| 1. |
- Bergström, Per, 1980, et al.
(författare)
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Differences in growth patterns among three bivalve species and in relation to exposure and implications for aquaculture and ecological functions
- 2024
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Ingår i: Estuarine, Coastal and Shelf Science. - 0272-7714. ; 303
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, similarities and differences in growth patterns, measured as changes in soft tissue weight and shell length, among three bivalve species in Sweden (blue mussels, Pacific oysters and European flat oysters) were studied with the aim to achieve information on spatial and temporal variability among these commercially important species. The study showed that there are significant differences in spatial growth pattern between blue mussels and both of the oyster species, where oysters grew faster in more protected locations compared to mussels, which had a generally faster growth in the exposed localities. The weight: length ratio also differed among species, where mussels had a lower ratio compared to oysters. Potential causes of the observed patterns and consequences for bivalve farming as well as implications for ecological functions are discussed. The results are valuable in site-selection processes at both local (individual farmers) and regional/national scales (planning processes etc), and indicates that spatial planning of bivalve aquaculture need inclusion of species specific growth parameters.
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| 2. |
- Mafambissa, Mizeque, et al.
(författare)
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Experimental spat collection of the pearl and rocky shore oysters on ceramic tile substrates
- 2024
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Ingår i: Aquaculture Reports. - 2352-5134. ; 36
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Tidskriftsartikel (refereegranskat)abstract
- Temporal and spatial variation in oyster larvae settlement is a crucial factor determining the abundance and success of adult populations in their natural environment. The overall understanding of oyster recruitment provides information on site selection and strategies employed for obtaining spats for oyster culture. In this study, spat of Pinctada capensis and Saccostrea cucullata were collected from four selected sites in a sub-tropical setting at Inhaca Island, Southern Mozambique during an experimental period of 8 months to assess the effect of different factors (season, duration and surface) on spat settlement and abundance. Ceramic tiles were deployed as artificial substrates from the surface to 5 m depth. They were replaced monthly. Overall, settlement on ceramic tiles was higher for S. cucullata than for pearl oyster P. capensis. There was a tendency for higher numbers of spat settling during the summer than winter for both species. For both species larger numbers of recruits were found on tiles deployed for four months than for two months and on the roughly textured surfaces compared to smooth. The results have also indicated that the ceramic tiles could be used as substrate for rocky shore oyster S. cucullata settlement in the late summer.
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| 3. |
- Anton, Victor, et al.
(författare)
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An open-source, citizen science and machine learning approach to analyse subsea movies
- 2021
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Ingår i: Biodiversity Data Journal. - 1314-2828. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Background The increasing access to autonomously-operated technologies offer vast opportunities to sample large volumes of biological data. However, these technologies also impose novel demands on ecologists who need to apply tools for data management and processing that= are efficient, publicly available and easy to use. Such tools are starting to be developed for wider community and here we present an approach to combine essential analytical functions for analysing large volumes of image data in marine ecological research. New information This paper describes the Koster Seafloor Observatory, an open-source approach to analysing large amounts of subsea movie data for marine ecological research. The approach incorporates three distinct modules to: manage and archive the subsea movies, involve citizen scientists to accurately classify the footage and, finally, train and test machine learning algorithms for detection of biological objects. This modular approach is based on open-source code and allows researchers to customise and further develop the presented functionalities to various types of data and questions related to analysis of marine imagery. We tested our approach for monitoring cold water corals in a Marine Protected Area in Sweden using videos from remotely-operated vehicles (ROVs). Our study resulted in a machine learning model with an adequate performance, which was entirely trained with classifications provided by citizen scientists. We illustrate the application of machine learning models for automated inventories and monitoring of cold water corals. Our approach shows how citizen science can be used to effectively extract occurrence and abundance data for key ecological species and habitats from underwater footage. We conclude that the combination of open-source tools, citizen science systems, machine learning and high performance computational resources are key to successfully analyse large amounts of underwater imagery in the future.
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| 4. |
- Bergström, Per, 1980, et al.
(författare)
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Deposition of shells modify nutrient fluxes in marine sediments: effects of nutrient enrichment and mitigation by bioturbation below mussel farms
- 2020
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Ingår i: Aquaculture Environment Interactions. - : Inter-Research Science Center. - 1869-215X .- 1869-7534. ; 12, s. 315-325
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Tidskriftsartikel (refereegranskat)abstract
- Farming of extractive species such as filter feeding bivalves has been proposed as a potential method to mitigate impacts of eutrophication in marine environments. For such efforts to be sustainable, potential negative effects from mussel farms, such as accumulation of biodeposits in sediment below them, need to be considered and addressed. Benthic burrowing macrofauna strongly influence biogeochemical processes in soft bottom marine habitats by sediment reworking and irrigation and, thus, have the potential to mitigate some of the negative impacts. However, not all biodeposits are organic matter; shells that accumulate on and in the sediment below mussel farms also have the potential to influence processes in the sediment, the activity of bioturbators and the fluxes across the sediment-water interface. In this study, we evaluated the mitigation potential of the bioturbating polychaete Hediste diversicolor in sediments enriched with mussel waste material and the relative impact of mussel shells within the sediment matrix. The polychaetes generally increased fluxes and sediment oxygen uptake. With an observed tendency of increased fluxes of nutrients in sediments containing shells compared to sediments without, the results indicate that the accumulation of shell has a potential to further increase the mitigative effect of the polychaetes by influencing the solute fluxes across the sediment-water interface.
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| 5. |
- Bergström, Per, 1980, et al.
(författare)
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Identifying high‐density areas of oysters using species distribution modeling: Lessons for conservation of the native Ostrea edulis and management of the invasive Magallana ( Crassostrea ) gigas in Sweden
- 2021
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Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 11:10, s. 5522-5532
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Tidskriftsartikel (refereegranskat)abstract
- AimUnderstanding spatial patterns of the distribution of adult native oyster, Ostrea edulis, and the invasive Magallana (Crassostrea) gigas is important for management of these populations. The aim of this study was to use ensemble SDM’s to (a) identify and predict conservation hotspots, (b) assess the current level of protection for O. edulis, and (c) quantify the amount of overlap between the two species where interactions with M. gigas are most likely.LocationSkagerrak, Sweden.MethodsWe used data collected by video at depths from 0.5 to 10 m in 436 sites. Models of occurrence and densities >1 m−2 were fitted and assessed using ensemble methods (“biomod2” package). Models of high-density hotspots were used to predict, map, and quantify areal extent of the species in order to assess the degree of overlap with protected areas and the potential for interactions between the two species.ResultsBoth species were widely distributed in the region. Observations of high-density habitats, mainly occurring at depths of ≈3 and 0.5 m for O. edulis and M. gigas, respectively, were found in 4% and 2% of the sites. Models provided useful predictions for both species (AUC = 0.85–0.99; sensitivity = 0.74–1.0; specificity = 0.72–0.97). High-density areas occupy roughly 15 km2 each with substantial overlap between species. 50% of these are protected only by fisheries regulations, 44% are found in Natura 2000 reserves and 6% of the predicted O. edulis enjoys protection in a national park.Main conclusionsData collection by video in combination with SDM’s provides a realistic approach for large-scale quantification of spatial patterns of marine population and habitats. O. edulis and M. gigas are common in the area, but a large proportion of the most valuable O. edulis habitats are not found in protected areas. The overlap between species suggests that efforts to manage the invasive M. gigas need to be integrated with management actions to conserve the native O. edulis.
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| 8. |
- Greeve, Youk, et al.
(författare)
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Estimating and scaling-up biomass and abundance of epi- and infaunal bivalves in a Swedish archipelago region: Implications for ecological functions and ecosystem services.
- 2023
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Ingår i: Frontiers in Marine Science. - : Frontiers Media SA. - 2296-7745. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Introduction As suspension-feeders, bivalves play a key role in maintaining regulatory functions of coastal ecosystems, which are linked to important ecosystem services. The functions attributed to bivalves depend on the life habits of a species (epi- or infauna) and their abundance and biomass. To properly quantify and assess these functions, detailed information the distribution, abundance and biomass at the ecosystem scale is critical. Amongst others, this requires an understanding on how environmental conditions shape special patterns in distribution. In this study we investigate this fundamental information on the Swedish west coast, an area where this information is lacking. Methods A survey which was designed to representatively sample both epi- and infaunal bivalves from randomized locations in various habitat types was conducted. Specifically, abundance and biomass of all species were recorded in the intertidal (0-0.5 m) and the shallow subtidal zone (0.5-2 m). The sites were distributed over an offshore gradient and at two exposure levels. This sampling structure allowed to extrapolate the results to an ecosystem level though information on the areal extent of these habitats using GIS layers. Results It was found that even though there exist a great variability among sites, in general epifaunal bivalves outweigh infaunal bivalves approximately 3 to 1. In terms of abundance, the ratio is more or less reversed and infaunal species occur in greater numbers. Most bivalves were found at an intermediate level of exposure, but due to the areal extend of the sheltered inner-archipelago this was the most important habitat for bivalve abundance and biomass. It was also found that invasive epifaunal oyster Magallana gigas and the invasive infaunal clam Ensis leei both dominated their respective groups in terms of biomass. Discussion Though the survey was relatively small, these results serve as a valuable insight of the relative importance of epi- and infaunal bivalves in this region. This gives understanding on which species and habitats are particularly important for ecosystem functions and services related to bivalves. This also provide a starting baseline for attempts to quantify ecosystem services provided by certain species or groups of bivalves in the future.
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| 9. |
- Hylén, Astrid, 1991, et al.
(författare)
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In situ characterization of benthic fluxes and denitrification efficiency in a newly re-established mussel farm
- 2021
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 782
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Tidskriftsartikel (refereegranskat)abstract
- Mussel farming has been proposed as a mechanism to mitigate eutrophication in coastal waters. However, localizing the intensive filtration of organic matter by mussels can cause a concomitant enrichment of organic matter in sediments below farms, which may influence biogeochemical processes and fates of nutrients in the system. In the context of mitigating eutrophication, it is important to quantify sedimentary changes induced at early life stages of mussel farms. Accordingly, this study investigated how a newly re-established mussel farm affected sedimentation rates, sediment characteristics, sediment-water solute fluxes and nitrate (NO3−) reduction rates (measured in situ) during the first year of production. Sedimentation rates were enhanced at the farm relative to a reference station, and both organic and inorganic carbon accumulated in the sediment with time. Increased organic matter input likely drove the slightly elevated sedimentary effluxes of ammonium (NH4+) and dissolved inorganic phosphorus (DIP) in the farm. Denitrification was the main NO3− reduction process, however, there was a relative increase in the remobilization of bioavailable nitrogen underneath the farm as dissimilatory nitrate reduction to ammonium (DNRA) rates were enhanced by >200% and the denitrification efficiency was 49% lower compared to the reference station. The sedimentary methane (CH4) release tended to be higher at the farm, but fluxes were not significantly different from reference conditions. Low sedimentary pigment concentrations indicated a reduced presence of benthic microalgae at the farm, which likely influenced sediment-water solute fluxes. Over the production cycle, the release of dissolved inorganic nitrogen (DIN) and DIP underneath the farm were respectively 426% and 510% relative to reference conditions. Impacts of the mussel farm were thus measurable already during the first year of establishment. These immediate changes to the sediment biogeochemistry, as well as long-term effects, should be considered when estimating the environmental impact of mussel aquaculture.
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| 10. |
- Kotta, Jonne, et al.
(författare)
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Cleaning up seas using blue growth initiatives: Mussel farming for eutrophication control in the Baltic Sea
- 2020
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 709
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Tidskriftsartikel (refereegranskat)abstract
- © 2019 The Authors Eutrophication is a serious threat to aquatic ecosystems globally with pronounced negative effects in the Baltic and other semi-enclosed estuaries and regional seas, where algal growth associated with excess nutrients causes widespread oxygen free “dead zones” and other threats to sustainability. Decades of policy initiatives to reduce external (land-based and atmospheric) nutrient loads have so far failed to control Baltic Sea eutrophication, which is compounded by significant internal release of legacy phosphorus (P) and biological nitrogen (N) fixation. Farming and harvesting of the native mussel species (Mytilus edulis/trossulus) is a promising internal measure for eutrophication control in the brackish Baltic Sea. Mussels from the more saline outer Baltic had higher N and P content than those from either the inner or central Baltic. Despite their relatively low nutrient content, harvesting farmed mussels from the central Baltic can be a cost-effective complement to land-based measures needed to reach eutrophication status targets and is an important contributor to circularity. Cost effectiveness of nutrient removal is more dependent on farm type than mussel nutrient content, suggesting the need for additional development of farm technology. Furthermore, current regulations are not sufficiently conducive to implementation of internal measures, and may constitute a bottleneck for reaching eutrophication status targets in the Baltic Sea and elsewhere.
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