Challenges in the Identification and Interpretation of Phenological Shifts: Anthropogenic Influences on Adult Migration Timing in Salmonids

Tillotson, Michael D.; Arostegui, Martin C.; Austin, Catherine S.; Lincoln, Alexandra E.; Matsubu, William; McElroy, Katherine Nicole; Quinn, Thomas P.

doi:10.1080/23308249.2021.1874292

Cited by 11 publications

(9 citation statements)

References 206 publications

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“…Future selection pressure against early migrating fish could cause a reduced frequency of the duplication and confer a fitness advantage to late migrating populations in which fish return over an extended period of time. This variation within and among populations may represent a portfolio effect that enables Chinook salmon to persist if environmental conditions were adverse during a part of the migration season (Narum et al, 2018; Schindler et al, 2010; Tillotson et al, 2021).…”

Section: Discussionmentioning

confidence: 99%

Genomic variation across Chinook salmon populations reveals effects of a duplication on migration alleles and supports fine scale structure

Horn

Narum

2023

Molecular Ecology

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The distribution of ecotypic variation in natural populations is influenced by neutral and adaptive evolutionary forces that are challenging to disentangle. This study provides a high-resolution portrait of genomic variation in Chinook salmon (Oncorhynchus tshawytscha) with emphasis on a region of major effect for ecotypic variation in migration timing. With a filtered data set of ~13 million single nucleotide polymorphisms (SNPs) from low-coverage whole genome resequencing of 53 populations (3566 barcoded individuals), we contrasted patterns of genomic structure within and among major lineages and examined the extent of a selective sweep at a major effect region underlying migration timing (GREB1L/ROCK1). Neutral variation provided support for fine-scale structure of populations, while allele frequency variation in GREB1L/ ROCK1 was highly correlated with mean return timing for early and late migrating populations within each of the lineages (r 2 = .58-.95; p < .001). However, the extent of selection within the genomic region controlling migration timing was much narrower in one lineage (interior stream-type) compared to the other two major lineages, which corresponded to the breadth of phenotypic variation in migration timing observed among lineages. Evidence of a duplicated block within GREB1L/ROCK1 may be responsible for reduced recombination in this portion of the genome and contributes to phenotypic variation within and across lineages. Lastly, SNP positions across GREB1L/ROCK1 were assessed for their utility in discriminating migration timing among lineages, and we recommend multiple markers nearest the duplication to provide highest accuracy in conservation applications such as those that aim to protect early migrating Chinook salmon. These results highlight the need to investigate variation throughout the genome and the effects of structural variants on ecologically relevant phenotypic variation in natural species.

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Section: Discussionmentioning

confidence: 99%

Genomic variation across Chinook salmon populations reveals effects of a duplication on migration alleles and supports fine scale structure

Horn

Narum

2023

Molecular Ecology

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“…Increasing water temperature has been identified as being a principal driver of the phenomenon (Kovach et al, 2013;Arevalo et al, 2020;Teichert et al, 2020) and modeling experiments using future climate projections indicate that earlier runs of fish are increasingly likely (Hedger et al, 2013;Teichert et al, 2020). While it is tempting to attribute any significant changes in migration phenology to the direct effects of climate warming, these species are impacted by interacting multiple stressors, including fishing, land use change, introgression with captive-bred individuals, food web disruption, the presence of dams and the incidence of parasites (Palstra et al, 2007;Belletti et al, 2020;Bolstad et al, 2021;Sobocinski et al, 2021;Tillotson et al, 2021). Shifts in phenology are therefore likely to be context-dependent, but worth exploring as we strive to understand, mitigate and adapt to the interconnected impacts of climate change and biodiversity loss on ecosystems.…”

Section: Introductionmentioning

confidence: 99%

Decadal Trends in the Migration Phenology of Diadromous Fishes Native to the Burrishoole Catchment, Ireland

et al. 2022

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Migration is an important ecological trait that allows animals to exploit resources in different habitats, obtaining extra energy for growth and reproduction. The phenology (or timing) of migration is a highly heritable trait, but is also controlled by environmental factors. Numerous studies have reported the advancement of species life-events with climate change, but the rate and significance of such advancement is likely to be species specific, spatially variable and dependent on interactions with population and ecosystem changes. This is particularly true for diadromous fishes which are sentinels of change in both freshwater and marine domains, and are subject to considerable multiple stressors including overfishing and habitat degradation. Here, we describe trends in the migration phenology of three native Irish migratory fishes over half a century, Atlantic salmon (Salmo salar), brown trout (Salmo trutta) and European eel (Anguilla anguilla). The trends were derived from daily counts of 745,263 fish moving upstream and downstream through the fish traps of the Burrishoole catchment, an internationally important monitoring infrastructure allowing a full census of migrating fish. We found that the start of the seaward migration of eel has advanced by one month since 1970. The commencement of the salmon smolt migration has advanced by one week, although the rest of the migration, and the entirety of the trout smolt run has remained stable. The beginning of the upstream migration of trout to freshwater has advanced by 20 days, while the end of the run is more than one month later than in the 1970’s. The greatest phenological shift has been in the upstream migration of adult salmon, with at least half of migrating fish returning between one and two months earlier from the marine environment compared to the 1970’s. The earlier return of these salmon is coincident with reduced marine survival and decreasing body size, indicating considerable oceanic challenges for this species. Our results demonstrate that the impacts of climate change on the phenology of diadromous fish are context-dependent and may interact with other factors. The mobilization of long-term datasets are crucial to parse the ecological impacts of climate change from other anthropogenic stresses.

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“…Most life cycle events of species are synchronized by abiotic factors, most of which are affected by global change [1][2][3]. In addition to photoperiod, water temperature and discharge are key triggers in riverine systems for the migration of organisms between reproductive, feeding or seasonal refuge habitats [4][5][6]. Water temperature governs the physiology and the internal state of ectothermic organisms (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…The interaction between global climate change and local anthropogenic pressures (including water withdrawal for human consumption, irrigation, industry and hydropower production) has altered thermal and hydrological regimes of many rivers throughout the world. This may have altered the occurrence of water temperature and discharge associations favourable to the migration of aquatic organisms and resulted in changes in migration timing (phenological shift), adaptation to new environmental conditions (local adaptation) or species extirpation [ 5 , 14 , 15 ].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Does global change increase the risk of maladaptation of Atlantic salmon migration through joint modifications of river temperature and discharge?

Arevalo

Maire²,

Tétard

et al. 2021

Proc. R. Soc. B.

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In freshwater ecosystems, water temperature and discharge are two intrinsically associated triggers of key events in the life cycle of aquatic organisms such as the migration of diadromous fishes. However, global changes have already profoundly altered the thermal and hydrological regimes of rivers, affecting the timing of fish migration as well as the environmental conditions under which it occurs. In this study, we focused on Atlantic salmon ( Salmo salar ), an iconic diadromous species whose individuals migrate between marine nursery areas and continental spawning grounds. An innovative multivariate method was developed to analyse long-term datasets of daily water temperature, discharge and both salmon juvenile downstream and adult upstream migrations in three French rivers (the Bresle, Oir and Nivelle rivers). While all three rivers have gradually warmed over the last 35 years, changes in discharge have been very heterogeneous. Juveniles more frequently used warmer temperatures to migrate. Adults migrating a few weeks before spawning more frequently used warm temperatures associated with high discharges. This has already led to modifications in preferential niches of both life stages and suggests a potential mismatch between these populations' ecological preference and changes in their local environment due to global change.

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Challenges in the Identification and Interpretation of Phenological Shifts: Anthropogenic Influences on Adult Migration Timing in Salmonids

Cited by 11 publications

References 206 publications

Genomic variation across Chinook salmon populations reveals effects of a duplication on migration alleles and supports fine scale structure

Genomic variation across Chinook salmon populations reveals effects of a duplication on migration alleles and supports fine scale structure

Decadal Trends in the Migration Phenology of Diadromous Fishes Native to the Burrishoole Catchment, Ireland

Does global change increase the risk of maladaptation of Atlantic salmon migration through joint modifications of river temperature and discharge?

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