INFORMATION TO USERS This manuscript has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bleedthrough, substandardmargins, and improper alignment can adversely affect reproduction. In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion. Oversize materials (e.g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand comer and continuing from left to right in equal sections with small overlaps. Each original is also photographed in one exposure and is included in reduced form at the back of the book. Photographs included in the original manuscript have been reproduced xerographically in this copy. Higher quality 6" x 9" black and white photographic prints are available for any photographs or illustrations appearing in this copy for an additional charge. Contact UMI directly to order. University Microfilms International A Bell & Howell Information Company 300 North Zeeb Road. Ann Arbor. Ml 48106-1346 USA 313/761-4700 800/521-0600 Order Number 9421005 Effects of fertilization and fish predation on trophic dynamics in aquatic ecosystems Qin, Jianguang, Ph.D. The Ohio State University, 1994 UMI 300 N. ZeebRd. Ann Arbor, MI 48106 EFFECTS OF FERTILIZATION AND FISH PREDATION ON TROPHIC DYNAMICS IN AQUATIC ECOSYSTEMS DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of the Ohio State University By Jianguang Qin, B.S., M.S. ★ * * * * The Ohio State University 1994 Dissertation Committee: Approved by David A. Culver Konrad Dabrowski William J. Mitsch Department of Zoology EFFECTS OF FERTILIZATION AND FISH PREDATION ON TROPHIC DYNAMICS IN AQUATIC ECOSYSTEMS By Jianguang Qin The Ohio State University, 1994 Associate Professor David A. Culver Abstract The impacts of nutrient and fish predation on trophic dynamics were studied by measuring the abundances of bacteria, phytoplankton and zooplankton, and fish growth and survival in ponds, enclosures and laboratory experiments. Two fertilizer types: inorganic fertilizer vs. organic fertilizer and two larval fish (8 mm TL) species: walleye (Stizostedion vitreum) and saugeye, a hybrid of walleye $ and sauger <J (Stizostedion canadense) were involved in the experimental manipulations. First, nutrient effects on plankton abundance and fish survival were tested in ponds using two fertilization regimens: inorganic fertilizer vs. inorganic plus organic fertilizer with a constant fish stocking density (25 fish m'3). The abundances of phytoplankton and zooplankton were not significantly different between the treatments, but fish survival in ponds with organic fertilizer was significantly lower due to low dissolved oxygen. The enclosure and laboratory experiments showed that organic fertilizer stimulated more growth of bacteria and flagellates than it did of other algae. Organic fertilizer increased oxygen consumption but not oxygen production. Because of low nitrogen and ii phosphorus contents and a high oxygen consumption rate, organic fertilizer is unlikely to provide adequate nutrients for algae and sufficient oxygen for fish. Second, within the context of the trophic cascade hypothesis, I tested the larval fish impact on plankton community structure. A 2x2 factorial design experiment, using two species of larval fish (walleye, saugeye) and two stocking densities (10 and 50 m'3), was performed while nutrient input remained the same in each treatment. The experiment demonstrated that larval walleye and saugeye at high density decreased large zooplankton but increased phytoplankton. Fish impacts on plankton biomass depended on fish density rather than fish species, suggesting that walleye and saugeye can be managed similarly. Finally, a factorial design experiment performed in experimental ponds, in which three densities (0, 25, 50 fish m'3) of larval walleye were cross-classified with two fertilizer types (inorganic or organic), demonstrated that phytoplankton abundance was enhanced by either increasing fish density or adding inorganic fertilizer, whereas zooplankton was suppressed only by increasing walleye density. Chironomid larval abundance was enhanced by adding organic fertilizer. The best fish growth was obtained in ponds with low fish density and inorganic fertilizer. To Stephanie, Ranming and my parents ACKNOWLEDGEMENTS I would especially like to thank my advisor, Dr. David A. Culver for his constant guidance, support and encouragement throughout my doctoral program here at The Ohio State University. I would like to extend my deepest appreciation to him for the opportunities he has provided me, and for the faith he placed in the projects I undertook. I would like to thank Drs. Konrad Dabrowski, William Mitsch and Bruce Vondracek for serving on my general examination committee, and providing many useful suggestions throughout my dissertation research. I would also like to thank Dr. Roy Stein, John Dettmers and Joe Mion for making constructive comments on two of my manuscripts. Intense interactions, arguments and discussions with Neng Yu, Sharook P. Madon, and Xavier T. Lazzaro have improved the quality of my research as well as my understanding of research in ecology, aquaculture and fisheries. Many thanks to Jim Stoeckel, Donald Stoeckel, Lisa Jackson, Darcy Uetrecht, Molly Giere, Lisa DePinto, and Mike Grove who were actively involved in field sampling and laboratory analysis. Thanks are due to Pat Keys at Senecaville Fish Hatchery, Jim Stafford, Robert Hesterman, Patrick Howard, and Daryl Rinker at the Hebron State Fish Hatchery, and Dick Chittum and Morton Pugh at the St. Mary's Fish Hatchery, who provided help and access to the experimental ponds. v This research was funded by Federal Aid in Sport Fish Restoration Project F-57-R and administered through the Ohio Division of wildlife. Funding was also provided via the Osburn Fellowship through the Graduate School, and the Department of Zoology, The Ohio State University. Thanks are due to many friends, colleagues and faculties at The Ohio State University who provided me an excellent learning environment. Most of all, I want to express my appreciation to my wife, Ranming, and my daughter, Stephanie. Their day-to-day understanding, encouragement, patience, and sacrifices have been a critical link to the success of this academic enterprise. VITA November 21, 1960................. Born - Hebei, People's Republic of China 1982.............................. B.Sc. Dalian Fisheries College Dalian, Liaoning, P. R. China 1982-1986......................... Teaching Assistant Dalian Fisheries College Dalian, Liaoning, P. R. China 1986—1988*•••••••••••••••••••••••*• M.S. Research and Teaching Assistant Department of Zoology The University of Oklahoma Norman, Oklahoma, USA 1988-present...................... Research and Teaching Associate Department of Zoology The Ohio State University Columbus, Ohio, USA PUBLICATIONS Qin, J., and D. A. Culver. 1993. Effect of young-of-the-year walleye (Percidae: Stizostedion vitreum) on plankton dynamics and water quality in ponds. Hydrobiologia (in press). Qin, J., D. A. Culver, and N. Yu. 1993. Comparative growth of larval walleye and saugeye, and their impact on zooplankton in experimental ponds. Progressive Fish-Culturist (in press). Culver, D. A., S. P. Madon, and J. Qin. 1993. Percid pond production techniques: Timing, enrichment, and stocking density manipulation. Journal of Applied Aquaculture 3: 9-31. Qin, J., and D. A. Culver 1992. Survival and growth of larval walleye, Stizostedion vitreum. and trophic dynamics in fertilized ponds. Aquaculture 108: 257-276. Qin, J., and S. T. Threlkeld, 1990. Experimental comparison on the effects of benthivorous and planktivorous fish on plankton community structure. Archiv fur Hydrobiologie 119: 121-141. vii He, Z, J. Qin, J. Wang, H. Wang, Z. Wang, and X. Xia. 1989. Studies on the saline and hypersaline zooplankton from Jinnan and Yinchuan regions. Acta Hydrobiologie Sinica 13: 24-37. He, Z., J. Qin, Y. Wang. 1988. The discovery of Moina monaolica Daday and its distribution in China. Journal of Dalian Fisheries College 2: 9-13. Qin, J., and C. Shen, Z. Wang, D. Yu, and J. Wang. 1986. The basic investigations on the fishery biology of Zhaling Lake and Eling Lake. Journal of Dalian Fisheries College 1: 20-27. He, Z., J. Qin, L. Yan, Y. Liu, Y. Han, and Z. Shi. 1985. A study of the biology and culture of Moina monaolica. Proceeding of a Symposium on Fish and Shrimp food in China. 188-193. Qin, J. 1984. A study on water quality of high-yield fish ponds in Haerbin area, Part II: Plankton. Journal of Dalian Fisheries College 1: 15-26. Qin, J., Z. Wang, M. Cai, and J. Wang. 1983. A study on the chemistry, biology and fisheries of Lake Keluke, China. Fisheries Science 4:17-21. Wang, J., M. Cai, J. Qin, J. Wang, and D. Yu. 1982. A Primary investigation of fisheries biology of Longyiangxia Reservoir before the establishment of the dam. Reservoir Fisheries 3: 2-11. FIELDS OF STUDY Major Field: Zoology Research Area: Aquatic Ecology and Fisheries