Prepared in cooperation with the U.S. Fish and Wildlife Service 

A Comparison of Mercury Burdens between St. Marks 

National Wildlife Refuge and St. Andrew Bay, Florida: 

Evaluation of Fish Body Burdens and Physiological 

Responses in Largemouth Bass, Spotted Seatrout, 

Striped Mullet, and Sunfish 

By D.H. Huge, R.H. Rauschenberger, C.M. Wieser, and J.M. Hemming 

Open-File Report 2011–1056

U.S. Department of the Interior 

U.S. Geological Survey 
ii

U.S. Department of the Interior 

KEN SALAZAR, Secretary 

U.S. Geological Survey 

Marcia K. McNutt, Director 

U.S. Geological Survey, Reston, Virginia 2011 

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Suggested citation: 

Huge, D.H., Rauschenberger, R.H., Wieser, C.M., and Hemming, J.M., 2011, A comparison of mercury 

burdens between St. Marks National Wildlife Refuge and St. Andrew Bay, Florida: Evaluation of fish body 

burdens and physiological responses in largemouth bass, spotted seatrout, striped mullet, and sunfish: U.S. 

Geological Survey Open-File Report 2011-1056, 35 p.

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endorsement by the U.S. Government. 

Although this report is in the public domain, permission must be secured from the individual 

copyright owners to reproduce any copyrighted material contained within this report. 
iii

Contents 

Abstract ......................................................................................................................................................................... 1

Introduction .................................................................................................................................................................... 1

Acknowledgments ...................................................................................................................................................... 3

Objectives and Hypotheses (Ho) .................................................................................................................................... 3

Methods ......................................................................................................................................................................... 4

Sampling Locations and Fish Collection .................................................................................................................... 4

Mercury Analyses....................................................................................................................................................... 5

Statistical Analyses .................................................................................................................................................... 5

Results ........................................................................................................................................................................... 6

Discussion ..................................................................................................................................................................... 8

Conclusions ................................................................................................................................................................. 10

References Cited ......................................................................................................................................................... 11

Figures 

Figure 1. Fish sampling stations in the St. Marks NWR study area. ........................................................................... 14

Figure 2. Fish sampling stations in the St. Andrew Bay study area. ........................................................................... 15

Figure 3. Summary and comparisons of mercury tissue concentrations in fish from St. Marks NWR and 

St. Andrew Bay. ........................................................................................................................................................... 16

Figure 4. Summary and comparisons of mercury tissue concentrations for species from St. Marks NWR 

and St. Andrew Bay. .................................................................................................................................................... 17

Figure 5. Examples of the distribution of mercury concentration in spotted seatrout with age for all seven 

study sites. ................................................................................................................................................................... 18

Figure 6. Examples of the distribution of mercury concentration in largemouth bass with age for all 

seven study sites. ........................................................................................................................................................ 19

Figure 7. Examples of the distribution of mercury concentration in spotted seatrout with length for all 

seven study sites. ........................................................................................................................................................ 20

Figure 8. Examples of the distribution of mercury concentration in sunfish with length for all seven 

study sites.. .................................................................................................................................................................. 21

Tables 

Table 1. Characteristics, mercury tissue concentrations (ng/g wet weight) and health parameters 

(hepatosomatic index. [HSI] and gonadosomatic index [GSI]) of striped mullet from St. Marks 

NWR and St. Andrew Bay, Florida, collected in July and September 2006. ................................................................ 22

Table 2. Characteristics, mercury tissue concentrations (ng/g wet weight) and health parameters 

(hepatosomatic index [HSI] and gonadosomatic index.[GSI]) of spotted seatrout from St. Marks 

NWR and St. Andrew Bay, Florida, collected during July and September 2006. ......................................................... 22

Table 3. Characteristics, mercury tissue concentrations (ng/g wet weight) and health parameters 

(hepatosomatic index [HSI] and gonadosomatic index. [[GSI]) of largemouth bass from St. Marks 

NWR and St. Andrew Bay, Florida, collected during July and September 2006 .......................................................... 23

Table 4. Characteristics, mercury tissue concentrations (ng/g wet weight) and health parameters 

(hepatosomatic index [HSI] and gonadosomatic index [GSI]) of sunfish from St. Marks NWR and 

St. Andrew Bay, Florida, collected during July and September 2006........................................................................... 24
iv

Table 5. Mercury concentrations in freshwater and estuarine fish species collected at St. Marks 

National Wildlife Refuge (SM) and St. Andrew Bay (AB). ............................................................................................ 25

Table 6. Size characteristics, mercury concentrations, and health indicators for freshwater fish from 

St. Andrew Bay and St. Marks National Wildlife Refuge. ............................................................................................. 27

Table 7. Size characteristics, mercury concentrations, and health indicators for estuarine fish from 

St. Andrew Bay and St. Marks National Wildlife Refuge. ............................................................................................. 28

Table 8. Comparison of mercury concentrations with fish length, weight, age, hepatosomatic index (HSI), 

and gonadosomatic index (GSI), by sex and species of estuarine fish from St. Andrew Bay and 

St. Marks National Wildlife Refuge. ............................................................................................................................. 29

Table 9. Comparison of mercury concentrations with fish length, weight, age, hepatosomatic index (HSI), 

and gonadosomatic index (GSI), by sex and species of freshwater fish from St. Andrew Bay and 

St. Marks National Wildlife Refuge. ............................................................................................................................. 31

Table 10. Comparison of mercury concentrations with length, weight, and age by species of freshwater fish 

from St. Andrew Bay and St. Marks National Wildlife Refuge.. .................................................................................... 33

Table 11. Comparison of mercury concentrations with length, weight, and age by species of estuarine fish 

from St. Andrew Bay and St. Marks National Wildlife Refuge.. .................................................................................... 34

Table 12. Percentage of spotted seatrout with consumption limits from sampling sites in St. Andrew Bay 

and St. Marks National Wildlife Refuge. ...................................................................................................................... 35

Table 13. Percentage of largemouth bass with consumption limits from sampling sites in St. Andrew Bay 

and St. Marks National Wildlife Refuge. ...................................................................................................................... 35

Table 14. Percentage of sunfish with consumption limits from sampling sites in St. Andrew Bay and 

St. Marks National Wildlife Refuge. ............................................................................................................................. 35
v 

Conversion Factors 

Multiply By To obtain

micrometer (μm) 0.0003937 inch (in.)

millimeter (mm) 0.03937 inch (in.)

meter (m) 3.1 foot (ft)

kilometer (km) 0.6214 mile (mi)

milligrams per kilogram (mg/kg) 1 parts per million (ppm)

nanograms per gram (ng/g) 1 parts per billion (ppb)

Acronyms 

GSI Gonadosomatic Index

GSMFC Gulf States Marine Fisheries Commission

Hg Mercury

HgC4H6O4C Mercuric II acetate

Hg2Cl2 Mercurous I chloride

HgCH3 Methyl mercury

HSI Hepatosomatic Index

mg Milligram

ng Nanogram

NWR National Wildlife Refuge

ppb Parts per billion

ppm Parts per million

μg Microgram

USEPA United States Environmental Protection Agency

USGS-SESC United States Geological Survey-Southeast Ecological Science Center
1 

A Comparison of Mercury Burdens between St. Marks 

National Wildlife Refuge and St. Andrew Bay, Florida: 

Evaluation of Fish Body Burdens and Physiological 

Responses in Largemouth Bass, Spotted Seatrout, 

Striped Mullet, and Sunfish 

By D.H. Huge1, R.H. Rauschenberger2, C.M. Wieser1, and J.M. Hemming3

Abstract 

Musculature from the dorsal region of 130 largemouth bass (Micropterus salmoides), 140 

sunfish (Lepomis sp.), 41 spotted seatrout (Cynoscion nebulosus) and 67 striped mullet (Mugil 

cephalus) were collected from five estuarine and five freshwater sites within the St. Marks National 

Wildlife Refuge and two estuarine and two freshwater sites from St. Andrew Bay, Florida, United 

States of America. Musculature was analyzed for total mercury content, sagittal otoliths were 

removed for age determination and physiological responses were measured. Largemouth bass and 

sunfish from the refuge had higher mercury concentrations in musculature than those from the bay. 

Male spotted seatrout, male striped mullet, male and female sunfish and female largemouth bass 

had mercury burdens positively correlated with length. The majority of all four species of fish 

from both study areas contained mercury levels below 1.5 part per million, the limit for safe 

consumption recommended the Florida Department of Health. In comparison, a significant 

percentage of largemouth bass and sunfish from several sampled sites, most notably Otter Lake and 

Lake Renfroe within St. Marks National Wildlife Refuge, had mercury levels consistent with the 

health department’s guidelines of “limited consumption” or “no consumption guidelines.”

Introduction 

Although mercury is a universal contaminant in the biosphere, its distribution is not uniform 

(U.S. Environmental Protection Agency [USEPA], 2001b; Gulf States Marine Fisheries 

Commission, 2002). Mercury sources can be natural or anthropogenic. Natural mercury sources 

include volcanoes and geothermal activity, forest fires, degassing of sediment or rock containing 

mercury, and seawater evaporation. The majority of anthropogenic sources of mercury include 

combustion processes where mercury is emitted as a byproduct, mining practices, sewage 

discharge, and metal refining operations (U.S. Environmental Protection Agency, 2006). 

 

1

 D.H. Huge (dane_huge@usgs.gov; 352-264-3540) and C. M. Wieser, U.S. Geological Survey-Southeast Ecological 

Science Center, 7920 NW 71st Street, Gainesville, Florida 32653. 

2

R. H. Rauschenberger, U.S. Fish and Wildlife Service, 6620 Southpoint Drive South, Suite 310, Jacksonville, Florida 

32216. 

3

J. M. Hemming, U.S. Fish and Wildlife Service, 1601 Balboa Avenue, Panama City, Florida 32405. 
2 

Understanding mercury distribution, or the fate and transport of mercury contamination, is 

paramount to protecting fish and wildlife species, as well as the human population. (Florida 

Department of Environmental Protection, 2007). 

The distribution of mercury depends on local and global source locations, air currents, 

physiochemical properties of the receiving environments, biotic and abiotic transformations, and 

biomagnification in certain animal species (Suter, 1993; Beyer and others, 1997). Much of the 

world’s mercury contamination travels in global air currents until eventual deposition onto land 

surface. Mercury enters aquatic environments through runoff of land deposits or direct deposition 

into water bodies. Mercury is biologically transformed to methyl mercury (HgCH3) in the aquatic 

environment. HgCH3 has an inherent tendency to concentrate in biological organisms, particularly

aquatic species, through incremental increases during transfer from the water to phytoplankton to 

zooplankton to planktivorous (plankton eating) fish to piscivorous fish, birds, wildlife, and humans 

(U.S. Environmental Protection Agency, 2001a). 

Numerous reports have documented that HgCH3 is more toxic to fish and wildlife than 

inorganic forms, such as mercuric II acetate (HgC4H6O4C) and mercurous I chloride (Hg2Cl2). 

These reports include behavioral effects and reproductive impairment resulting from neurological 

damage caused by HgCH3 exposure in fish and wildlife (Scherer, 1975; Scheuhammer, 1991; 

Suter, 1993; Clarkson, 1994; Beyer and others, 1997). These effects also extend to humans, 

particularly during prenatal exposure (D’Itri and D’Itri, 1977; U.S. Environmental Protection 

Agency, 2001a; Gulf States Marine Fisheries Commission, 2002).

The ten states within the U.S. Fish and Wildlife Service Southeast Region have issued fish 

consumption advisories due to mercury contamination (Facemire and others, 1995). More recently, 

Florida and the other Gulf Coast states have issued statewide mercury-based consumption 

advisories on select fish species (U.S. Environmental Protection Agency, 2001a ). Additionally, 

reports of mercury-contaminated fish in northwest Florida are of particular regional concern due to 

relatively high seafood consumption in the area and seafood’s importance to the local economy 

through fish export and tourism (Brim and others, 1992, 1994; Rider and Adams, 2000). The 

problematic effects of elevated mercury levels on wildlife are well documented (Royals and Lange,

1990; Facemire and Chlebowski, 1991; Wood and others, 1993; Adams and others, 1998), 

including migratory birds, marine mammals, and other aquatic and semi-aquatic species (Stickney 

and others, 1975; Heinz, 1979; Gulf States Marine Fisheries Commission, 2002). 

Concerns over potential health risks from the consumption of mercury-contaminated Gulf 

of Mexico fish instigated the development of a Gulf-wide initiative to examine the extent of 

mercury contamination in fish (Gulf States Marine Fisheries Commission 2002). The number of 

mercury-contaminated fish advisories has increased consistently in the United States over recent 

years (U.S. Environmental Protection Agency, 2001b). Gulf-states fish consumption advisories are 

common (up to 100 advisories per year) and often statewide due to unacceptable high levels of 

mercury found in fish that inhabit various aquatic ecosystems (U.S. Environmental Protection 

Agency, 2001b). The level of mercury recommended for human fish consumption in Florida is 

based on the action level of 1.0 part per million (ppm; mg/kg ww), as set by the U.S. Food and 

Drug Administration and World Health Organization. This recommendation is as follows: 

unlimited consumption of fish when mercury concentrations are under 0.5 ppm, limited 

consumption of fish when concentrations are between 0.5 and 1.5 ppm (young children and women 

of childbearing age are most at risk), and no fish consumption when concentrations exceed 1.5 

ppm. 
3 

Problems exist with national and global mercury criteria. For example, the level at which 

mercury is known to be detrimental to the developing child is highly uncertain and under much 

debate (Clapp and Grandjean, 2002). Some studies report that negative effect levels are far lower 

than action levels currently used to warn people of possible dangers (Clapp and Grandjean, 2002). 

The action levels of mercury for fish and wildlife are even more uncertain. Additionally, it is not 

rare for midsized piscivorous fish to contain mercury concentrations that exceed limited 

consumption thresholds (Brim and others, 1992, 1994; Rider and Adams, 2000). These fish may 

serve as sentinels or biological indicators of the level of mercury contamination in piscivorous 

birds and other fish-eating organisms. Certain mercury levels measured in these fish have been 

reported to cause behavioral and reproductive problems in fish-eating birds and other piscivorous 

wildlife species (Stickney and others, 1975, Heinz, 1979, Royals and Lange, 1990, Facemire and 

Chlebowski 1991, Wood and others, 1993, Adams and others, 1998). However, relatively small 

sample sizes within selected species have been examined to determine levels of mercury 

contamination due to the large areas that need to be evaluated. A firm understanding of the relative 

state of mercury levels in unique ecosystems, such as wildlife refuges, would provide important 

information for policy development and decision making involving fishery status, management 

actions, and the need for land acquisition to provide buffers between source inputs and sensitive 

resources. 

National wildlife refuges provide sanctuaries for fish and wildlife resources including 

federally listed endangered and threatened species, migratory birds, and anadromous fish species. 

Fish and wildlife species living on wildlife refuges, however, are subject to mercury exposure. 

Changes in land use can alter the natural environment, resulting in greater than normal 

concentrations of mercury uptake, which progresses upward through the food chain. The main 

objective of this study was to conduct a comparative assessment of mercury contamination and fish 

health indicators for several species of fish from St. Marks National Wildlife Refuge (NWR) and 

St. Andrew Bay, and to compare these results to State of Florida Fish Consumption Advisories. 

Acknowledgments 

Funding for this project was provided by the U.S. Fish and Wildlife Service and the U.S. 

Geological Survey. Numerous people played critical roles in the completion of this project. In 

particular we thank Lynn Lefebvre, Robert Dorazio, and Tim Bargar for their assistance and/or 

peer review; Travis Smith and Robert Lewis for their assistance in field work and sample 

collection; Joe Reinman and Michael Keys for their logistical support at St. Marks National 

Wildlife Refuge; and others who substantially helped in the review and preparation of this report. 

Objectives and Hypotheses (H0) 

Evaluate mercury levels in fish musculature from largemouth bass (Micropterus salmoides), 

spotted seatrout (Cynoscion nebulosus), striped mullet (Mugil cephalus), and sunfish (Lepomis

sp.), and conduct area-specific comparisons among species from various trophic levels and/or 

feeding strategies. Compare sample sites within the St. Marks NWR and St. Andrew Bay (nonnational wildlife refuge area). Compare with other mercury data from previous studies along 

the Gulf Coast.

Hypothesis: There is no difference between mercury concentrations in fish musculature 

taken within areas of St. Marks NWR or St. Andrew Bay. 
4 

Compare biomarkers of fish health between fish collected at St. Marks NWR and those 

sampled at St. Andrew Bay. 

Hypothesis: Biomarkers of fish health are not different between fish collected at St. Marks 

NWR and fish sampled at St. Andrews Bay (non-national wildlife refuge area). 

Assess the general and reproductive health of largemouth bass, spotted seatrout, striped mullet, 

and sunfish with respect to relative mercury contamination. Assessments will include use of 

total mercury concentrations in fish musculature, gonadosomatic index (GSI), and 

hepatosomatic index (HSI). 

Hypothesis: mercury fish tissue concentration will not be significantly correlated with GSI 

and HSI. 

Assess species-specific size and age relative to mercury levels in musculature. Data will be 

examined to determine relationships between fish size, age, and mercury contamination for 

potential use in developing slot limits or consumptive restrictions based on size. 

Hypothesis: There is no relationship between fish size and the amount of mercury in fish 

musculature. 

Hypothesis: There is no relationship between the age of sampled fish and the amount of 

mercury found in the musculature. 

Assess the percentage of sampled fish that exceeded State of Florida Fish Consumption 

Advisories.

The results of these objectives will provide information that benefits local resource 

managers. For example, knowledge of the state of contamination within and around St. Marks 

NWR may help resource managers develop management and policy strategies for specific areas 

that benefit fish and wildlife and mitigate potential risks. Furthermore, finding higher mercury 

concentrations in fish from St. Andrew Bay (non-national wildlife refuge area) may indicate 

differences in local mercury inputs and underscore the value of St. Marks NWR and the National 

Wildlife Refuge System. Lastly, given the increasing industrial and residential development 

occurring in the Florida Panhandle, resource managers need data on pre-urbanization contaminant 

loading to better protect trust resources now and in the future. 

Methods 

Sampling Locations and Fish Collection 

Mullet and seatrout were collected from estuarine sites, and sunfish and largemouth bass 

were collected from freshwater sites within St. Marks NWR (fig. 1) and the St. Andrew Bay 

watershed (fig. 2). A total of 358 adult fish were collected for total mercury analysis. A total of 

243 fish were collected from St. Marks NWR; 73 from five sites within estuarine ecosystems and 

170 from five sites within freshwater ecosystems. For the St. Andrew Bay watershed, a total of 10

spotted seatrout were caught from two estuarine sites. A composite site sample of 25 striped mullet 

was purchased from a local commercial fishing supplier (Miller & Ellis Seafood, Panama City, 

Florida) who had caught the fish in St. Andrew Bay within the past 24 hours. Largemouth bass (n 

= 40) and sunfish (n = 40) were collected from two freshwater sites. Twenty fish were collected to 

provide sufficient statistical analysis power, given the variability reported in previous evaluations 

of mercury contamination of this national wildlife refuge and elsewhere along the Gulf. 
5 

All freshwater fish and striped mullet, with the exception of the purchased mullet, were 

collected with a boat-mounted Smith-Root GPP-9.0 Electrofisher (Vancouver, Washington, USA). 

Spotted seatrout were collected using traditional rod and reel fishing techniques, using artificial 

lures as bait. All fish were processed within 24 hours of their collection. 

Fish processing was performed according to standard operating procedures (Environmental 

Protection Agency, 2000) to minimize risk of cross contamination. Generally, measurements were 

taken upon collection and included length, weight, gonad weight, liver weight, and sex. Sagittal 

otoliths were collected in the field as fish were processed for inclusion of age as a determinant 

parameter (Nielson and Johnson, 1983). Spotted seatrout and mullet otoliths were processed and 

mounted by the Florida Fish and Wildlife Conservation Commission Fish and Wildlife Research 

Institute, St. Petersburg, Florida, and age was determined by U.S. Geological Survey-Florida 

Integrated Science Center (USGS-SESC), Gainesville, Florida (Nielson and Johnson, 1983,

Vanderkooy and Guindon-Tisdel, 2003). Largemouth bass and sunfish otoliths were processed and 

read by the South Carolina Cooperative Fish and Wildlife Research Unit, Clemson, South Carolina. 

A muscle tissue sample (fillet without the skin) was taken from the dorsal region, posterior to the 

first dorsal fin, wrapped in aluminum foil, and placed in a plastic bag on wet ice. Three filet knives 

were rotated throughout collections. Prior to collecting each sample, individual knives were first 

rinsed in soapy water, tap water, ethyl-alcohol, and finally acetone to remove possible organics. 

Upon returning to the laboratory, samples were frozen at -20 ̊C until mercury analysis was 

performed. 

Mercury Analyses 

Total mercury analyses were performed by the USGS-SESC Ecotoxicology Laboratory. 

Fish musculature samples were analyzed by using a direct mercury analyzer (Milestone DMA-80), 

and processed using the following USEPA (1998) method: 

Controlled heating in an oxygenated decomposition furnace was used to liberate from solid and 

aqueous samples in the instrument. The sample was dried and then thermally and chemically 

decomposed within the decomposition furnace. The decomposition products are carried by 

flowing oxygen to the catalytic section of the furnace. Here, oxidation is completed and 

halogens and nitrogen/sulfur oxides are trapped. The remaining decomposition products were 

then carried to an amalgamator that selectively traps mercury. After the system is flushed with 

oxygen to remove any remaining gases or decomposition products, the amalgamator is rapidly 

heated, releasing mercury vapor. Flowing oxygen carries the vapor through absorbance cells 

positioned in the light path of a single wavelength atomic absorption spectrophotometer. 

Absorbance (peak height or peak area) is measured at 253.7 nm as a function of mercury 

concentration.

The typical working range for this method is 0.05–600 ng and the instrument detection limit 

for this method is 0.01 ng total mercury. This method is accepted for the Resource Conservation 

Recovery Act work as method 7473. 

Statistical Analyses 

With respect to sample location and sex, descriptive statistics were calculated for length 

(mm), weight (g), age (yr), mercury tissue concentrations (ng/g ww), HSI (liver weight/BW), and 

GSI (gonad weight/BW) for each species. Prior to comparison, size characteristics, mercury 

concentrations, and biomarkers were evaluated and met necessary assumptions for parametric tests 
6 

(normality and homogeneity of variance). Comparisons of endpoints between St. Andrew Bay and 

St. Marks NWR (Ho #1, #2) were conducted using a mixed model procedure appropriate for 

nested, unbalanced designs (SAS/STAT software PROC MIXED, Version 9.1.3, SAS Institute, 

2000-2004) to determine if differences existed among size parameters, mercury tissue 

concentrations, and health indicators. Samples of individual fish were nested within each 

respective area. Comparisons of size parameters, tissue concentrations, HSI, and GSI were 

conducted separately for each species and gender because of the ecological and physiological 

differences between species and genders. For example, endpoints in male bass from St. Andrew 

Bay were compared to those of male bass from St. Marks NWR. Data are presented as mean ± SE, 

unless otherwise noted. 

Associations among biomarkers were examined with Pearson correlation coefficients to 

determine interactions between tissue mercury concentrations and size and age (Ho #3) 

(SAS/STAT software PROC CORR, Version 9.1.3, SAS Institute, 2000-2004). Pearson correlation 

coefficients were also calculated between mercury tissue concentrations and size and age 

parameters for each species, with genders, sample sites, and areas combined (Ho #4). The reason 

for examining each species by combining gender, sample sites, and areas for each species was that 

species-specific length limits are likely the most practical way to manage and set guidelines for fish 

harvest. For example, if length and mercury tissue concentrations were positively correlated in 

bass and indicated that bass larger than 12 inches in length are not safe for human consumption, 

then management guidelines or regulations could be developed that advise or require people to 

release bass above 12 inches in length. 

Correlations among mercury tissue concentrations, HSI, and GSI were conducted to 

evaluate relationships between health or reproductive endpoints and mercury exposure, because 

mercury is a neurotoxin (Goyer and Clarkson, 2001) and endocrine disruptor (Gross and others, 

2003). Correlations were conducted for each species and gender to control for the species and 

gender-specific differences that may affect HSI and GSI. 

For each sampling site and species, the percentage of sampled fish that exceeded State of 

Florida Fish Consumption Advisories was calculated as the number of fish with mercury tissue 

concentrations exceeding advisories divided by the total number of fish collected (specific aim #5). 

This analysis aids in identifying the extent of mercury contamination within a population within a 

site and the relative extent of contamination in populations among sites. 

Results 

Mean length, weight, age, mercury concentration, HSI, and GSI were determined by study 

area (refuge and non-refuge), sampling site, and sex of each species of fish collected (tables 1-4). 

The highest mean mercury concentration in fish musculature samples (1.234 ± 0.481 ppm; table 5) 

was found in largemouth bass from Lake Renfroe (fig. 1) at the St. Marks NWR, and the lowest 

(0.003 ± 0.002 ppm) was found in striped mullet from the Lower Wakulla River (part of the 

refuge). The highest individual mercury concentration (2.412 ppm) was detected in a single 

largemouth bass sample from the St. Marks NWR, and the lowest (0.001 ppm) was detected in a 

single striped mullet sample, also from the refuge. 

Results support the hypothesis that overall differences in mercury tissue concentrations 

exist among largemouth bass, spotted seatrout, sunfish, and striped mullet (fig. 3). Further, the two 

freshwater species, largemouth bass and sunfish, sampled from the refuge had significantly higher 

mercury concentrations (p = 0.00002 and p = 3.06 x 10-8, respectively) than those from the bay (fig. 

4). The mercury concentration values in the freshwater species from the refuge were notably 
7 

higher than those from the bay (χ = 859 vs. 528 ppb for St. Marks and St. Andrew bass, 

respectively, and χ = 366 and 130 ppb for St. Marks vs. St. Andrew sunfish, respectively; fig.4, 

table 5). Mercury concentration in sunfish from the Deer Point collection site in St. Andrew Bay 

was an order of magnitude higher than the Martin Bay site (232 vs. 28 ppb). The relatively low 

concentration (91ppb) in sunfish from the Upper Wakulla River in St. Marks NWR was also 

noteworthy (figs. 1 and 2; table 5). 

Conversely, the estuarine species, striped mullet and spotted seatrout, taken from St. 

Andrew Bay had significantly higher mercury concentrations (p = 0.00008 and 0.01520, 

respectively, than those from St. Marks NWR (fig. 4). However, the differences in mercury 

concentration values in the estuarine species from these two collection areas were not as striking as 

the differences between the freshwater species (fig. 4; tables 5-7). 

Correlations among mercury tissue burdens and fish length, weight, age, HSI, and GSI were 

evaluated by area, species and sex to determine the relationships among mercury burdens, physical 

characteristics, and health and reproductive function (tables 6-9). In male and female striped 

mullet, mercury burdens were positively correlated with GSI (table 8), and mean GSI was greater 

in male specimens from St. Andrew Bay (3.14) than St. Marks NWR (0.09) (table 7). Female 

sunfish had a negative correlation between mercury and gonadosomatic index (table 9), and similar 

mean GSI values for specimens from St. Andrew Bay and St. Marks NWR (table 6). No clear 

pattern of correlation emerged for any other species between mercury and HSI or GSI (tables 8-9). 

Length and weight were highly correlated for both female and male largemouth bass (r= 

0.96 and 0.92, respectively), female and male sunfish (r=0.93 and 0.92 respectively), and spotted 

seatrout females (r=0.96) (tables 8-9). Age was significantly correlated with mercury concentration 

for all species but mullet (tables 8-11). Age was correlated with length and weight for all species 

(tables 10-11).

To examine the potential for using size limits as a risk guidance tool, the relationships 

between mercury burdens, length, and age were evaluated for each species (tables 10-11). For 

largemouth bass, mercury burdens were correlated with age > weight > length, respectively. For 

sunfish, mercury burdens were correlated with age > length > weight, respectively. For spotted 

seatrout, mercury burdens were correlated with age > weight > length, respectively. For striped 

mullet, however, mercury burdens were not correlated with age, weight, or length. 

A publication entitled “Your Guide to Eating Fish Caught in Florida,” published by the 

Florida Department of Health (2007), provides consumption guidelines based upon mercury levels 

in freshwater and marine fish species. Fish that have more than 1.5 ppm of mercury in the edible 

flesh are considered unsafe for consumption. Those containing less than 0.5 ppm are considered 

safe for unlimited consumption. Consumption should be limited for fish with concentrations from 

0.5 to 1.5 ppm. Using the most conservative consumption guidelines, those for women of 

childbearing age and young children, the guidelines that correspond to the results of this study, by 

sampling site and fish species, are available online: 

(http://fisc.er.usgs.gov/maps/fishconsumptionguidelinesmercurylevels.html). 

All of the striped mullet samples that were collected (n = 67) from all sites fell into the 

category of unlimited consumption. Although the sample size was small (n = 3), all spotted 

seatrout from Oyster Bay (fig. 1) fell into the category of unlimited consumption; 93 percent of 

spotted seatrout from the lower Aucilla River (n = 15) also fell into the unlimited consumption 

category (table 12). No samples of spotted seatrout fell into the category of no consumption. For 

largemouth bass, 20 percent of those collected from Otter Lake (n = 20) and Lake Renfroe (n = 10) 

fell into the category of no consumption, but the remaining 80 percent were categorized as limited 
8 

consumption (table 13). All largemouth bass from East River Pool (n = 18) were categorized as 

limited consumption; 50 percent of largemouth bass from the Upper Wakulla River (n = 12) were 

categorized as limited consumption and 50% as unlimited consumption (table 13). In addition, 90 

percent of largemouth bass from Deer Point Lake (n = 20) were categorized as limited 

consumption, but 90 percent of largemouth bass from Martin Bayou (n = 20) were categorized as 

unlimited consumption (table 12). No samples of sunfish (n = 130) fell into the category of no 

consumption; however, 100 percent of sunfish (n = 10) collected from Lake Renfroe fell into the 

category of limited consumption (table 14). All of the sunfish samples from Martin Bayou (n = 20) 

and the Upper Wakulla River (n = 20) and 95 percent of those from East River Pool (n = 20) fell 

into the unlimited consumption category (table 14).

For spotted seatrout from St. Marks NWR (n = 31), 81 percent fell into the category of 

unlimited consumption, but only 40 percent of those from St. Andrew Bay (n = 10) fell into the 

same category. Half of the largemouth bass collected from St. Andrew Bay (n = 40) fell into the 

category of unlimited consumption, but only 15 percent from St. Marks NWR (n = 80) fell into this 

category (table 13).

Discussion 

Mercury may be expelled into the environment through natural or anthropogenic sources 

and may be dispersed locally via an industrial effluent discharge or geographically through 

atmospheric deposition due to waste incineration or fossil fuel combustion. A survey that 

examined sediment contamination at the St. Marks NWR revealed that, although mercury 

contamination of sediments was not found on the refuge, it was found at five nearby non-refuge 

sites (Hemming and others, 2002). Urban stormwater runoff, industrial point-source discharges, 

historic oil spillage, recreational boats, and marina repair operations may be contributing to 

increased levels of mercury found in sediments of St. Andrew Bay (Brim, 1998). It is possible that 

mercury deposition in this region has resulted in increasing concentration of mercury in species of 

freshwater predatory fishes. 

Mercury concentration levels found in musculature from largemouth bass and sunfish at the 

St. Marks NWR were significantly higher than those found in the same species of fish located near 

the non-refuge, urbanized St. Andrew Bay area (fig. 4). Although mercury concentrations found in 

musculature samples from spotted seatrout and striped mullet at St. Andrew Bay were significantly 

higher than those found in the same species of fish located at the St. Marks NWR, the spotted 

seatrout were collected from only one site at St. Andrew Bay, and the sample size (n=10) was 

relatively small. Collecting an adequate number of spotted seatrout within the legal slot limit at the 

bay was not possible. The sample of spotted seatrout was collected within West and North bays of 

St. Andrew Bay. West Bay receives thermal effluent from the Gulf Power Plant cooling system 

and municipal wastewater effluent from the City of Panama City Beach as well as moderate barge 

traffic through the Gulf Intracoastal Waterway. North Bay contains adjacent industrial facilities, 

including light industries, an international airport, and boat repair and manufacturing yards (Brim, 

1998). Possibly because the estuary of the St. Marks NWR has less of these anthropogenic 

activities, lower levels of mercury were detected in musculature of spotted seatrout and striped 

mullet. Although statistically different, concentrations of mercury in striped mullet from St. 

Andrew Bay and St. Marks NWR were low relative to the other three species tested.

GSI, the ratio of gonad weight to body weight, and HSI, the ratio of liver weight to body 

weight, are commonly used endpoints in whole animal toxicity studies. Although GSI and HSI are 

not specific to a particular toxicant mechanism, they are good predictors of reproductive success 
9 

and contaminant stress (Di Giulio and Tillitt, 1999; Slooff and others, 1983). This study showed 

positive correlations between mercury burden and GSI in male and female striped mullet. It also 

showed higher mean GSI values in estuarine fish from St. Andrew Bay, where mercury levels 

tended to be higher in these species (striped mullet and spotted seatrout). There was no correlative 

pattern between mercury burden and HSI in any of the species examined. Factors such as species’ 

dietary and reproductive differences, the possible presence of additional contaminants and their 

synergistic interactions, as well as abiotic factors, such as dissolved oxygen levels, water hardness, 

salinity and temperature, may explain inconsistencies among these endpoints and mercury 

concentrations. 

Numerous studies monitoring mercury levels in various species of fishes have been 

performed on a local level within Florida as well as on a national scale. Spotted seatrout collected 

from the following areas within the state of Florida displayed the following mean mercury 

concentrations: Apalachicola Bay (0.33 ppm), Charlotte Harbor (0.42 ppm), Florida Everglades 

(0.43 ppm), Choctawhatchee Bay (0.40 ppm), Indian River Lagoon (0.47 ppm), northeast Florida 

(0.16 ppm), and Tampa Bay (0.4 ppm) (Adams and others, 2003). Striped mullet collected from 

the following areas within the state of Florida displayed mean mercury concentrations: Charlotte 

Harbor (0.06 ppm), Choctawhatchee Bay (0.12) ppm, Indian River Lagoon (0.06 ppm), Florida 

Keys/Florida Bay (0.02 ppm), and Tampa Bay (0.08 ppm) (Adams and others, 2003). 

Several species of fish, including spotted seatrout, crevalle jack (Caranx hippos), ladyfish 

(Elops saurus), bluefish (Pomatomus saltatrix), and gafftopsail catfish (Bagre marinus) that were 

sampled from Eastern Florida Bay, displayed mercury levels exceeding 0.5 ppm. The forage fish 

bay anchovy (Anchoa mitchilli), rainwater killifish (Lucania parva), and silver jenny 

(Eucinostomus gula) from the same area showed much lower mercury concentrations (0.165, 

0.125, and 0.820 ug/g, respectively), suggesting that mercury is bioaccumulated as progression in 

the food chain occurs (Evans and Engel 1998). 

The following mercury levels have been reported in other species of marine and estuarine 

fish: 0.78 ppm in bull sharks (Carcharhinus leucas) from the Indian River Lagoon, 0.39 ppm in 

snook (Centropomus undecimalis) from Tampa Bay, 0.68 ppm in gag (Mycteroperca microlepis) 

from Volusia County, 0.35 ppm in Spanish mackerel (Scomberomorus maculatus) from 

Apalachicola Bay, and 0.13 ppm in Gulf flounder (Paralichthys albigutta) from Apalachicola Bay 

(Adams et al. 2003). Mean total mercury levels in red drum (Sciaenops ocellatus) from the Florida 

Keys/Florida Bay area were 0.50 ppm (Adams and Onorato, 2005). The same study also showed 

that red drum from offshore waters adjacent to Tampa Bay contained mean mercury levels of 0.26 

ppm. 

Lange and others, (1994) examined mercury concentrations in largemouth bass, bluegill 

(Lepomis macrochirus), and redear sunfish (L. microlophus) from Lake Tohopekaliga, Florida. 

The mean mercury concentration for largemouth bass was 0.60 ppm, and the mean for the sunfish 

was 0.07 ppm. Largemouth bass in Florida also had mercury concentrations of 0.04 ppm from 

Lake Apopka, 0.15 ppm from Lake George, 0.56 ppm from Lake Istokpoga, 0.34 ppm from Lake 

Minneola, 0.17 ppm from Lake Okeechobee, 0.19 ppm from Lake Panasofkee, 0.49 ppm from 

Lake Placid, and 0.86 ppm from Lake Talquin, (Lange and others, 1993). 

On a regional scale, mercury levels were shown by the Gulf States Marine Fisheries 

Commission (2002) to be relatively consistent within this report’s study areas. Spotted seatrout 

from estuarine areas in Louisiana had mean mercury concentrations of 0.201 ppm, and spotted 

seatrout from Texas had mean mercury levels of 0.175 ppm (Piehler 2003, Sager 2004). Striped 
10

mullet in estuarine waters of Alabama and Louisiana displayed mercury levels below detectable 

limits (Alabama Department of Environmental Monitoring 2003, Piehler 2003).

Freshwater fish from Gulf Coast states also had mercury levels comparable to those found 

at our study sites. Mean tissue mercury concentrations of largemouth bass were 0.830 and 0.467 

ppm from Texas and Louisiana, respectively (Texas Department of Health Seafood Safety Division 

1995, Piehler 2003). Mean tissue mercury concentrations of sunfish from Texas and Louisiana 

were 0.39 ppm and 0.22 ppm, respectively (Texas Department of Health Seafood Safety Division 

1995, Dupre and others, 1999). 

Conclusions 

(Correspond to Objectives/Hypotheses on p. 3-4) 

1. Hypothesis rejected. Results support the hypothesis that mercury concentrations in fish 

musculature differ between St. Marks National Wildlife Refuge and St. Andrew Bay (nonnational wildlife refuge area). Results also support the hypothesis that there are overall 

differences in mercury tissue concentrations among largemouth bass, sunfish, spotted 

seatrout, and striped mullet. The two freshwater species, largemouth bass and sunfish, 

sampled from the refuge had significantly higher mercury concentrations than those from 

the bay. 

2. Hypothesis partially rejected. Mean gonadosomatic indices for male and female spotted 

seatrout from St. Andrew Bay were an order of magnitude higher than those for male and 

female spotted seatrout from St. Marks NWR, and male striped mullet gonadosomatic 

indices were at least one order of magnitude higher than those for male striped mullet from 

the refuge. Male and female largemouth bass and sunfish gonadosomatic indices did not 

differ markedly between areas. There were no consistent differences between areas in 

hepatosomatic indices for any of the species sampled. 

3. Hypothesis partially rejected. Male and female striped mullet had positive correlations 

between mercury burden and gonadosomatic index, whereas male seatrout, male and female 

largemouth bass, and sunfish did not (female seatrout approached significance). Female 

sunfish had a negative correlation between mercury and gonadosomatic index. Mercury 

burden and hepatosomatic index were not correlated for any sex-species combination. 

4. Hypothesis rejected, except for striped mullet. For three of the four species sampled, age, 

weight, and length were correlated with mercury concentration. In largemouth bass, 

sunfish, and spotted seatrout, age was the variable most highly correlated with mercury 

concentration. Weight and length were also correlated, but to a lesser degree. 

5. The data collected during the present study are consistent with current advisories posted by 

the Florida Department of Health for water bodies within the study area, with the exception 

of Lake Renfroe. In this study, data for Lake Renfroe appear to be more consistent with the 

“once per month for all other individuals” advisory than the current advisory of “once per 

week for all other individuals.” In addition, with regard to women of childbearing years 

and young children, data for Lake Renfroe are more consistent with the “do not eat” 

advisory than the current advisory of “once per month.” Also, although the majority of 

largemouth bass were within the limits set forth by the Florida Department of Health, five 

individual fish that were collected in this study exceeded the 1.5 part per million limit 

advisory. 
11

6. Conversely, although the Florida Department of Health recommends limiting the 

consumption of striped mullet caught in all coastal waters to two per week for women of 

childbearing age and young children, all samples of striped mullet collected in this study 

were below the 0.5 part per million limit advisory. 

7. For all species but mullet, age, length, and weight were the most highly correlated 

characteristics with mercury burden. Although age is more expensive and difficult to 

determine, length and weight are readily determined, and these factors could be reasonable 

indicators of mercury exposure risk. 

8. Periodic monitoring of mercury in St. Marks NWR and other areas in Florida will increase 

knowledge of mercury content and form in the various environmental compartments and aid 

in ensuring that fish consumption advisories and ecological risk assessments are based on 

the most current information. 

9. Laboratory experiments in a controlled environment should be performed to validate 

observations and conclusions presented here on correlation of mercury concentrations with 

bioindicators, which were based on analyses of field data. 

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13

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14

Figure 1. Fish sampling stations in the St. Marks National Wildlife Refuge study area. 
15

Figure 2. Fish sampling stations in the St. Andrew Bay study area. 
16

Figure 3. Summary and comparisons of mercury tissue concentration (nanograms per gram, wet weight) in 

fish from St. Marks National Wildlife Refuge and St. Andrew Bay. Bars indicate mean ± SE and letters 

(z–w) indicate significant differences among adjusted means, with means adjusted for the effect of area 

(PROC MIXED, SAS 2006). 

0

100

200

300

400

500

600

700

800

Bass Trout Sunfish Mullet

ng/ g w.w.

 z

y

x

Hg 

w

conc. Hg concentration (ng/g, wet weight)
17

Figure 4. Summary and comparisons of mercury tissue concentrations (nanograms per gram, wet weight) 

for species from St. Marks National Wildlife Refuge and St. Andrew Bay. Bars indicate mean ± SE and 

numbers within/above bars indicate sample size. Letters (z–x, a–c) indicate significant differences 

between species within each site (PROC GLM, SAS 2006). 

0

100

200

300

400

500

600

700

800

900

1000

Bass Trout Sunfish Mullet Bass Trout Sunfish Mullet

St. Andrew Bay St. Marks NWR

Hg concentration (nanograms per gram, wet weight)

z z

y

x

a

b

b

 c

 40

 10

 40 

25

80

 31

 42

 42
18

Figure 5. Examples of the distribution of mercury concentration in spotted seatrout with age for all seven 

study sites. The regression equation is y = 0.1158x + 0.1938; r2 = 0.5093; p-value = 4.35 x 10-5.

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0 1 2 3 4 5

Hg Concentration (parts per million)

Age (years)

Spotted Seatrout Age vs. Mercury Concentration
19

Figure 6. Examples of the distribution of mercury concentration in largemouth bass with age for all seven 

study sites. The regression equation is y = 0.1293x + 0.2219; r2 = 0.2361; p-value = 0.0201. 

0

0.5

1

1.5

2

2.5

3

0 1 2 3 4 5 6 7 8 9 10

Hg concentration (parts per million)

Age (years)

Largemouth Bass Age vs. Mercury Concentration
20

Figure 7. Examples of the distribution of mercury concentration in spotted seatrout with length for all seven 

study sites. The regression equation is y = 0.0013x – 0.1154; r2 = 0.1312; p-value = 0.01994. 

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

0 100 200 300 400 500 600

Hg Concentration (parts per million)

Length (millimeters)

Spotted Seatrout Length vs. Hg Concentration
21

Figure 8. Examples of the distribution of mercury concentration in sunfish with length for all seven study 

sites. The regression equation is y = 0.0031x – 0.3198; r2 = 0.112; p-value = 0.00024.

0

0.2

0.4

0.6

0.8

1

1.2

1.4

0 50 100 150 200 250 300 350

Hg Concentration (parts per million)

Length (millimeters)

Sunfish Length vs. Hg Concentration
22

Table 1. Characteristics, mercury tissue concentrations (ng/g wet weight) and health parameters (hepatosomatic index [HSI], and gonadosomatic 

index [GSI]) of striped mullet from St. Marks National Wildlife Refuge and St. Andrew Bay, Florida, collected in July and September 2006. 

 [Mean ± SE (N). Abbreviations: ARL, Aucilla River Lower, LWR, Lower Wakulla River, OCB=Ochlockonee Bay1 

Area Sex Length (mm) Mass (g) Age (yr) [Hg] (ng/g) HSI GSI

St. Andrew

Female 412 ± 13.1 (10) 649 ± 55 (10) 3 ± 0.1 (8) 11.5 ± 2.4 (10) 1.3 ± 0.06 (10) 0.97 ± 0.19 (10)

Male 379 ± 4.1 (15) 487 ± 18.2 (15) 3 ± 0.1 (13) 12.6 ± 1.81 (15) 1.5 ± 0.05 (15) 3.14 ± 0.845 (15)

St. Marks

ARL Female 444 ± 4.5 (2) 1023 ± 33 (2) 3 ± 1 (2) 9.1 ± 0.8 (2) 1.5 ± 0.17 (2) 0.43 ± 0.031 (2)

Male 272 ± 4 (18) 238 ± 9.5 (18) 2 ± 0.1 (18) 6.1 ± 0.4 (18) 1.4 ± 0.03 (18) 0.05 ± 0.008 (18)

LWR Female 417 ± 9.1 (14) 927 ± 84.2 (14) 3 ± 0.2 (11) 3.2 ± 0.51 (14) 1.6 ± 0.07 (14) 0.69 ± 0.074 (14)

Male 364 ± 8.8 (6) 530 ± 37.3 (6) 2 ± 0.3 (4) 3.5 ± 0.52 (6) 1.5 ± 0.08 (6) 0.23 ± 0.079 (6)

OCB Female 399 ± 2.5 (2) 770 ± 20 (2) 3 ± 0 (2) 15.1 ± 0.38 (2) 1.7 ± 0.29 (2) 1.61 ± 0.462 (2)

Male No sample No sample No sample No sample No sample No sample

Table 2. Characteristics, mercury tissue concentrations (ng/g wet weight) and health parameters (hepatosomatic index [HSI], and gonadosomatic 

index [GSI]) of spotted seatrout from St. Marks National Wildlife Refuge and St. Andrew Bay, Florida, collected during July and September 2006. 

 [Mean ± SE (N). Abbreviations: HB, Hathaway Bridge, C, Callaway; ARL, Aucilla River Lower; GCB, Goose Creek Bay; LWR, Lower Wakulla River; OCB, 

 Ochlockonee Bay; OYB, Oyster Bay] 

Area1 Sex Length (mm) Mass (g) Age (yr) [Hg] (ng/g) HSI GSI

St. Andrew

HB Female 414 ± 15.6 (7) 626 ± 75.4 (7) 3 ± 0.4 (7) 538.75 ± 35.02 (7) 1.0 ± 0.12 (7) 2.17 ± 0.44 (7)

Male 386 ± 5.5 (2) 471 ± 21 (2) 3 ± 0.5 (2) 417.42 ± 69.81 (2) 0.47 ± 0.01 (2) 1.41 ± 0.03 (2)

C Female 445 ± (1) 754 ± 0 (1) 3 ± 0 (1) 587.29 (1) 1.27 (1) 3.41 (1)

St. Marks

ARL Female 431 ± 10.6 (11) 732 ± 58.3 (11) 2 ± 0.1 (11) 309.01 ± 23.05 (11) 1.07 ± 0.07 (11) 0.57 ± 0.02 (11)

Male 401 ± 8.5 (4) 607 ± 43 (4) 2 ± 0.3 (4) 429.1 ± 26.6 (4) 1.09 ± 0.11 (4) 0.14 ± 0.02 (4)

GCB Female 452 ± 27.7 (4) 922 ± 200.6 (4) 2 ± 0.9 (3) 467.64 ± 117.97 (4) 1.62 ± 0.06 (4) 0.55 ± 0.06 (4)

Male 406 ± 2 (2) 620 ± 28 (2) 3 ± 0.5 (2) 572.69 ± 83.69 (2) 1.35 ± 0.04 (2) 0.19 ± 0.02 (2)

LWR Female 385 ± 0 (1) 504 ± 0 (1) 1 ± 0 (1) 391.6 (1) 0.77 (1) 0.62 (1)

Male 404 ± 0 (1) 634 ± 0 (1) 2 ± 0 (1) 630.15 (1) 1.25 (1) 0.19 (1)

OCB Female 420 ± 20.8 (4) 627 ± 88.2 (4) 2 ± 0.3 (4) 473.02 ± 34.67 (4) 0.88 ± 0.07 (4) 0.56 ± 0.05 (4)

Male 396 ± 0 (1) 538 ± 0 (1) 2 ± 0 (1) 517.46 (1) 1.1 ± (1) 0.13 (1)

OYB Female 443 ± 17.5 (2) 832 ± 98 (2) 2± 0(2) 456.95 ± 2.32 (2) 1.39 ± 0.03 (2) 0.66 ± 0.02 (2)

Male 421 ± 0 (1) 606 ± 0 (1) 2 ± 0 (1) 379.4 (1) 0.76 (1) 0.13 (1)
23

Table 3. Characteristics, mercury tissue concentrations (ng/g wet weight) and health parameters (hepatosomatic index [HSI], and gonadosomatic 

index [GSI]) of largemouth bass from St. Marks National Wildlife Refuge and St. Andrew Bay, Florida, collected during July and September 2006. 

 [Mean ± SE (N). Abbreviations: DPL, Deer Point Lake; MB, Martin Bayou; ARU, Aucilla River Upper; UWR, Upper Wakulla River; ERP, East River Pool; 

 LR, Lake Renfroe; OL, Otter Lake] 

Area1 Sex Length (mm) Mass (g) Age (yr) [Hg] (ng/g) HSI GSI

St. Andrew

DPL Female 376.91 ± 18.16 (11) 744.55 ± 108.93 (11) 3.73 ± 0.49 (11) 610.63 ± 56.75 (11) 0.88 ± 0.06 (11) 0.32 ± 0.03 (11)

Male 346.33 ± 8.35 (9) 554.89 ± 40.70 (9) 4.22 ± 0.32 (9) 1042.92 ± 92.76 (9) 0.79 ± 0.06 (9) 0.04 ± 0.004 (9)

MB Female 384.36 ± 15.11 (11) 812.64 ± 105.52 (11) 3.36 ± 0.45 (11) 242.7 ± 46.10 (11) 0.73 ± 0.06 (11) 0.32 ± 0.03 (11)

Male 358.33 ± 10.93 (9) 640.89 ± 72.43 (9) 3.22 ± 0.28 (9) 262.37 ± 50.5 (9) 0.86 ± 0.08 (9) 0.03 ± 0.003 (8)

St. Marks

ARU Female 325.14 ± 12.95 (7) 442.29 ± 49.01 (7) 3.5 ± 0.22 (9) 602.54 ± 58.59 (9) 0.87 ± 0.07 (9) 0.91 ± 0.2 (9)

Male 314.46 ± 4.61 (13) 408.0 ± 20.0 (13) 4.23 ± 0.32 (6) 625.19 ± 55.17 (7) 0.84 ± 0.05 (7) 1.09 ± 0.97 (7)

UWR Female 369.63 ± 19.29 (8) 755.25 ± 128.83 (8) 4.0 ± 0.27 (13) 461.84 ± 56.21 (13) 1.02 ± 0.09 (13) 1.06 ± 0.35 (13)

Male 327.5 ± 6.96 (4) 449.0 ± 32.30 (4) 4.25 ± 0.48 (8) 447.75 ± 76.83 (8) 0.82 ± 0.05 (8) 0.12 ± 0.02 (8)

ERP Female 329.17 ± 16.79 (6) 442.0 ± 53.65 (6) 3.33 ± 0.33 (4) 762.37 ± 70.06 (4) 0.73 ± 0.07 (4) 0.34 ± 0.08 (4)

Male 316.0 ± 6.13 (12) 405.67 ± 31.0 (12) 3.83 ± (6) 893.66 ± 51.05 (6) 0.8 ± 0.05 (6) 0.04 ± 0.002 (6)

LR Female 341.57 ± 27.97 (7) 672.29 ± 215.08 (7) 4.57 ± 1.04 (12) 1345.66 ± 196.24 (12) 0.69 ± 0.05 (12) 0.26 ± 0.04 (12)

Male 282.33 ± 6.89 (3) 294.0 ± 52.20 (3) 2.67 ± 0.33 (7) 975.07 ± 172.93 (7) 1.19 ± 0.38 (7) 0.03 ± 0.0007 (7)

OL Female 384.1 ± 15.03 (10) 833.3 ± 102.91 (10) 5.8 ± 0.59 (10) 1190.22 ± 131.97 (10) 0.92 ± 0.05 (10) 0.29 ± 0.02 (10)

Male 343.6 ± 12.29 (10) 612.8 ± 87.24 (10) 5.3 ± 0.65 (10) 1131.17 ± 92.31 (10) 0.86 ± 0.07 (9) 0.04 ± 0.005 (8)
24

Table 4. Characteristics, mercury tissue concentrations (ng/g wet weight) and health parameters (hepatosomatic index [HSI], and gonadosomatic 

index [GSI]) of sunfish from St. Marks National Wildlife Refuge and St. Andrew Bay, Florida, collected during July and September 2006. 

 [Mean ± SE (N). Abbreviations: DPL, Deer Point Lake; MB, Martin Bayou; ARU, Aucilla River Upper; UWR, Upper Wakulla River; ERP, East River Pool; 

 LR, Lake Renfroe; OL, Otter Lake] 

Area1 Sex Length (mm) Mass (g) Age (yr) [Hg] (ng/g) HSI GSI

St. Andrew

DPL Female 206.1 ± 11.56 (10) 174.2 ± 25.14 (10) 3.5 ± 0.70 (10) 192.92 ± 52.79 (10) 0.78 ± 0.04 (10) 1.16 ± 0.42 (10)

Male 201.3 ± 7.73 (10) 169.6 ± 23.78 (10) 3.8 ± 0.55 (10) 270.51 ± 61.90 (10) 0.76 ± 0.05 (10) 0.25 ± 0.08 (8)

MB Female 185.55 ± 7.28 (11) 133.09 ± 16.82 (11) 2.09 ± 0.37 (11) 27.26 ± 4.42 (11) 1.37 ± 0.11 (11) 3.31 ± 0.69 (11)

Male 179.33 ± 10.84 (9) 124.22 ± 23.12 (9) 2.44 ± 0.29 (9) 29.09 ± 9.19 (9) 1.16 ± 0.12 (8) 0.34 ± 0.15 (7)

St. Marks

ARU Female 202.33 ± 15.83 (9) 187.11 ± 63.02 (9) 3.0 ± 0.27 (8) 320.86±76.61 (9) 1.03 ± 0.08 (9) 2.74 ± 0.56 (9)

Male 191.5 ± 7.02 (10) 138.6 ± 16.15 (10) 2.9 ± 0.28 (10) 205.98 ± 42.48 (10) 0.74 ± 0.09 (10) 0.33 ± 0.09 (10)

UWR Female 224.8 ± 17.18 (5) 241.6 ± 55.32 (5) 3.8 ± 0.49 (5) 75.02 ± 17.25 (5) 1.17 ± 0.07 (5) 3.97 ± 0.80 (5)

Male 183.87 ± 7.35 (15) 133.33 ± 13.10 (15) 3.0 ± 0.40 (15) 95.95 ± 18.01 (15) 0.93 ± 0.05 (15) 1.06 ± 0.46 (15)

ERP Female 200.08 ± 5.71 (12) 170.33 ± 12.31 (12) 3.67 ± 0.45 (12) 287.76 ± 37.90 (12) 0.85 ± 0.03 (12) 2.60 ± 0.43 (12)

Male 202.0 ± 9.29 (8) 184.0 ± 26.20 (8) 3.38 ± 0.38 (8) 238.55 ± 27.58 (8) 0.74 ± 0.04 (8) 0.75 ± 0.21 (6)

LR Female 184.6 ± 8.80 (5) 130.4 ± 15.77 (5) 3.8 ± 0.37 (5) 654.08 ± 50.04 (5) 0.58 ± 0.08 (5) 0.43 ± 0.03 (5)

Male 191.6 ± 4.91 (5) 153.6 ± 14.02 (5) 3.8 ± 0.20 (5) 662.78 ± 37.95 (5) 0.70 ± 0.02 (5) 0.12 ± 0.008 (5)

OL Female 200.57 ± 7.14 (14) 159.86 ± 17.77(14) 3.79 ± (14) 709.76 ± 71.27 (14) 5.27 ± 4.59 (14) 0.60 ± 0.13 (14)

Male 205.5 ± 11.64 (6) 184.33 ± 26.96 (6) 3.83 ± 0.40 (6) 598.55 ± 113.39 (6) 0.83 ± 0.09 (6) 0.07 ± 0.02 (6)
25

Table 5. Mercury concentrations in freshwater and estuarine fish species collected at St. Marks National Wildlife 

Refuge (SM) and St. Andrew Bay (AB). 

 [Mercury concentrations are listed in parts per million, mg/kg w.w.] 

Site Fish Species n

Mean Hg 

Concentration Range Std dev

Aucilla River Upper, SM Largemouth Bass 20 0.624 0.295-1.056 0.1808

Sunfish 20 0.286 0.057-0.692 0.1963

East River Pool, SM Largemouth Bass 18 0.853 0.559-1.167 0.1815

Sunfish 20 0.268 0.105-0.517 0.1133

Otter Lake, SM Largemouth Bass 20 1.161 0.548-2.043 0.3518

Sunfish 20 0.676 0.292-1.182 0.2676

Lake Renfroe, SM Largemouth Bass 10 1.234 0.667-2.413 0.4813

Sunfish 10 0.658 0.546-0.830 0.0937

Wakulla River Upper, SM Largemouth Bass 12 0.457 0.227-0.666 0.1502

Sunfish 20 0.091 0.024-0.309 0.0631

Deerpoint Lake, AB Largemouth Bass 20 0.805 0.263-1.458 0.3161

Sunfish 20 0.232 0.052-0.665 0.1815

Martin Bayou, AB Largemouth Bass 20 0.252 0.109-0.545 0.1485

Sunfish 20 0.028 0.013-0.098 0.0208

Wakulla River Lower, SM Spotted Sea Trout 2 0.511 0.390-0.630 0.1687

Striped Mullet 20 0.003 0.001-0.007 0.0017

Oyster Bay, SM Spotted Sea Trout 3 0.431 0.379-0.459 0.1619

Striped Mullet **0 **0 **0

Goose Creek Bay, SM Spotted Sea Trout 6 0.503 0.302-0.805 0.1978

Striped Mullet **0 **0 **0

Aucilla River Lower, SM Spotted Sea Trout 15 0.341 0.214-0.506 0.0883

Striped Mullet 20 0.006 0.004-0.010 0.0019
26

Site Fish Species n

Mean Hg 

Concentration Range Std dev

"Ochlockonee Bay, SM" Spotted Sea Trout 5 0.482 0.388-0.555 0.0711

Striped Mullet 2 0.015 0.015-0.015 0.0005

"Hathaway Bridge, AB" Spotted Sea Trout 9 0.512 0.348-0.674 0.1026

"Calloway, AB" Spotted Sea Trout 1 0.587 0.587 .

St. Andrew Bay Striped Mullet 25 0.012 0.003-0.027 0.0071

Composite Sample

Largemouth bass

St. Marks NWR 80 0.859 0.227-2.413 0.3931

St. Andrew Bay 40 0.528 0.007-0.393 0.3715

Sunfish

St. Marks NWR 90 0.366 0.024-1.182 0.2833

St. Andrew Bay 40 0.13 0.013-0.665 0.164

Spotted seatrout

St. Marks NWR 31 0.415 0.214-0.805 0.132

St. Andrew Bay 10 0.519 0.348-0.674 0.1

Striped mullet

St. Marks NWR 42 0.005 0.000-0.015 0.0032

St. Andrew Bay 25 0.012 0.003-0.027 0.0071

*Hathaway Bridge and Calloway sites were combined as a composite sample. Each fish was individually analyzed for 

mercury concentration. 

** 0 indicates that we were unable to collect samples of this species at this site. 

"Samples were collected from July 25, 2006 to March 31, 2007. Mercury values were determined in 500mg-fish fillet 

sub-samples using a Direct Mercury Analyzer." 
27

Table 6. Size characteristics, mercury concentrations, and health indicators for 

freshwater fish from St. Andrew Bay and St. Marks National Wildlife Refuge. 

 [Mean ± SE (N). Abbreviations: HSI, hepatosomatic index; GSI gonadosomatic index] 

Descriptor St. Andrew St. Marks

Sunfish

Female

Length 195.3 ± 6.91 (21) 201.7 ± 4.67 (45)

Mass 152.7 ± 15.19 (21) 173.9 ± 15.35 (45)

Age 2.8 ± 0.41 (21) 3.6 ± 0.19 (44)

Hg1106.15 ± 30.734 (21) 442.73 ± 44.45 (45)

HSI 1.09 ± 0.088 (21) 2.27 ± 1.424 (45)

GSI 2.29 ± 0.469 (21) 1.91 ± 0.256 (45)

Male

Length 190.9 ± 6.86 (19) 192.7 ± 3.85 (44)

Mass 148.1 ± 17.02 (19) 153 ± 8.76 (44)

Age 3.2 ± 0.35 (19) 3.3 ± 0.18 (44)

Hg1156.15 ± 42.819 (19) 279.83 ± 37.111 (44)

HSI 0.94 ± 0.074 (18) 0.81 ± 0.032 (44)

GSI 0.3 ± 0.081 (15) 0.59 ± 0.175 (42)

Largemouth bass

Female

Length 380.6 ± 11.56 (22) 353.7 ± 8.89 (38)

Mass 778.6 ± 74.37 (22) 653.4 ± 59.65 (38)

Age 3.5 ± 0.33 (22) 4.4 ± 0.3 (37)

Hg1426.66 ± 53.706 (22) 889.7 ± 76.138 (38)

HSI 0.81 ± 0.045 (22) 0.86 ± 0.034 (38)

GSI 0.32 ± 0.024 (22) 0.57 ± 0.097 (38)

Male

Length 352.3 ± 6.83 (18) 320.8 ± 4.4 (42)

Mass 597.9 ± 41.63 (18) 451.9 ± 26.6 (42)

Age 3.7 ± 0.24 (18) 4.3 ± 0.23 (42)

Hg1652.64 ± 107.631 (18) 830.46 ± 48.104 (42)

HSI 0.83 ± 0.05 (18) 0.86 ± 0.039 (41)

GSI 0.04 ± 0.003 (17) 0.39 ± 0.315 (40)

1Mercury concentrations are listed in parts per billion, ng/g w.w.
28

Table 7. Size characteristics, mercury concentrations, and health indicators for estuarine fish 

from St. Andrew Bay and St. Marks National Wildlife Refuge. 

 [Mean ± SE (N) Abbreviations: HSI, hepatosomatic index; GSI gonadosomatic index] 

Descriptor St. Andrew St. Marks

Striped mullet

Female

Length 412 ± 13.1 (10) 418 ± 7.5 (18)

Mass 649 ± 55 (10) 920 ± 66.7 (18)

Age 3 ± 0.1 (8) 3 ± 0.2 (15)

Hg111.5 ± 2.399 (10) 5.18 ± 1.036 (18)

HSI 1.28 ± 0.06 (10) 1.57 ± 0.065 (18)

GSI 0.97 ± 0.19 (10) 0.76 ± 0.102 (18)

Male

Length 379 ± 4.1 (15) 295 ± 9 (24)

Mass 487 ± 18.2 (15) 311 ± 28.6 (24)

Age 3 ± 0.1 (13) 2 ± 0.1 (22)

Hg112.6 ± 1.807 (15) 5.44 ± 0.401 (24)

HSI 1.48 ± 0.049 (15) 1.41 ± 0.033 (24)

GSI 3.14 ± 0.845 (15) 0.09 ± 0.026 (24)

Spotted seatrout

Female

Length 417.8 ± 14.1 (8) 431.6 ± 8.33 (22)

Mass 642 ± 67.25 (8) 745.8 ± 51.5 (22)

Age 2.9 ± 0.35 (8) 1.8 ± 0.15 (21)

Hg1544.8 ± 30.93 (8) 384.9 ± 28.37 (22)

HSI 1 ± 0.11 (8) 1.1 ± 0.07 (22)

GSI 2.3 ± 0.41 (8) 0.6 ± 0.02 (22)

Male

Length 385.5 ± 5.5 (2) 403.9 ± 4.23 (9)

Mass 471 ± 21 (2) 605.1 ± 20.25 (9)

Age 2.5 ± 0.5 (2) 2.2 ± 0.15 (9)

Hg1417.4 ± 69.81 (2) 487.6 ± 34.07 (9)

HSI 0.5 ± 0.01 (2) 1.1 ± 0.08 (9)

GSI 1.4 ± 0.03 (2) 0.2 ± 0.01 (9)

1Mercury concentrations are listed in parts per billion, ng/g w.w.
29

Table 8. Comparison of mercury concentrations with fish length, weight, age, hepatosomatic index (HSI), and 

gonadosomatic index (GSI), by sex and species of estuarine fish from St. Andrew Bay and St. Marks 

National Wildlife Refuge. 

 [r = Pearson correlation coefficient; p ≤ 0.003 considered significant (Bonferroni correction = 0.05/15) N = sample 

 size; * indicates significant r value] 

Mullet female

Descriptor Length Weight Age Hg HSI GSI

r 0.8208* 0.0373 0.1662 0.3656 0.3622

Length p <.0001 0.8657 0.3978 0.0557 0.0582

N 28 23 28 28 28

r -0.186 -0.1491 0.4289 0.158

Weight p 0.3954 0.4486 0.0227 0.422

N 23 28 28 28

r 0.1609 0.1398 -0.0423

Age p 0.4631 0.5245 0.848

N 23 23 23

r -0.2028 0.5363*

Hg p 0.3005 0.0033

N 28 28

r 0.2899

HSI p 0.1345

N 28

Mullet male

Descriptor Length Weight Age Hg HSI GSI

r 0.9579* 0.5594* 0.3775 0.2569 0.4359

Length p <.0001 0.0005 0.0178 0.1143 0.0055

N 39 35 39 39 39

r 0.4593 0.3091 0.219 0.3995

Weight p 0.0055 0.0555 0.1804 0.0117

N 35 39 39 39

r 0.3095 0.4269 0.1383

Age p 0.0704 0.0105 0.428

N 35 35 35

r -0.0325 0.7369*

Hg p 0.844 <.0001

N 39 39

r -0.1737

HSI p 0.2903

N 39
30

Table 8. Comparison of mercury concentrations with fish length, weight, age, hepatosomatic index (HSI), and 

gonadosomatic index (GSI), by sex and species of estuarine fish from St. Andrew Bay and St. Marks 

National Wildlife Refuge.—Continued 

 [r = Pearson correlation coefficient; p ≤ 0.008 considered significant (Bonferroni correction = 0.05/6) N = sample 

 size; * indicates significant r value] 

Trout female

Descriptor Length Weight Age Hg HSI GSI

r 0.9597* 0.5749* 0.4758 0.3735 -0.1079

Length p <.0001 0.0011 0.0079 0.042 0.5701

N 30 29 30 30 30

r 0.5484* 0.4837 0.4918 -0.1144

Weight p 0.0021 0.0068 0.0058 0.5469

N 29 30 30 30

r 0.74293* 0.269 0.4367

Age p 0.0002 0.1582 0.0178

N 29 29 29

r 0.2438 0.4915

Hg p 0.1942 0.0058

N 30 30

r 0.0152

HSI p 0.9361

N 30

Trout male

Descriptor Length Weight Age Hg HSI GSI

r 0.7366 0.2385 0.2496 0.3747 -0.5175

Length p 0.0097 0.4799 0.4591 0.2562 0.103

N 11 11 11 11 11

r 0.1434 0.3692 0.5551 -0.6931

Weight p 0.674 0.2638 0.0763 0.018

N 11 11 11 11

r 0.4784 -0.1139 0.2688

Age p 0.1366 0.7388 0.424

N 11 11 11

r 0.4985 -0.2429

Hg p 0.1185 0.4716

N 11 11

r -0.7722

HSI p 0.0053

N 11
31

Table 9. Comparison of mercury concentrations with fish length, weight, age, hepatosomatic index (HSI), and 

gonadosomatic index (GSI), by sex and species of freshwater fish from St. Andrew Bay and St. Marks 

National Wildlife Refuge. 

 [r = Pearson correlation coefficient; p ≤ 0.008 considered significant (Bonferroni correction = 0.05/6) N = sample 

 size; * indicates significant r value] 

Bass female

Descriptor Length Weight Age Hg HSI GSI

r 0.9614* 0.4806* 0.2651 0.1381 0.0097

Length p <.0001 0.0001 0.0406 0.2925 0.9413

N 60 59 60 60 60

r 0.5037* 0.3371 0.1894 0.02343

Weight p <.0001 0.0084 0.147 0.859

N 59 60 60 60

r 0.4941* 0.1224 -0.0323

Age p <.0001 0.3555 0.8079

N 59 59 59

r 0.0042 -0.1324

Hg p 0.9741 0.313

N 60 60

r 0.2669

HSI p 0.0392

N 60

Bass male

Descriptor Length Weight Age Hg HSI GSI

r 0.9191* 0.3848* 0.1202 -0.2583 -0.0391

Length p <.0001 0.0024 0.3603 0.0482 0.7723

N 60 60 60 59 57

r 0.4335* 0.155 -0.1103 -0.0321

Weight p 0.0005 0.2369 0.4053 0.8125

N 60 60 59 57

r 0.4745* 0.0362 0.0004

Age p 0.0001 0.7852 0.9974

N 60 59 57

r -0.0276 -0.047

Hg p 0.8355 0.728

N 59 57

r 0.0767

HSI p 0.5705

N 57
32

Table 9. Comparison of mercury concentrations with fish length, weight, age, hepatosomatic index (HSI), and 

gonadosomatic index (GSI), by sex and species of freshwater fish from St. Andrew Bay and St. Marks 

National Wildlife Refuge.—Continued 

 [r = Pearson correlation coefficient; p ≤ 0.008 considered significant (Bonferroni correction = 0.05/6) N = sample 

 size; * indicates significant r value] 

Sunfish female

Descriptor Length Weight Age Hg HSI GSI

r 0.9343* 0.7056* 0.3045 0.1181 0.0946

Length p <.0001 <.0001 0.0129 0.3449 0.4496

N 66 65 66 66 66

r 0.6638* 0.2277 0.1282 0.1298

Weight p <.0001 0.0659 0.3047 0.2989

N 65 66 66 66

r 0.5165* 0.1285 -0.1035

Age p <.0001 0.3075 0.4117

N 65 65 65

r -0.0362 -0.4131*

Hg p 0.7724 0.0006

N 66 66

r -0.0893

HSI p 0.4757

N 66

Sunfish male

Descriptor Length Weight Age Hg HSI GSI

r 0.9248* 0.7239* 0.3671* -0.3033 -0.0905

Length p <.0001 <.0001 0.0031 0.0165 0.5029

N 63 63 63 62 57

r 0.7700* 0.3703* -0.2023 -0.065

Weight p <.0001 0.0028 0.1148 0.6305

N 63 63 62 57

r 0.4177* -0.06 -0.101

Age p 0.0007 0.6427 0.4547

N 63 62 57

r -0.3307 -0.1916

Hg p 0.0087 0.1533

N 62 57

r 0.0025

HSI p 0.9847

N 57
33

Table 10. Comparison of mercury concentrations with length, weight, and age by species of freshwater fish from 

St. Andrew Bay and St. Marks National Wildlife Refuge.. 

 [r = Pearson correlation coefficient; p ≤ 0.008 considered significant (Bonferroni correction = 0.05/6) 

 N = sample size; * indicates significant r value] 

Bass

Statistic Length Weight Age Hg

r 0.9563* 0.4150* 0.1791

Length p <.0001 <.0001 0.0503

N 120 119 120

r 0.4440* 0.2387

Weight p <.0001 0.0086

N 119 120

r 0.4859*

Age p <.0001

N 119

 

Sunfish

Statistic Length Weight Age Hg

r 0.9260* 0.7054* 0.3335*

Length p <.0001 <.0001 0.0001

N 130 129 130

r 0.7011* 0.2769*

Weight p <.0001 0.0014

N 129 130

r 0.4793*

Age p <.0001

N 129
34

Table 11. Comparison of mercury concentrations with length, weight, and age by species of estuarine fish from 

St. Andrew Bay and St. Marks National Wildlife Refuge. 

 [r = Pearson correlation coefficient; p ≤ 0.008 considered significant (Bonferroni correction = 0.05/6) 

 N = sample size; * indicates significant r value] 

Trout

Statistic Length Weight Age Hg

r 0.9547* 0.4793* 0.3622

Length p <.0001 0.0018 0.0199

N 41 40 41

r 0.4652* 0.3914

Weight p 0.0025 0.0114

N 40 41

r 0.7136*

Age p <.0001

N 40

Mullet

Statistic Length Weight Age Hg

r 0.8847* 0.5465* 0.1731

Length p <.0001 <.0001 0.1612

N 67 58 67

r 0.3539* -0.0237

Weight p 0.0064 0.849

N 58 67

r 0.2002

Age p 0.1318

N 58
35

Table 12. Percentage of spotted seatrout with consumption limits from sampling sites in St. Andrew Bay and St. 

Marks National Wildlife Refuge. 

Site Species

Percentage of 

unlimited 

consumption

Percentage of 

limited 

consumption

Percentage of 

no consumption n

Lower Wakulla River Spotted seatrout 50 50 0 2

Oyster Bay Spotted seatrout 100 0 0 3

Goose Creek Bay Spotted seatrout 67 33 0 6

Lower Aucilla River Spotted seatrout 93 7 0 15

Ochlochonee Bay Spotted seatrout 60 40 0 5

Callaway Spotted seatrout 0 100 0 1

Hathaway Bridge Spotted seatrout 44 56 0 9

Table 13. Percentage of largemouth bass with consumption limits from sampling sites in St. Andrew Bay and St. 

Marks National Wildlife Refuge. 

Site Species

Percentage of 

unlimited 

consumption

Percentage of 

limited 

consumption

Percentage of 

no consumption n

Upper Aucilla River Largemouth Bass 70 30 0 20

East River Pool Largemouth Bass 0 100 0 18

Otter Lake Largemouth Bass 0 80 20 20

Lake Renfroe Largemouth Bass 0 80 20 10

Upper Wakulla River 

(CSM) Largemouth Bass 50 50 0 12

Deer point Lake Largemouth Bass 10 90 0 20

Martin Bayou Largemouth Bass 90 10 0 20

Table 14. Percentage of sunfish with consumption limits from sampling sites in St. Andrew Bay and St. Marks 

National Wildlife Refuge. 

Site Species

Percentage of 

unlimited 

consumption

Percentage of 

limited 

consumption

Percentage of 

no consumption n

Upper Aucilla River Sunfish 80 20 0 20

East River Pool Sunfish 95 5 0 20

Otter Lake Sunfish 30 70 0 20

Lake Renfroe Sunfish 0 100 0 10

Upper Wakulla River 

(CSM) Sunfish 100 0 0 20

Deer point Lake Sunfish 85 15 0 20

Martin Bayou Sunfish 100 0 0 20