Resource Partitioning Across Ontogeny and Feeding Strategy for Three Lake Erie Fishes
Cecilia Heuvel, University of Windsor, GLIER, [email protected]
G. Doug Haffner, Great Lakes Institute, Univ. of Windsor, [email protected]
Scott Colborne, Michigan State University, [email protected]
Aaron Fisk, University of Windsor, [email protected]
Abstract
Ecological niche can be influenced by ontogeny and resource partitioning but this has rarely been assessed across similar-sized freshwater species that feed differently as adults. Additionally, a species role is often defined by adult life stages, despite the possibility that it may play other roles due to changes in niche driven by ontogeny. We investigated ontogenetic feeding ecology using isotopic niche of three similarly-sized fish species with different feeding strategies (Benthivore: freshwater drum, Aplodinotus grunniens; Piscivore: walleye, Sander vitreus; and Omnivore: white perch, Morone americana) in Lake Erie’s western basin using stable isotopes of carbon (?13C), nitrogen (?15N) and sulphur (?34S). Walleye showed no ontogenetic changes in isotopic niche with length for any isotope, but freshwater drum exhibited two ontogenetic isotopic niche shifts and white perch demonstrated a significant decrease in niche area with increasing total length. Between species, small (400mm) had distinct differences in niche between species along the ?15N and ?34S axes, indicating they were partitioning resources through habitat and trophic level. Medium fish (200-400mm) differentiated their niches between along the ?13C and ?34S axes, indicating differentiation through habitat use. This study demonstrates that fish species with different adult feeding strategies can partition resources through different mechanisms with ontogeny.
3. Keyword
stable isotopes
4. Additional Keyword
resource partitioning
5. Additional Keyword
ontogeny
6. Additional Keyword
trophic ecology