Effects on Water Quality of Additional Mechanical Aeration in the Waste-Treatment Cells in Split-Pond Aquaculture Systems for Hybrid Catfish Production by Lauren Nicole Jescovitch A dissertation submitted to the Graduate Faculty of Auburn University in partial fulfillment of the requirements for the Degree of Doctor of Philosophy Auburn, Alabama May 7, 2017 Keywords: split-ponds, aeration, water quality, pond engineering Copyright 2017 by Lauren Nicole Jescovitch Approved by Claude E Boyd, Chair, Professor Emeritus, School of Fisheries, Aquaculture and Aquatic Sciences Yolanda Brady, Associate Professor Emerita, School of Fisheries, Aquaculture and Aquatic Sciences Donald Allen Davis, Alumni Professor, School of Fisheries, Aquaculture and Aquatic Sciences Philip Chaney, Associate Professor, Department of Geosciences George W Crandell, Associate Dean, Graduate School Abstract Split-pond aquaculture is a new, innovative system for intensification of pond aquaculture in the southeastern USA Split ponds have a fish cell and a waste cell, approximately 20% water surface area and 80% water surface area, respectively, in which water recirculates to improve water quality and allow more intensive production than possible in traditional ponds This three-year study focuses on the possible benefits of using mechanical aeration in the wastetreatment section of the split-pond culture system The present study was conducted on a commercial catfish farm in west Alabama that has eight split-ponds, each with a fish-holding section of approximately 8,000 m2 Water quality was assessed through a variety of parameters that had the potential to be affected by oxygen using standard analytical chemical procedures in the field and laboratory Further investigation also determined poor circulation rates and aeration in split-ponds because of poor management This dissertation discusses water quality and intensification of pond aquaculture, water quality and aeration in split-pond waste cells, and best practices of the split-pond design ii Acknowledgments The author would like to offer her love and sincere gratitude to her family for their continuous support throughout this dissertation She also wants to thank Dr Claude E Boyd for giving her the opportunity to learn and study aquaculture, and gain teaching experience for the past 5-years under his guidance and wisdom The author would like to express appreciation to June Burns, committee members, colleagues and lab mates - especially Piyajit Pratipasen and Hisham Abdelrahman – for assistance in this study and support for various professional opportunities that she completed while attending Auburn University iii Table of Contents Abstract ii Acknowledgments iii Table of Contents iv List of Tables vi List of Figures viii Chapter – Introduction & Review of Literature 1.1 Water Quality in Aquaculture 1.1.1 Mechanical Aeration and Dissolved Oxygen 1.1.2 Organic Matter 1.1.3 Nitrification 1.2 Traditional Pond Design in Southeastern USA 1.2.1 Split-Pond Design Chapter – Split-Pond Water Quality 13 2.1 Abstract 13 2.2 Introduction 14 2.3 Materials and Methods 16 2.3.1 Design 16 2.3.2 Water quality analyses 17 2.3.3 Non-routine Analyses 19 2.4.4 Statistical Analyses 20 2.4 Results 20 2.4.1 Production 20 iv 2.4.2 Background water quality 21 2.4.3 Water quality 21 2.4.4 Non-Routine analyses 23 2.5 Discussion 24 2.5.1 Complications 28 2.6 Conclusions 30 Chapter – Split-Pond Aquaculture System Design and Dissolved Oxygen Management 49 3.1 Abstract 49 3.2 Introduction 50 3.3 Materials and Methods 52 3.3.1 Design 52 3.3.2 Circulation and mixing 53 3.3.3 Dissolved oxygen 54 3.4.4 Statistical Analyses 54 3.4 Results 55 3.4.1 Production 55 3.4.2 Circulation and mixing 55 3.4.3 Dissolved oxygen 56 3.5 Discussion 57 3.5.1 Design 57 3.5.2 Production and water quality management 60 3.5.3 Paddlewheels/Pumps 61 3.5.4 Complications 62 3.6 Conclusion 63 v List of Tables Table 2.1 Average pond measurements for fish and waste cells for control and aerated waste cell ponds using Google Earth Pro for surface area and a meter stick for depth 35 Table 2.2 Average stocking rates, feed inputs, production, net yields, and feed conversion ratio (FCR) for control and aerated-waste cell ponds for multiple-batch management system over three years (2014-2016) Area includes both fish and waste cell assimilation Significant differences are noted by letters (P