Piscivore effect on size distribution and planktivorous behavior of slimy sculpin in arctic Alaskan lakes

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Christopher Michael Jones (Creator)
Institution
The University of North Carolina at Greensboro (UNCG )
Web Site: http://library.uncg.edu/
Advisor
Anne Hershey

Abstract: Slimy sculpin (Cottus cognatus) are known as a bottom-dwelling fish that feed primarily on benthic invertebrates. However, in arctic lakes, sculpin may also be somewhat planktivorous. Previous studies have shown that the habitat distribution of sculpin is modified by lake trout (Salvelinus namaycush), a piscivore. Here, I hypothesized that lake trout and another piscivore, arctic char (Salvelinus alpinus), alter sculpin behavior to restrict planktivory and reduce growth. Sculpin were sampled from three different lake types: lakes with lake trout, lakes with arctic char and lakes with no piscivore. Results showed that sculpin were significantly larger in lakes lacking piscivores, consistent with my hypothesis. Piscivores did not affect prey mass or prey types based on sculpin stomach content analyses. However, in all lakes, zooplankton were a substantial prey item of sculpin. Stable isotope analyses showed enrichment in 13C and depletion in 15N in sculpin from arctic char lakes in comparison to both of the other lake types. These results are indicative that the effects of piscivores on sculpin populations are generally indirect, altering body size but not habitat distribution or prey selection. However, differences in stable isotope ratios suggest a trophic segregation may be present in sculpin in arctic char lakes compared to sculpin only lakes.

Additional Information

Publication
Thesis
Language: English
Date: 2010
Keywords
Slimy sculpin (Cottus cognatus), Alaska, Piscivores
Subjects
Lake ecology $z Arctic regions.
Sculpins $z Arctic regions.
Lake trout.
Predation (Biology)