Stable isotopes show food web changes after invasion by the predatory cladoceran Cercopagis pengoi in a Baltic Sea bay
2005 (English)In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 143, no 2, 251-259 p.Article in journal (Refereed) Published
Cercopagis pengoi, a recent invader to the Baltic Sea and the Laurentian Great Lakes, is a potential competitor with fish for zooplankton prey. We used stable C and N isotope ratios to elucidate trophic relationships between C. pengoi, zooplankton (microzooplankton, 90–200 m, mostly copepod nauplii and rotifers; mesozooplankton, >200 m, mostly copepods), and zooplanktivorous fish (herring, size range 5–15 cm and sprat, 9–11 cm) in a coastal area of the northern Baltic Sea. The isotope ratios in C. pengoi and fish were much higher than those of zooplankton, showing general trends of enrichment with trophic level. Young-of-the-year (YOY) herring had a significantly higher 15N/14N ratio than C. pengoi, suggesting of a trophic linkage between the two species. To evaluate the possible relative importance of different food sources for C. pengoi and YOY herring, two-source isotope-mixing models for N were used, with micro- and mesozooplankton as prey for C. pengoi and mesozooplankton and C. pengoi as prey for YOY herring. These models indicate that mesozooplankton was the major food source of both species. However, microzooplankton may be important prey for young stages of C. pengoi. Comparative analyses of the herring trophic position before and after the invasion by C. pengoi showed a trophic level shift from 2.6 to 3.4, indicating substantial alterations in the food web structure. Our findings contribute to a growing body of evidence, showing that C. pengoi can modify food webs and trophic interactions in invaded ecosystems.
Place, publisher, year, edition, pages
2005. Vol. 143, no 2, 251-259 p.
Diet, Effects of preservation and storage, Invasive species, Zooplankton, Zooplanktivorous fish
IdentifiersURN: urn:nbn:se:su:diva-25730DOI: 10.1007/s00442-004-1791-0OAI: oai:DiVA.org:su-25730DiVA: diva2:200386