Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Man, murres and modern fisheries: A case study in the Baltic Sea
Stockholm University, Faculty of Science, Department of Systems Ecology. (Natural Resources Management)
2012 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

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.

Place, publisher, year, edition, pages
Stockholm: Department of Systems Ecology, Stockholm University , 2012. , 18 p.
Keyword [en]
Seabirds, ecosystem dynamics, fisheries, indicators, ecosystem services, Baltic Sea, common murre, common guillemot, Uria aalge
National Category
Biological Sciences
Research subject
Natural Resources Management
Identifiers
URN: urn:nbn:se:su:diva-68704OAI: oai:DiVA.org:su-68704DiVA: diva2:473221
Presentation
2012-01-30, Room 312, Stockholm Resilience Centre, Kräftriket 2 B, Stockholm, 10:00 (English)
Opponent
Supervisors
Note

At the time of the defence the following paper was unpublished and had a status as follows: Paper nr 2: Manuscript

Available from: 2012-11-30 Created: 2012-01-05 Last updated: 2012-12-14Bibliographically approved
List of papers
1. Contrasting effects of food quality and quantity on a marine top predator
Open this publication in new window or tab >>Contrasting effects of food quality and quantity on a marine top predator
2012 (English)In: Marine Ecology Progress Series, ISSN 0171-8630, E-ISSN 1616-1599, Vol. 444, 239-249 p.Article in journal (Refereed) Published
Abstract [en]

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.

Keyword
Junk food, Trophic cascades, Ecosystem approach, Environmental change, Climate change, Alcidae, Common guillemot
National Category
Environmental Sciences
Research subject
Natural Resources Management
Identifiers
urn:nbn:se:su:diva-70425 (URN)10.3354/meps09417 (DOI)000298970900017 ()
Note

4

Available from: 2012-01-20 Created: 2012-01-20 Last updated: 2017-12-08Bibliographically approved
2. Trends, changes and uncertainties in bycatch of common murres in the Baltic Sea
Open this publication in new window or tab >>Trends, changes and uncertainties in bycatch of common murres in the Baltic Sea
Show others...
(English)Manuscript (preprint) (Other academic)
National Category
Natural Sciences
Identifiers
urn:nbn:se:su:diva-83750 (URN)
Available from: 2012-12-13 Created: 2012-12-13 Last updated: 2015-11-13Bibliographically approved

Open Access in DiVA

No full text

Search in DiVA

By author/editor
Kadin, Martina
By organisation
Department of Systems Ecology
Biological Sciences

Search outside of DiVA

GoogleGoogle Scholar

urn-nbn

Altmetric score

urn-nbn
Total: 207 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf