Résumé
Species Distribution Models (SDM) are useful tools providing results that can be extrapolated to anticipate species range shifts, under climate change scenarios. SDM studies integrating spatial constraints are significantly lacking in the marine environment, leading to optimistic predictions. This is particularly true for anadromous species in which marine distributions can be driven by their affinity to their natal rivers. Acipenser sturio is a critically endangered anadromous fish for which two stocked populations are currently maintained in the Gironde-Garonne-Dordogne (France) and Elbe (Germany) river systems. Benefiting from bycatch reports of A. sturio, we applied a SDM process that explicitly considers distance to home when evaluating habitat suitability. More precisely, we included the variable ‘distance to mouth of the natal river system’ into SDM inputs to test and characterize its influence on the marine distribution of A. sturio. We used this model to obtain the marine distribution under current climatic conditions with the two source populations and under population recovery scenarios (functional populations hypothesized to exist in ten currently unoccupied river systems). We projected the model under future conditions with two climatic scenarios (RCP 4.5 and 8.5) and three time slices over the 2023–2099 period. Constrained-ranges of both existing and hypothetical populations are projected to expand in the future. We observed an overall increase of habitat suitability, with new suitable sectors localized further from natal river mouths. By informing on the suitable marine surface that each hypothetical population holds and adds to the existing ones, our approach aims at informing about the feasibility of species recovery and marine habitats protection strategies. Our findings highlight the need for including dispersal information in marine SDM. The application of our dispersal-constrained approach may be considered for other less-well-known species for which dispersal point sources are identifiable, such as other diadromous species in different study areas.
Auteurs, date et publication :
Auteurs Anaïs Charbonnel , Géraldine Lassalle , Patrick Lambert , Eric Quinton , Jörn Geßner , Eric Rochard , Steve Colclough , Niels Brevé , Marie-Laure Acolas
Publication : Ecological Indicators
Date : 2025
Volume : 160
Pages : 111762
Catégorie(s)
#INRAE #XPORésumé
The European sturgeon (Acipenser sturio) is a critically endangered anadromous fish species with the last remaining population living in the Gironde estuary, thanks to restocking programs. Between 2010 and 2018, trawling surveys (1022 trawl tows) in the estuary caught 452 sturgeons (fork length (FL) from 25.5 cm to 154 cm). Based on previous knowledge about the species ecology, individuals have been categorized into two groups, Estuarine Dwellers (ED; FL below 68 cm) that are using mainly the estuary, and Sea Explorers (SE; FL equal or above 68 cm) that could accomplish migration at sea. ED and SE were found in the estuary at all seasons with densities being the highest in autumn for SE and in all season except spring for ED. Hotspot analyses were made at the seasonal scale to localise ED and SE concentrations. Differences were analysed according to environmental variables (temperature, water column height, salinity and concentration in suspended matters) extracted from a hydrodynamic model (MARS3D), which all contribute to fish localisation at all seasons. In all seasons, both groups were using common areas located downstream (overlap from 26 to 33%) except in autumn, when different areas were used (12% overlap). SE were encountered downstream in deeper areas with higher salinity and lower temperature (except in winter). For this group, temperature seems to be a limiting factor. ED occupied downstream as well as upstream areas with lower salinity and higher temperature in summer, but there was no habitat selection linked to simulated environmental variables in spring and autumn. Since ED are mainly using the estuary they are probably accustomed to the range of values of the abiotic variables characterising the estuary and other factors are probably at play in spring and autumn, such as prey distribution. Comparison with the location of ancient wild cohorts highlights common hotspot areas downstream with our stocked population but the disappearance of a former upstream hotspot. We explained this difference by the environmental changes witnessed by the estuarine environment in the last decades. Our results highlights important areas for both groups that could help the design of conservation measures.
Auteurs, date et publication :
Auteurs Marie Lamour , Romaric Le Barh , Marie-Line Merg , Florent Grasso , Eric Quinton , Eric Rochard , Céline Le Pichon , Marie-Laure Acolas
Publication : Estuarine, Coastal and Shelf Science
Date : 2025
Volume : 298
Pages : 108656
Catégorie(s)
#INRAE #XPORésumé
Extensive pesticide use for agriculture can diffusely pollute aquatic ecosystems through leaching and runoff events and has the potential to negatively affect non-target organisms. Atrazine and S-metolachlor are two widely used herbicides often detected in high concentrations in rivers that drain nearby agricultural lands. Previous studies focused on concentrationresponse exposure of algal monospecific cultures, over a short exposure period, with classical descriptors such as cell density, mortality or photosynthetic efficiency as response variables. In this study, we exposed algal biofilms (periphyton) to a concentration gradient of atrazine and S-metolachlor for 14 days. We focused on fatty acid composition as the main concentration-response descriptor, and we also measured chlorophyll a fluorescence. Results showed that atrazine increased cyanobacteria and diatom chlorophyll a fluorescence. Both herbicides caused dissimilarities in fatty acid profiles between control and high exposure concentrations, but S-metolachlor had a stronger effect than atrazine on the observed increase or reduction in saturated fatty acids (SFAs) and very long-chain fatty acids (VLCFAs), respectively. Our study demonstrates that two commonly used herbicides, atrazine and S-metolachlor, can negatively affect the taxonomic composition and fatty acid profiles of stream periphyton, thereby altering the nutritional quality of this resource for primary consumers.
Auteurs, date et publication :
Auteurs Laura Malbezin , Soizic Morin , Isabelle Lavoie
Publication : Ecotoxicology
Date : 2025
Volume : 33
Issue : 2
Pages : 190-204
Catégorie(s)
#INRAE #XPOAuteurs, date et publication :
Auteurs Romain Vrba , Isabelle Lavoie , Nicolas Creusot , Mélissa Eon , Débora Millan-Navarro , Agnès Feurtet-Mazel , Nicolas Mazzella , Aurélie Moreira , Dolors Planas , Soizic Morin
Publication : Aquatic Toxicology
Date : 2025
Volume : 272
Pages : 106972
Catégorie(s)
#INRAE #XPORésumé
The aim of this study was to investigate the influence of environmental characteristics and anthropogenic pressures on the abundance of estuarine European eels (Anguilla anguilla L.) during their continental growth phase. European eels were collected with fyke nets from spring to autumn in twenty-nine estuaries along the French English Channel and the Atlantic coast. Eel abundance (catch per unit effort, CPUE) was assessed for all eels and by size class for small (total length < 300 mm), intermediate (≥300 to <450 mm), and large (≥450 mm) eels. The environmental characteristics of the French estuaries were described by twelve descriptor variables, mainly related to hydro-morphological and sedimentary factors. Based on principal component analysis and hierarchical clustering analysis, estuary size was identified as the main explanatory variable and used to compare eel abundance. Eel abundance differed significantly according to estuary size, with higher abundances observed in small estuaries (7.22 to 13.00 ind. fyke nets 24 h−1) compared to large estuaries (0.13 to 0.71 ind. fyke nets 24 h−1). Spatial variation in eel abundance was correlated with differences in estuary size for all eel size classes. The influence of anthropogenic pressures on eel abundance was assessed by nine anthropogenic estuarine pressure indicators. The results indicate that high values of the anthropogenic pressure indicators were correlated with low eel abundance. This study highlights that large French estuaries subject to stronger anthropogenic pressures were less favourable habitats than small estuaries with less anthropogenic pressure.
Auteurs, date et publication :
Auteurs Jérémy Denis , Mario Lepage , Marie-Christine Gruselle , Rachid Amara
Publication : Fishes
Date : 2024
Volume : 9
Issue : 2
Pages : 44
Catégorie(s)
#INRAE #XPORésumé
Estuaries are considered as key habitats for the early life stages of fish. However, in the face of massive destruction of many estuarine intertidal areas, management and conservation measures are needed. Fish condition indicators may be used as a proxy of habitat quality and provide valuable information for management of coastal areas. In this study, the larvae of golden mullet (Chelon auratus) and European glass eels (Anguilla anguilla) were sampled in three sites of the Gironde Estuary. Different lipid classes and fatty acids were quantified: phospholipids (globally, phosphatidylethanolamine and phosphatidylcholine), triglycerides, omega-3 (particularly docosahexaenoic and eicosapentaenoic acids), omega-6 and C18:1. These biomarkers provide information on the nutritional status of the larvae as well as on prey availability and larvae diet between sites. One site significantly differed from the others as it seemed to offer abundant and better-quality prey. The very high levels of omega-3 contained in mullet larvae suggested that this site provided a high amount of diatoms. However, the mullet larvae that colonized this site also showed physiological stress that could be explained by exposure to pollutants through their prey. This work constitutes an essential baseline for developing biomarkers to assess the quality of habitats in a global change context.
Auteurs, date et publication :
Auteurs Elorri Arevalo , Nicolas Mazzella , Henrique N. Cabral , Aurélie Moreira , Gwilherm Jan , Bertrand Villeneuve , Carl Possémé , Mario Lepage
Publication : Journal of Fish Biology
Date : 2025
Volume : 105
Issue : 1
Pages : 201-213
Catégorie(s)
#INRAE #XPORésumé
Abstract
Diadromous fish have exhibited a dramatic decline since the end of the 20th century. The allis shad (
Alosa alosa
) population in the Gironde‐Garonne‐Dordogne (GGD) system, once considered as a reference in Europe, remains low despite a fishing ban in 2008. One hypothesis to explain this decline is that the downstream migration and growth dynamics of young stages have changed due to environmental modifications in the rivers and estuary. We retrospectively analysed juvenile growth and migration patterns using otoliths from adults caught in the GGD system 30 years apart during their spawning migration, in 1987 and 2016. We coupled otolith daily growth increments and laser ablation inductively‐coupled plasma mass spectrometry measurements of Sr:Ca, Ba:Ca, and Mn:Ca ratios along the longest growth axis from hatching to an age of 100 days (i.e., during the juvenile stage). A back‐calculation allowed us to estimate the size of juveniles at the entrance into the brackish estuary. Based on the geochemistry data, we distinguished four different zones that juveniles encountered during their downstream migration: freshwater, fluvial estuary, brackish estuary, and lower estuary. We identified three migration patterns during the first 100 days of their life: (a) Individuals that reached the lower estuary zone, (b) individuals that reached the brackish estuary zone, and (c) individuals that reached the fluvial estuary zone. On average, juveniles from the 1987 subsample stayed slightly longer in freshwater than juveniles from the 2016 subsample. In addition, juveniles from the 2016 subsample entered the brackish estuary at a smaller size. This result suggests that juveniles from the 2016 subsample might have encountered more difficult conditions during their downstream migration, which we attribute to a longer exposure to the turbid maximum zone. This assumption is supported by the microchemical analyses of the otoliths, which suggests based on wider Mn:Ca peaks that juveniles in 2010s experienced a longer period of physiological stress during their downstream migration than juveniles in 1980s. Finally, juveniles from the 2016 subsample took longer than 100 days to exit the lower estuary than we would have expected from previous studies. Adding a new marker (i.e., Ba:Ca) helped us refine the interpretation of the downstream migration for each individual.
Auteurs, date et publication :
Auteurs Elodie Boussinet , David José Nachón , Aldo Sottolichio , Aude Lochet , Stefan Stoll , Gilles Bareille , Helene Tabouret , Christophe Pécheyran , Marie‐Laure Acolas , Françoise Daverat
Publication : Journal of Fish Biology
Date : 2025
Volume : 104
Issue : 4
Pages : 1054-1066
Catégorie(s)
#INRAE #XPORésumé
Urban ecosystems are subjected to multiple anthropogenic stresses, which impact aquatic communities. Artificial light at night (ALAN) for instance can significantly alter the composition of algal communities as well as the photosynthetic cycles of autotrophic organisms, possibly leading to cellular oxidative stress. The combined effects of ALAN and chemical contamination could increase oxidative impacts in aquatic primary producers, although such combined effects remain insufficiently explored. To address this knowledge gap, a one-month experimental approach was implemented under controlled conditions to elucidate effects of ALAN and dodecylbenzyldimethylammonium chloride (DDBAC) on aquatic biofilms. DDBAC is a biocide commonly used in virucidal products, and is found in urban aquatic ecosystems. The bioaccumulation of DDBAC in biofilms exposed or not to ALAN was analyzed. The responses of taxonomic composition, photosynthetic activity, and fatty acid composition of biofilms were examined. The results indicate that ALAN negatively affects photosynthetic yield and chlorophyll production of biofilms. Additionally, exposure to DDBAC at environmental concentrations induces lipid peroxidation, with an increase of oxylipins. This experimental study provides first insights on the consequences of ALAN and DDBAC for aquatic ecosystems. It also opens avenues for the identification of new biomarkers that could be used to monitor urban pollution impacts in natural environments.
Auteurs, date et publication :
Auteurs Caroline Roux , Cassandre Madru , Débora Millan Navarro , Gwilherm Jan , Nicolas Mazzella , Aurélie Moreira , Jacky Vedrenne , Laure Carassou , Soizic Morin
Publication : Journal of Hazardous Materials
Date : 2025
Volume : 472
Pages : 134523
Catégorie(s)
#INRAE #XPORésumé
Water pollution is a significant threat to aquatic ecosystems. Various methods of monitoring, such as in situ approaches, are currently available to assess its impact. In this paper we examine the use of fish in active biomonitoring to study contamination and toxicity of surface waters. We analysed 148 previous studies conducted between 2005 and 2022, including both marine and freshwater environments, focusing on the characteristics of the organisms used as well as the principal goals of these studies. The main conclusions we drew are that a wide range of protocols and organisms have been used but there is no standardised method for assessing the quality of aquatic ecosystems on a more global scale. Additionally, the most commonly used developmental stages have been juveniles and adults. At these stages, the most frequently used species were the fathead minnow (Pimephales promelas) and two salmonids: rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta). Few studies used earlier stages of development (embryos or larvae), mostly due to the difficulty of obtaining fish embryos and caging them in the field. Finally, we identified research gaps in active biomonitoring for water quality assessment which could indicate useful directions for future research and development.
Auteurs, date et publication :
Auteurs Sarah Bancel , Jérôme Cachot , Corentin Bon , Éric Rochard , Olivier Geffard
Publication : Environmental Pollution
Date : 2025
Volume : 360
Pages : 124661