Proceedings, Volume 146, 2026

Mediterranean rivers experience various pressures that cause native fish populations to decline. This is the case of Achondrostoma asturicense, a threatened endemic species recently classified as "endangered" (EN) by the Portuguese Red Book. In north...

Introduction: River fragmentation caused by hydropower infrastructure remains a primary threat to aquatic biodiversity, creating a critical need for fish passage solutions that can adapt to high environmental variability. Although adaptive management...

The vertebrate mitochondrial genome (mitogenome) is a small, circular DNA molecule typically ~16–17 kb in length, encoding 37 genes that are essential for the electron transport chain, the mechanism that drives mostly all the ATP synthesis in c...

Introduction: Species Distribution Models (SDMs) are widely used to infer environmental drivers of freshwater fish distributions and to project biodiversity responses to climate and land-use change. However, freshwater ecosystems present specific con...

Introduction: AQUArestore is a three-year project focused on promoting adaptive ecological restoration strategies for river ecosystems in the vulnerable cross-border region of Portugal. The project responds to pressing environmental challenges across...

Introduction: The liver is a central metabolic regulator responsible not only for energy storage and allocation but also for the production of essential egg proteins. In seasonal breeders such as brown trout, physiological demands increase during spa...

Introduction: Temperature is a key environmental factor influencing the physiological and biochemical processes of aquatic organisms, including xenobiotic metabolism. Understanding how temperature modulates the toxicological effects of pollutants suc...

Introduction: Synthetic cathinones (SC) are an emerging class of neuroactive contaminants increasingly detected in aquatic systems due to their widespread recreational use. Their continuous release at ng–µg L⁻¹ levels is particularl...

Environmental contamination by rare earth elements (REEs) is increasing globally due to their extensive use in modern technologies, medicine, agriculture, and aquaculture. Their release into aquatic systems via wastewater discharge, industrial emissi...

Introduction: Understanding the movement ecology of invasive species such as the European catfish Silurus glanis, with documented strong impacts on freshwater fish communities, is essential to improve the effectiveness of management and containment a...

Introduction: The temperature of rivers in the Iberian Peninsula has increased due to global warming. In addition, these rivers are polluted by contaminants of emerging concern, such as polycyclic aromatic hydrocarbons (PAHs). Higher temperatures and...

Introduction: The physical characteristics of microplastics (MPs), particularly their size and color, closely resemble natural food prey for several marine organisms, leading to active or accidental ingestion by marine species, including fish larvae....

Introduction: The early stages of fish represent a critical phase for survival and recruitment, as they are highly vulnerable to both biotic and abiotic factors, as well as anthropogenic pressures. To enhance survival, many marine species use estuari...

Introduction: Long-term ecological monitoring is essential to understand the responses of fish communities to global change in transitional ecosystems. Coastal lagoons are particularly vulnerable to eutrophication, which can trigger abrupt regime shi...

Introduction: Glucagon-like peptide-1 receptor agonists (GLP-1 RAs), such as liraglutide (LIR), are widely used in humans to treat type 2 diabetes mellitus, obesity, and non-alcoholic fatty liver disease. In mammals, GLP-1 RAs have been shown to infl...

Introduction: Elasmobranchs are an important component of deep-water and slope ecosystems, playing a key role in benthic and demersal food webs. Many species inhabiting offshore banks of the northeastern Atlantic are characterized by low productivity...

Introduction: Despite more than two decades of implementation, the European Water Framework Directive (WFD) still faces major challenges in achieving good ecological status across European water bodies. Key limitations persist in connectivity restora...

European catfish, an invasive alien species (IAS) that inhabits the Tagus River in Extremadura, is a threat to freshwater biodiversity and the local economy. As a freshwater mega-predator, it eats all kinds of fish, impacting local ichthyofauna as we...

Introduction: Fish and humans share evolutionarily conserved pathways regulating lipid metabolism. However, the effects of pharmaceuticals on lipid homeostasis in fish remain poorly understood, particularly regarding mechanistic lipid dysregulation a...

Introduction: The colossal European catfish (Silurus glanis) is the largest invasive freshwater fish on the Iberian Peninsula, reaching up to 2.8 metres and 130 kg in weight. Its large size makes it a highly valued target for recreational anglers, le...

Introduction: Chemical pollution of water bodies constitutes a global problem with huge impacts on fish populations. Consequently, the assessment of the effects of contaminants, especially on the nervous system, has become essential. The zebrafish (D...

Introduction: Inland fisheries in their diverse forms are an important activity in Portugal, currently involving about 100,000 fishers. Despite their relevance, there is still limited knowledge regarding the economic multiplier effect associated with...

Introduction: Understanding population structure is essential for fisheries management and stock identification. In marine species, spatial differentiation may arise from environmental conditions and biological factors, even when populations appear c...

Introduction: The fartet (Apricaphanius iberus) and the samaruc (Valencia hispanica) are two endemic fish species from the Valencian Community that have experienced significant population declines due to habitat degradation, competition with invasive...

Introduction: Competitive sport angling is a specialized form of recreational fishing in which participants compete in tournaments throughout the year to obtain annual rankings. In Portugal, competitive anglers may exhibit high levels of engagement a...

Introduction: Aquatic ecosystems are major reservoirs for both legacy and emerging contaminants, facilitating their distribution throughout the environment and bioaccumulation across different trophic levels. As such, wildlife acts as a valuable tool...

Freshwater ecosystems in southern Europe are increasingly impacted by fish invasions from central and northern regions, often facilitated by warmer climates and reduced natural-enemy pressure. The European catfish (Silurus glanis), the largest freshw...

Fish venom biology reaches far beyond addressing risks of human envenomation. The critical understanding of venom composition and the drivers that modulate it will enable scientists to deliver a span of novel bioresources with multiple potential biot...

Introduction: Coastal fishes can adapt to water warming and hypoxia; however, acute tolerance does not necessarily predict longer-term performance and survival. This may be especially important in sedentary, site-faithful species with limited escape...

Introduction: The Touvedo hydropower plant, located on the Lima River 47 km from its mouth, is equipped with a fish lift (2.14 m long × 1.29 m wide × 2.85 m high) on the left bank designed to facilitate fish migration past the dam. This m...

Habitat alteration and biological invasions are two main drivers of biodiversity loss at the global scale. Eutrophication and invasive fish greatly disturb freshwater native communities. This is of particular conservation concern in the Iberian Penin...

Introduction: Freshwater ecosystems are global biodiversity hotspots, yet they remain highly vulnerable to biological invasions. Non-native freshwater fish species (NNFS) have established self-sustaining populations across nearly all biogeographic re...

Introduction: Freshwater ecosystems are among the most threatened worldwide, with river fragmentation, primarily caused by dams and weirs, identified as a major driver of biodiversity loss. This issue is particularly acute in Europe, where more than...

Introduction: The Catalan chub (Squalius laietanus) is a freshwater cyprinid endemic to Catalonia, from the lower course of the Ebro River to the Tech, Tet, Agly, and Massane rivers in France. Classified as Vulnerable in the IUCN Red List (2024), its...

Introduction: Estuaries are dynamic environments that structure fish populations and can be investigated through geochemical signatures recorded in otoliths throughout the lives of individuals. Objective: This study aimed to assess the spatial geoche...

Introduction: The invasive European catfish (Silurus glanis) is actively spreading across Iberian freshwaters, with no effective management measures in place to control its growing abundance or prevent its establishment in new localities. It poses a...

Our objective is to assess the potential of ichthyological material from scientific collections for contemporary trophic studies by determining whether stomach contents of freshwater fish preserved in museum collections are well conserved and therefo...

Introduction: The vulnerable status of endemic Iberian fish like A. iberus and V. hispanica, together with limited knowledge of their reproductive biology, makes understanding temperature effects on hatching essential for defining their thermal limit...

LIFE REVIVE aims to restore ecological status and ecosystem services in the Lima and Vouga river basins (NW Iberian Peninsula), where hydromorphological alteration and hydropower-driven flow regulation are major causes of water bodies failing to reac...

Introduction: Studying the structure and dynamics of living communities is essential from both ecological and wildlife management perspectives. Objective: The main objective of this study was to analyze the fish community structure inhabiting differe...

Introduction: The Cananéia–Iguape Lagoon Complex, part of the Lagamar Mosaic of Conservation Units, comprises interconnected ecosystems that facilitate the dispersal and exchange of larvae, juveniles, and adults across habitats. This con...

Introduction: Freshwater systems are increasingly being impacted by a plethora of pressures. Freshwater fish are thus periled, urging the need to investigate the drivers of population decrease to better counteract them, in order to provide some conse...

Introduction: The restoration of river connectivity through fishways is essential for the conservation of native freshwater fish, yet it may inadvertently facilitate the upstream spread of non-native invasive species. This trade-off is particularly r...

Introduction: The rationale of traditional toxicity assessments, such as fish lethality tests (e.g., OECD TG 203), is to use forced exposure tests to characterise the ecotoxicity of chemicals by deriving concentration–response relationships bas...

The Iberian Peninsula hosts one of the world’s most endemic fish faunas. Its extensive evolutionary, palaeogeographic, and geological history has produced a distinctive freshwater fish fauna. Many of these species have very limited distribution...

Introduction: Populations of freshwater fish species of the Iberian Peninsula have been declining since the mid-20th century, and several types of actions (from in situ to ex situ actions) have been applied over the past decades. However, limited kno...

Introduction: Freshwater ecosystems are increasingly threatened by river fragmentation caused by the accumulation of small barriers such as weirs. These structures disrupt longitudinal connectivity and hinder fish movements, restricting access to ess...

Introduction: Climate warming and drought are intensifying thermal stress in Mediterranean freshwater systems, potentially favoring invasive fish with broad physiological tolerance. Extended environmental tolerance and increased aerobic scope are ind...

Introduction: Estuaries are among the most productive ecosystems in the world, holding great ecological and economic importance. As transitional zones between rivers and the sea, they experience abrupt abiotic changes linked to the tidal cycle, as we...

Introduction: Sharks are key species in marine ecosystems, and their conservation is a priority across European waters. However, several fisheries unintentionally capture sharks as bycatch, raising concerns about their post-capture survival. In the G...