The neglected ecology of the sand goby: Abundance and feeding in the Baltic sublittoral
Stockholm University, Faculty of Science, Department of Systems Ecology2008 (English)Doctoral thesis, comprehensive summary (Other academic)
I investigated the ecology and population density of the sand goby, Pomatoschistus minutus, at sub-thermocline depth in the north-western Baltic proper. Most previous research on the sand goby, and the co-occurring closely related common goby, P. microps, has focused on their stay in shallow waters, while important parts of their life cycles have been largely neglected.
Photography was used to assess goby population density and size distribution, a basis for estimations of the potential annual food consumption of the goby community. Diet analysis of the most abundant goby, the sand goby, was combined with the population censuses to estimate the contribution of different prey to the goby consumption. Both benthic and pelagic prey were consumed, including two non-indigenous species. The amphipod Monoporeia affinis was by far the most important prey for the overall consumption, while pelagic and benthic copepods, and naidid oligochaetes were important prey for sand gobies < 3.5 cm. Goby predation is likely to influence the populations of naidid oligochaetes and the amphipod M. affinis, as large parts of their production may be consumed.
The potential goby consumption was calculated to be about 72 kJ m-2 yr-1, which corresponds to 14-60 % of the annual production on soft bottoms in the area. In a laboratory study of the sand goby activity, active swimming occurred preferentially at night and burying in the sediment mostly at day. Both behaviours may lead to underestimates in photographic censuses of up to 40 %. The goby community in the sublittoral links the benthic and pelagic sub-systems in the area by being able to remove a substantial amount of energy from the benthic production, by inclusion of pelagic prey, and by holding an intermediate position in the coastal marine food web of the Baltic Sea. Consequently, their role in the flow of energy, elements and substances, some potentially harmful, between the pelagic and benthic ecosystem should be further investigated.
Place, publisher, year, edition, pages
Stockholm: Systemekologiska institutionen , 2008. , 36 p.
sand goby; sublittoral; sub-thermocline; abundance; feeding; consumption; activity
Research subject Marine Ecology
IdentifiersURN: urn:nbn:se:su:diva-8128ISBN: 978-91-7155-700-1OAI: oai:DiVA.org:su-8128DiVA: diva2:199622
2008-09-19, Nordenskiöldsalen, Geovetenskapens hus, Svante Arrhenius väg 8 C, Stockholm, 10:00
Bonsdorff, Erik, Professor
Elmgren, Ragnar, ProfessorHansson, Sture, ProfessorEjdung, Gunilla, Doktor
List of papers