| 1. |
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Aquatic Conservation with Focus on Margaritifera margaritifera : Proceedings of the International Conference in Sundsvall, Sweden, 12-14 August, 2009
- 2012
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Proceedings (redaktörskap) (övrigt vetenskapligt/konstnärligt)abstract
- The freshwater pearl mussel Margaritifera margaritifera (L.) has attracted a large human interest, since the mussel is fascinating from biological, cultural andenvironmental perspectives. The mussel has a complicated life cycle dependingon host fish, and has great demands on its habitat. Furthermore, the mussel is anenvironmental indicator, and is used as an umbrella and flagship species. Pearl fishing has been described in Sweden as early as in the 16th century and by Carl Linnaeus in the 18th century.Many freshwater pearl mussel populations have insufficient recruitment and therefore decrease in numbers, and many populations are even extinct. Therefore, conservation work on the freshwater pearl mussel is going on all over Europe. Actions to preserve the freshwater pearl mussel will also favour other aquatic species – freshwater pearl mussel conservation is aquatic biodiversity conservation! WWF (World Wide Fund for Nature) Sweden implemented the project “The Freshwater Pearl Mussel and its habitats in Sweden” during 2004-2009 (LIFE04NAT/SE/000231). The overall objective was to improve the habitats of juvenile freshwater pearl mussels and the host fish brown trout Salmo trutta in21 streams. The actions were improvements of the biotopes, re-introduction of mussels, information to the stakeholders, and development of planning methods. An international conference “Aquatic Conservation with Focus on the Freshwater Pearl Mussel Margaritifera margaritifera” was held in Sundsvall 12–14 August, 2009. In these proceedings, presentations from the conference are published.
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| 2. |
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| 3. |
- Arvidsson, Björn L, 1952-, et al.
(författare)
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Recruitment of the threatened mussel Margaritifera margaritifera in relation to mussel population size, mussel density and host density
- 2012
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Ingår i: Aquatic conservation. - Malden, MA : John Wiley & Sons. - 1052-7613 .- 1099-0755. ; 22, s. 526-532
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Tidskriftsartikel (refereegranskat)abstract
- Anthropogenic, abiotic factors are considered main causes of recruitment failure of unionid mussels, including the freshwater pearl mussel (Margaritifera margaritifera). In this large-scale investigation, we instead examined the relationship between biotic factors and mussel recruitment.Juvenile mussel density was positively related to both mussel population size and density of which the last appeared to be a more accurate measure of recruitment.Host fish density of young-of-the-year and older brown trout (Salmo trutta) were positively related to recruitment. Moreover, the mean density of both age classes of fish, when grouped into density classes was positively related to juvenile mussel density, an effect that decreased at trout densities above 10 trout 100 m-2.There was a higher relative importance of mussel population size and density than trout density to recruitment.To increase recruitment of juvenile mussels, managers may apply measures that increase mussel density, and trout density up to about 10 trout 100 m-2 in connection to mussel beds. Mussel beds may also be managed and one possible measure within small and sparse mussel populations may be to concentrate the remaining mussels to areas where trout density is high. Likewise, young-of-the-year trout may also be moved to areas of high mussel density, as young trout individuals are relatively resident during their first year. This may increase mussel larval infection rates and mussel recruitment.
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| 4. |
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| 6. |
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| 7. |
- Calles, Olle, 1974-, et al.
(författare)
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Fish Migration River Monitoring Plan
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Fish have problems passing the Afsluitdijk Dam that separates the Wadden Sea from Lake IJsselmeer. To re-establish the connectivity and thereby allow fish to pass there is an initiative to build a fishway, the Fish Migration River (FMR), at the Konwerderzand sluice complex. This report proposes a monitoring program to evaluate the functionality of the FMR, but also to monitor passage possibilities through the existing sluices. The goals of the monitoring plan are to estimate 1) The overall passage past the Afsluitdijk dam to and from Lake IJsselmeer, 2) The attraction efficiency, 3) The passage efficiency, and 4) The use of the FMR as habitat and for acclimatization for the transition into freshwater.We present an overview of previous and ongoing monitoring in the area to establish the current state of knowledge. The report also includes a presentation of available and suitable methods for a future monitoring program considering the broad spectra of target fish species, and their abundances. The proposed program includes a description of study design and available techniques and cost-estimates of the monitoring program.The proposed program will target ten species: European eel (aal), flounder (bot), three-spined stickleback (dreidoornige stekelbaars), twait shad (fint), North Sea houting (houting), river lamprey (rieverprik), smelt (spiering), Atlantic salmon (zalm), brown trout (forel) and sea lamprey (zeeprik). The monitoring program includes plans for how to capture, tag and track the study fish using the most suitable tagging techniques. Furthermore, the most optimal sites for installation of automatic data detection stations are identified.The total cost for the proposed project is 3.5 M€ and covers both investments in equipment and costs for personnel. However, if costs for investments in techniques such as RFId-stations and fish counters are excluded, the total cost is reduced to 1 M€ for a program running two years before and four years after the completion of the FMR. The program is considered sufficient to evaluate the FMR at Kornwerederzand from the most important perspectives: the overall passage efficiency and the use of the FMR as habitat.It should be noted that this report is the first step towards a full-scale monitoring program, giving insight into possible methods, study design and associated costs. The next important step will be to develop the program in more detail and to start the initial phase of the monitoring project. We predict that such activities will identify the need for, and the relevance of, a more extensive monitoring program to study the effects of the FMR on a population level and on a large geographical scale.
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| 8. |
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| 9. |
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| 10. |
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| 11. |
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| 12. |
- Eggers, Florian, et al.
(författare)
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Methods for the Assessment of Fishways (Upstream Fish Passage)
- 2024
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Ingår i: Advances in Hydraulic Research. - : Springer Science+Business Media B.V.. - 9783031560927 ; , s. 67-79
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Fragmentation of rivers by manmade barriers has impeded the ability of riverine fish to move freely. Barriers can be improved by fishways that can partially mitigate the negative impacts by acting as aquatic corridors. Effective fishways require knowledge about the physiological and spatial demands of fish species, but the existing knowledge largely derived from laboratory settings. Evaluating fishway performance is needed for optimisation of their hydraulic design and positioning. Qualitative methods include trapping, electrofishing, and camera observations to estimate the number of individuals passing (effectiveness). For quantitative assessment, the study of individual fish behaviour can identify fishway sections in need of improvement and estimate associated efficiencies. This can be accomplished by telemetric techniques such as PIT tagging, radio, and hydroacoustic telemetry.
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| 13. |
- Ferreira-Rodríguez, Noé, et al.
(författare)
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Freshwater Mussels as Sentinels for Safe Drinking Water Supply in Europe
- 2023
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Ingår i: ACS - ES & T Water. - : American Chemical Society (ACS). - 2690-0637. ; 3:12, s. 3730-3735
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Tidskriftsartikel (refereegranskat)abstract
- In the context of the European Union (EU) Drinking Water Directive, freshwater mussels (Order Unionoida: Bivalvia) can help us face the challenges of safe drinking water provisions for all citizens in the EU. Specifically, the implementation of high frequency noninvasive (HFNI) valvometers allows the early detection of eventual pollution events in drinking water treatment plants. Currently real-time behavioral analysis is deployed in a number of EU countries, and we foresee a bright future as new technological advances are developed concerning HFNI valvometers.
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| 14. |
- Filipsson, Karl, et al.
(författare)
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Do predator odours and warmer winters affect growth of salmonid embryos?
- 2023
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Ingår i: Ecology of Freshwater Fish. - : John Wiley & Sons. - 0906-6691 .- 1600-0633. ; :1
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Tidskriftsartikel (refereegranskat)abstract
- Conditions early in ontogeny can have considerable effects later on in life. Many salmonids spawn during the autumn, and temperature during subsequent embryogenesis may have far-reaching effects on life-history traits, especially when considering ongoing climate change. Even biotic conditions during embryogenesis, such as predation threat, may affect later life stages. Here, we examined how predator odours and increased temperatures affect embryonic growth and development of a fish (brown trout Salmo trutta). We found that embryos had lower body mass and greater yolk volume close to hatching when subjected to predator odours. Trout embryos incubated at temperatures representing natural winter conditions were larger than embryos incubated at higher temperatures, although the latter hatched earlier. Fry sizes at emergence did not differ between treatments, perhaps because of compensatory growth during spring. This study shows that predator presence can have similar effects on embryonic growth of salmonids as warming winters, with possible impact later in ontogeny.
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| 15. |
- Filipsson, Karl
(författare)
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Early life stages of brown trout - Anti-predator responses under warming winters
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- During winter, juvenile salmonids in boreal streams are vulnerable to predation, mainly from mammals and birds. Encounters with terrestrial predators can be reduced or avoided if fish limit activity to the darker periods of the day or to periods with surface ice. As piscivorous fish also are active in winter, they may be a threat under low light conditions when juvenile salmonids do not avoid terrestrial predators. Abiotic conditions, especially temperature, have major effects on fish in winter. High temperatures alter ice conditions in winter and lead to increased metabolism and physiological performance of fish. Water temperature also influences embryogenesis, with repercussions for fish throughout their life. Considering the rapid warming of winters in boreal regions, insights into how salmonids are adapted to winter conditions can aid in efforts to predict and mitigate anthropogenic effects that alter the winter environment.In this doctoral thesis, I explore anti-predator responses of brown trout (Salmo trutta) during its early life stages. I have examined the effects of predators, temperature, light and ice on the behaviour and physiology of juvenile trout during winter. In addition, I have studied how temperature and predators affect embryogenesis and the behaviour of fry after hatching. Anti-predator responses were evident in both the behaviour and physiology of juveniles and during embryogenesis. Trout exhibited diel behavioural changes when piscivorous fish were present, and were more vigilant towards piscivorous fish in darkness. Furthermore, temperature affected trout behaviour and physiology, with higher activity levels and lower mRNA expression of stress-related genes at higher temperatures. Trout also behaved differently depending on the temperature they experienced as eggs, as increased egg-incubation temperatures resulted in trout being more active and prone to risk taking.
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| 16. |
- Filipsson, Karl, et al.
(författare)
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Effects of temperature and a piscivorous fish on diel winter behaviour of juvenile brown trout (Salmo trutta)
- 2019
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Ingår i: Freshwater Biology. - : Wiley. - 0046-5070 .- 1365-2427. ; 64:1+, s. 1797-1805
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Tidskriftsartikel (refereegranskat)abstract
- Low winter temperatures constrain predator-detection and escape capabilities, making poikilotherms vulnerable to predation. Investigations of temperature effects on predator-prey interactions can therefore be of special importance in light of ongoing climate change, where winter temperatures are predicted to increase substantially at northern latitudes. Behavioral responses of stream fishes to terrestrial predators in winter are well recognised, whereas responses to predatory fish have received little attention. Using stream flumes, we examined the anti-predator behaviour of one-summer-old brown trout (Salmo trutta) at 3 and 8 degrees C in the presence and absence of burbot (Lota lota) under night, dawn, and daylight conditions. Burbot was placed upstream of the trout, separated by net screens. Lower temperature and the presence of burbot reduced trout activity. Light increased trout shelter use, and trout sheltered more in the presence of burbot. An interaction between the presence of burbot and light conditions affected trout position in the flumes: at night and dawn, trout positioned themselves further downstream when burbot were present than when absent, whereas during the day, trout maintained the same position in the presence or absence of the predator. Our results suggest that piscivorous fish, in addition to terrestrial predators, shape the behaviour of prey fishes in streams during winter. We show how predator avoidance results in altered diel patterns of juvenile brown trout under winter conditions, and that temperature has additional effects on trout behaviour.
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| 17. |
- Filipsson, Karl, et al.
(författare)
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Encystment of parasitic freshwater pearl mussel (Margaritifera margaritifera) larvae coincides with increased metabolic rate and haematocrit in juvenile brown trout (Salmo trutta)
- 2017
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Ingår i: Parasitology Research. - : Springer Science and Business Media LLC. - 0932-0113 .- 1432-1955. ; 116, s. 1353-1360
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Tidskriftsartikel (refereegranskat)abstract
- © 2017 The Author(s)Gill parasites on fish are likely to negatively influence their host by inhibiting respiration, oxygen transport capacity and overall fitness. The glochidia larvae of the endangered freshwater pearl mussel (FPM, Margaritifera margaritifera (Linnaeus, 1758)) are obligate parasites on the gills of juvenile salmonid fish. We investigated the effects of FPM glochidia encystment on the metabolism and haematology of brown trout (Salmo trutta Linnaeus, 1758). Specifically, we measured whole-animal oxygen uptake rates at rest and following an exhaustive exercise protocol using intermittent flow-through respirometry, as well as haematocrit, in infested and uninfested trout. Glochidia encystment significantly affected whole-animal metabolic rate, as infested trout exhibited higher standard and maximum metabolic rates. Furthermore, glochidia-infested trout also had elevated levels of haematocrit. The combination of an increased metabolism and haematocrit in infested fish indicates that glochidia encystment has a physiological effect on the trout, perhaps as a compensatory response to the potential respiratory stress caused by the glochidia. When relating glochidia load to metabolism and haematocrit, fish with low numbers of encysted glochidia were the ones with particularly elevated metabolism and haematocrit. Standard metabolic rate decreased with substantial glochidia loads towards levels similar to those of uninfested fish. This suggests that initial effects visible at low levels of encystment may be countered by additional physiological effects at high loads, e.g. potential changes in energy utilization, and also that high numbers of glochidia may restrict oxygen uptake by the gills.
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| 18. |
- Filipsson, Karl, 1991-
(författare)
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From behaviour to genes: anti-predator responses of brown trout (Salmo trutta) under winter conditions
- 2020
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Temperature has major effects on the performance of poikilotherms. In encounters with predators, low winter temperatures constrain predator detection and escape capabilities in prey fishes. Most studies of the anti-predator responses of fish under winter conditions focus on endothermic terrestrial predators, whereas effects of piscivorous fish are generally overlooked. The studies presented in this thesis explore behavioural and physiological responses of juvenile brown trout (Salmo trutta) at winter temperatures of 3 and 8 °C in the presence and absence of a winter-active piscivorous fish (burbot, Lota lota). In Paper I, I report behavioural responses of trout in relation to the time of day. At the lower temperature and in the presence of burbot, trout reduced their activity. Trout used overhead shelter the most during the day and in the presence of burbot. Trout also spatially avoided burbot at night and at dawn but not during the day. In Paper II, I examined plasma cortisol and mRNA expression of stress-related genes. A redundancy analysis showed that both temperature and the presence of burbot explained a significant amount of the observed variation. Trout had higher cortisol levels when exposed to the burbot. Analyses of individual gene expressions revealed that trout had higher mRNA expression at 3 than at 8 °C for 11 of the 16 examined genes. Only one gene, RBP1, was expressed to a higher degree in the presence of burbot, but there were also interaction effects between temperature and burbot presence for two genes coding for serotonin and glucocorticoid receptors. My studies show that piscivorous fish shape anti-predator responses of juvenile brown trout, both behaviourally and at the gene level, under winter conditions. The observed thermal effects on mRNA levels underscore the importance of temperature in fish stress responses, with implications for stream salmonids in a warmer climate.
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| 19. |
- Filipsson, Karl, et al.
(författare)
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Heavy loads of parasitic freshwater pearl mussel (Margaritifera margaritifera L.) larvae impair foraging, activity and dominance performance in juvenile brown trout (Salmo trutta L.)
- 2018
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Ingår i: Ecology of Freshwater Fish. - : Wiley. - 0906-6691 .- 1600-0633. ; 27:1, s. 70-77
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Tidskriftsartikel (refereegranskat)abstract
- © 2016 John Wiley & Sons A/S.The life cycle of the endangered freshwater pearl mussel (Margaritifera margaritifera) includes a parasitic larval phase (glochidia) on the gills of a salmonid host. Glochidia encystment has been shown to affect both swimming ability and prey capture success of brown trout (Salmo trutta), which suggests possible fitness consequences for host fish. To further investigate the relationship between glochidia encystment and behavioural parameters in brown trout, pairs (n = 14) of wild-caught trout (infested vs. uninfested) were allowed to drift feed in large stream aquaria and foraging success, activity, agonistic behaviour and fish coloration were observed. No differences were found between infested and uninfested fish except for in coloration, where infested fish were significantly darker than uninfested fish. Glochidia load per fish varied from one to several hundred glochidia, however, and high loads had significant effects on foraging, activity and behaviour. Trout with high glochidia loads captured less prey, were less active and showed more subordinate behaviour than did fish with lower loads. Heavy glochidia loads therefore may negatively influence host fitness due to reduced competitive ability. These findings have implications not only for management of mussel populations in the streams, but also for captive breeding programmes which perhaps should avoid high infestation rates. Thus, low levels of infestation on host fish which do not affect trout behaviour but maintains mussel populations may be optimal in these cases.
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| 20. |
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| 21. |
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| 22. |
- Filipsson, Karl, et al.
(författare)
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Temperature and predator-mediated regulation of plasma cortisol and brain gene expression in juvenile brown trout (Salmo trutta)
- 2020
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Ingår i: Frontiers in Zoology. - : BioMed Central. - 1742-9994. ; 17:1
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Tidskriftsartikel (refereegranskat)abstract
- Background Temperature affects many aspects of performance in poikilotherms, including how prey respond when encountering predators. Studies of anti-predator responses in fish mainly have focused on behaviour, whereas physiological responses regulated through the hypothalamic-pituitary-interrenal axis have received little attention. We examined plasma cortisol and mRNA levels of stress-related genes in juvenile brown trout (Salmo trutta) at 3 and 8 degrees C in the presence and absence of a piscivorous fish (burbot,Lota lota). Results A redundancy analysis revealed that both water temperature and the presence of the predator explained a significant amount of the observed variation in cortisol and mRNA levels (11.4 and 2.8%, respectively). Trout had higher cortisol levels in the presence than in the absence of the predator. Analyses of individual gene expressions revealed that trout had significantly higher mRNA levels for 11 of the 16 examined genes at 3 than at 8 degrees C, and for one gene (retinol-binding protein 1), mRNA levels were higher in the presence than in the absence of the predator. Moreover, we found interaction effects between temperature and predator presence for two genes that code for serotonin and glucocorticoid receptors. Conclusions Our results suggest that piscivorous fish elicit primary stress responses in juvenile salmonids and that some of these responses may be temperature dependent. In addition, this study emphasizes the strong temperature dependence of primary stress responses in poikilotherms, with possible implications for a warming climate.
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| 23. |
- Filipsson, Karl, et al.
(författare)
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Temperature during embryonic development in brown trout influences juvenile behaviour in encounters with predators
- 2024
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Ingår i: Journal of Zoology. - : John Wiley & Sons. - 0952-8369 .- 1469-7998. ; 322:3, s. 241-250
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Tidskriftsartikel (refereegranskat)abstract
- Variation in thermal conditions during embryogenesis can have far-reaching impact throughout ontogeny and may give rise to behavioural variation. Many animals, such as salmonids, exhibit behavioural trade-offs related to foraging and predator avoidance. How embryonic temperature affects these behaviours has remained unexplored. Not only abiotic conditions during embryogenesis but also biotic factors such as predator conditioning may affect fish behaviour, especially anti-predator responses. We examined how elevated temperatures and predator odours throughout embryogenesis affect the behaviour of 28-37 mm young-of-the-year brown trout (Salmo trutta) in encounters with predators, namely Atlantic salmon (Salmo salar; 20 cm) and burbot (Lota lota; 40 cm). Juvenile brown trout were more active and aggressive if they were incubated in warmer water as eggs than if they were incubated in colder water, and trout remained inactive longer when encountering predators if they were cold incubated. Brown trout were less active and aggressive when an Atlantic salmon was present than when a burbot or no predator was present. Behavioural responses did not differ between trout that had been subjected to water with versus without predator odours during embryogenesis, possibly because brown trout were not subjected to conspecific alarm cues during egg incubation. This study shows that thermal conditions during embryogenesis can influence fish behaviour early in life and thus contribute to behavioural variation, with potential effects on life history. Considering the rapid warming of northern regions, elevated embryonic temperatures may contribute substantially to variation in salmonid behaviour in the near future. Variation in environmental conditions during embryogenesis of salmonids can have far-reaching impact throughout ontogeny and may give rise to variation in anti-predator behaviour. In a laboratory experiment, we showed that elevated temperatures throughout embryogenesis increased the activity and aggression of 28-37 mm brown trout fry and reduced the time to first movement in encounters with predators (burbot and Atlantic salmon). Predator odour during embryogenesis did not affect brown trout fry behaviour.image
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| 24. |
- Filipsson, Karl, et al.
(författare)
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Winter Behavior of Juvenile Brown Trout in a Changing Climate : How Do Light and Ice Cover Affect Encounters with Instream Predators?
- 2023
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Ingår i: Fishes. - 2410-3888. ; 8:10
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- During winter, stream fishes are vulnerable to semi-aquatic predators like mammals and birds and reduce encounters by being active in darkness or under surface ice. Less is known about the behavior of fishes towards instream piscivorous fishes. Here, we examined how surface ice and light affected the anti-predator behavior of juvenile brown trout (Salmo trutta Linnaeus, 1758) in relation to piscivorous burbot (Lota lota Linnaeus, 1758) and northern pike (Esox lucius Linnaeus, 1758) at 4 degrees C in experimental flumes. Trout had lower foraging and swimming activity and spent more time sheltering when predators were present than when absent. In daylight, trout's swimming activity was not affected by predators, whereas in darkness trout were less active when predators were present. Trout consumed more drifting prey during the day when ice was present, and they positioned themselves further upstream when under ice cover, regardless of light conditions. Trout stayed closer to conspecifics under ice, but only in the presence of pike. Piscivorous fishes thus constitute an essential part of the predatory landscape of juvenile trout in winter, and thus loss of ice cover caused by climate warming will likely affect trout's interactions with predators.
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| 25. |
- Geist, Juergen, et al.
(författare)
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Captive breeding of European freshwater mussels as a conservation tool : A review
- 2023
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Ingår i: Aquatic conservation. - : John Wiley & Sons. - 1052-7613 .- 1099-0755. ; 33:11, s. 1321-1359
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Tidskriftsartikel (refereegranskat)abstract
- Freshwater mussels are declining throughout their range. Their important ecological functions along with insufficient levels of natural recruitment have prompted captive breeding for population augmentation and questions about the usefulness and applicability of such measures. This article reviews the current state of captive breeding and rearing programmes for freshwater mussels in Europe. It considers the various species, strategies, and techniques of propagation, as well as the different levels of effort required according to rearing method, highlighting the key factors of success. Within the last 30 years, 46 breeding activities in 16 European countries have been reported, mainly of Margaritifera margaritifera and Unio crassus. Some facilities propagate species that are in a very critical situation, such as Pseudunio auricularius, Unio mancus, and Unio ravoisieri, or multiple species concurrently. In some streams, the number of released captive-bred mussels already exceeds the size of the remaining natural population. Rearing efforts range from highly intensive laboratory incubation to lower intensity methods using in-river mussel cages or silos. Most breeding efforts are funded by national and EU LIFE(+) grants, are well documented, and consider the genetic integrity of the propagated mussels. Limited long-term funding perspectives, the availability of experienced staff, water quality, and feeding/survival during early life stages are seen as the most important challenges. Successful captive breeding programmes need to be combined with restoration of the habitats into which the mussels are released. This work will benefit from an evidence-based approach, knowledge exchange among facilities, and an overall breeding strategy comprising multiple countries and conservation units.
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| 26. |
- Gomes-Dos-Santos, A., et al.
(författare)
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The Crown Pearl : a draft genome assembly of the European freshwater pearl mussel Margaritifera margaritifera (Linnaeus, 1758)
- 2021
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Ingår i: DNA research. - : Oxford University Press. - 1340-2838 .- 1756-1663. ; 28:2
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Tidskriftsartikel (refereegranskat)abstract
- Since historical times, the inherent human fascination with pearls turned the freshwater pearl mussel Margaritifera margaritifera (Linnaeus, 1758) into a highly valuable cultural and economic resource. Although pearl harvesting in M. margaritifera is nowadays residual, other human threats have aggravated the species conservation status, especially in Europe. This mussel presents a myriad of rare biological features, e.g. high longevity coupled with low senescence and Doubly Uniparental Inheritance of mitochondrial DNA, for which the underlying molecular mechanisms are poorly known. Here, the first draft genome assembly of M. margaritifera was produced using a combination of Illumina Paired-end and Mate-pair approaches. The genome assembly was 2.4 Gb long, possessing 105,185 scaffolds and a scaffold N50 length of 288,726 bp. The ab initio gene prediction allowed the identification of 35,119 protein-coding genes. This genome represents an essential resource for studying this species' unique biological and evolutionary features and ultimately will help to develop new tools to promote its conservation.
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| 27. |
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| 28. |
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| 29. |
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| 30. |
- Gustafsson, Stina, 1985-
(författare)
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Habitat compensation in nature-like fishways : Effects on benthos and fish
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The construction of nature-like fishways has become an increasingly common measure to restore longitudinal connectivity in streams and rivers affected by hydroelectric development. These fishways also have the potential to function as habitat compensation measures when running waters have been degraded or lost. The habitat potential has however often been overlooked, and therefore the aim of this thesis was to examine the potential of nature-like fishways for habitat compensation, with special focus on the effect of added habitat heterogeneity.This thesis examines the effects of habitat diversity on the macroinvertebrate family composition and functional organization in a nature-like, biocanal-type fishway. The biocanal contained four habitat types; riffle, pool, braided channel and floodplain. The effects of habitat diversity and large woody debris on brown trout habitat choice was also investigated in the biocanal. In addition, and prior to introduction of the threatened freshwater pearl mussel into the biocanal, the suitability of different brown trout strains as hosts for the mussel was examined.The results show that the habitat heterogeneity in the biocanal contributed to an increased macroinvertebrate family diversity. The functional organization of the macroinvertebrate community suggests that it was a heterotrophic system and more functionally similar to the main river than to the small streams that it was created to resemble. Brown trout habitat choice studies showed that high densities of large woody debris increase the probability of fish remaining at the site of release. Testing of different brown trout strains as host for the freshwater pearl mussel revealed that both wild and hatchery-reared brown trout strains were suitable hosts. In summary, the results indicate that it is possible to create a fish passage with added value through its high habitat function and that nature-like fishways can be designed to reach multiple species restoration goals.
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| 31. |
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| 32. |
- Gustafsson, Stina, et al.
(författare)
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Macroinvertebrate colonization of a nature-like fishway : The effects of adding habitat heterogeneity
- 2013
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Ingår i: Ecological Engineering: The Journal of Ecosystem Restoration. - : Elsevier BV. - 0925-8574. ; 61, s. 345-353
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Tidskriftsartikel (refereegranskat)abstract
- Nature-like fishways are designed to imitate the characteristics of natural streams, thereby providing both fish passage and habitat for a variety of aquatic organisms. To date, however, the potential for habitat rehabilitation of nature-like fishways has not been fully realized. To develop the concept of how to design a nature-like fishway, a 500-m long nature-like fishway, termed the biocanal, was constructed at the Eldforsen hydroelectric facility, Sweden. It included four habitat types: riffle, pool, floodplain and braided (i.e. with islands), each replicated three times. The riffle sections were considered controls for typical Swedish nature-like fishways. Thus the biocanal had a more varied in-stream environment than those of conventional fishways. To test the prediction that the biocanal had a positive effect on biodiversity, we compared the physical habitat and benthic fauna composition of the more diverse habitat types in the biocanal to the riffle habitats. We also made comparisons between the biocanal and six natural reference streams in the area. After two years, 63% of the benthic fauna families found in the reference streams had colonized the biocanal. Families present in the reference streams, but not in the biocanal, were predominantly slow colonizers or taxa linked to riparian vegetation, which was scarce and in an early successional stage along the biocanal. In the biocanal, pool and floodplain habitats contained the highest number of families, the highest family diversity (Shannon-Weaver) and the highest densities of Ephemeroptera, Plecoptera and Trichoptera. Since these habitats contained more families and had higher diversities than the riffle habitats which are typical of conventional nature-like fishways, we suggest that the construction of biocanals indeed possesses the potential for high biodiversity. (C) 2013 Elsevier B.V. All rights reserved.
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| 33. |
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| 34. |
- Gustafsson, Stina
(författare)
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The Macroinvertebrate Community in a Nature-like Fishway with Habitat Compensation Properties
- 2012
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Nature-like fishways are often constructed to restore connectivity in streams exploited for hydropower. They also have the potential to compensate for important habitats that have been degraded or lost. The aim of this thesis was to improve knowledge of the concept of nature-like fishway design, with special focus on their habitat compensation potential. This was done by comparing a nature-like fishway with four different habitat types, termed the biocanal, to six nearby natural reference creeks. In paper I the macroinvertebrate colonization of the biocanal was studied and the community composition was compared to that of the natural reference creeks.Furthermore, the potential for the biocanal to contain a diverse macroinvertebrate fauna was investigated. The results showed that the species composition of the benthic fauna in the biocanal was approaching that of the reference creeks and that the different habitat types in the biocanal contributed to the increased family diversity. In paper II the functional organization of the biocanal was studied using the functional feeding group approach. The results showed that after two years, the functional organization in the biocanal resembles that of the natural reference creeks.
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| 35. |
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| 36. |
- Harbicht, Andrew, et al.
(författare)
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Environmental and anthropogenic correlates of migratory speeds among Atlantic salmon smolts
- 2021
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Ingår i: Rivers Research and Applications. - : Wiley. - 1535-1459 .- 1535-1467. ; 37:3, s. 358-372
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Tidskriftsartikel (refereegranskat)abstract
- Dams, weirs, and hydropower facilities are often cited as migratory barriers which impart significant reductions in fitness among migratory fish species. Even where upstream and downstream passage options are available, barrier passage can still often result in energetic or physical costs which compound delays or cause mortality. Past studies have identified variables associated with such fitness reductions, though few examine their effects in the context of the whole river scale. To this end, we assessed the migratory rates and downstream passage of radio-tagged Atlantic salmon (Salmo salar) smolts through nine river sections (including two reservoir sections and one dammed section) along a 20 km stretch of river. Migration stoppages were not found to be elevated in reservoir or dammed sections, while migration rates were best described by physical river properties (width), biological traits (smolt total length), and seasonal variables (diel period) rather than anthropogenic factors. These results suggest the negative effect of reservoirs may primarily be due to their influence on river width and may be negligible when width is largely unaffected by an impoundment. Similarly, spilling water during fish migrations as a mitigative measure appears to make delays negligible. These conditions and actions may not completely marginalize the effect of dams, however, as a negative trend was still observed resulting from passage effects at the dam.
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| 37. |
- Hart, Paul BJ, et al.
(författare)
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Familiarity with a partner facilitates the movementof drift foraging juvenile grayling (Thymallus thymallus) into a new habitatarea
- 2014
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Ingår i: Environmental Biology of Fishes. - : Springer Science and Business Media LLC. - 0378-1909 .- 1573-5133. ; 97:5, s. 515-522
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Tidskriftsartikel (refereegranskat)abstract
- Preferring one social partner over another can enhance fitness. This paper reports that juvenile grayling were significantly more likely to enter and forage in new, upstream habitats when paired with familiar versus unfamiliar social partners. Fish paired with unfamiliar partners or when alone were more reluctant to enter the new area. The entry times for both fish in a familiar pair were significantly correlated, but uncorrelated for unfamiliar fish. These differences between familiars and unfamiliars were consistent over a 2-week period. Fish with familiar partners spent more time within three body lengths of each other than did those with unfamiliars. The results are discussed in relation to optimality models of drift foraging, which do not included sociality. It is suggested that the social dimension creates a more dynamic foraging response to variable environmental conditions and could have consequences for growth.
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| 38. |
- Lafage, Denis, et al.
(författare)
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Local and landscape drivers of aquatic-to-terrestrial subsidies in riparian ecosystems : A worldwide meta-analysis
- 2019
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Ingår i: Ecosphere. - : John Wiley & Sons. - 2150-8925 .- 2150-8925. ; 10:4, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- Cross-boundary fluxes of organisms and matter, termed “subsidies,” are now recognized to be reciprocal and of roughly equal importance for both aquatic and terrestrial systems, even if terrestrial input to aquatic ecosystems has received most attention. The magnitude of aquatic-to-terrestrial subsidies is well documented, but the drivers behind these subsidies and their utilization by terrestrial consumers are characteristically local-scale studies, limiting the inferences that can be drawn for broader geographic scales. We therefore built and analyzed a database of stable isotope data extracted from 21 studies worldwide, to identify both landscape-scale (catchment) and local-scale (100-m riparian zone) variables that may affect the diet of terrestrial predators in riparian ecosystems. Our meta-analysis revealed a greater magnitude of aquatic-to-terrestrial subsidies (>50%) than previously reported, albeit with large geographic and inter-annual variations. Moreover, we demonstrated a large effect of landscape-scale factors on aquatic-to-terrestrial subsidies, particularly anthropogenic land use and tree cover. Local human population was the only relevant factor at the local scale. We also found that studies on landscape-scale and anthropogenic land use effects on aquatic-to-terrestrial subsidies are strongly under-represented in the ecological literature, which limits the general inferences that can currently be drawn about landscape effects. We suggest that landscape-scale studies could improve our understanding of how land use and environmental change might influence future patterns of biodiversity and ecosystem function.
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| 39. |
- Lopes-Lima, M., et al.
(författare)
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Integrative phylogenetic, phylogeographic and morphological characterisation of the Unio crassus species complex reveals cryptic diversity with important conservation implications
- 2024
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Ingår i: Molecular Phylogenetics and Evolution. - : Academic Press Inc.. - 1055-7903 .- 1095-9513. ; 195
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Tidskriftsartikel (refereegranskat)abstract
- The global decline of freshwater mussels and their crucial ecological services highlight the need to understand their phylogeny, phylogeography and patterns of genetic diversity to guide conservation efforts. Such knowledge is urgently needed for Unio crassus, a highly imperilled species originally widespread throughout Europe and southwest Asia. Recent studies have resurrected several species from synonymy based on mitochondrial data, revealing U. crassus to be a complex of cryptic species. To address long-standing taxonomic uncertainties hindering effective conservation, we integrate morphometric, phylogenetic, and phylogeographic analyses to examine species diversity within the U. crassus complex across its entire range. Phylogenetic analyses were performed using cytochrome c oxidase subunit I (815 specimens from 182 populations) and, for selected specimens, whole mitogenome sequences and Anchored Hybrid Enrichment (AHE) data on ∼ 600 nuclear loci. Mito-nuclear discordance was detected, consistent with mitochondrial DNA gene flow between some species during the Pliocene and Pleistocene. Fossil-calibrated phylogenies based on AHE data support a Mediterranean origin for the U. crassus complex in the Early Miocene. The results of our integrative approach support 12 species in the group: the previously recognised Unio bruguierianus, Unio carneus, Unio crassus, Unio damascensis, Unio ionicus, Unio sesirmensis, and Unio tumidiformis, and the reinstatement of five nominal taxa: Unio desectus stat. rev., Unio gontierii stat. rev., Unio mardinensis stat. rev., Unio nanus stat. rev., and Unio vicarius stat. rev. Morphometric analyses of shell contours reveal important morphospace overlaps among these species, highlighting cryptic, but geographically structured, diversity. The distribution, taxonomy, phylogeography, and conservation of each species are succinctly described.
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| 40. |
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| 41. |
- Nylin, Sören, et al.
(författare)
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Embracing Colonizations : A New Paradigm for Species Association Dynamics
- 2018
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Ingår i: Trends in Ecology and Evolution. - Elsevier : Elsevier BV. - 0169-5347 .- 1872-8383. ; 33:1, s. 4-14
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Tidskriftsartikel (refereegranskat)abstract
- Parasite-host and insect-plant research have divergent traditions despite the fact that most phytophagous insects live parasitically on their host plants. In parasitology it is a traditional assumption that parasites are typically highly specialized; cospeciation between parasites and hosts is a frequently expressed default expectation. Insect-plant theory has been more concerned with host shifts than with cospeciation, and more with hierarchies among hosts than with extreme specialization. We suggest that the divergent assumptions in the respective fields have hidden a fundamental similarity with an important role for potential as well as actual hosts, and hence for host colonizations via ecological fitting. A common research program is proposed which better prepares us for the challenges from introduced species and global change. Parasites are typically assumed to be highly specialized on their hosts and well adapted to them, yet they frequently colonize new hosts - including humans, causing EIDs.This parasite paradox has caused a growing unease with the traditional assumptions in parasitology, which differ markedly from those in the field of insect-plant studies.We report the results of a workshop where parasitologists and insect-plant researchers met to explore the possibility that the two systems may be more similar than the divergent research traditions suggest, so that a common research program can be developed to better prepare us for future challenges.
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| 42. |
- Piccolo, John, 1964-, et al.
(författare)
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Future rivers, dams and ecocentrism.
- 2019
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Ingår i: The Ecological Citizen. - 2515-1967. ; 2:2, s. 173-177
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Tidskriftsartikel (refereegranskat)abstract
- In this article the authors look at the subject of ecocentrism and future rivers, focusing mainly on the effects of hydroelectric production. Although rivers also have been dammed for irrigation and flood control in addition to hydroelectricity, the production of ‘carbon-free’ energy has recently been touted as a major solution to climate change. The trade-off between clean energy and the negative impacts of hydropower offers much food for thought for ecocentric theory – how much biodiversity loss are we justified in allowing now, for example, to avert complete ecosystem collapse in the future if we continue to rely on fossil fuel? The authors intend this article to be a starting point for discussion of rivers and ecocentrism in general, and they conclude with some specific suggestions regarding rivers and hydropower.
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| 43. |
- Rock, Sebastian L., et al.
(författare)
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Effects of parasitic freshwater mussels on their host fishes : a review
- 2022
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Ingår i: Parasitology. - : Cambridge University Press. - 0031-1820 .- 1469-8161. ; 149:14, s. 1958-1975
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Tidskriftsartikel (refereegranskat)abstract
- Freshwater mussels in the order Unionida are highly adapted to parasitize fish for the primary purpose of dispersal. The parasitic larval stage affixes itself to the gills or fins of the host where it becomes encysted in the tissue, eventually excysting to develop into a free-living adult. Research on the parasitic interactions between unionids and their host fishes has garnered attention recently due to the increase in worldwide preservation efforts surrounding this highly endangered and ecologically significant order. With the exception of heavy infestation events, these mussels cause minor effects to their hosts, typically only observable effect in combination with other stressors. Moreover, the range of effect intensities on the host varies greatly with the species involved in the interaction, an effect that may arise from different evolutionary strategies between long- and short-infesting mussels; a distinction not typically made in conservation practices. Lower growth and reduced osmotic potential in infested hosts are commonly observed and correlated to infestation load. These effects are typically also associated with increases in metabolic rate and behaviour indicative of stress. Host fish seem to compensate for this through a combination of rapid wound healing in the parasitized areas and higher ventilation rates. The findings are heavily biased towards Margaritifera margaritifera, a unique mussel not well suited for cross-species generalizations. Furthermore, the small body of molecular and genetic studies should be expanded as many conclusions are drawn from studies on the ultimate effects of glochidiosis rather than proximate studies on the underlying mechanisms.
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| 44. |
- Schneider, Lea Dominique
(författare)
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Conservation ecology of the thick-shelled river mussel Unio crassus : The importance of parasite-host interactions
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Unionoid mussels are globally threatened and their conservation requires species-specific knowledge on their ecology and parasite-host interaction. Unio crassus is one of Europe’s most threatened unionoid species and has a temporary obligate parasitic life stage (glochidia) on fish. A lack of suitable hosts is probably a major limitation for mussel recruitment, but host species composition, suitability and availability in time and space have yet to be fully explored. This thesis examines different aspects of the host fish species, including their composition, suitability and ecological importance, in relation to U. crassus, using both field and laboratory studies. The effects of mussel and host density on mussel reproductive potential were considered, as were aspects of evolutionary adaptations between mussels and fish and how climate change may affect their interaction.The results show that U. crassus is a host generalist, parasitizing a variety of fish species. Host suitability and density, which varied among fish species and rivers, affected the level of glochidia encapsulation, hence mussel reproductive potential, more so than the density of mussels taking part in reproduction. Ecologically important hosts included both highly suitable primary hosts, and less suitable hosts that were highly abundant. Whether or not U. crassus has specific adaptations to its hosts to enhance juvenile transformation remains unclear. No distinct pattern of local adaptation was found, nor was there an effect of host fish presence on the timing of glochidia release by adult mussels. Instead, temperature played a major role, with results suggesting that changes in spring water temperature regimes can cause temporal and spatial mismatches in the mussel-host interaction. This thesis indicates that investigations of local mussel-host interactions help in identifying mechanisms important for unionoid conservation management and prioritization.
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| 45. |
- Schneider, Lea Dominique, et al.
(författare)
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Effects of mussel and host fish density on reproduction potential of a threatened unionoid mussel: prioritization of conservation locations in management trade-offs
- 2019
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Ingår i: Biodiversity and Conservation. - : Springer Science and Business Media LLC. - 0960-3115 .- 1572-9710. ; 28:2, s. 259-273
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Tidskriftsartikel (refereegranskat)abstract
- Management decisions in conservation of threatened species require trading off social needs against biodiversity values, including the prioritization of conservation locations, i.e. where conservation efforts should take place. To improve conservation decisions for the thick-shelled river mussel, Unio crassus, a highly threatened temporary parasite on fish, we performed a field study on how mussel and host fish density (European bullhead, Cottus gobio, and common minnow, Phoxinus phoxinus) affect reproduction potential of the mussel at different sites along a river. We assumed that the proportions of gravid mussels would be higher at high mussel density, and result in enhanced glochidia (mussel larvae) encapsulation rates on fish. We also expected the highest glochidia density'a proxy for the potential number of recruits per stream area, assessed by multiplying glochidia encapsulation rates on fish by fish density, to occur at high mussel density sites. Such river sites, producing many offspring and conveying important conservation values, may thus be prioritized. However, contrary to our assumptions, higher glochidia density and higher proportions of gravid mussels occurred at lower density mussel sites. We also found that P. phoxinus had higher glochidia encapsulation rates than C. gobio, possibly related to species-specific behavioural and life-history traits. Even so, glochidia density was similar for both fish species, reflecting comparable ecological functions in hosts. The results of this study suggest that mussel and host fish densities should be considered along with glochidia density in conservation prioritization and management trade-offs.
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| 46. |
- Schneider, Lea Dominique, et al.
(författare)
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Evaluating temperature- and host-dependent reproduction in the parasitic freshwater mussel Unio crassus
- 2018
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Ingår i: Hydrobiologia. - : Springer Science and Business Media LLC. - 0018-8158 .- 1573-5117. ; 810:1, s. 283-293
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Tidskriftsartikel (refereegranskat)abstract
- Adaptation to temperature regimes and host presence may enhance fitness in parasites. In an experimental study, we evaluated the timing of glochidia release by Unio crassus subjected to three spring water temperature regimes in the presence and absence of the host fish Cottus gobio. The timing of glochidia release was delayed at (i) constantly low temperatures (<10°C), in contrast to earlier and pronounced releases at (ii) natural temperature increases that level off at intermediate temperatures (10–15°C), and (iii) higher-than-normal temperatures (10–20°C). Mussels from treatment (i) that had not released glochidia during the experiment did so soon after being moved to the temperature in (ii), indicating a temperature threshold for glochidia release. Neither host fish presence nor the combined effect of temperature and host fish presence significantly affected the timing of glochidia release. The treatment with natural spring water temperatures indicated possible fitness benefits for U. crassus through combined effects of high intensities of glochidia releases and high survival of released glochidia. The furthered understanding of climate change effects on mussel and host phenology in seasonal environments, potentially inducing temporal mismatches of glochidia release to host availability, is key to mussel conservation.
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| 47. |
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| 48. |
- Schneider, Lea Dominique, et al.
(författare)
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Local adaptation studies and conservation: Parasite-host interactions between the endangered freshwater mussel Unio crassus and its host fish
- 2017
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Ingår i: Aquatic Conservation-Marine and Freshwater Ecosystems. - : Wiley. - 1052-7613 .- 1099-0755. ; 27:6, s. 1261-1269
-
Tidskriftsartikel (refereegranskat)abstract
- Parasite-host interactions can involve strong reciprocal selection pressure, and may lead to locally adapted specializations. The highly threatened unionoid mussels are temporary parasites on fish, but local adaptation has not yet been investigated for many species. Patterns of local adaptation of one of Europe's most threatened unionoids, the thick-shelled river mussel (Unio crassus) were investigated. Eurasian minnows (Phoxinus phoxinus) from two rivers (separate drainage areas) were cross-infested in the laboratory with sympatric and allopatric mussel larvae, while bullheads (Cottus gobio), inhabiting only one of the rivers, were infested with sympatric or allopatric mussel larvae. Larval encystment, juvenile mussel excystment and survival were measured. For one river, but not the other, juvenile excystment from P. phoxinus was highest when infested with sympatric mussels. The opposite pattern was found for C. gobio in this river, where juvenile excystment and post-parasitic juvenile survival from allopatric C. gobio were highest. The results thus cannot confirm local adaptation of U. crassus to P. phoxinus in the study rivers, as excystment was not consistently higher in all sympatric mussel-host combinations, whereas there were potential maladaptive signs of U. crassus in relation to C. gobio. There was no loss of encysted larvae 3 days after infestation until juvenile excystment. Most juveniles were excysted between 17 and 29 days after infestation, and the numbers of excysted juveniles increased with fish size. The results have implications for parasite-host ecology and conservation management with regard to unionoid propagation and re-introduction. This includes the need to (1) test suitability and adaptation patterns between U. crassus and multiple host fish species, (2) evaluate the suitability of certain unionoids and host fish strains after more than 3 days, and (3) determine whether large fish produce more juvenile mussels than smaller fish.
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| 49. |
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| 50. |
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