| 1. |
- Bourlat, Sarah, et al.
(författare)
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Wrasse fishery on the Swedish West Coast: towards ecosystem-based management
- 2021
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Ingår i: ICES Journal of Marine Science. - : Oxford University Press (OUP). - 1054-3139 .- 1095-9289. ; :fsaa249
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Tidskriftsartikel (refereegranskat)abstract
- Fishing and translocation of marine species for use in aquaculture is widespread. Corkwing, goldsinny, and ballan wrasse (Symphodus melops, Ctenolabrus rupestris, and Labrus bergylta) are fished on the Swedish west coast for use as cleaner-fish in Norwegian salmon farms. Here, we aim to provide knowledge and recommendations to support ecosystem-based management for wrasse fisheries in Sweden. We compared fished and non-fished areas to test if current fishery levels have led to stock depletion. To gain insight on the role of wrasse in the algal belt trophic chain, we analysed the gut contents of goldsinny and corkwing using metabarcoding. Finally, we analysed the trophic interactions of wrasse and potential prey in a mesocosm study. We could not detect any signs of stock depletion or altered size structure in fished areas compared to the protected control area. Gut analyses confirmed both goldsinny and corkwing as non-specialized, omnivorous opportunists and revealed, with 189 prey taxa detected, a broader spectrum of prey than previously known. Common prey items included mesoherbivores such as small gastropods and crustaceans, but also insects and algae. We conclude that there are no visible signs of stock depletion at the current removal level of wrasses by the fishery. However, this emerging fishery should be closely monitored for potential cascading effects on the algal belt ecosystem, and our study could provide a baseline for future monitoring.
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| 2. |
- De Wit, Pierre, 1978, et al.
(författare)
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A decade of progress in marine evolutionary biology
- 2022
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Ingår i: Evolutionary Applications. - : Wiley. - 1752-4571. ; 16:2, s. 193-201
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- This article summarizes the Evolutionary Applications Special Issue, “A decade of progress in Marine Evolutionary Biology.” The globally connected ocean, from its pelagic depths to its highly varied coastlines, inspired Charles Darwin to develop the theory of evolution during the voyage of the Beagle. As technology has developed, there has been a dramatic increase in our knowledge about life on our blue planet. This Special Issue, composed of 19 original papers and seven reviews, represents a small contribution to the larger picture of recent research in evolutionary biology, and how such advancements come about through the connection of researchers, their fields, and their knowledge. The first European network for marine evolutionary biology, the Linnaeus Centre for Marine Evolutionary Biology (CeMEB), was developed to study evolutionary processes in the marine environment under global change. Though hosted by the University of Gothenburg in Sweden, the network quickly grew to encompass researchers throughout Europe and beyond. Today, more than a decade after its foundation, CeMEB's focus on the evolutionary consequences of global change is more relevant than ever, and knowledge gained from marine evolution research is urgently needed in management and conservation. This Special Issue, organized and developed through the CeMEB network, contains contributions from all over the world and provides a snapshot of the current state of the field, thus forming an important basis for future research directions.
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| 3. |
- Faust, Ellika, et al.
(författare)
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Cleaner fish escape salmon farms and hybridize with local wrasse populations
- 2018
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Ingår i: Royal Society Open Science. - : The Royal Society. - 2054-5703. ; 5:3
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Tidskriftsartikel (refereegranskat)abstract
- The genetic impact of farmed fish escaping aquaculture is a highly debated issue. However, non-target species, such as cleaner fish used to remove sea lice from farmed fish, are rarely considered. Here, we report that wild corkwing wrasse (Symphodus melops), which are transported long distances to be used as cleaner fish in salmon farms, escape and hybridize with local populations. Recently, increasing numbers of corkwing wrasse have been reported in Flatanger in Norway, north of its described distribution range, an area heavily relying on the import of cleaner fish from Skagerrak. Using genetic markers identified with 2bRAD sequencing, we show that, although the Flatanger population largely is a result of a northward range expansion, there is also evidence of considerable gene flow from southern populations in Skagerrak and Kattegat. Of the 40 corkwing wrasses sampled in Flatanger, we discovered two individuals with clear southern genotypes, one first-generation hybrid, and 12 potential second-generation hybrids. In summary, we provide evidence that corkwing wrasse escape from fish farms and hybridize with local populations at the leading edge of an ongoing range expansion. Although the magnitude and significance of escapees warrant further investigation, these results should be taken into consideration in the use of translocated cleaner fish. © 2018 The Authors.
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| 4. |
- Faust, Ellika
(författare)
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Crossing barriers: Genetic consequences of translocating wild cleaner fish for aquaculture
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Several species of fish show a symbiotic cleaning behaviour, where they assist other species by feeding and removing dead skin or ectoparasites. Some of these cleaner fish species are used as a low-cost parasite control in salmon aquaculture, often considered to be more environmentally friendly than other delousing methods. Approximately 54 million cleaner fish are annually used in Norwegian salmon farms. This has resulted in an increasing fishing pressure on wild cleaner fish populations. Together with long-distance translocation, this raises concerns of potential overfishing, anthropogenic introductions, and hybridisation. Recently, increasing numbers of corkwing wrasse (Symphodus melops), have been reported in mid Norway, north of its described distribution range. This is an area heavily relying on the import and translocation of cleaner fish from Skagerrak-Kattegat, more than 1000 km away. Using genetic markers, I show that the new population is both a result of a northward range expansion, as well as a translocation of individuals from southern populations. Further investigation revealed that escapees and hybrids may constitute up to 20 % of the populations at the northern edge of the species distribution. In contrast, escapees and hybrids are rare in other parts along the Norwegian west coast, where salmon farming is also common. The set of genetic markers has a high power to detect escapees and hybrids, and can be applied to monitoring of wild populations. Investigations of corkwing wrasse in Skagerrak-Kattegat revealed reduced genetic diversity, a weak pattern of isolation by distance, and surprisingly little population structure. This suggests a very recent colonisation and high connectivity among sites in this region. Along the Swedish west coast, I evaluate the potential effects of the newly established wrasse fishery on local ecosystems and populations, and provide a baseline to support ecosystem-based management for wrasse fisheries in Sweden. I also investigate the genetic population structure of lumpfish (Cyclopterus lumpus) across the Atlantic, which is the most commonly used cleaner fish species. I show that there is a lot more structure than previously known, and identify eight genetically divergent regions. Hierarchical analysis of these regions demonstrates additional local and cryptic substructure. The genetic markers used her can also be applied for management of wild lumpfish populations and the identification of population origin. Overall, these findings provide important information both for aquaculture management and conservation of wild populations, and have implications for the increasing use and translocation of cleaner fish for parasite control in aquaculture. Moving genetic material between isolated populations could drastically alter the genetic composition and erode population structure, potentially resulting in loss of local adaptation and hampering natural range expansion. Although the ecological and evolutionary significance of escapees warrants further investigation, these results should be taken into consideration in the use of translocated cleaner fish.
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| 5. |
- Faust, Ellika
(författare)
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Genetic Identification of Corkwing Wrasse Cleaner Fish Escaping from Norwegian Aquaculture
- 2020
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The genetic impact of farmed fish escaping aquaculture is a highly debated issue. However, non-target species, such as cleaner fish that are used in fish farms to remove parasitic sea lice, are rarely considered. Here, we report that wild corkwing wrasse (Symphodus melops), which are transported long distances to be used as cleaner fish in salmon farms, escape and hybridize with local wrasse populations. Recently, increasing numbers of corkwing wrasse have been reported north of its described distribution range, in Flatanger in Trøndelag in Norway, an area heavily relying on the import of cleaner fish from Skagerrak. Using a high number of nuclear genetic markers identified with 2bRAD sequencing, we show that, although the Flatanger population is largely a result of a northward range expansion, there is also evidence of considerable gene flow from southern populations in Skagerrak. Of the 40 corkwing wrasses first sampled in Flatanger, we discovered two individuals with clear southern genotypes, one first-generation hybrid, and 12 potential second-generation hybrids. Thus, we found clear evidence of gene flow from source populations of translocated cleaner fish at the edge of an ongoing northwards range expansion. To better understand the extent of gene flow we then greatly expanded our sampling. Based on patterns of genetic divergence and homogeneity, we identified a smaller battery of 84 SNPs which is able to detect escapees with a Skagerrak origin as well as first and secondgeneration hybrids with high accuracy and power. We then used these SNPs to investigate the magnitude and geographic extent of escaping and hybridizing cleaner fish along the Norwegian coast. We found that escapees and hybrids may constitute up to 20 % of the local populations at the northern edge of the species distribution. In other parts of the Norwegian coast where salmon farming is also common, we found surprisingly few escapees and hybrids. Possible causes for few escapees and hybrids found in these areas are difficult to evaluate with the current lack of reporting of translocations by aquaculture operators. Overall, these findings provide critical information both for aquaculture management and conservation of wild populations of non-target species, and have implications for the increasing use of cleaner fish as parasite control in fish farms, that is both poorly documented and regulated. Moving genetic material between isolated populations could drastically alter the genetic composition and erode population structure, potentially resulting in loss of local adaptation and hampering natural range expansion. Although the ecological and evolutionary significance of escapees warrant further investigation, these results should be taken into consideration in the use of translocated cleaner fish.
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| 6. |
- Faust, Ellika, et al.
(författare)
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Not that clean: Aquaculture-mediated translocation of cleaner fish has led to hybridization on the northern edge of the species' range
- 2021
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Ingår i: Evolutionary Applications. - : Wiley. - 1752-4571. ; 14:6, s. 1572-87
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Tidskriftsartikel (refereegranskat)abstract
- Translocation and introduction of non-native organisms can have major impacts on local populations and ecosystems. Nevertheless, translocations are common practices in agri- and aquaculture. Each year, millions of wild-caught wrasses are transported large distances to be used as cleaner fish for parasite control in marine salmon farms. Recently, it was documented that translocated cleaner fish are able to escape and reproduce with local wild populations. This is especially a challenge in Norway, which is the world's largest salmon producer. Here, a panel of 84 informative SNPs was developed to identify the presence of nonlocal corkwing wrasse (Symphodus melops) escapees and admixed individuals in wild populations in western Norway. Applying this panel to ~2000 individuals, escapees and hybrids were found to constitute up to 20% of the local population at the northern edge of the species’ distribution. The introduction of southern genetic material at the northern edge of the species distribution range has altered the local genetic composition and could obstruct local adaptation and further range expansion. Surprisingly, in other parts of the species distribution where salmon farming is also common, few escapees and hybrids were found. Why hybridization seems to be common only in the far north is discussed in the context of demographic and transport history. However, the current lack of reporting of escapes makes it difficult to evaluate possible causes for why some aquaculture-dense areas have more escapees and hybrids than others. The results obtained in this study, and the observed high genomic divergence between the main export and import regions, puts the sustainability of mass translocation of nonlocal wild wrasse into question and suggests that the current management regime needs re-evaluation.
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| 7. |
- Faust, Ellika, et al.
(författare)
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Origin and route of establishment of the invasive Pacific oyster Crassostrea gigas in Scandinavia
- 2017
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Ingår i: Marine Ecology Progress Series. - : Inter-Research Science Center. - 0171-8630 .- 1616-1599. ; 575, s. 95-105
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Tidskriftsartikel (refereegranskat)abstract
- Identifying the routes and rates of introductions is fundamental for the understanding of marine invasions. Recurring introductions over the last 50 yr have led to the establishment of feral Pacific oyster Crassostrea gigas populations throughout Europe. In the northern countries, Sweden and Norway, the species first occurred in large numbers in 2006. Here, we investigated the relative importance of introduction via re-laying of cultured oysters imported for consumption from France, Ireland or the Netherlands, and dispersal of oyster larvae by ocean currents from wild oyster populations in Denmark. Using microsatellite DNA markers, we estimated genetic differentiation among Pacific oysters collected at 4 Swedish locations, 3 Norwegian locations and 9 potential source locations in Denmark, Ireland, the Netherlands and France. All Swedish samples and 1 Norwegian sample(Tromlingene) were genetically similar to each other and the Danish samples and showed significant genetic differentiation from all other populations. Consequently, it appears that the Pacific oyster populations in Sweden, Denmark and Tromlingene are closely connected and/or share a recent origin. The 2 remaining Norwegian samples(Hui and Espevik) differed from each other and all other populations, but showed similarities to wild oyster samples from Scandinavia and Ireland, respectively. Overall, the results underline a complex origin of Norwegian oysters, with gene flow from Swedish/Danish populations, as well as other unidentified sources. The apparent connectivity among most of the Scandinavian populations has implications for regional management of this invasive species, and highlights possible scenarios for other marine invasive species with a similar life history.
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| 8. |
- Green, Leon, et al.
(författare)
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Ancestral Sperm Ecotypes Reveal Multiple Invasions of a Non-Native Fish in Northern Europe
- 2021
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Ingår i: Cells. - : MDPI AG. - 2073-4409. ; 10:7
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Tidskriftsartikel (refereegranskat)abstract
- For externally fertilising organisms in the aquatic environment, the abiotic fertilisation medium can be a strong selecting force. Among bony fishes, sperm are adapted to function in a narrow salinity range. A notable exception is the family Gobiidae, where several species reproduce across a wide salinity range. The family also contains several wide-spread invasive species. To better understand how these fishes tolerate such varying conditions, we measured sperm performance in relation to salinity from a freshwater and a brackish population within their ancestral Ponto-Caspian region of the round goby, Neogobius melanostomus. These two ancestral populations were then compared to nine additional invaded sites across northern Europe, both in terms of their sperm traits and by using genomic SNP markers. Our results show clear patterns of ancestral adaptations to freshwater and brackish salinities in their sperm performance. Population genomic analyses show that the ancestral ecotypes have generally established themselves in environments that fit their sperm adaptations. Sites close to ports with intense shipping show that both outbreeding and admixture can affect the sperm performance of a population in a given salinity. Rapid adaptation to local conditions is also supported at some sites. Historical and contemporary evolution in the traits of the round goby sperm cells is tightly linked to the population and seascape genomics as well as biogeographic processes in these invasive fishes. Since the risk of a population establishing in an area is related to the genotype by environment match, port connectivity and the ancestry of the round goby population can likely be useful for predicting the species spread.
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| 9. |
- Green, Leon, et al.
(författare)
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Invader at the edge - Genomic origins and physiological differences of round gobies across a steep urban salinity gradient
- 2023
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Ingår i: Evolutionary Applications. - : Wiley. - 1752-4571. ; 16:2, s. 321-37
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Tidskriftsartikel (refereegranskat)abstract
- Species invasions are a global problem of increasing concern, especially in highly connected aquatic environments. Despite this, salinity conditions can pose physiological barriers to their spread, and understanding them is important for management. In Scandinavia's largest cargo port, the invasive round goby (Neogobius melanostomus) is established across a steep salinity gradient. We used 12,937 SNPs to identify the genetic origin and diversity of three sites along the salinity gradient and round goby from western, central and northern Baltic Sea, as well as north European rivers. Fish from two sites from the extreme ends of the gradient were also acclimated to freshwater and seawater, and tested for respiratory and osmoregulatory physiology. Fish from the high-salinity environment in the outer port showed higher genetic diversity, and closer relatedness to the other regions, compared to fish from lower salinity upstream the river. Fish from the high-salinity site also had higher maximum metabolic rate, fewer blood cells and lower blood Ca2+. Despite these genotypic and phenotypic differences, salinity acclimation affected fish from both sites in the same way: seawater increased the blood osmolality and Na+ levels, and freshwater increased the levels of the stress hormone cortisol. Our results show genotypic and phenotypic differences over short spatial scales across this steep salinity gradient. These patterns of the physiologically robust round goby are likely driven by multiple introductions into the high-salinity site, and a process of sorting, likely based on behaviour or selection, along the gradient. This euryhaline fish risks spreading from this area, and seascape genomics and phenotypic characterization can inform management strategies even within an area as small as a coastal harbour inlet.
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| 10. |
- Jansson, E., et al.
(författare)
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Genetic study reveals local differentiation persisting in the face of high connectivity and a genomic inversion likely linked with sexual antagonism in a common marine fish
- 2023
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Ingår i: Ices Journal of Marine Science. - : Oxford University Press (OUP). - 1054-3139 .- 1095-9289. ; 8:4, s. 1103-12
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Tidskriftsartikel (refereegranskat)abstract
- Sustainable harvest of wild populations requires knowledge of the underlying population structure. The focus of this study is on goldsinny wrasse (Ctenolabrus rupestris), a small marine fish inhabiting coastal waters of the north-eastern Atlantic. This species is caught in large numbers to serve as cleaner fish in salmonid aquaculture. We genotyped 2073 goldsinny wrasse from 43 sites along the Scandinavian coastline with 143 SNPs. Seven of the SNPs were linked and likely reside within a large genomic inversion dominated by one haplotype. The heterokaryotype of the putative inversion displayed sex-specific growth patterns, potentially resolving sexual antagonism for this trait. The unlinked 134 SNPs showed modest isolation-by-distance with samples from the northernmost locations showing highest divergence, whereas sites farther south were much more interconnected. Genetic divergence (F-ST) was highly variable among sites within regions, suggesting a varying degree of connectivity and local divergence. We conclude that despite a high degree of gene-flow mediated through pelagic dispersal in early life stages, regional and some local population structure remains due to limited adult movement in addition to other unidentified factors. Consequently, the species might be more vulnerable to local disturbances than previously anticipated.
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