Aaron Barkoh

Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)


Wildlife and Fisheries Science

First Advisor

Timothy Modde


Four genera of zooplankton and cladoceran egg cases, collected from a municipal sewage lagoon, were made available as food to green sunfish (Lepomis cyanellus) and bluegill (Lepomis macrochirus) fry, to examine their food selectivity. Green sunfish and bluegill fry ranged in size from 8.5-11.0 mm and 8.0-10.5 mm at stocking and were reared for 31 and 30 days, respectively. The gut contents of 1488 green sunfish and 1440 bluegill fry, representing day and night samples were examined. Diet composition was evaluated using the linear food selection index. Both green sunfish and bluegill fry selected for Cvclops vernalis and consistently selected against cladoceran egg cases and Potamocypris spp. Moina brachiata was consistently selected for by bluegills but was initially consumed by green sunfish in approximately the same proportion as they were available and later preferentially selected for by larger green sunfish fry. The mean length of prey species selected for, increased linearly with mean length of green sunfish fry; the food length relation for bluegill fry as the fish increased in size was curvilinear. There were no significant (P>0.05) differences between day and night prey species and prey size selection. The number of prey organisms consumed by bluegill fry increased linearly with mean length of fish, and the differences between day and night quantities were significant (P≤0.05). The relationship between the number of prey organisms ingested and mean length of green sunfish fry was exponential. The differences in numbers of prey items ingested by green sunfish during lighted and dark hours were only significant (P≤0.05) for fry of mean total length 12.7 mm and greater.

Library of Congress Subject Headings

Green sunfish -- Feeding and feeds
Bluegill -- Feeding and feeds
Fishes -- Feeding and feeds


Includes bibliographical references (pages 35-39)



Number of Pages



South Dakota State University


No Copyright - Non-Commercial Use Only