumar
Keyword(s):  
Brown Trout ◽  
Relative Abundance ◽  
Salmo Trutta ◽  
Propagule Pressure ◽  
Interference Competition ◽  
Fish Fauna ◽  
Native Fish ◽  
Management Actions ◽  
Snow Trout ◽  
Brown Trout Salmo Trutta

Abstract Often regarded as a potential threat to the native fish fauna worldwide, the Brown Trout (Salmo trutta), has successfully established its population in the majority of the Himalayan rivers post its introduction dating back to the eighteenth century. Over the years, the species has gained infamy as a sport fish and is considered a profitable source of income to the locals ensuing a heightened propagule pressure due to lack of appropriate management actions. No comprehensive study has been conducted to date in order to understand the mechanism by which the Brown Trout poses threat to the native fish populations. Through the present study, we could assess its competition with the native Snow Trout (Schizothorax richardsonii) to understand the spatial assemblage of both the species across space in Tirthan, a pristine high-altitude river of the western Himalaya. River Tirthan is one of the major tributaries of River Beas traversing for most of its stretch within the protected boundaries of the Great Himalayan National Park Conservation Area. A total of 108 sampling points were chosen from confluence to origin of rivers/streams, ranging from 989 to 3677msl. A total of 28 explanatory variables were recorded at each point. Overall, the Brown Trout adults were found to be greater in relative abundance (66.1%) than the Snow Trout adults (33.9%). The fingerlings of Snow Trout on the other hand, were distinctively high in relative abundance (61.9%) than those of the invasive Brown Trout (38.1%). Non-native trout showed higher abundance in the higher stream orders i.e. in the main streams while natives mostly restricted themselves to the lower order streams. Redundancy analysis (RDA) for species and environmental covariates resulted in 40.75% of constrained variance with higher eigen values for Redundancy analysis1 and Redundancy analysis2. Ward’s minimum variance clustering of Hellinger transformed data revealed sites agglomerating into six reasonable distinct subgroups with respect to species abundances. Immature individuals of non-native and native trout used similar habitat conditions, but they differed in using habitats at adult stage. Our results show a competitive dominance of Brown Trout in terms of higher abundance and maximum space utilization that highlight an urgent action for preventing its introductions to new areas. We recommend a national policy of ‘The Indian Invasive Species Act’ and management level interventions to control overstocking in the areas of established population.

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