Effect of Aquafeed on Productivity of Red Amaranth and on Water Quality under Aquaponic

71 Pages·2017·2.88 MB·English

Florida International University
FIU Digital Commons
FIU Electronic Theses and Dissertations University Graduate School
3-28-2014
Effect of Aquafeed on Productivity of Red
Amaranth and on Water Quality under Aquaponic
Cultivation
Miles D. Medina
Florida International University, [email protected]
DOI:10.25148/etd.FI14040848
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Recommended Citation
Medina, Miles D., "Effect of Aquafeed on Productivity of Red Amaranth and on Water Quality under Aquaponic Cultivation" (2014).
FIU Electronic Theses and Dissertations. 1206.
https://digitalcommons.fiu.edu/etd/1206
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FLORIDA INTERNATIONAL UNIVERSITY
Miami, Florida

EFFECT OF AQUAFEED ON PRODUCTIVITY OF RED AMARANTH AND ON
WATER QUALITY UNDER AQUAPONIC CULTIVATION

A thesis submitted in partial fulfillment of the
requirements for the degree of
MASTER OF SCIENCE
in
ENVIRONMENTAL STUDIES
by
Miles Medina

2014
To: Dean Kenneth G. Furton
College of Arts and Sciences

This thesis, written by Miles Medina, and entitled Effect of Aquafeed on Productivity of
Red Amaranth and on Water Quality under Aquaponic Cultivation, having been approved
in respect to style and intellectual content, is referred to you for judgment.

We have read this thesis and recommend that it be approved.

___________________________________________
Alok Deoraj

___________________________________________
Mahadev Bhat, Co-Major Professor

___________________________________________
Krishnaswamy Jayachandran, Co-Major Professor

Date of Defense: March 28, 2014

The thesis of Miles Medina is approved.

___________________________________________
Dean Kenneth G. Furton
College of Arts and Sciences

___________________________________________
Dean Lakshmi N. Reddi
University Graduate School

Florida International University, 2014

ii
© Copyright 2014 by Miles Medina

All rights reserved.

iii
ACKNOWLEDGMENTS
I would like to thank the members of my committee for their support. I will
always be grateful for the opportunities provided to me by the FIU Agroecology Program
under the direction of Drs. Mahadev Bhat and Krish Jayachandran, my Co-Major
Professors. Over the course of my degree program, Dr. Bhat’s enthusiastic
encouragement and our stimulating conversations were a source of strength. During my
thesis research his help and guidance were indispensible. Dr. Jayachandran’s technical
knowledge and good humor helped me stay relaxed and focused as obstacles presented
themselves. He provided essential lab training and the opportunity to present this work at
a national conference. I am also grateful to Dr. Alok Deoraj, committee member, whose
knowledge of aquaculture was most helpful in the development of the research questions
and during the design the experiment.
I would also like to thank Dr. Kateel Shetty and fellow graduate student Nina de
la Rosa for their assistance in the lab. I am grateful to Stephany Alvarez, Luis Garbinski,
Joshua Muñoz and Edy Cicilio for their help during construction of the aquaponic units.
And I am particularly grateful to undergraduate Carlos Pulido who fed the fish and
collected data while I was out of town at a conference. I would also like to thank Manny
García-Barbón for donating the Blue tilapia used in the study.
Finally, I wish to thank the USDA for funding under the National Institute of
Food and Agriculture's Hispanic Serving Institutions Higher Education Grant # 2011-
38422-30804.
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ABSTRACT OF THE THESIS
EFFECT OF AQUAFEED ON PRODUCTIVITY OF RED AMARANTH AND ON
WATER QUALITY UNDER AQUAPONIC CULTIVATION
by
Miles Medina
Florida International University, 2014
Miami, Florida
Professor Krishnaswamy Jayachandran, Co-Major Professor
Professor Mahadev Bhat, Co-Major Professor
Aquaponics, the integrated production of fish and hydroponic crops in a
recirculating system, is an intensive cultivation method in which metabolic fish wastes
fertilize plants. This study compares the effects of two aquafeeds on Red amaranth
(Amaranthus tricolor) productivity and on water quality under cultivation of Blue tilapia
(Oreochromis aureus), with three aquaponic units (n=3) per treatment over a 60-day trial.
The fishmeal-based control feed contains higher crude protein (40%) and phosphorus
(1.12%) than the plant-based alternative feed (32% and 0.40%). The alternative feed
resulted in a significantly higher amaranth crop yield (p<0.05) with significantly lower
nitrate-N and TDS concentrations in the culture water over the course of the trial.
Orthophosphate, TAN, pH and DO levels were not significantly different between
treatments. An economic analysis revealed that an improved crop yield from a lower-
input aquafeed could potentially increase total aquaponic farm revenue in spite of a
reduction in fish yield.
v
TABLE OF CONTENTS
CHAPTER PAGE
I. INTRODUCTION........................................................................................................... 1
Study objectives......................................................................................................... 3

II. LITERATURE REVIEW............................................................................................... 5
The global context of modern aquaculture................................................................ 5
Inland aquaculture: From wastewater-fed to recirculating systems.......................... 7
Ecological considerations for intensive aquaculture................................................. 9
Potential ecological benefits of urban aquaponic production.................................. 11
Structure and function of aquaponic systems........................................................... 14
Maintenance of water quality in aquaponic production........................................... 16
Environmental tolerances of tilapia.......................................................................... 18

III. METHODOLOGY...................................................................................................... 20
Design and setting of the aquaponic units ............................................................... 20
Experimental treatments .......................................................................................... 22
Data collection ......................................................................................................... 24
Statistical analysis ................................................................................................... 25
Economic analysis ................................................................................................... 25
Limitations of the study ........................................................................................... 26

IV. RESULTS AND DISCUSSION................................................................................. 27
Fish growth and feed conversion.............................................................................. 27
Plant growth and yield.............................................................................................. 30
Total ammonia-N (TAN) concentration................................................................... 34
Nitrate-N concentration............................................................................................ 35
Orthophosphate concentration.................................................................................. 37
Total dissolved solids (TDS) concentration and electroconductivity (EC).............. 38
pH............................................................................................................................. 41
Dissolved oxygen (DO) concentration and saturation level..................................... 42
Economic benefit from alternative aquafeeds.......................................................... 43

V. CONCLUSION............................................................................................................ 48

LIST OF REFERENCES.................................................................................................. 51

APPENDICES................................................................................................................... 57
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LIST OF TABLES
TABLE PAGE

1. Feeding rate schedule.................................................................................................... 23
2. Fish biomass data per replicate (source data)................................................................ 28
3. Normalized plant growth data per replicate.................................................................. 31
4. Normalized mean plant growth data per treatment group............................................. 31
5. P-values and statistical power given by one-way ANOVA, based
on normalized plant growth data................................................................................... 32

6. Confidence intervals and p-values given by one-way ANCOVA,
based on normalized plant growth data........................................................................ 33
7. Additional revenue generated from improved crop yields from
adoption of an alternative aquafeed, under Scenarios 1a and 1b.................................. 44

8. Percentage change in total revenue as a function of changes in crop
and fish yields from adoption of an alternative aquafeed, under Scenario 2................ 45

vii
LIST OF FIGURES
FIGURE PAGE
1. World production of fish and other aquatic animals, 1980-2010................................... 6
2. Diagram of one of the six aquaponic test units............................................................. 21
3. Net fish growth per treatment group (source data)........................................................ 28
4. TAN concentration per replicate (source data)............................................................. 34
5. Normalized nitrate-N concentration per replicate......................................................... 36
6. Normalized orthophosphate concentration per replicate............................................... 37
7. Normalized TDS concentration per replicate................................................................ 39
8. Electroconductivity per replicate (source data)............................................................. 39
9. Normalized mean TDS and nitrate concentrations per treatment group....................... 40
10. pH per replicate........................................................................................................... 41
11. Dissolved oxygen concentration per replicate............................................................. 42
12. Dissolved oxygen saturation level per replicate.......................................................... 43
13. Change in total revenue under Scenario 2, based on experimental results................. 47

viii
ABBREVIATIONS AND ACRONYMS

CP Crude protein

DO Dissolved oxygen

EC Electroconductivity

FAO Food and Agriculture Organization of the United Nations

FCR Feed conversion ratio

RAS Recirculating aquaculture system

SGR Specific growth rate

TAN Total ammonia nitrogen

TDS Total dissolved solids

UVI University of the Virgin Islands
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