influence of freshwater inflow on the abundance and distribution of decapod zooplankton in the

116 Pages·2014·1.95 MB·English

by  Jaime E Cook

INFLUENCE OF FRESHWATER INFLOW ON THE ABUNDANCE AND
DISTRIBUTION OF DECAPOD ZOOPLANKTON IN THE CALOOSAHATCHEE RIVER,
FLORIDA

A Thesis

Presented to

The Faculty of the College of Arts and Sciences

Florida Gulf Coast University

In Partial Fulfillment

Of the Requirements for the Degree of

Master of Science

By

Jaime Cook

2014
APPROVAL SHEET

This thesis is submitted in partial fulfillment

for the requirements for the degree of

Master of Science

_________________________________

Jaime E. Cook

Approved: May 2014

_________________________________

S. Greg Tolley, Ph.D.
Committee Chair / Advisor

_________________________________

Scott Burghart, Ph.D.

_________________________________

Brian Bovard, Ph.D.

The final copy of this thesis has been examined by the signatories, and we find that both the
content and the form meet acceptable presentation standards to scholary work in the above
mentioned discipline.
i
Acknowledgments

I would like to thank my advisor, Greg Tolley, for all of his encouragement, guidance and
knowledge for this project. Thank you to my committee members, Scott Burghart and Brian
Bovard, for their valuable insight, allowing me to improve the quality of this work. This
research benefited greatly from Dr. Burghart’s role in the project as well as mentoring me in
larval identification as well as Dr. Bovard’s knowledge of data analysis.

I’d also like to thank staff at the University of South Florida lab, Kara Radabaugh and Gregg
Ellis, for their assistance with sampling processing. In addition, this work would not have
been possible without the assistance of my fellow graduate students, Brooke Black, Julie
Neurohr, and Jennifer (Nelson) Carpenter for their assistance with sample collection,
laboratory work and invaluable feedback throughout this project.

Thank you to my family, David, Patricia, Jared, Jason, Josh, and Dana Cook for their support
and encouragement in the pursuit of my Master’s Degree. Finally, thank you to my son,
Matthew Cook, for all of his patience and love throughout this process. This project would not
have been possible without his tremendous support.
ii
Abstract

In order to understand the influence of variable freshwater inflow to estuaries and
subsequent fluctuations in salinity on zooplankton community structure and larval recruitment,
the distribution and abundance of decapod crustacean larvae in the Caloosahatchee River and
Estuary, Florida were quantified using monthly plankton tows for two years. Larvae
preferring high salinities (Callinectes sapidus, Dissodactylus spp., Menippe mercenaria,
Petrolisthes armatus, and Pinnotheres maculatus) were concentrated near the mouth of the
river; euryhaline larvae (Eurypanopeus depressus and Panopeus spp.) occurred abundantly
throughout the river; and the low-salinity species Rhithropanopeus harrisii was found
upstream. Total larval abundance peaked in late-spring, prior to the onset of the wet season.
Additionally, C. sapidus, E. depressus, M. mercenaria, Panopeus spp. and R. harrisii
exhibited significant shifts downstream with the onset of the wet season. P. armatus was the
only species to demonstrate significant changes in total abundance among calendar seasons,
with significant increases occurring during the spring. Species-specific centers of abundance
and total abundance demonstrated significant correlations with both average continuous
inflow and daily discrete inflow for lags of up to 120 days prior to sampling. C. sapidus, E.
depressus, M. mercenaria, P. armatus, Panopeus spp. and R. harrisii were negatively
correlated with inflow. Center of abundance and total abundance of Dissodactylus spp. and P.
maculatus were positively correlated with daily discrete inflow. These commensal crabs did
not respond in the same way to changes in salinity as expected based on the other species
surveyed. These results suggest the importance of considering the impacts of freshwater
discharges on both the spatial and seasonal variation in larval supply within the estuary.
iii
Table of Contents
Acknowledgments...................................................................................................................... i
Abstract...................................................................................................................................... ii
Table of Contents...................................................................................................................... iii
List of Tables............................................................................................................................ v
List of Figures and Appendices............................................................................................... vii
Introduction.................................................................................................................................1
Materials and Methods...............................................................................................................5
Study Site.......................................................................................................................5
Zooplankton Sampling...................................................................................................5
Zooplankton Processing................................................................................................7
Environmental Factors..................................................................................................7
Data Analysis.................................................................................................................8
Statistical Analysis........................................................................................................10
Results......................................................................................................................................11
Larval Relationships to Water Quality.........................................................................11
Spatial and Temporal Variation in Abundance............................................................13
Variation in Location and Abundance between Seasons.............................................16
Relationships between Location and Abundance due to Freshwater Inflow...............19
Discussion................................................................................................................................22
Abundance and Distribution of Decapod Larvae.........................................................23
Seasonal Variation of Larvae.......................................................................................32
Effects of Freshwater Inflow........................................................................................41
Implications on Future Practices..................................................................................51
iv
References................................................................................................................................55
Tables......................................................................................................................................64
Figures.....................................................................................................................................73
Appendix A.............................................................................................................................95
Appendix B.............................................................................................................................98
Appendix C.............................................................................................................................101
Appendix D............................................................................................................................104
v
List of Tables
Table 1. Plankton sampling locations in the Caloosahatchee River and Estuary.....................64
Table 2. Sampling dates during the study period.....................................................................64
Table 3. Water quality data for each sampling station..............................................................65
Table 4. Results of correlation analysis between river kilometer and environmental data.......65
Table 5. Results of correlation analysis between water quality factors and density of
individual species......................................................................................................................66
Table 6. Results of correlation analysis between salinity and total abundance of larvae by
species......................................................................................................................................66
Table 7. Callinectes sapidus: One-way ANOVA with zone as factor.....................................66
Table 8. Menippe mercenaria: One-way ANOVA with zone as factor...................................67
Table 9. Total abundance of Menippe mercenaria: Two-way ANOVA with station and
season (wet/dry) as factors........................................................................................................67
Table 10. Total abundance of Petrolisthes armatus: Two-way ANOVA with station and
season (wet/dry) as factors........................................................................................................67
Table 11. Total abundance of Panopeus spp.: Two-way ANOVA with station and season
(wet/dry) as factors....................................................................................................................67
Table 12. Total abundance of Eurypanopeus depressus: Two-way ANOVA with station and
season (4 seasons) as factors.....................................................................................................68
Table 13. Total abundance of Panopeus spp.: Two-way ANOVA with station and season (4
seasons) as factors.....................................................................................................................68
Table 14. Total abundance of Menippe mercenaria: Two-way ANOVA with station and
season (4 seasons) as factors.....................................................................................................68
Table 15. Total abundance of Petrolisthes armatus: Two-way ANOVA with station and
season (4 seasons) as factors.....................................................................................................69
vi
Table 16. Results of correlation analysis between total abundance of larvae in 2008–2009 and
2009–2010................................................................................................................................69
Table 17. Results of one-way ANOVA comparing species-specific center of abundance
between wet and dry seasons....................................................................................................69
Table 18. Results of one-way ANOVA comparing species-specific total abundance of larvae
between wet and dry seasons....................................................................................................70
Table 19. Results of one-way ANOVA comparing species-specific center of abundance
between calendar seasons..........................................................................................................70
Table 20. Results of one-way ANOVA comparing species-specific total abundance of larvae
between calendar seasons..........................................................................................................71
Table 21. Results of correlation analysis between average continuous freshwater inflow and
river location of individual species for lags of up to 120 days prior to sampling.....................71
Table 22. Results of correlation analysis between average continuous freshwater inflow and
total abundance of individual species for lags of up to 120 days prior to sampling.................72
Table 23. Results of correlation analysis between discrete freshwater inflow and river
location of individual species for lags of up to 120 days prior to sampling......................72
Table 24. Results of correlation analysis between discrete freshwater inflow and total
abundance of individual species for lags of up to 120 days prior to sampling.........................72
vii
List of Figures and Appendices
Figure 1. Map of the study area within the Caloosahatchee River and Estuary......................73
Figure 2. Freshwater inflow to the Caloosahatchee River recorded at the W.P. Franklin Lock
and Dam from May 1, 2008—April 23, 2010...........................................................................74
Figure 3. Sampling zones constructed to calculate total volume of the study area..................75
Figure 4. Relationship between river kilometer, mean salinity and minimum dissolved
oxygen concentrations over the 24-month study.......................................................................76
Figure 5. Relationship between average dissolved oxygen concentration and density of larvae
by species.................................................................................................................................77
Figure 6. Relationship between minimum dissolved oxygen concentration and density of
larvae by species........................................................................................................................78
Figure 7. Relationship between mean salinity and total abundance of larvae by species........79
Figure 8. Relationship between average dissolved oxygen concentration and total abundance
of Eurypanopeus depressus larvae............................................................................................80
Figure 9. Relationship between river kilometer and total number of larvae............................80
Figure 10. Relationship between river kilometer and total number of larvae by species........81
Figure 11. Total abundance of all larvae by species for the sampling period May 2008–April
2010...........................................................................................................................................82
Figure 12. Total abundance of Callinectes sapidus larvae by sampling month.......................82
Figure 13. Total abundance of Menippe mercenaria larvae by sampling month....................83
Figure 14. Total abundance of Petrolisthes armatus larvae by sampling month.....................83
Figure 15. Total abundance of Pinnotheres maculatus larvae by sampling month.................84
Figure 16. Total abundance of Dissodactylus spp. larvae by sampling month........................84
Figure 17. Total abundance of Eurypanopeus depressus larvae by sampling month..............85
Figure 18. Total abundance of Panopeus spp. larvae by sampling month...............................85
viii
Figure 19. Total abundance of Rhithropanopeus harrisii larvae by sampling month.............86
Figure 20. Comparison of center of abundance of Callinectes sapidus and Menippe
mercenaria larvae among calendar seasons..............................................................................87
Figure 21. Comparison of center of abundance of Eurypanopeus depressus and
Rhithropanopeus harrisii larvae among calendar seasons........................................................88
Figure 22. Comparison of total abundance of Petrolisthes armatus larvae among calendar
seasons.......................................................................................................................................89
Figure 23. Relationship between average continuous freshwater inflow and center of
abundance by species................................................................................................................90
Figure 24. Relationship between average continuous freshwater inflow and total abundance
by species..................................................................................................................................91
Figure 25. Relationship between discrete freshwater inflow and center of abundance by
species.......................................................................................................................................92
Figure 26. Relationship between discrete freshwater inflow and center of abundance for
Dissodactylus spp. and Pinnotheres maculatus........................................................................93
Figure 27. Relationship between discrete freshwater inflow and total abundance by
species.......................................................................................................................................94
Appendix A. Correlation coefficients vs. lag time relationships between center of abundance
and mean continuous inflow..................................................................................................95
Appendix B. Correlation coefficients vs. lag time relationships between total abundance and
mean continuous inflow.........................................................................................................98
Appendix C. Correlation coefficients vs. lag time relationships between center of abundance
and daily discrete inflow.........................................................................................................101
Appendix D. Correlation coefficients vs. lag time relationships between total abundance and
daily discrete inflow................................................................................................................104