Introduction: Characterizing the thermal habitat of fish is key to understanding their ecological... more Introduction: Characterizing the thermal habitat of fish is key to understanding their ecological requirements in order to make appropriate management plans for the preservation of fish populations in the context of climate change. Little is known about the thermal habitat of the early life stages of fish (larvae and juveniles), as most methods have been designed for large, easily handled individuals. In particular, the study of otoliths holds great promise for unveiling the early thermal history of fish, although it is challenging to implement due to the very small size of the biological material.Methods: The stable oxygen isotope content (δ18O) of biogenic carbonates (such as otoliths) can be used to reconstruct the life temperature of fish individuals. However, relationships between δ18O of otoliths and ambient temperature are scarce and mainly developed for commercial species. In this study, we assessed the δ18O of juvenile European chub (Squalius cephalus, Linnaeus 1758) living...
Recent advances in molecular biomonitoring open new horizons for aquatic ecosystem assessment. Ra... more Recent advances in molecular biomonitoring open new horizons for aquatic ecosystem assessment. Rapid and cost-effective methods based on organismal DNA or environmental DNA (eDNA) now offer the opportunity to produce inventories of indicator taxa that can subsequently be used to assess biodiversity and ecological quality. However, the integration of these new DNA-based methods into current monitoring practices is not straightforward, and will require coordinated actions in the coming years at national and international levels. To plan and stimulate such an integration, the European network DNAqua-Net (COST Action CA15219) brought together international experts from academia, as well as key environmental biomonitoring stakeholders from different European countries. Together, this transdisciplinary consortium developed a roadmap for implementing DNA-based methods with a focus on inland waters assessed by the EU Water Framework Directive (2000/60/EC). This was done through a series of ...
In view of the very strong degradation of aquatic ecosystems, it is urgent to set up monitoring s... more In view of the very strong degradation of aquatic ecosystems, it is urgent to set up monitoring systems that are best able to report on the effects of the stresses they undergo. This is particularly true in developing countries, where specific and relevant quality standards and funding for monitoring programs are lacking. The objective of this study was to make a relevant and objective choice of physico-chemical parameters informative of the main stressors occurring on African lakes and to identify their alteration thresholds. Based on statistical analyses of the relationship between several driving forces and the physico-chemical parameters of the Nokoué lagoon, relevant physico-chemical parameters were selected for its monitoring. An innovative method based on Bayesian statistical modeling was used. Eleven physico-chemical parameters were selected for their response to at least one stressor and their threshold quality standards also established: Total Phosphorus (<4.5mg/L) , Or...
Ce guide est une aide à la lecture, à la compréhension et à l'application des normes (Afnor T... more Ce guide est une aide à la lecture, à la compréhension et à l'application des normes (Afnor T90-714 et T90-718), traitant de la caractérisation des habitats des rives et du littoral et de la caractérisation des altérations des berges des plans d'eau.Il s'applique aux écosystèmes lentiques d'eau douce continentaux, de quelques hectares à plusieurs milliers d’hectares, qu'ils soient d'origine naturelle ou anthropique.La méthode proposée se décline en trois étapes principales :- la préparation de supports cartographiques de saisie ;- la prospection in situ du plan d'eau et la retranscription des observations sur les supports ;- la saisie et la bancarisation des informations recueillies sous un format numérique géoréférencé.Ce guide a notamment vocation à appuyer la mise en œuvre des actions de surveillance réglementaire de la DCE, mais peut également être utilisé dans le cadre de toute étude écologique sur un système lacustre, nécessitant la prise en compte ...
Compressed file containing: 1) Forward sequence file 2) Reverse sequence file 3) File with experi... more Compressed file containing: 1) Forward sequence file 2) Reverse sequence file 3) File with experiment name, sample name and the tags, the forward primer and the reverse primer sequence associated
Global biodiversity in freshwater and the oceans is declining at high rates. Reliable tools for a... more Global biodiversity in freshwater and the oceans is declining at high rates. Reliable tools for assessing and monitoring aquatic biodiversity, especially for rare and secretive species, are important for efficient and timely management. Recent advances in DNA sequencing have provided a new tool for species detection from DNA present into the environment. In this study, we tested if an environmental DNA (eDNA) metabarcoding approach, using water samples, can be used for addressing significant questions in ecology and conservation. Two key aquatic vertebrate groups were targeted: amphibians and bony fish. The reliability of this method was cautiously validated in silico, in vitro, and in situ. When compared with traditional surveys or historical data, eDNA metabarcoding showed a much better detection probability overall. For amphibians, the detection probability with eDNA metabarcoding was 0.97 (CI = 0.90-0.99) versus 0.58 (CI = 0.50-0.63) for traditional surveys. For fish, in 89% of the studied sites, the number of taxa detected using the eDNA metabarcoding approach was higher or identical to the number detected using traditional methods. We argue that the proposed DNA-based approach has the potential to become the next-generation tool for ecological studies and standardized biodiversity monitoring in a wide range of aquatic ecosystems
This assesses features of otoliths from laboratory‐reared embryos, larvae and juvenile European c... more This assesses features of otoliths from laboratory‐reared embryos, larvae and juvenile European chub Squalius cephalus from hatching to 180 days post‐hatching (dph). We observed the development of the three pairs of otoliths (lapilli, sagittae and asterisci) and more precisely shape changes, as well as timing and deposition rate of increments of the lapilli. The lapilli and the sagittae were present at hatching, whereas the asterisci formed between 20 and 30 dph. The lapillus and sagitta shapes were round until 20 dph. From 60 dph the anterior and the posterior rostra of the sagittae were well developed, but very thin, making this otolith too fragile to manipulate for further studies of shape and validation of otolith increment deposition rate. The lapilli provided reliable age estimates for free embryos, larvae and juveniles up to 120 dph. However, caution should be taken when ageing fish older than 150 dph as an underestimation was noticeable. The regression of the number of otoli...
AimOur aim was to document geographical patterns of variation in the body‐size structure of Europ... more AimOur aim was to document geographical patterns of variation in the body‐size structure of European lake fish assemblages along abiotic gradients, and any differences in fish assemblage structure. We hypothesized that patterns in the body‐size structure of entire lake fish assemblages are primarily temperature driven and consistent with the dominant pattern of the temperature–size rule, which suggests a decrease in adult body size with increasing developmental temperature for many ectothermic species.Location356 European lakes.MethodsVariation in the body‐size structure of fish assemblages was explored on a continental scale along gradients of temperature, morphometry, productivity and fish assemblage structure for 356 European lakes. The mean fish assemblage body‐size and individual body‐size distributions were selected as size metrics. Separate analyses were conducted for lakes located within five ecoregion subsets (Borealic Uplands/Tundra, FennoScandian Shield, Central Plains, W...
Introduction: Characterizing the thermal habitat of fish is key to understanding their ecological... more Introduction: Characterizing the thermal habitat of fish is key to understanding their ecological requirements in order to make appropriate management plans for the preservation of fish populations in the context of climate change. Little is known about the thermal habitat of the early life stages of fish (larvae and juveniles), as most methods have been designed for large, easily handled individuals. In particular, the study of otoliths holds great promise for unveiling the early thermal history of fish, although it is challenging to implement due to the very small size of the biological material.Methods: The stable oxygen isotope content (δ18O) of biogenic carbonates (such as otoliths) can be used to reconstruct the life temperature of fish individuals. However, relationships between δ18O of otoliths and ambient temperature are scarce and mainly developed for commercial species. In this study, we assessed the δ18O of juvenile European chub (Squalius cephalus, Linnaeus 1758) living...
Recent advances in molecular biomonitoring open new horizons for aquatic ecosystem assessment. Ra... more Recent advances in molecular biomonitoring open new horizons for aquatic ecosystem assessment. Rapid and cost-effective methods based on organismal DNA or environmental DNA (eDNA) now offer the opportunity to produce inventories of indicator taxa that can subsequently be used to assess biodiversity and ecological quality. However, the integration of these new DNA-based methods into current monitoring practices is not straightforward, and will require coordinated actions in the coming years at national and international levels. To plan and stimulate such an integration, the European network DNAqua-Net (COST Action CA15219) brought together international experts from academia, as well as key environmental biomonitoring stakeholders from different European countries. Together, this transdisciplinary consortium developed a roadmap for implementing DNA-based methods with a focus on inland waters assessed by the EU Water Framework Directive (2000/60/EC). This was done through a series of ...
In view of the very strong degradation of aquatic ecosystems, it is urgent to set up monitoring s... more In view of the very strong degradation of aquatic ecosystems, it is urgent to set up monitoring systems that are best able to report on the effects of the stresses they undergo. This is particularly true in developing countries, where specific and relevant quality standards and funding for monitoring programs are lacking. The objective of this study was to make a relevant and objective choice of physico-chemical parameters informative of the main stressors occurring on African lakes and to identify their alteration thresholds. Based on statistical analyses of the relationship between several driving forces and the physico-chemical parameters of the Nokoué lagoon, relevant physico-chemical parameters were selected for its monitoring. An innovative method based on Bayesian statistical modeling was used. Eleven physico-chemical parameters were selected for their response to at least one stressor and their threshold quality standards also established: Total Phosphorus (<4.5mg/L) , Or...
Ce guide est une aide à la lecture, à la compréhension et à l'application des normes (Afnor T... more Ce guide est une aide à la lecture, à la compréhension et à l'application des normes (Afnor T90-714 et T90-718), traitant de la caractérisation des habitats des rives et du littoral et de la caractérisation des altérations des berges des plans d'eau.Il s'applique aux écosystèmes lentiques d'eau douce continentaux, de quelques hectares à plusieurs milliers d’hectares, qu'ils soient d'origine naturelle ou anthropique.La méthode proposée se décline en trois étapes principales :- la préparation de supports cartographiques de saisie ;- la prospection in situ du plan d'eau et la retranscription des observations sur les supports ;- la saisie et la bancarisation des informations recueillies sous un format numérique géoréférencé.Ce guide a notamment vocation à appuyer la mise en œuvre des actions de surveillance réglementaire de la DCE, mais peut également être utilisé dans le cadre de toute étude écologique sur un système lacustre, nécessitant la prise en compte ...
Compressed file containing: 1) Forward sequence file 2) Reverse sequence file 3) File with experi... more Compressed file containing: 1) Forward sequence file 2) Reverse sequence file 3) File with experiment name, sample name and the tags, the forward primer and the reverse primer sequence associated
Global biodiversity in freshwater and the oceans is declining at high rates. Reliable tools for a... more Global biodiversity in freshwater and the oceans is declining at high rates. Reliable tools for assessing and monitoring aquatic biodiversity, especially for rare and secretive species, are important for efficient and timely management. Recent advances in DNA sequencing have provided a new tool for species detection from DNA present into the environment. In this study, we tested if an environmental DNA (eDNA) metabarcoding approach, using water samples, can be used for addressing significant questions in ecology and conservation. Two key aquatic vertebrate groups were targeted: amphibians and bony fish. The reliability of this method was cautiously validated in silico, in vitro, and in situ. When compared with traditional surveys or historical data, eDNA metabarcoding showed a much better detection probability overall. For amphibians, the detection probability with eDNA metabarcoding was 0.97 (CI = 0.90-0.99) versus 0.58 (CI = 0.50-0.63) for traditional surveys. For fish, in 89% of the studied sites, the number of taxa detected using the eDNA metabarcoding approach was higher or identical to the number detected using traditional methods. We argue that the proposed DNA-based approach has the potential to become the next-generation tool for ecological studies and standardized biodiversity monitoring in a wide range of aquatic ecosystems
This assesses features of otoliths from laboratory‐reared embryos, larvae and juvenile European c... more This assesses features of otoliths from laboratory‐reared embryos, larvae and juvenile European chub Squalius cephalus from hatching to 180 days post‐hatching (dph). We observed the development of the three pairs of otoliths (lapilli, sagittae and asterisci) and more precisely shape changes, as well as timing and deposition rate of increments of the lapilli. The lapilli and the sagittae were present at hatching, whereas the asterisci formed between 20 and 30 dph. The lapillus and sagitta shapes were round until 20 dph. From 60 dph the anterior and the posterior rostra of the sagittae were well developed, but very thin, making this otolith too fragile to manipulate for further studies of shape and validation of otolith increment deposition rate. The lapilli provided reliable age estimates for free embryos, larvae and juveniles up to 120 dph. However, caution should be taken when ageing fish older than 150 dph as an underestimation was noticeable. The regression of the number of otoli...
AimOur aim was to document geographical patterns of variation in the body‐size structure of Europ... more AimOur aim was to document geographical patterns of variation in the body‐size structure of European lake fish assemblages along abiotic gradients, and any differences in fish assemblage structure. We hypothesized that patterns in the body‐size structure of entire lake fish assemblages are primarily temperature driven and consistent with the dominant pattern of the temperature–size rule, which suggests a decrease in adult body size with increasing developmental temperature for many ectothermic species.Location356 European lakes.MethodsVariation in the body‐size structure of fish assemblages was explored on a continental scale along gradients of temperature, morphometry, productivity and fish assemblage structure for 356 European lakes. The mean fish assemblage body‐size and individual body‐size distributions were selected as size metrics. Separate analyses were conducted for lakes located within five ecoregion subsets (Borealic Uplands/Tundra, FennoScandian Shield, Central Plains, W...
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