River Damming Impacts on Fish Habitat and Associated Conservation Measures

Reviews of Geophysics, Год журнала: 2023, Номер 61(4)

Опубликована: Дек. 1, 2023

Abstract River damming has brought great benefits to flood mitigation, energy and food production, will continue play a significant role in global supply, particularly Asia, Africa, South America. However, dams have extensively altered river dynamics, including riverine connectivity, hydrological, thermal, sediment solute regimes, the channel morphology. These alterations detrimental effects on quality quantity of fish habitat associated impacts aquatic life. Indeed, been implicated decline numerous fishes, emphasizing need for effective conservation measures. Here, we present synthesis critical issues concerning physical habitats, with particular focus key species across continents. We also consider current measures their applicability different contexts. Finally, identify future research needs. The information presented herein help support sustainable dam operation under constraints climate change human

Язык: Английский

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Northern shifts in the migration of Japanese glass eels to subarctic Hokkaido Island over the past three decades

Ocean Dynamics, Год журнала: 2025, Номер 75(1)

Опубликована: Янв. 1, 2025

Язык: Английский

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The Blueprint of the European Eel Life Cycle: Does Life‐History Strategy Undermine or Provide Hope for Population Recovery?

Fish and Fisheries, Год журнала: 2025, Номер unknown

Опубликована: Март 30, 2025

ABSTRACT The life cycle of the European eel ( Anguilla anguilla ) is inherently risky because it relies on successful migration larvae and adults across thousands kilometres Atlantic Ocean. In between these migrations, eels need to grow develop maximise their potential for reproduction. Eels have a number life‐history characteristics at each stage that minimise mortality, starvation predation risks opportunities growth. larval silver phases, select specific habitats adopt efficient swimming behaviours failure risks. glass yellow phase, opposite case, plasticity adaptability enable occupation broad ecological niche maximises growth enables continent‐wide distribution. Under natural conditions, enough individuals survive, reproduce so population resilient However, there increasing evidence impacts anthropogenic activities may be particularly sensitive to, resulting in declining with reduced resilience. Climate‐linked oceanic risk factors are likely significant influence recruitment but not well understood cannot easily modified. interventions mitigate known environment offer hope recovery. A greater understanding phase during essential management Anthropocene fully effective.

Язык: Английский

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Exploring first-feeding diets for European eel larval culture: Insights at morphological, nutritional, and molecular levels

PLoS ONE, Год журнала: 2023, Номер 18(4), С. e0283680 - e0283680

Опубликована: Апрель 27, 2023

Closing the life cycle of European eel (Anguilla anguilla) in captivity is targeted to provide a sustainable, year-round supply juveniles for aquaculture. Present focus on nutritional requirements during larval first-feeding period. In this study, three experimental diets were tested hatchery-produced larvae from onset stage commencing 10 days post hatch (dph) until 28 dph. Larval mortality was recorded daily, while sampling conducted at regular intervals record biometrics and analyze expression genes related digestion, appetite, feed intake growth. Two periods high identified: first appeared shortly after introduction feeds (10-12 dph), second occurred 20-24 dph, indicating "point no return". This interpretation supported molecular level by gene encoding "hunger hormone" ghrelin (ghrl) that peaked 22 dph all dietary trials, suggesting most fasting. However, fed diet 3, ghrl downregulated beyond which indicated those longer starving stage, upregulation major digestive enzymes (try, tgl, amyl2a) advocated their healthy development. Moreover, as well (pomca) growth (gh) continued increase towards These results together with registered highest survival, largest dry weight increase, enhanced (length body area) pointed 3 best-performing. As whole, study represents landmark being document survival point return, providing novel insights into development functions feeding stage.

Язык: Английский

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Role of estuarine habitats for the feeding ecology of the European eel (Anguilla anguilla L.)

PLoS ONE, Год журнала: 2022, Номер 17(7), С. e0270348 - e0270348

Опубликована: Июль 6, 2022

This study aims to characterize and compare the feeding ecology of European eels ( Anguilla anguilla L.) during continental phase (i.e. yellow silver) along a salinity gradient lower, middle upper) in six northern France estuaries brackish water). The diet stable isotopic δ 15 N 13 C values) compositions collected with fyke net (Slack, Wimereux, Liane, Canche, Authie Somme estuaries) located French coast eastern English Channel per season over year were described by combining gut content isotope analyses. Eel guts dominated typical BW prey, Malacostraca Actinopterygii (54% 40%, respectively), gammare Gammarus zaddachi green crab Carcinus maenas (38% 14%, smaller A . juvenile flounder, Platichthys flesus (19% respectively) being most frequently found their guts. values majority confirmed sea- water-specific carbon resources. Dietary niche revealed no clear change between total length, silvering stages seasons, but significant difference gradients estuaries. Eels showed enrichment from upper lower while an inverse effect, lowest part highest part. Higher variability larger suggested that feed on wide range food sources than While fed mainly ones had trophic level prey. spatial dietary is discussed relation biological structure eel environmental variables.

Язык: Английский

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Anthropogenic Contaminants Shape the Fitness of the Endangered European Eel: A Machine Learning Approach

Fishes, Год журнала: 2022, Номер 7(5), С. 274 - 274

Опубликована: Окт. 5, 2022

European eel is thought to be a symbol of the effects global change on aquatic biodiversity. The species has persisted for millions years and faced drastic environmental fluctuations thanks its phenotypic plasticity. However, recently declined historically low levels under synergistic human pressures. Sublethal chemical contamination been shown alter reproductive capacity, but impacts required actions are not fully addressed by conservation plans. This paper proposes modelling approach quantify sublethal anthropogenic pollutants expression life history traits related fitness critically endangered eel. Material Methods: We sampled female silver eels from eight different catchments across Europe previously representative spectrum variability contamination. measured 11 fitness-related within four main categories: fecundity, adaptability plasticity, migratory readiness, spawning potential. used machine learning in models explore reaction (expression these traits) according geographical parameters, parasite burdens (the introduced nematode Anguillicoloides crassus) contaminants (persistent organic (POPs) muscular tissue trace elements (TEs) gonads, livers muscles). Finally, we simulated, two management scenarios—contamination reduction increase—on fecundity recruitment. Results: Contamination our sampling was have stronger control than do geographic factors that currently described literature. modelled scenarios assess benefit mitigation: suggest reducing concentrations lowest values occurred design would double compared current situation. Discussion: Remediation could represent viable option increasing resilience populations, with much more solely fishing mortality. More broadly, work provides an innovative way quantitative assessment norms species’ biological inorganic pollutions thus opening new pathways revert erosion

Язык: Английский

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The evolving story of catadromy in the European eel (Anguilla anguilla)

ICES Journal of Marine Science, Год журнала: 2023, Номер 80(9), С. 2253 - 2265

Опубликована: Сен. 27, 2023

Abstract Anguillid eels were once considered to be the classic example of catadromy. However, alternative life cycles have been reported, including skipping freshwater phase and habitat shifting between fresh, brackish, saltwater throughout growth phase. There is a lack knowledge regarding these alternate strategies, for example, proportion individuals in population that adopt them compared We provide description cycle strategies temperate anguillids, their possible drivers, methods available investigate them. These (lethal non-lethal), include otolith microchemistry, fatty acid stable isotope analyses, parasite identification, blood transcriptomics, electronic tags. argue since current management framework European eel other based mainly on component population, it ignores growing saline waters. Many factors are thought responsible precipitous decline more prevalent systems. Therefore, contribution may important than currently estimated. The habitat-shifting ability all crucial persistence recovery those species endangered.

Язык: Английский

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Importance of marine-estuarine-riverine connectivity to larvae and early juveniles of estuary-associated fish taxa

Environmental Biology of Fishes, Год журнала: 2023, Номер 106(10), С. 1983 - 2009

Опубликована: Окт. 1, 2023

Язык: Английский

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Panmixia in the American eel extends to its tropical range of distribution: Biological implications and policymaking challenges

Evolutionary Applications, Год журнала: 2023, Номер 16(12), С. 1872 - 1888

Опубликована: Ноя. 17, 2023

Abstract The American eel ( Anguilla rostrata ) has long been regarded as a panmictic fish and confirmed such in the northern part of its range. In this paper, we tested for first time whether panmixia extends to tropical range species. To do so, assembled reference genome (975 Mbp, 19 chromosomes) combining (PacBio Nanopore short (Illumina paired‐end) reads technologies support both study future research. test population structure, estimated genotype likelihoods from low‐coverage whole‐genome sequencing 460 eels, collected at 21 sampling sites (in seven geographic regions) ranging Canada Trinidad Tobago. We genetic distance between regions, performed ADMIXTURE‐like clustering analysis multivariate analysis, found no evidence thus confirming that addition, two genomic regions with putative inversions were observed, geographically widespread present similar frequencies all regions. discuss implications lack structure Our results are key research implementation conservation measures throughout Additionally, our can be applied fisheries management aquaculture

Язык: Английский

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Fish passage solution: European eel kinematics and behaviour in shear layer turbulent flows

Ecological Engineering, Год журнала: 2024, Номер 203, С. 107254 - 107254

Опубликована: Апрель 24, 2024

High velocity barriers pose a risk to upstream migrating European eels (Anguilla anguilla, Linnaeus) as the flow can be too fast for them swim against.These delay or even prevent migration, potentially exacerbating population declines of this critically endangered species.Eel tiles are an emerging solution application, already successfully deployed increase passage at gravity barriers.Here, eel mounted bed open channel recirculating flume were assessed in terms passage, behaviour and kinematics relative movement absence tiles.The effectively increased allowed rest without need back downstream.The also reduced amount energy needed travel upstream.For first time swimming was examined with multiple shear layers turbulent structures varying lengthscale.Swimming analysed complex flows revealed new gait layer beside tile.By allowing continuously move upstream, decrease predation infection resting hotspots.Overall, effective helping pass experimental flume.

Язык: Английский

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