Impacts from Aquaculture Activities

172 Pages·2002·7.15 MB·English

Fossil Chironomids as Indicators of Water Quality
Impacts from Aquaculture Activities
by
Saloni Clerk
A thesis submined to the Department of Biology
in conformity with the requirements for
the degree of Master of Science
Queen's University
Kingston. Ontario. Canada
January. 2002
Copyright 8 Saloni Clerk. 2002
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ABSTRACT
Aquaculture activities pose a fairly new threat to water quality of inland lakes. Discharge
of fish wastes and uneaten fish food can contribute significafii nutrients to lakes and Iead to
potentially serious eutrophication problems. Hypolimnetic anoxia resulting from aquaculture
activities is of panicular concem. as low oxygen conditions can be harmful to both the aquatic
environment as well as fish farming activities themselves. Assessing the impact of aquaculture
activities on deepwater oxvgen levels is difficult. as monitoring data were rarely gathered
regarding pre-impact conditions.
Paleolimnological investigations were carried out in the Nonh Channel of Lake Huron
and in Plane Lake. Michigan, to determine water quality impacts from aquaculture activities.
Larval Chironomidae (Diptera) head capsule assemblages were used as proxy indicators of
oxygen to track changes in deepwater oxygen coinciding with the establishment of fish farming
activities. In addition. chironom id m icrofossils were uxd to determine pre-impact conditions and
recovery rates in lakes that have supponed intensive aquaculture activities in the past.
Fossil c hironom id assern blages from the LaCloche Channel, Lake Huron. indicated that
significant deterioration of the oxygen environment coincided with the establishment of cage
aquaculture activities. Marked reductions in chironomid taxa that are indicative of well-
oxygenated conditions occurred around the estirnated time of fish farming activities.
Concurrently, littoral taxa comprised a higher percentage of the chironomid assemblages. In
Plaite Lake. Michigan. hatchery effluents had similar impacts on chironomid assemblages.
Recovery in the LaCloche Channel as well as Plane Lake were not detected, despite the cessation
of cage aquaculture in the LaCloche Channel and significant reductions in nutrient loadings to
Platte Lake. These findings are in agreement with available monitoring data. Hence. chironomids
infer that long-term impacts in deepwater oxygen conditions may result from aquaculture
activities.
Regional analyses in the North Channel of Lake Huron. as well as downcore analysis in
Lake Wolsey. Manitoulin Island, indicated that site characteristics (production level. length of
operation. morphometry. flushing rates), as well as natural and anthropogenic disturbances. are
important variables that may modi. the impacts that fish fanning activities have on the
environment.
CONTRIBUTIONS
I conducted al l chironom id analyses in my thesis. Diatorn analysis was performed by
Dan Selbie in the Lacloche core (Chapter 2). OP^ dating and diatom analysis was conducted by
Petra Werner in Lake Wolsey (Chapter 3).
ACKNOWLEDGEMENTS
I feel very fortunate to have ken part of the PEARL lab over the past few years. John
Smol has been a very supportive supervisor who has always fit me into his busy schedule to
provide guidance and encouragement. 1 first learned about chironomids from Roberto Quinlan as
a year undergraduate student. Roberto has been a great person to leam from and I am deeply
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thankful to him for showing me the ropes again after my year off (it is amazing. what you can
forget). 1 am also grateful to Dn. Brian Cumming and Scott Lamoureux for being on my
cornmittee and for providing useful suggestions and advice. I appreciate the assistance of Peggy
Gale and Gary Whelan in providing data on my study sites and for helping to CO-ordinatef ield
work. Thanks also goes to Jennifer Morse and Bronwyn Keatly for their help in prepping
samples.
Being pan of the PEARL lab has ken a tremendous experience. Everyone has in
someway contributed to this thesis and helped me to make the most of my time here at Queen's.
For providing scholarly advice. encouragement, and perspective, I thank especially Kat. Francine.
Petra and Rene. Fieldwork was a highlight of research and would not have been the same
without Petra and Dan (minus the Kung-Foo movies.. .). The lab has definitely been a great
leaming and working environment. From debates on musical taste (a G&R fan I will never be! ),
cheese parties (1 will find out one day.. .), pronunciation, and Iively discussions on tofu turkeys I
thank Neal. Andrew. Dan. and Jon. You guys definiteiy made me count faster! Thanks also to
rny dear friends Celeste and Ally for sharing in a11 those life 'moments' and going through this
with me.
My parents have provided much love and support. Thanks to my brother, Aashish, and
sister. Neha. for always king there to count on.
TABLE OF CONTENTS
ABSTRACT
CONTRIBUTIONS
ACKNOWLEOGEMENTS
TABLE OF CONTENTS
LlST OF TABLES
LlST OF FIGURES X
LlST OF ABBREVIATIONS XII
CHAPTER 1: INTRODUCTION AND LITERATURE REVIEW
Introduction
Literature Review
Backgrounri on Cage Culture
Nutrient enrichen!f i.om fish fmnrs
Environmental impucrs offish farms
Assessing impacts of cage culture
Importance and conrrol of mygen in lakes.
Chiranomid Lije QcIe and EcoZogy
Chironomids as Puleoindiccirors
CHAPTER 2: WATER QUALITY IMPACTS FROM CAGE AQUACULTURE
OPERATIONS IN THE NORTH CHANNEL OF LAKE HURON
introduction
Site Description
LaCIoche Site
Bedford Harbour. Eastern 1sl and and Fisher Harbour sires
Material and Meth o&
.d nalyses
Results
LaCloche Sire
Bedford Harbour. Eartem Island. and Fisher Harbour sites
Discussion 40
Conclusions 50
CHAPTER 3: CHIRONOMID-INFERRED CHANGES IN DISSOLVED OXYGEN IN
LAKE WOLSEY, MANITOULIN ISLAND: THE EFFECTS OF CAGE AQUACULTURE
AND OTHER DISTURBANCES 52
Site Description 53
Materials and Metb ods
A nalyses
Results and Discussion 59
Conclusions 73
CHAPTER 4: IMPACTS OF HATCHERY EFFLUENTS ON DEEP WATER OXYGEN
LEVELS IN PLATTE UKE,M ICHIGAN, BASED ON FOSSIL CHlRONOMlDS 75
Introduction 75
Site description and history
flatte River Stute Fish Hutchery
Metb ods
Sedirnent cores
Daring
Water contenr and loss on ignition (SG core)
Chironornid analyses
R nalyses
Results and Discussion
Sediment duting and core chronolugy
Cornparison of /'-CS and stable Pb distributions in sediments
Water content and loss on ignitionf or the SG core
Chironomid analvses
Core chronologv based on chironomid assemblages
Chironomid-baced axygen reconst~ionisn Platte Lake
Conclusions 110
CHAPTER 5: GENERAL DISCUSSION AND SUMMARY 111
APPENDIX 2A: RAW COUNTS OF CHIRONOMID HEAD CAPSULES IN THE
LACLOCHE CHANNEL 128
APPENDIX 2B: ' 3 7 A~C~Tl VlTY IN THE LACLOCHE CHANNEL 129
APPENDIX 2C: SPECIES DlVERSlfY IN THE LACLOCHE CHANNEL 130
APPENDlX 20: HYDROGRAPH OF LAKE HURON 131
APPENDIX 2E: RAW COUNTS OF CHlRONOMlD HEAD CAPSULES IN BEDFORD
HARBOUR, FISHER HARBOUR AND EASTERN ISLAND 132
APPENDIX 3A: M WC OUNTS OF CHlRONOMlD HEAD CAPSULES IN LAKE
WOLSEY 133
APQENDIX 4A: RAW COUNTS OF CHIRONOMID HEAD CAPSULES IN PLATTE
LAKE (SG CORE) 134
APPENDIX 4B: RAW COUNTS OF CHlRONOMlD HEAD CAPSULES IN PLATTE
LAKE (PL-1 CORE) 135
LIST OF TABLES
Table 2.1 Abbreviations for chironomid ta\a in the PCA diagram of species 37
and site scores from the Lacloche Channel
Table 3. 1 Physical and chemical characteristics of Lake Wolsey 55
Table 4. 1 Physical and chernical data for Platte Lake 78
Table 4.2 Phosphorus loadings to Big Platte Lake from hatchery effluents 83
from 1977- 1996
Table 4.3 Abbreviations for chironornid taxa in the PCA diagram ofs pecies 98
and site scores from Platte Lake