Adaptive trait utility in the feeding apparatus of European whitefish (Coregonus lavaretus): Relationships between feeding morphology and maximum and minimum prey size in the diet of whitefish
Independent thesis Advanced level (degree of Master (Two Years)), 40 credits / 60 HE creditsStudent thesis
Whitefish (Coregonus lavaretus) populations diverge into morphs that differ in body size along a benthic-limnetic axis and throughout the depth of the water column. This process is assumedly initiated by the presence of northern pike (Esox lucius) and is followed by morphological adaptations to available food resources. In this study eight populations of whitefish was studied with the purpose of increasing the knowledge about adaptive trait utility in the feeding apparatus of whitefish. This was done by analyzing the mean and absolute maximum and minimum prey size ingested by fish along four morphological trait gradients. The morphological traits was body size, gill raker number and density, and gape size. The results show clear evidence of morphological adaptations in both the benthic and limnetic habitat, furthermore, when comparing the two prey size responses (mean and absolute values) it becomes clear that none of the studied whitefish is physically constrained in terms of the largest prey they can ingest. However, large fish seem to be limited in eating small prey sizes. Interestingly, I also found strong indicators for filter feeding adaptation for one of the studied populations.
Place, publisher, year, edition, pages
2015. , 16 p.
trait utility, gill rakers, adaptive radiation, morphological adaptation, feeding niche
IdentifiersURN: urn:nbn:se:umu:diva-104986OAI: oai:DiVA.org:umu-104986DiVA: diva2:839858
Master's Programme in Ecology
2015-06-05, KB5C2, 11:00 (English)
Englund, Göran, Professor
Byström, Pär, Universitetslektor