CORRELATIONS BETWEEN FISH ABUNDANCE AND PHYSICOCHEMICAL by

146 Pages·2011·2.69 MB·English

CORRELATIONS BETWEEN FISH ABUNDANCE AND PHYSICOCHEMICAL
PARAMETERS IN HUMBOLDT BAY, CALIFORNIA

by
Kirsten C. Lomeli

A Thesis
Presented to
The Faculty of Humboldt State University

In Partial Fulfillment
Of the Requirements for the Degree
Master of Science
In Natural Resources: Fisheries Biology

September, 2011
ABSTRACT
Correlations between fish abundance and physicochemical parameters in Humboldt Bay,
California.

Kirsten C. Lomeli
Eelgrass habitats, within estuaries, are known to be important nursery zones for
several fish species. However, they are considered to be harsh environments due to wide
fluctuations in physicochemical factors. The objectives of this study were to determine
the extent of correlations between fish and their physical surroundings, to minimally
explore interactions between climatic and physicochemical parameters, and to investigate
the use of geostatistical interpolation tools to elucidate physicochemical changes spatially
and temporally. This research was conducted in Humboldt Bay, Humboldt County,
California from June 2006 to August 2008. Three eelgrass sites (Samoa, Indian Island
and North Bay) were sampled monthly using an epibenthic otter trawl. In addition to fish
populations, physicochemical and climatic parameters were assessed. These included
water temperature, salinity, dissolved oxygen, pH, turbidity, average monthly
precipitation and average monthly wind speed. A Canonical Correspondence Analysis
was run to evaluate fish community/environment relationships. To examine fish
species/environment relationships, an empirical distribution function was constructed
using the physicochemical parameters and weighted by fish species abundances. Then a
randomization test using the Kolmogorov-Smirnov test statistic indicated the strength of
the cdf correlations. Universal Krig estimates of water temperature and salinity were

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calculated using Geographic Information Systems geostatistical analyst to transform data
into spatially referenced surfaces. A total of 16,261 fish, representing 21 families and 40
species were captured in this study. Fish abundance was greatest during 2007. Twelve
fish species accounted for 94% of the total fish catch. Annually, species richness and
diversity were significantly different; each being greatest in 2008. Within each year,
species diversity and fish abundances were highest during the spring and summer
months. Fish were strongly correlated with environmental parameters. Juvenile
Cymatogaster aggregata preferred warmer water temperatures, greater than 16°C, while
adults were found at lower water temperatures. Pholis ornata exhibited the highest
abundances during 2007 warmer water temperatures and lower precipitation rates.
Gasterosteus aculeatus and Pholis ornata showed strong associations to both water
temperature and precipitation. Gasterosteus aculeatus adults appeared to prefer warmer
water temperatures than juveniles, but both life stage abundances decreased with slight
increases in precipitation. Sebastes melanops and Embiotoca lateralis showed strong
associations with high turbidity, while Osmerid spp. showed a strong correlation with
high dissolved oxygen readings. In general, the warmer summer water temperatures at the
North Bay location attracted juvenile fish, while adult fish were more common at the
Samoa location. Interpolated water temperature and salinity surfaces successfully showed
general patterns in physicochemical parameters over space and could prove very useful in
simplifying complex spatial physicochemical and fish distribution patterns.

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AKNOWLEDGEMENTS
Funding for this project was provided by California Center for Integrated Coastal
Observation, Research and Education (CICORE). Many thanks to my major advisor Dr.
Timothy Mulligan and my committee members Dr. Helen Mulligan and Dr. Steve
Steinberg for all the support and the hours they spent carefully reviewing this paper. I
would like to thank my husband, Mark Lomeli for his patience, support and guidance
throughout this process. Thank you to Dave Hoskins, Grant Eberle for the boat handling
and others who helped with the trawling including Dave Kyle, Jolyon Walkley, Carl
Meredith, Russell Black, Ryan Slezak, and Drew Barrett.

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TABLE OF CONTENTS
ABSTRACT ....................................................................................................................... iii
AKNOWLEDGEMENTS....................................................................................................v
TABLE OF CONTENTS ................................................................................................... vi
LIST OF TABLES ............................................................................................................ vii
LIST OF FIGURES ........................................................................................................... ix
LIST OF APPENDICES ....................................................................................................xv
INTRODUCTION ...............................................................................................................1
METHODS ..........................................................................................................................6
Site Description ........................................................................................................6
Statistical Analyses ................................................................................................14
Spatial Analysis .....................................................................................................21
RESULTS ..........................................................................................................................28
Correlation Matrix .................................................................................................39
Fish Associations with Environmental Parameters using Canonical
Correspondence Analysis.......................................................................................42
Empirical Cumulative Distribution Functions (cdf) to Test the Strength of Fish
and Environmental Associations............................................................................49
Kriging of Environmental Parameters ...................................................................79
Physicochemical Comparisons ..............................................................................90
DISCUSSION ....................................................................................................................96
REFERENCES ................................................................................................................103
APPENDICES .................................................................................................................108

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LIST OF TABLES
Table Page
1 Physicochemical parameters sampled on Humboldt Bay, Humboldt County,
California. Instruments utilized are coded below as: A = thermometer and
refractometer, B = Datasonde 600xl multiprobe and C = Datasonde 1600
multiprobe. ............................................................................................................ 12
2 Grouping of physical parameters filtered through Principle Components
Analysis (PCA) as a variable selection routine for Canonical Correspondence
Analysis. X indicates inclusion. ............................................................................ 15
3 Fish caught in Humboldt Bay, California from June 2006 to August 2008.
Percent equals % of total for given year. .............................................................. 28
4 Fish species caught at each sample location in Humboldt Bay, California
from June 2006 to August 2008. X indicates capture of at least one specimen. .. 30
5 Seasonal abundances of the 12 most abundant fish species caught in
Humboldt Bay, California from June 2006 to August 2008. ................................ 33
6 Lengths (mm) of the 12 most abundant fish species caught in Humboldt Bay,
California from June 2006 to August 2008........................................................... 34
7 Yearly ranges of environmental variables, Humboldt bay, California
measured from June 2006 to August 2008. .......................................................... 36
8 Ranges of environmental variables for each sample location, Humboldt Bay,
California measured from June 2006 to August ................................................... 37
9 ANOVA results of fish abundances and each physicochemical parameter in
Humboldt Bay, California measured from June 2006 to August 2008. *
indicates a significant result at p≤0.05. ................................................................. 38
10 Range of physicochemical parameters for the 12 most abundant fish species
caught from June 2006 to August 2008, Humboldt Bay, California. ................... 40
11 Pearson Correlation Coefficients of climatic and physicochemical
parameters, Humboldt Bay, California from June 2006 to August 2008. Bold
values indicate significant results (p≤0.05). ......................................................... 41

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LIST OF TABLES (CONTINUED)
Table Page
12 Cumulative distribution function of the Kolmogorov-Smirnov test statistic
summary of pooled (first row), annual and sample location fish catch data
from June 2006 to August 2008. *** = very strong, ** = moderate, and * =
mild relationships with physical parameters. ........................................................ 62

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LIST OF FIGURES
Figure Page
1 Study location, Humboldt Bay, Humboldt County, California. ............................. 7
2 Samoa sample site (N40.4639, W124.1262) Humboldt Bay, California. Samoa
was sampled by otter trawl from June 2006 to August 2008. (Source: “Humboldt
Bay.” 40° 46’ 32.07”N and 124° 12’ 13.10”W. Google Earth. June 9, 2006 to
September 25, 2006. November 30, 2009.) ............................................................ 9
3 Indian Island sample site (N40.4900, W124.1028), Humboldt Bay, California.
Indian Island was sampled by otter trawl from June 2006 to February 2007.
(Source: “Humboldt Bay.” 40° 49’ 37.22”N and 124° 08’ 55.17”W. Google
Earth. February 8, 2006 to June 9, 2006. November 30, 2009.) ........................... 10
4 North Bay sample site (N40.8198, W124.1335), Humboldt Bay, California. North
Bay sampled by otter trawl from March 2007 to August 2008. (Source:
“Humboldt Bay.” 40° 49’ 47.47”N and 124° 08’ 05.12”W. Google Earth.
February 8, 2006 to September 25, 2006. November 30, 2009.) .......................... 11
5 Illustration of the calculation of the Kolmogorov-Smirnov test statistic. The
“max” indicates the maximum vertical distance between the environmental
cumulative distribution function (f(t)) and the fish species weighted cumulative
distribution function g(t))………………………………………………………...20
6 Universal Krige interpolated sample locations, Humboldt Bay, Humboldt County,
California. ............................................................................................................. 25
7 Canonical Correspondence Analysis on Group 1 environmental parameters with
salinity (precipitation removed) and the top 12 fish species captured in Humboldt
Bay, California in the summer, winter, fall and spring from 2007 to 2008. (The
species are listed by the first three letters of the genus and the specific epithet,
they include: Hypomesus pretiosus, Gasterosteus aculeatus, Aulorhynchus
flavidus, Syngnathus leptorhynchus, Sebastes melanops, Hexagrammos
decagrammus, Leptocottus armatus, Cymatogaster aggregata, Embiotoca
lateralis, Pholis ornata, Parophrys vetulus and Osmerid spp. = Osmspp.) ......... 43

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LIST OF FIGURES (CONTINUED)
Figure Page
8 Canonical Correspondence Analysis on Group 1 environmental parameters with
precipitation (salinity removed) and the top 12 fish species captured in Humboldt
Bay, California in the summer, winter, fall and spring from 2007 to 2008. (The
species are listed by the first three letters of the genus and the specific epithet,
they include: Hypomesus pretiosus, Gasterosteus aculeatus, Aulorhynchus
flavidus, Syngnathus leptorhynchus, Sebastes melanops, Hexagrammos
decagrammus, Leptocottus armatus, Cymatogaster aggregata, Embiotoca
lateralis, Pholis ornata, Parophrys vetulus and Osmerid spp. = Osmspp.) ......... 44
9 Canonical Correspondence Analysis on Group 2 environmental parameters with
salinity (precipitation removed) and the top 12 fish species captured in Humboldt
Bay, California in the summer, winter, fall and spring from 2007 to 2008. (The
species are listed by the first three letters of the genus and the specific epithet,
they include: Hypomesus pretiosus, Gasterosteus aculeatus, Aulorhynchus
flavidus, Syngnathus leptorhynchus, Sebastes melanops, Hexagrammos
decagrammus, Leptocottus armatus, Cymatogaster aggregata, Embiotoca
lateralis, Pholis ornata, Parophrys vetulus and Osmerid spp. = Osmspp.) ......... 45
10 Canonical Correspondence Analysis on Group 2 environmental parameters with
precipitation (salinity removed) and the top 12 fish species captured in Humboldt
Bay, California in the summer, winter, fall and spring from 2007 to 2008. (The
species are listed by the first three letters of the genus and the specific epithet,
they include: Hypomesus pretiosus, Gasterosteus aculeatus, Aulorhynchus
flavidus, Syngnathus leptorhynchus, Sebastes melanops, Hexagrammos
decagrammus, Leptocottus armatus, Cymatogaster aggregata, Embiotoca
lateralis, Pholis ornata, Parophrys vetulus and Osmerid spp. = Osmspp.) ......... 46
11 Cumulative distribution function of water temperature relationship for
Cymatogaster aggregata in Humboldt Bay, California from June 2006 to August
2008. The p-value represents the probability of attaining the Kolmogorov-
Smirnov test statistic in a randomized distribution under the null hypothesis. .... 50
12 Cumulative distribution function of precipitation relationship for Gasterosteus
aculeatus in Humboldt Bay, California from April 2006 to August 2008. The p
value represents the probability of attaining the Kolmogorov-Smirnov test statistic
in a randomized distribution under the null hypothesis. ....................................... 51

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LIST OF FIGURES (CONTINUED)
Figure Page
13 Cumulative distribution function of water temperature relationships for
Cymatogaster aggregata in Humboldt Bay, California from January 2007 to
August 2008. The p-value represents the probability of attaining the Kolmogorov-
Smirnov test statistic in a randomized distribution under the null hypothesis. .... 52
14 Cumulative distribution function of water temperature relationships for
Gasterosteus aculeatus in Humboldt Bay, California from January 2007 to
August 2008. The p-value represents the probability of attaining the Kolmogorov-
Smirnov test statistic in a randomized distribution under the null hypothesis. .... 53
15 Cumulative distribution function of turbidity relationship for Sebastes melanops
in Humboldt Bay, California from January 2007 to August 2008. The p-value
represents the probability of attaining the Kolmogorov-Smirnov test statistic in a
randomized distribution under the null hypothesis. .............................................. 54
16 Cumulative distribution function of turbidity relationship for Cumulative
distribution function of turbidity relationship for Embiotoca lateralis in Humboldt
Bay, California from January 2007 to August 2008. The p-value represents the
probability of attaining the Kolmogorov-Smirnov test statistic in a randomized
distribution under the null hypothesis. .................................................................. 55
17 Cumulative distribution function of precipitation relationship for Sebastes
melanops and Pholis ornata in Humboldt Bay, California from January to
December 2007. The p-value represents the probability of attaining the
Kolmogorov-Smirnov test statistic in a randomized distribution under the null
hypothesis. ............................................................................................................ 56
18 Cumulative distribution function of precipitation relationship for Sebastes
melanops and Pholis ornata in Humboldt Bay, California from January to August
2008. The p-value represents the probability of attaining the Kolmogorov-
Smirnov test statistic in a randomized distribution under the null hypothesis. .... 57
19 Cumulative distribution function of dissolved oxygen relationship for Osmerid
spp. in Humboldt Bay, California from January 2007 to August 2008. The p-value
represents the probability of attaining the Kolmogorov-Smirnov test statistic in a
randomized distribution under the null hypothesis. .............................................. 58

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