| 1. |
- Evans, Thomas J., et al.
(författare)
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Foraging behaviour of common murres in the Baltic Sea, recorded by simultaneous attachment of GPS and time-depth recorder devices
- 2013
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Ingår i: Marine Ecology Progress Series. - : Inter-Research Science Center. - 0171-8630 .- 1616-1599. ; 475, s. 277-
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Tidskriftsartikel (refereegranskat)abstract
- Global positioning system and time-depth recorders were deployed in combination to investigate the foraging behaviour of common murres Uria aalge breeding at Stora Karlso Island, Baltic Sea, during the chick-rearing period. In the pre-breeding period the main prey species of murres, sprat Sprattus sprattus, is targeted by commercial fisheries, likely reducing prey availability during the breeding season. Foraging trips typically consisted of a short flight followed by a period sitting on the sea surface (0.39 +/- 0.48 h), followed by several (5.3 +/- 3.8) diving bouts interspersed by flights and water surface activity. Following the final diving bout, murres returned directly to the colony. Overnight foraging trips lasted longer than daytime trips, and that result corresponded with greater diving activity and reduced dive depths around dawn and dusk, likely times of high prey accessibility. High outward flight groundspeeds (20.0 +/- 2.8 m s(-1)) were aided by tailwinds, and lower inward flight groundspeeds (15.1 +/- 2.5 m s(-1)) were impeded by headwinds. Flights following the wind direction may reflect a strategy to reduce crosswind drift. Foraging intensity was lower than reported by most other studies of murres, suggesting more abundant or aggregated prey.
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| 2. |
- Hentati-Sundberg, Jonas, 1983-, et al.
(författare)
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The Karlsö Murre Lab methodology can stimulate innovative seabird research
- 2012
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Ingår i: Marine Ornithology. - 1018-3337 .- 2074-1235. ; 40, s. 11-16
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Tidskriftsartikel (refereegranskat)abstract
- Studies of seabirds have contributed substantially to theoretical and applied ecology, but practical limitations in the field and lack of knowledge of the life history of studied birds often constitute significant hurdles to progress in research. In the middle of the largest seabird colony in the Baltic Sea, on the island of Stora Karlsö, we have built an artificial breeding site for Common Murres Uria aalge. The Karlsö Murre Lab enables high-resolution studies with minimal disturbance of the breeding birds. It became operational, with the first recruitment of breeding murres, in 2009. Building materials and location were chosen to minimize environmental impact. The lab was constructed to allow future outfitting with a range of high-technology devices. Since most of the fledged chicks in the subcolony have been ringed over the last 10 years, this will enable recruitment and studies using advanced technology of birds with known life history. Hence, we will be able to perform seabird studies with a resolution that is impossible in a strictly natural environment. Better knowledge of links between seabirds and their environment facilitates the use of seabirds as indicators, which in turn can improve marine ecosystem-based management.
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| 3. |
- Kadin, Martina, et al.
(författare)
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Contrasting effects of food quality and quantity on a marine top predator
- 2012
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Ingår i: Marine Ecology Progress Series. - : Inter-Research Science Center. - 0171-8630 .- 1616-1599. ; 444, s. 239-249
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Tidskriftsartikel (refereegranskat)abstract
- Overfishing of predatory fish has contributed to an increase in forage-fish stocks. At the same time, a rising demand for forage fish to supply fishmeal markets, in combination with climate change, has put strong pressure on these stocks, and this, in turn, has had an impact on marine top predators. We examined how inter-annual variation in food quality (sprat Sprattus sprattus weight-at-age) and quantity (sprat abundance) influenced Baltic Sea common murres Uria aalge during chick-rearing. Fledging success, i.e. survival from hatching to fledging, showed a positive relationship with food quality, but we found no effect of food quantity. We found no relationship between food quality and parental behaviour or chick feeding parameters, but a negative relationship between food quantity and trip duration. Our data indicate that there was room for parental birds to increase their effort to compensate for reduced food quality, but we found no signs of such compensation. We analysed different types of fish and seabird life-history data to separate effects of food quantity and quality on a top predator. Understanding such effects can contribute to clarifying causes and consequences for observed changes in life-history parameters and population dynamics of top predators.
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| 4. |
- Kadin, Martina
(författare)
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Man, murres and modern fisheries : A case study in the Baltic Sea
- 2012
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Overfishing and climate change put increasing pressure on marine systems, with effects on commercially targeted fish and top predators dependent on these resources. To achieve sustainable resource use, governance mechanisms need to incorporate knowledge about ecosystem dynamics. Another key for success is the perception among actors about the challenges oceans are facing. Seabirds have become well-known symbols of coasts and oceans and their struggles with the consequences of human actions provide an illustration of the need to properly govern marine resources. Seabirds can be useful indicators of states of marine systems, forming tools that can help informing ecosystem approaches to management. The thesis focuses on the piscivorous seabird the common murre Uria aalge in the Baltic Sea, investigating two different aspects of interactions between seabirds and fisheries. In paper I, the effects of food quality and quantity during the chick-rearing period were investigated. Food quality (sprat Sprattus sprattus weight-at-age), but not quantity (sprat abundance), was positively related to murre fledging success. The adjustments of parental effort in relation to quality and quantity showed the opposite pattern – no relationships between parental effort and sprat weight-at-age but a negative relationship between sprat abundance and the duration of foraging trips. Paper II uses a long-term ring recovery dataset to study murre bycatch in Baltic Sea fisheries. We found an increase in the proportion bycatch between 1972 and 2008, and a strong bimodal intraannual pattern in bycatches, with peaks in spring and autumn, similar in three investigated periods. Uncertain finding dates were common and could potentially affect conclusions about intraannual patterns. Reported bycatches were concentrated to waters around the Hel peninsula, Poland. In recent years, 2000-2008, an increase of reported bycatch could be observed in the southeastern parts of the Baltic Sea. The findings of this thesis can aid the selection and interpretation of indicators for ecosystem approaches to Baltic Sea fisheries management, and further be used to communicate the need for such approaches.
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| 5. |
- Kadin, Martina, 1981-
(författare)
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Seabirds as food for thought : An integrative study on seabird ecology and ecosystem services in changing marine systems
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The importance of the benefits that humans obtain from the oceans is increasingly recognized, along with the rapid decline in marine resources that threatens these benefits. Studying seabirds – top predators in marine ecosystems, can provide insights about multiple pressures and the state of the oceans. The thesis links studies of seabirds through the lens of ecosystem services with an ecological case study. Paper I reviews ecosystem services, finding that seabirds contribute to provisioning, regulating, supporting and cultural services. Seabirds serve as mobile links in marine and terrestrial ecosystems, through regulating and supporting services. Further, scientific knowledge and indicators based on seabirds can be seen as an ecosystem service as they facilitate management. Papers II-IV proceed to build such knowledge about the importance of food quality and quantity for breeding seabirds, in particular common murres Uria aalge in the Baltic Sea. Here, there is a negative relationship between quantity (sprat Sprattus sprattus abundance) and quality (sprat weight-at-age). Quality, but not quantity, was positively related to common murre fledging success while parental foraging trips had shorter duration when quantity was higher, but showed no relationship with food quality (paper II). Paper III describes foraging behaviour of adults and found indications of good foraging conditions at sea. Parents made efforts to adjust provisioning of food according to the needs of the chicks (paper IV), but the adjustments did not seem to be enough to counteract the impact of lower food quality. Paper V explores ecosystem services obtained from seabirds over time identifying a shift from provisioning to cultural services, where current cultural services are often connected. The integration of ecosystem services with seabird ecology shows that seabirds are illustrative of changes in marine resources and provide ways to help people reconnect with the health of marine systems.
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| 6. |
- Österblom, Henrik, et al.
(författare)
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Incentives, social-ecological feedbacks and European fisheries
- 2011
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Ingår i: Marine Policy. - : Elsevier BV. - 0308-597X .- 1872-9460. ; 35:5, s. 568-574
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Tidskriftsartikel (refereegranskat)abstract
- The European Common Fisheries Policy (CFP) has failed to deliver on social, economic and ecological goals. This failure is in part the result of a number of social-ecological feedback mechanisms. The policy is currently undergoing reform, with unknown practical outcomes. Here, relatively successful fisheries policies outside the European Union are reviewed. Through interviews and workshops with scientists, managers and other stakeholders, complemented with literature reviews, practices that can create incentives for long-term sustainability are investigated. The focus is on how the provision of clear and trusted scientific evidence can stimulate defensible decisions, in turn creating incentives for compliance, leading to positive social-ecological outcomes. Despite differences between Europe and the investigated case studies, the prospects of an increased regionalization within the European CFP provides the best starting point for implementing best practice identified in this study.
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