A species’ diet is central to shaping both its life history and the dynamics of its populations. I measured diet and morphology of Black Perch (Embiotoca jacksoni) within eight different populations located throughout the Southern California Bight. Diet was assessed using three different methods including stable isotope analysis (SIA), stomach content analysis (SCA), and electivity (E), an index that accounts for differences in prey availability. My goals were 1) to evaluate the degree to which diets varied among populations, and 2) to assess the agreement of SIA and SCA by comparing estimated diets in three focal populations where I also analyzed isotopes of prey.
The results revealed considerable among-population variation in morphology, including traits such as eye size (among-population component of variance (APCV) = 27%) and gape (APCV = 24%). However, there were no obvious patterns such as island versus mainland morphotypes, or spatial similarity in morphology. The APCV in diet was substantial (42% for SIA, 37% for SCA) and significant among population variation in electivity (18% of total) suggested that fish in different populations preferred different sets of prey. There was modest agreement between diet reconstructed from stable isotope signatures, and diet inferred from stomach contents. Stable isotope mixing models indicated that decapods and polychaetes may be more common or important prey than stomach contents suggest. These results indicate that diets of Black Perch populations may be more variable than previously thought; that populations vary with respect to prey preference; and that SCA can be augmented with SIA to provide more accurate estimate diets within wild populations.
|Advisor:||Johnson, Darren W.|
|Commitee:||Bracken, Matthew E.S., Whitcraft, Christine R.|
|School:||California State University, Long Beach|
|School Location:||United States -- California|
|Source:||MAI 58/02M(E), Masters Abstracts International|
Copyright in each Dissertation and Thesis is retained by the author. All Rights Reserved
The supplemental file or files you are about to download were provided to ProQuest by the author as part of a
dissertation or thesis. The supplemental files are provided "AS IS" without warranty. ProQuest is not responsible for the
content, format or impact on the supplemental file(s) on our system. in some cases, the file type may be unknown or
may be a .exe file. We recommend caution as you open such files.
Copyright of the original materials contained in the supplemental file is retained by the author and your access to the
supplemental files is subject to the ProQuest Terms and Conditions of use.
Depending on the size of the file(s) you are downloading, the system may take some time to download them. Please be