Research article - Peer-reviewed, 2018
Fish and seabird spatial distribution and abundance around the largest seabird colony in the baltic sea
Hentati-Sundberg, Jonas; Evans, Thomas; Osterblom, Henrik; Hjelm, Joakim; Larson, Niklas; Bakken, Vidar; Svenson, Anders; Olsson, OlofAbstract
We studied the at-sea distribution of two auks (Common Murre Uria aalge, Razorbill Alca torda), two gulls (Lesser Black-backed Gull Larus fuscus, Herring Gull Larus argentatus), and Great Cormorant Phalacrocorax carbo during the peak breeding season of 2014 around Stora Karlso, the main Baltic Sea seabird colony. Simultaneously, we quantified forage fish abundance and distribution using hydro-acoustics and pelagic trawling. The auks and gulls had a roughly similar distribution, foraging mainly about 40 km west-northwest from the colony. Great Cormorants were found only in inshore areas, close to the colony. Sprat Sprattus sprattus and herring Clupea harengus biomass was, respectively, 1.38 and 2.68 mt/km(2) averaged over the whole study area. These estimates represent a total biomass for small pelagic fish of 17 900 t in the 4 408 km(2) study area. The estimated prey consumption over the breeding season was 2 310 t for Common Murre and Razorbill combined. Thus, auks may have a non-negligible impact on their prey sources in the region. Common Murres foraged closer to the colony (median 36.3 km) than Razorbills (median 41.1 km), but we found no significant correlation between auk at-sea numbers and fish densities. We discuss how new technology can contribute to detailed monitoring of the interactions between seabirds and fish at different spatial and temporal scales, with the ultimate aim of providing a scientific basis for ecosystem-based management.Published in
Marine Ornithology2018, volume: 46, number: 1, pages: 61-68
Authors' information
Swedish University of Agricultural Sciences, Department of Aquatic Resources
Stockholm University
Evans, Thomas
Lund University
Österblom, Henrik
Stockholm University
Swedish University of Agricultural Sciences, Department of Aquatic Resources
Swedish University of Agricultural Sciences, Department of Aquatic Resources
Bakken, Vidar
No organisation
Swedish University of Agricultural Sciences, Department of Aquatic Resources
Olsson, Olof
Stockholm University
UKÄ Subject classification
Zoology
Fish and Aquacultural Science
Ecology
URI (permanent link to this page)
https://res.slu.se/id/publ/95588