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

Frontiers in Ecology and Evolution, Journal Year: 2022, Volume and Issue: 10

Published: July 5, 2022

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

Language: Английский

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The decline of the ecosystem services generated by anadromous fish in the Iberian Peninsula

Hydrobiologia, Journal Year: 2023, Volume and Issue: 850(12-13), P. 2927 - 2961

Published: April 5, 2023

Abstract This work aims to present an historical review of the ecosystem services provided by anadromous fish (i.e., species that migrate from sea river spawn) throughout Human time, as well main related threats, focusing on Iberian Peninsula region. Anadromous provide important provision, cultural, regulatory and supporting across their distribution range have been extensively exploited humans since prehistoric times. In Peninsula, lamprey, allis twaite shads, trout, Atlantic salmon European sturgeon were once abundantly in several basins covering what is now Portuguese Spanish territory. These suffered a severe decline range, mainly due habitat loss overexploitation. Considered regal delicacies, these fishes statement tables highest social classes, much appreciated bounty for poorer population are still part local gastronomy economy. Such high economic cultural interest encouraged intensive fishing. Currently, management efforts being implemented, pairing rehabilitation (e.g., construction passes obstacles migration such weirs dams) with sustainable fisheries. Considering climate change scenario, bound endure increased pressures, demanding novel approaches ensure numbers able secure exploitation.

Language: Английский

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Predation of Atlantic salmon across ontogenetic stages and impacts on populations

Canadian Journal of Fisheries and Aquatic Sciences, Journal Year: 2023, Volume and Issue: unknown

Published: June 26, 2023

Managers and stakeholders increasingly ask whether predation is a driving force behind the poor status of many species, predator control likely to be successful management action intervene. We review existing literature on Atlantic salmon Salmo salar control, as well general ecological theory role in life cycle this iconic fish. Many bird, mammal, fish predators target at different stages. In healthy populations, compensated for by reduced intraspecific competition during freshwater stage. There little evidence that alone has been an underlying mechanism populations below conservation limits. However, depending predator's response abundance, may keep decimated from recovering, even when actual causes decline have removed. Under such scenario, contribute recovery, but there are no strong examples clearly demonstrate efficacy managing recover threatened challenging further applications.

Language: Английский

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A commentary on the role of hatcheries and stocking programs in salmon conservation and adapting ourselves to less‐than‐wild futures

Fish and Fisheries, Journal Year: 2024, Volume and Issue: 25(4), P. 750 - 760

Published: May 31, 2024

Abstract Hatcheries and stocking programs serve a variety of objectives, including the conservation salmon populations. Much attention has been given to importance genetic integrity adaptive capacity stocks, particularly as they interact with hatchery‐origin fish. Literature on hatchery increasingly focused indicators quality success, genetically ‘wild’ valued over hatchery‐influenced salmon. However, in Anthropocene is challenging paradigms wildness definitions success. For populations that exist ragged edge climate change where threats are unlikely be remediated status ecologies past, role hatcheries becomes convoluted. If or ‘natural’ depend archetypes situated historic ecologies, then what do futures look like? In context, we argue expand from primarily criteria for additional cognizant hybrid ecosystems future human‐salmon relationships. We draw concept epistemologies within context conservation‐oriented critically reflect knowledge values underlie efforts changing which situated. critique discourses rooted western thought make suggestions toward reimagining conservation‐via‐hatchery allows expansive futures. Critically, conclude warnings against using arguments this paper social permission use panacea.

Language: Английский

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A Resist‐Accept‐Direct (RAD) future for Salmon in Maine and California: Salmon at the southern edge

Fisheries Management and Ecology, Journal Year: 2022, Volume and Issue: 29(4), P. 456 - 474

Published: June 23, 2022

Abstract North American salmon once ranged from ocean waters near the Arctic Circle southward to southern New England on Atlantic and Mexico Pacific. The colonial industrial transformation of rivers oceans have led extirpation or endangered status many populations. Today, chronic anthropogenic stressors interact with climate change, which means that effective conservation must address changes in transformed ecosystems. Conservation goals are designed recover both species their habitats. While seemingly congruent, habitat fish management different timetables due speed climate, habitat, biological processes relative regulatory processes, restoration, project implementation. Resist‐Accept‐Direct (RAD) framework facilitated exploration ideas actions restore suitable conditions for listed under Endangered Species Act at edge. Creative big solutions needed RAD provided a way examine options sustain an era change.

Language: Английский

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Atlantic salmon habitat-abundance modeling using machine learning methods

Ecological Indicators, Journal Year: 2024, Volume and Issue: 160, P. 111832 - 111832

Published: March 1, 2024

Climate change and anthropogenic activities have impacts on fish habitat suitability, demanding more accurate modeling of species abundance for effective conservation management. In this study, we applied Machine Learning techniques to model the habitat-abundance relationship juvenile Atlantic salmon (Salmo salar) in Teno catchment Finland Norway. To capture complexity nonlinearity relationship, employed Support Vector Regression (SVR), Random Forest (RF), Gradient Boosting (GB), Classification (SVC) compared their performances. Among regression models considered, those incorporating input variables such as substrate, shade, vegetation demonstrate higher performance. yields highest mean cross-validation score (R2 = 0.58), produces test 0.6) among techniques. The scores obtained classification are notably across all scenarios. A comparison between results highlights challenges accurately relationship. This study provides insights into potential machine learning complex riverine environments. findings emphasize importance considering limitations models, particularly ecological contexts, need further research address temporal variations improve precision modeling.

Language: Английский

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Reintroducing Atlantic salmon in the river Rhine for decades: Why did it not result in the return of a viable population?

River Research and Applications, Journal Year: 2024, Volume and Issue: 40(7), P. 1164 - 1182

Published: April 21, 2024

Abstract Freshwater species biodiversity is under threat. The average global decline for migratory fish estimated to be more than 75% since 1970. Atlantic salmon one of these with a steep in north‐western Europe and it even went extinct the river Rhine 1950s. causes this have been posted habitat loss, pollution, climate change overfishing. Annual stocking late 1980s resulted an initial increase numbers after which collapsed again. In paper, we lay out recent decline, estimate losses smolts adults at different sections freshwater elaborate on potential losses. We found that population has declined rapidly over past two decades, current spawning only ~350–800 individuals. percentage returning as grounds 0.5%–0.6%, well below 3% supposedly needed maintain self‐sustaining population. Many individuals disappear during their migrations, highest disappearing German tributaries (44%) Dutch lower (71%), while both (74%) (78%) Rhine. Causes per section remain unclear possible threats, some specific Rhine, are being discussed. large inland waters, compared open sea losses, indicate restocking might result ecological restoration carried so far along intensively shipped highly regulated course associated high levels predation, increasingly limited by future change.

Language: Английский

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Nutrient limitation in Atlantic salmon rivers and streams: Causes, consequences, and management strategies

Aquatic Conservation Marine and Freshwater Ecosystems, Journal Year: 2022, Volume and Issue: 32(6), P. 1073 - 1091

Published: March 29, 2022

Freshwater catchments can experience nutrient deficits that result in reduced primary and secondary productivity. The most commonly limiting nutrients are nitrogen phosphorus, either separately or together. This review considers the impact of increasing limitation temperate basin stream river systems, focusing on upland areas currently previously supported wild Atlantic salmon (Salmo salar) populations.Anthropogenic changes to land use increases barriers have altered dynamics, with particular impacts other migratory fish species which may be net importers streams. Declining populations further reduce sources, reducing ecosystem fisheries productivity below desired levels.Experimental manipulations levels examined this cultural oligotrophication. There is evidence growth biomass juvenile increased via appropriate additions nutrients, offering potential as a conservation tool. However, research required understand long-term effects these ecosystems, assess vulnerability downstream habitats eutrophication result.Although purposeful addition aim enhancing conserving salmonid justified some cases, it should undertaken an adaptive management framework. In addition, linked retention processing, integrated into large-scale habitat restoration recovery efforts.Both scientific community recognize ecological costs benefits associated adding streams change non-stationary world.

Language: Английский

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Facilitating the recovery of insect communities in restored streams by increasing oviposition habitat

Ecological Applications, Journal Year: 2023, Volume and Issue: 34(2)

Published: Dec. 10, 2023

Abstract Recruitment limitation is known to influence species abundances and distributions. Recognition of how why it occurs both in natural designed environments could improve restoration. Aquatic insects, for instance, rarely reestablish restored streams levels comparable reference even years after We experimentally increased oviposition habitat five out 10 western North Carolina test whether insect egg‐laying was limiting populations streams. A main goal adding the form rocks that partially protrude above water surface be used increase abundance richness stream eggs larval insects Adding enhanced several response variables (e.g., protruding rocks, number eggs, egg masses, morphotype richness, stability) similar those found Following addition mass by 186% 77% restored‐treated Densities attached their showed an overall pattern consistent with treatment effects due combination nonsignificant significant increases taxa not just one taxon. Our results indicate these are limited alleviated this component recruitment limitation. However, weaker indicates additional post‐recruitment factors, such as or mortality, may still a full recovery This study shows importance integrating information from animal life histories, ecology, geomorphology into restoration practices aquatic which commonly assess quality biological efficacy

Language: Английский

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A Review of Factors Potentially Contributing to the Long-Term Decline of Atlantic Salmon in the Conne River, Newfoundland, Canada

Reviews in Fisheries Science & Aquaculture, Journal Year: 2024, Volume and Issue: 32(3), P. 479 - 504

Published: April 18, 2024

Species extinction and population extirpation are now widespread across aquatic ecosystems with many diadromous species, including Atlantic salmon (Salmo salar), in decline throughout much of the North Atlantic. Declines can occur simultaneously at both large small regional scales rendering factors driving decreases more elusive. On south coast Newfoundland abundance Conne River fell by 92% over a period almost four decades contrast most other populations region suggesting local may be contributing to decline. Here potentially long-term reviewed (1) examining trends survival different life stages, (2) presenting synopsis on presence absence impacting productivity this population, (3) using semi-quantitative two dimensional classification system, based expert opinion, rank decline, (4) utilizing quantitative Random Forest analysis complement opinion approach identifying possibly affecting population. Results from qualitative analyses identified associated aquaculture as possible driver Additional include influence climate change predation freshwater marine habitats. As various native range extirpation, results further highlight necessity river-specific addition monitoring fine-scale demographic threat information prioritization research necessary for conserving or restoring endangered populations.

Language: Английский

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