Periodic Reporting for period 1 - THERMOS (Thermal phenotypes and behavioural syndromes as predictors of resilience to climate change in European freshwater fish)
Período documentado: 2020-10-21 hasta 2022-10-20
Climate change is resulting in warming air temperatures, with the rate of change progressing substantially faster than previous natural climate change events. Predicting, preventing and/ or ameliorating the consequences of climate change is thus a major strategic objective for the European Union, particularly in respect of ecology and biodiversity. In Europe, while many species are shifting their distributions to areas of higher latitude and/ or altitude to track their ‘climate niche’, this can be constrained if habitats are closed environments, such as river catchments that have physical boundaries which inhibit the inter-catchment movements of species. In fishes, the fine-tuning of body temperatures can be achieved through ‘behavioural thermoregulation’, where individuals utilise microhabitats that provide their preferred thermal conditions, especially as some rivers are characterised by high variability in their water temperatures. However, the extent to which river fishes might have inherent resilience to warming through their behavioural thermoregulation remains unknown, despite the responses of biodiversity to climate change will of high societal importance through ensuring populations remain sustainable despite warming effects, and understandings of population resilience being important for management responses.
This project was designed to specifically overcome this major knowledge gap through two objectives. Firstly, we quantified the in-river movements of European barbel (a climatically sensitive fish) in a lowland river to test how the body temperatures of individuals vary from their general environment, and how these differences relate to their movements and traits. We then experimentally quantified (in laboratory conditions), the thermal and behavioural phenotypes of European barbel in relation to pro-active and active behavioural syndromes and pace of life syndromes. The accomplishment of both objectives increases understandings of the resilience of riverine fishes to climate change, especially in relation to the interaction of individual phenotypes with environment changes.
This project was designed to specifically overcome this major knowledge gap through two objectives. Firstly, we quantified the in-river movements of European barbel (a climatically sensitive fish) in a lowland river to test how the body temperatures of individuals vary from their general environment, and how these differences relate to their movements and traits. We then experimentally quantified (in laboratory conditions), the thermal and behavioural phenotypes of European barbel in relation to pro-active and active behavioural syndromes and pace of life syndromes. The accomplishment of both objectives increases understandings of the resilience of riverine fishes to climate change, especially in relation to the interaction of individual phenotypes with environment changes.
In-river movements
We tested relationships between movement ecology and physiology (as body temperatures) in European barbel through implanting fish with acoustic transmitters that enabled their tracking in the study river for over 12 months. These transmitters were also fitted with temperature sensors, thus the data captured for individual fish were the timing of detection on the acoustic receiver (where there were up to 60 receivers located though the river) and their body temperature at the time of recording. To supplement these tagged barbel, common bream were also implanted with the same type of transmitter to generate data on a fish species which have lower variability in individual movement patterns. The main result to date is that in European barbel, consistent differences in the movements, behaviours and habitat use of individuals meant that there were consistent differences recorded in their body temperatures during warm water periods. Some fish revealed preferences for using relatively cool water (<18 oC) whilst other fish, at the same time, were in relatively warm water (>22 oC). This indicates that there is high individual variability in the thermal preferences of individuals, with some preferentially using warmer waters.
Thermal & behavioural phenotypes
We tested for the presence of thermal and behavioural phenotypes of European barbel through laboratory trials. Initial trials tested the suitability of a series of tests for measuring behavioural phenotypes and the consistency of individual behaviours through measuring the fish responses on three occasions. All fish used in trials were marked individually to allow their tracking through experiments. Analyses indicated that the three trials provided a strong measure of the extent of individual variation in the behaviour of these fish and that this variation was repeatable across the three replicates. These trials were then applied to quantifying the behavioural and thermal phenotypes of European barbel by firstly exposing a new set of individuals to the behavioural trials and then measuring their thermal phenotype. Once the fish had completed the behavioural trials, they were used in a ‘shuttle-box’ system, in which individuals are exposed to two linked chambers and can move freely between them24. Each chamber starts at different temperatures (e.g. 17/ 22oC); as the fish moves between the chambers, their water temperatures are altered until equilibrium is reached across both chambers, which indicates the individual’s temperature preference.
Our objectives had then planned to use these fish within experimental river channels to test how the measured phenotype diversity is expressed in natural conditions. However, time lost in the project due to Covid-19 restrictions (lock-down between January and April 2021) meant this could not be completed. Instead, the time when access was lost to experimental facilities was used to complete a systematic review and meta-analysis on the extent of behavioural thermoregulation in freshwater fishes. The results revealed that across the literature, while behavioural thermoregulation is a feature of many fish populations, this has primarily been measured as a response to warming temperatures by salmonid fishes, with most studies completed in North America. The extent of the temperature difference between these habitats decreased with increasing latitude, with juvenile and non-migratory fishes tolerating greater temperature differences than adult and anadromous. Median temperature differences between the warm water and cool water refuge was 3.8oC.
We tested relationships between movement ecology and physiology (as body temperatures) in European barbel through implanting fish with acoustic transmitters that enabled their tracking in the study river for over 12 months. These transmitters were also fitted with temperature sensors, thus the data captured for individual fish were the timing of detection on the acoustic receiver (where there were up to 60 receivers located though the river) and their body temperature at the time of recording. To supplement these tagged barbel, common bream were also implanted with the same type of transmitter to generate data on a fish species which have lower variability in individual movement patterns. The main result to date is that in European barbel, consistent differences in the movements, behaviours and habitat use of individuals meant that there were consistent differences recorded in their body temperatures during warm water periods. Some fish revealed preferences for using relatively cool water (<18 oC) whilst other fish, at the same time, were in relatively warm water (>22 oC). This indicates that there is high individual variability in the thermal preferences of individuals, with some preferentially using warmer waters.
Thermal & behavioural phenotypes
We tested for the presence of thermal and behavioural phenotypes of European barbel through laboratory trials. Initial trials tested the suitability of a series of tests for measuring behavioural phenotypes and the consistency of individual behaviours through measuring the fish responses on three occasions. All fish used in trials were marked individually to allow their tracking through experiments. Analyses indicated that the three trials provided a strong measure of the extent of individual variation in the behaviour of these fish and that this variation was repeatable across the three replicates. These trials were then applied to quantifying the behavioural and thermal phenotypes of European barbel by firstly exposing a new set of individuals to the behavioural trials and then measuring their thermal phenotype. Once the fish had completed the behavioural trials, they were used in a ‘shuttle-box’ system, in which individuals are exposed to two linked chambers and can move freely between them24. Each chamber starts at different temperatures (e.g. 17/ 22oC); as the fish moves between the chambers, their water temperatures are altered until equilibrium is reached across both chambers, which indicates the individual’s temperature preference.
Our objectives had then planned to use these fish within experimental river channels to test how the measured phenotype diversity is expressed in natural conditions. However, time lost in the project due to Covid-19 restrictions (lock-down between January and April 2021) meant this could not be completed. Instead, the time when access was lost to experimental facilities was used to complete a systematic review and meta-analysis on the extent of behavioural thermoregulation in freshwater fishes. The results revealed that across the literature, while behavioural thermoregulation is a feature of many fish populations, this has primarily been measured as a response to warming temperatures by salmonid fishes, with most studies completed in North America. The extent of the temperature difference between these habitats decreased with increasing latitude, with juvenile and non-migratory fishes tolerating greater temperature differences than adult and anadromous. Median temperature differences between the warm water and cool water refuge was 3.8oC.
Progress beyond state-of-the-art are:
Application of biotelemetry to riverine fishes
Our application of acoustic transmitters fitted with temperature sensors enabled the measurement of fish movements and their physiology so that we could map their physical and thermal habitat use and in relation to their behavioural ecology.
Quantifying pace-of-life syndromes in riverine fishes
We have quantified how the behavioural and thermal phenotypes of river fishes correlate for the first time, with the resultant pace-of-life-syndrome providing novel insights into the extent of intra-specific phenotypic diversity in fish populations and its implications for population resilience to environmental change, especially climate change.
Results to date are:
- Publication of the systematic review and meta-analysis on behavioural thermoregulation in freshwater fish
- All analyses and preparation of the manuscript of behavioural phenotypes of European barbel
Expected results are:
- The extent of expressed behavioural thermoregulation in two riverine fish species in a lowland river
- Pace-of-life-syndrome of European barbel (integration of behaviour and thermal phenotypes).
Impacts of these results will be on fish and fisheries management, river habitat management and climate change mitigation programmes. The results will directly inform how lowland rivers can be managed to ensure sustainability in their fish communities in the face of increasing water temperatures. From a socio-economic perspective, this project will have a large impact across Europe, as regulators and conservation managers learn more on how they should better manage river habitats to reduce the effects of warming and maintain phenotypic diversity in fish communities.
Application of biotelemetry to riverine fishes
Our application of acoustic transmitters fitted with temperature sensors enabled the measurement of fish movements and their physiology so that we could map their physical and thermal habitat use and in relation to their behavioural ecology.
Quantifying pace-of-life syndromes in riverine fishes
We have quantified how the behavioural and thermal phenotypes of river fishes correlate for the first time, with the resultant pace-of-life-syndrome providing novel insights into the extent of intra-specific phenotypic diversity in fish populations and its implications for population resilience to environmental change, especially climate change.
Results to date are:
- Publication of the systematic review and meta-analysis on behavioural thermoregulation in freshwater fish
- All analyses and preparation of the manuscript of behavioural phenotypes of European barbel
Expected results are:
- The extent of expressed behavioural thermoregulation in two riverine fish species in a lowland river
- Pace-of-life-syndrome of European barbel (integration of behaviour and thermal phenotypes).
Impacts of these results will be on fish and fisheries management, river habitat management and climate change mitigation programmes. The results will directly inform how lowland rivers can be managed to ensure sustainability in their fish communities in the face of increasing water temperatures. From a socio-economic perspective, this project will have a large impact across Europe, as regulators and conservation managers learn more on how they should better manage river habitats to reduce the effects of warming and maintain phenotypic diversity in fish communities.