Spatial variation in landlocked Atlantic Salmon smolt survival associated with dam passage, avian predation, and stocking location

North American Journal of Fisheries Management, Journal Year: 2025, Volume and Issue: unknown

Published: March 19, 2025

ABSTRACT Objective We evaluated survival differences between upstream and downstream stocking for landlocked Atlantic Salmon Salmo salar smolts in a tributary to Lake Champlain. Methods radio-tagged stocked them concurrently with 22,000 at two release sites 2 years. The location (DS, river kilometer 16, no dam passage) was historically used site tailrace, whereas the (US, 27, dams pass) side channel first time. estimated survival, counted birds during stocking, searched nesting colonies transmitters. Results Within reaches, per DS group markedly lower than that US (US 2021 2022 = 0.98, respectively; 0.82, 0.69, respectively). At site, we documented tenfold increase avian predators following detected site. Passage >96% both dams, but postpassage (per kilometer) much second (2021 0.78, 0.82) compared 0.96, 0.97). Surprisingly, cumulative Champlain higher fish were released 43%; 32%) despite passage additional migratory distance. least 20% (2021) 7% (2022) of successful migrants later consumed by delta or Conclusions Upstream did not consistently result likely due habituated annually reoccurring tailrace increased stocking-related mortality highlight importance evaluating sites, as substantial loss could be avoided simple changes practices. Avian predation major source mortality, necessitating further studies understand address issues within

Language: Английский

---

Atlantic salmon (Salmo salar) age at maturity is strongly affected by temperature, population and age-at-maturity genotype

Conservation Physiology, Journal Year: 2023, Volume and Issue: 11(1)

Published: Jan. 1, 2023

Abstract Age at maturity is a key life history trait involving trade-off between survival risk and reproductive investment, an important factor for population structures. In ectotherms, warming environment may have dramatic influence on development history, but this differ populations. While increasing number of studies examined population-dependent reactions with temperature, few investigated in the context maturation timing. Atlantic salmon, species high conservation relevance, good study topic as it displays considerable variation age maturity, which large proportion has been associated genomic region including strong candidate gene vgll3. Until now, effect different environments populations not studied. Using large-scale common-garden experiment, we find effects population-of-origin, vgll3 genotype 2-year-old male salmon (Salmo salar). With temperature difference 1.8°C, probability was 4.8 times higher warm treatment than cold treatment. This population-specific southern (60.48°N) compared to northern (65.01°N) population. The early vgll3*E allele significantly probability, there no interaction or Both body condition mass maturation. association only present Our findings demonstrate that (i) can vary their response change terms (ii) intrinsic growth could be thermal sensitivity (iii) might similar environments.

Language: Английский

---

Premises for a digital twin of the Atlantic salmon in its world: Agency, robustness, subjectivity and prediction

Aquaculture Fish and Fisheries, Journal Year: 2024, Volume and Issue: 4(1)

Published: Feb. 1, 2024

Abstract Aquaculture of Atlantic salmon Salmo salar is in transition to precision fish farming and digitalization. As it easier, cheaper safer study a digital replica than the system itself, model can potentially improve monitoring prediction facilities operations replace live many what‐if experiments. Regulators, consumers voters also want insight into how like be aquaculture. However, such information credible only if natural physiology behaviour living adequately represented. To able predict unfamiliar, confusing stressful situations, modeller must aim for sufficiently realistic behavioural based on animal's proximate robustness mechanisms. We review knowledge status algorithms evolution has formed control decisions set priorities ontogeny. Teleost body through genes, hormones, nerves, muscles, sensing, cognition behaviour, latter being agentic, predictive subjective, man‐made environment. These are challenges when constructing salmon. This perspective useful modelling other domesticated wild animals Anthropocene environments.

Language: Английский

---

Comparing the migration behavior and survival of Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) smolts

Journal of Fish Biology, Journal Year: 2024, Volume and Issue: unknown

Published: April 15, 2024

Abstract Many organisms rely on migrations between habitats to maximize lifetime fitness, but these can be risky due a suite of factors. In anadromous salmonids, the smolt migration from fresh water sea is critical life stage, during which smolts experience high mortality multiple sources. This study investigated migratory behavior and survival Atlantic salmon ( Salmo salar ) brown trout trutta their seaward using acoustic telemetry March May 2021. Due extinction wild in River Gudenaa after construction Tange hydropower plant, this used hatchery‐reared originating nearby Danish river. A total 75 smolts, were tagged with transmitters released into Gudenaa, Denmark. The downstream movements fish monitored receivers deployed river fjord. Hatchery‐reared initiated first, followed by salmon, being last migrate. There was no difference riverine progression rates among three groups, noticeable differences emerged once fjord: (wild hatchery) slowed down, whereas maintained speed. Riverine predominantly nocturnal for all smolts; however, daytime increased at fjord arrays. Day‐of‐year significantly influenced diurnal patterns fjord, where later year. had reasonably good overall entry (≥66%), poor (c.26%). major bottleneck trout. We found strong evidence rate or explain lower survival. demonstrates that differ life‐history strategy already post‐smolt phase, stocking sub‐optimal aid populations.

Language: Английский

---

Time series covering up to four decades reveals major changes and drivers of marine growth and proportion of repeat spawners in an Atlantic salmon population

Ecology and Evolution, Journal Year: 2022, Volume and Issue: 12(4)

Published: April 1, 2022

Abstract Wild Atlantic salmon populations have declined in many regions and are affected by diverse natural anthropogenic factors. To facilitate management guidelines, precise knowledge of mechanisms driving population changes demographics life history traits is needed. Our analyses were conducted on (a) age growth data from scales caught angling the river Etneelva, Norway, covering smolt year classes 1980 to 2018, (b) extensive sampling whole spawning run fish trap 2013 onwards, (c) time series sea surface temperature, zooplankton biomass, lice infestation intensity. Marine during first at displayed a distinct stepwise decline across four decades. Simultaneously, shifted predominantly 1SW 2SW salmon, proportion repeat spawners increased 3 7%. The latter observation most evident females likely due decreased marine exploitation. Female tended be less catchable than males anglers. Depending period analyzed, rate was both positively negatively associated with temperature. Zooplankton biomass growth, while intensity growth. Collectively, these results linked oceanic conditions harvest regimes. conflicting regarding influence temperature caused long‐term increases which may triggered (or coincided with) ecosystem shifts creating generally poorer over time, but within shorter datasets warmer years gave higher We encourage authorities expand use permanently monitored reference rivers complete trapping facilities, like generating valuable for future analyses.

Language: Английский

---

Unveiling the UNESCO Biosphere Reserve of the Berlengas Archipelago in Portugal as a Hotspot of Fish Species Using eDNA Metabarcoding and the Collaboration of Fishing Crews

Journal of Marine Science and Engineering, Journal Year: 2025, Volume and Issue: 13(1), P. 60 - 60

Published: Jan. 1, 2025

Managing fishery resources is crucial to ensure the marine environment continues provide diverse goods and services. To overcome difficulties of classical methods used for fish stock management, molecular tools have shown potential address this issue assessing both targeted non-targeted species. This study aims evaluate spatiotemporal diversity using 12S rRNA gene eDNA metabarcoding sequencing in Berlengas archipelago compare two seawater sampling sources: samples collected by fishermen during their activities those our research team. The results indicated that autumn presented highest area around Berlenga Island was richest area, increasing biodiversity across region. Fisher-collected were generally less than team but detected species typical deeper open-ocean habitats, validating method. Our also highlighted eDNA’s role monitoring detecting unexpected region, such as Atlantic salmon (Salmo salar) cod (Gadus morhua), while cautioning against false positives like orange clownfish (Amphiprion percula) blue tilapia (Oreochromis aureus). Future optimisation methodology could better refine ecosystem dynamics UNESCO Biosphere Reserve Archipelago, Portugal.

Language: Английский

---

Assessing Trends and Challenges: Insights From 30 Years of Monitoring and Management of Threatened Southern Atlantic Salmon Populations

Aquatic Conservation Marine and Freshwater Ecosystems, Journal Year: 2025, Volume and Issue: 35(1)

Published: Jan. 1, 2025

ABSTRACT The Atlantic salmon ( Salmo salar ) has suffered significant population declines worldwide, prompting urgent conservation efforts, especially in its southern distribution area. This study is aimed at characterising the dynamics of Bidasoa River (Spain), by focusing on fluctuations and long‐term trends returns, characteristics effects angling stocking activities. For this, monitoring data spanning three decades (1993–2023) from a station anglers' captures were used together with activities provided Fish Management Section Navarre Government. Results reveal cyclical patterns driven distinctive wavelengths linked to life cycle, climatic variations local habitat connectivity improvements. was primarily dominated one‐sea‐winter males returning during autumn–winter season. Over period, reduction body size observed, likely reflecting challenging marine conditions. Angling pressure notably skewed towards multi‐sea‐winter females, which could influence natural recruitment dynamics. Despite low mean return rate stocked (0.13%), they contributed one‐third annual underscoring their potential role supporting persistence albeit expense reducing spawning, amid broader ecological challenges. provides valuable insights into complex interplay anthropogenic factors affecting populations European rivers. These are crucial for developing implementing effective strategies preserving salmon, species cultural importance.

Language: Английский

---

Premises for digital twins reporting on Atlantic salmon wellbeing

Behavioural Processes, Journal Year: 2025, Volume and Issue: 226, P. 105163 - 105163

Published: Feb. 4, 2025

Many species of fish, birds and mammals commonly live in human captivity; Atlantic salmon Salmo salar is one them. The international legal status the welfare captive animals slowly developing still requires rigorous specification. For example, even though fish have complex cognition elements sentience, United Nations' animal principles take a functional health-centred perspective overlooking cognitive-affective component. Wellbeing problems remain major source slow growth high mortality intensive aquaculture salmon. value system for decision making vertebrates based on expectations emotional wellbeing options available linked with individual's assessment its future. We propose new approach monitoring improving (or any other or wild vertebrate) modelling salmon's by digital twins, which are simulation models that implement bodily mechanisms organism. Indeed, predictions boredom, stress can all be captured computational evolutionary model factors underlying behaviour. explain how such an agent-based twins constructed subjective experience along prediction near future allostasis (the preparation expected future). attempt to identify building blocks required twin deliver early warnings about escalating issues could eventually lead negative effects health aquaculture. These would provide critical insights optimizing production processes significantly reduce reliance experiments. Overall, reports population support implementation 3Rs - replacement, reduction, refinement offering actionable information farmers as well consumers, voters, politicians regulators relevant guide experimental work across species.

Language: Английский

---

Pathogen and Gene Expression Profiles of Atlantic Salmon From an Endangered Population

Aquatic Conservation Marine and Freshwater Ecosystems, Journal Year: 2025, Volume and Issue: 35(4)

Published: April 1, 2025

ABSTRACT The role of pathogens in impacting the behaviour and fate salmonids has been studied extensively for some selected such as sea lice. However, whole pathobiome fish are seldom considered may confound influence study species situ. In this study, we investigated presence returning adult wild hatchery salmon river Vosso using gill samples analysed high‐throughput PCR with a selection assays targeting different pathogens. addition, were gene expressions that have previously linked to imminent mortality, thermal stress, inflammation related biomarkers. These data individual collected from acoustic telemetry tags inserted abdomen fish. Previous analyses suggested area is different; however, there was no evidence or expression two groups (39 14 hatchery) could explain behavioural differences between these groups. Furthermore, neither pathogen profile nor had significant relationship metrics survival Results suggest screenings insufficient predict fates migrating salmon. threatened population Norway after collapsing 1980s; contribute ongoing efforts identify factors limiting recovery decades poor returns.

Language: Английский

---

Population Genetics of Atlantic Salmon (Salmo salar) in Prince Edward Island, Canada

Ecology and Evolution, Journal Year: 2025, Volume and Issue: 15(5)

Published: May 1, 2025

ABSTRACT Atlantic salmon ( Salmo salar ) have experienced population declines across their native range. Widespread stocking has been a recovery strategy, but there is growing awareness that may put genetic integrity at risk. In Prince Edward Island, Canada, over 37 million stocked since 1880. This study used panel of six microsatellites and next‐generation sequencing to evaluate the composition 884 individuals from 20 rivers. Bayesian clustering methods inferred groupings were generally consistent with spatial distribution A cluster in northeastern PEI was most distinct, separately all methods. Distance between rivers accounted for 25.8% variations, whereas intensity did not predict variation. The heavily river changed few years, suggesting wild free‐ranging fish could outcompete fish. Currently, multiple stocks are post‐glacial biogeography rather than history. Clarification these adaptations required guide incorporation genetics into management strategies benefit conservation.

Language: Английский

---