Atlantic salmon of wild and hatchery origin have different migration patterns

Canadian Journal of Fisheries and Aquatic Sciences, Journal Year: 2022, Volume and Issue: 80(4), P. 690 - 699

Published: Dec. 16, 2022

Hatcheries are frequently used to support or restore threatened Atlantic salmon populations. However, little is known about how rearing affects behaviour and fitness of hatchery adults that return the river spawn. We acoustic telemetry compare migration patterns exhibited by ( N = 16) wild 12) spawners within a system in Norway. Hatchery this study were released as smolts identified their missing adipose fin upon rivers after 1+ winters spent at sea. Hatchery-origin displayed aberrant reverse movement behaviour, moving with frequent reversals between fjord, was not observed any salmon. No difference survival outmigration timing spawning found for two groups. The effect origin on behavior may have implications stock assessments made assess progress restoration river, particularly if behavioural differences impact catchability detections returning adult consequences different uncertain; however, movements energetically costly ultimately

Language: Английский

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Connecting population functionality with distribution model predictions to support freshwater and marine management of diadromous fish species

Biological Conservation, Journal Year: 2023, Volume and Issue: 287, P. 110324 - 110324

Published: Oct. 9, 2023

Diadromous fish species have a complex life cycle during which they migrate between marine and freshwater habitats. They experience multiple human-induced pressures in both environments, likely exacerbated by climate change, leading to dramatic population declines across their distribution ranges. Currently Species Distribution Models (SDMs) been applied separately continental habitats improve our understanding of lifecycles help with management. Integrating the freshwater-sea continuum into decisions would now be step further improving With this objective, we developed decision tree that links SDM outputs current observations functionality suggested management guidance options for viability these species. Potential effects change were included through future projections guide integrative long-term Several criteria proposed assess validity considering main sources uncertainties local expert knowledge on habitat status. The framework was approximately one hundred catchments from southern Portugal Scandinavia four diadromous At European level, differed two anadromous catadromous Platichthys flesus Chelon ramada populations seemed better state than those Alosa alosa A. fallax. Finally, national experts, focused distributed along latitudinal gradient test methodology demonstrate challenges terms continuity.

Language: Английский

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Determining early marine survival and predation by endothermic predators on acoustically tagged Atlantic salmon (Salmo salar) post-smolts

Canadian Journal of Fisheries and Aquatic Sciences, Journal Year: 2023, Volume and Issue: 81(4), P. 387 - 402

Published: Dec. 22, 2023

Many Atlantic salmon ( Salmo salar) populations have experienced significant declines for decades throughout North America and Europe. Mortality due to marine mammal predation during their early life could be an important factor contributing these limiting population recoveries. However, quantifying events, particularly the extent of on salmon, remains a challenge. In this study, we estimated contribution mesothermic endothermic species mortality post-smolts using acoustic telemetry. Predation events were inferred from changes in temperatures depths by acoustically tagged hatchery-reared smolts. No consumed predators, with most being classified as mammals. Post-smolt study period was low overall both years (13.1%–16.7%), accounting 33.1%–42.9% all (5.2%–5.6% mortality). Our results suggest that current return adult observed area recent not heavily influenced first weeks at sea.

Language: Английский

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Interannual variation in survival of wild Atlantic salmon smolts through a dynamic estuarine habitat

Fisheries Management and Ecology, Journal Year: 2024, Volume and Issue: 31(6)

Published: Jan. 16, 2024

Abstract Migration timing is critical for diadromous fish, especially survival. through fresh water and estuarine transitional waterbodies may be an important early life survival bottleneck potential exposure to anthropogenic pressures predators. Monitoring smolt movement riverine habitats identifying causes of mortality the directing focused, mitigating management actions. Acoustic telemetry was used track 186 Atlantic salmon smolts during migration from river Boyne Irish Sea on east coast Ireland 2019–2021. success release sea entry that ranged 47% 81% linked biotic (predation) abiotic effects (water flow temperature). Predation associated with interannual variation in survival, 5.4% consumed by marine mammals 26.3% lost unknown fates. Our findings contribute understanding predation also how temperature, tidal phase can influence this stage Salmon, a species decline across its range.

Language: Английский

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MANAGEMENT PLAN FOR RECREATIONAL FISHING IN THE HYDROGRAPHIC ÂNCORA RIVER BASIN

ENVIRONMENTAL SMOKE, Journal Year: 2024, Volume and Issue: Special Issue

Published: May 6, 2024

This work is the result of most recent studies carried out by ICNF in drainage basin future recreational fishing area (ZPL) Âncora river. These supported design a plan for sustainable management and exploitation this river basin, which part Minho Lima Hydrographic Region (RH1). Seven sampling stations were set up purpose. Six main watercourse one Regueiro dos Enxurros, middle an successive waterfalls, just before its confluence with da Lapa Ladrão, considered to be source River. At these stations, hydromorphological quality assessments on 500 m stretches using River Habitat Survey (RHS) methodology fish community monitoring (three per station, total twenty-one inventories) electrofishing technique. The results made it possible consider implementing more measures continental bodies water. In context, options took marked account conservation objectives associated presence European eels (Anguilla anguilla) red (Achondrostoma spp.), wide distribution trout (Salmo trutta) reduced boga (Pseudochondrostoma duriense) whose upper third conditioned very peculiar geomorphology, filled numerous slopes, give rise beautiful waterfalls. With information collected, data age, growth physical condition ichthyofauna assessed was studied, their relationship different types habitat they occurred established. show that are watercourses "Excellent" habitats, but levels artificialization ranging from "severely modified" "predominantly unmodified", anthropogenic actions over time. Trout widely distributed species along watercourse. absence exotic aquaculture samples lack medium large water impoundment structures hydrographic network evaluated should emphasized. existing compartmentalization materialized micro-weirs (many allow aquatic organisms migrate good year) few waterfalls (natural cascades) prevent passing through. isometric all balanced robustness maximum lifespan 6 years. As practical study, Recreational Fishing Management Exploration Plan will created, support promote LPZ, reconciling activity nature objectives.

Language: Английский

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