Pinellas County Seagrass Resource 

Assessment & Monitoring Program 

Status Report 1998-2007 

Cynthia A. Meyer and Kelli Hammer Levy 

Pinellas County Department of Environmental Management 

Watershed Management Division 

300 South Garden Avenue 

Clearwater, Florida 33756 

Email: watershed@pinellascounty.org

www.pinellascounty.org/Environment/

August 2008 
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Acknowledgements 

Thank you for all of your support, hard work, long days, and dedication! 

Will Davis, Andy Squires, Craig Dye, Kelli Levy, Scott Deitche, Mark Flock, Eric Fehrman, 

Melissa Harrison, Don Hicks, Robert McWilliams, Jim Meyer, Sue Myers, Ryan Ryczek, 

Melanie Weed, Pamela Leasure, Angela Young, Nancy Page, and Phillip Hoffman. 

Walt Avery, Roger Johansson, and John Pacowta from the City of Tampa Bay Study Group; 

Paul Carlson and Alice Ketron, Florida Wildlife Commission; 

Kris Kaufman and William Grant, Southwest Florida Water Management District 

Special thanks to Dr. Bob Mulller, FWRI, for his advice and encouragement. 

Melissa Harrison assisting with seagrass assessment. 
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 Executive Summary

The seagrass resource provides essential functions to the marine ecosystem including 

nutrient cycling, detritus production, sediment formation, and shelter to increase the 

productivity of the ecosystem (Dawes et. al., 2004). In an effort to assess and monitor the 

seagrass resource, Pinellas County participates in a combination of transect monitoring and 

remote sensing programs. Since 1998, the Water Resources Management Section of the 

Pinellas County Department of Environmental Management has conducted seagrass 

resource monitoring in Boca Ciega Bay (BCB) and Clearwater Harbor and St. Joseph Sound 

(CLW/STJS). 

Pinellas County monitors 11 fixed transect sites in BCB in accordance with the Tampa Bay 

Estuary Program Interlocal Agreement. In CLW/STJS, Pinellas County monitored 14 fixed 

transect sites from 1998-2005. In 2006, Pinellas County replaced the 14 fixed transects with 

a stratified random transect monitoring design. The stratified random design included 63 

sites in 2006 and 65 sites in 2007. Fourteen of the stratified random transects remained 

stationary and intersect at the historical monitoring transects. All of the transects were 

monitored during October and November of each year after the growing season ended. In 

addition to the transect monitoring program, Pinellas County participates in a cooperative 

aerial seagrass mapping program managed by the Southwest Florida Water Management 

District (SWFWMD). The aerial photointerpretation mapping provides acreage estimates for 

the seagrass resource bi-annually. Results of the seagrass assessment and monitoring 

program activities: 

 General Results: 

• The prominent seagrass species in the BCB and CLW/STJS consisted of Halodule wrightii, 

Syringodium filiforme, and Thalassia testudinum. Various marine algae were also found 

including ten attached algae and four species of Caluerpa. 

• The condition of the seagrass varied from poor-very good with the majority of the sites rated 

as fair-good. 

 Fixed Transect Results: 

• The seagrass abundance and density along the fixed transects remained relatively stable 

along the BCB and CLW/STJS throughout the monitoring program. 

• Halophila engelmanni was observed in CLW/STJS along two transects in 2001 and 2002. 

• In BCB transects BCB-01 and BCB-04 the seagrass abundance and length of bed increased, 

and remained stable along the other nine transects. 

• In CLW/STJS the length of bed increased at CLW-08, decreased at CLW-04, varied at CLW05, and remained stable at the other 11 transect locations. 

• Some transects in BCB and CLW/STJS showed a temporary decrease in density from 2004-

2005, most likely correlated with the hurricane events. 

 Stratified Random Transect Results 

• The seagrass resource in CLW/STJS remained stable and in good condition. 

• Abundance and density of the seagrass showed little variation. 

• The geographic extent of the seagrass resource expands beyond the aerial mapping 

estimations. 

• The study statistically supports the detection of spatial distribution and ecotone by strata, 

depth zone, and species. 

Overall, the Pinellas County seagrass assessment and monitoring activities suggest that the 

seagrass resource remained stable in BCB and CLW/STJS from 1998-2007. This does not 

discount the indications of positive and negative variation within the resource. Further 

information is necessary to determine the spatial and temporal changes in the seagrass 

resource in relation to water quality, especially in the unstable areas of the resource. This 

report summarizes the information from the fixed transect and stratified random transect 

monitoring activities. 

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ii 
Table of Contents

1.0 Background 1 

2.0 Introduction 2 

 2.1 Study Area 2 

 2.2 Aerial Seagrass Mapping 3 

 2.3 Seagrass Habitat Components 5 

 2.4 Project Objectives 7 

3.0 Part I: Fixed Transect Monitoring 9 

3.1 Methods: Fixed Transect Monitoring 9

 3.2 Results: Fixed Transect Monitoring 10 

 3.2.1 Transect sites in Boca Ciega Bay (BCB) 13

 3.2.2 Transects in Clearwater Harbor and St. Joseph Sound 59

 (CLW/STJS) 

3.3 Discussion: Fixed Transect Monitoring 103 

4.0 Part II: Stratified Random Transect Monitoring 105 

 4.1 Methods: Stratified Random Transect Monitoring 105 

 4.2 Part II- Results: Stratified Random Transect Monitoring 107 

 4.2.1 Mean Abundance 107 

 4.2.2 Shoot Density 110 

 4.2.3 Blade Length 110 

 4.2.4 Health and Epibionts 111 

 4.2.5 Sediment Type and Depth 112 

 4.2.6 Water Quality 113 

 4.3 Part II- Discussion: Stratified Random Transect Monitoring 114 

5.0 Conclusion and Summary 117 

6.0 References 121 

Seagrass bed in St. Joseph Sound, Pinellas County, FL. 

iii 
iv 

List of Figures

Figure 1 Map of Pinellas County Seagrass Areas 3 

Figure 2 Estimated SAV acreages calculated from aerial photointerpretation 4 

Figure 3 Submerged Aquatic Vegetation (SAV) mapped in 2006 5 

Figure 4 Prominent seagrass species in Pinellas County, FL 6 

Figure 5 Marine algae found in Clearwater Harbor and St. Joseph Sound, FL 6 

Figure 6 Common epiphytes/epifauna found on seagrass in Pinellas County, FL 7 

Figure 7 Boca Ciega Bay fixed transect locations 1998-2007 13 

Figure 8 Clearwater fixed transect locations 1998-2005 59 

Figure 9 Map of seagrass strata. 105 

Figure 10 Spatial representation of the SAV species mean abundance 108 

Figure 11 Mean abundance of marine algae and the presence of scallops 109 

Figure 12 Mean shoot density (shoots per m2) by species and year 110 

Figure 13 Mean blade length for seagrass species 111 

Figure 14 Spatial representation of SAV Health, Epibionts, Sediment type, and Depth 112 

Figure 15 Mean water quality data collected during seagrass monitoring 113 

Figure 16 Combination of field survey data and aerial SAV map 115 

Figure 17 Seagrass data collected by the WQMP in 2006 and 2007 116 

Figure 18 Creation of a boat propeller scar through the seagrass monitoring transect 117 

Figure 19 Seasonal Spatial Interpolation of the water quality data 2004-2006 119

List of Tables

Table 1 SAV acreage calculated from aerial photointerpretation 4 

Table 2 Change in SAV acreage calculated from aerial photointerpretation 4 

Table 3 Summary of fixed transect data 1998-2007. 11 

Acronyms

BCB Boca Ciega Bay 

CLW Clearwater Harbor 

CLWN Clearwater Harbor North 

CLWS Clearwater Harbor South 

COT City of Tampa 

STJS Saint Joseph Sound 

SWFWMD Southwest Florida Water Management District 

TBEP Tampa Bay Estuary Program 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 1

1.0 Background 

In the early 1990s the Tampa Bay Estuary Program (TBEP) addressed the importance of 

monitoring trends and conditions of seagrass beds in Tampa Bay as an indicator of bay 

wide health. The Technical Advisory Committee of TBEP outlined an extensive bay wide 

seagrass monitoring program in 1994 (Coastal Environmental, Inc., 1994.) This was 

accomplished by monitoring fixed transects at various locations throughout the Tampa Bay 

area. Objectives of the seagrass transect monitoring program: 

• Determination of temporal and spatial seagrass species zonation, water depth, and 

seagrass density along transect (Braun-Blanquet rating); 

• Determination of relevant water quality and water column light attenuation data 

(Avery and Johansson, 2001) at each transect; and 

• Measurement of epiphyte/epifauna types and density on seagrass blades. 

In 1997, the City of Tampa’s (COT) Bay Study Group set up the first transects. After 

completion, COT presented preliminary results to the Tampa Bay Interagency Seagrass 

Monitoring Program (Avery and Johansson, 2001). In 1998, Pinellas County began 

seagrass monitoring in accordance with the TBEP Interlocal Agreement. Other members of 

the Tampa Bay Seagrass Monitoring group include: 

• City of Tampa Bay Study Group 

• Tampa Bay Watch, Inc. 

• Florida Fish and Wildlife Conservation Commission - Florida Wildlife Research 

Institute 

• Environmental Protection Commission of Hillsborough County 

• Manatee County Environmental Management Department 

• Hillsborough County Cockroach Bay Aquatic Preserve 

• Southwest Florida Water Management District 

From 1998-2005, Pinellas County’s seagrass monitoring program had 25 transects: 11 in 

Boca Ciega Bay (BCB) and 14 in Clearwater Harbor/St. Joseph Sound (CLW/STJS). The 

BCB transects were surveyed as part of the Tampa Bay-wide consortium of organizations 

that monitor seagrass transects in the bay to assess long-term and short-term trends in 

zonation, abundance, epibiont coverage, and species composition. Due to the extensive 

seagrass resource in CLW/STJS (14,700 acres), Pinellas County discontinued monitoring 

the 14 fixed transects, and implemented a stratified random monitoring program to increase 

the geographic extent. 

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2.0 Introduction 

 Seagrasses are flowering plants, angiosperms, specialized for living in marine nearshore 

environments (Short, 2001). Areas containing dense populations of seagrasses are considered 

seagrass habitat. Ecological functions provided by seagrass habitat include structural and 

physiological characteristics that support species living in the seagrass communities. Functions 

such as nutrient cycling, detritus production, sediment formation, and shelter increase the 

productivity of the ecosystem (Dawes et. al., 2004). Seagrass requires available light for 

photosynthesis. Thus, good water clarity is crucial to the persistence and growth of the seagrass 

beds. Disturbances in water quality such as nitrification, sediment re-suspension, and illicit 

discharges can negatively affect the water quality and clarity. Additionally, anthropogenic and 

natural stresses impact the health, sustainability, and persistence of the seagrass resource. 

The complexity of the interacting anthropogenic and natural conditions adds to the intricate 

dynamics of the Pinellas County marine ecosystem. Managers acknowledge the relationship 

between the anthropogenic factors and the degradation of the seagrass resource and realize the 

importance of sustaining this valuable ecosystem (Chauvaud et al., 1998). Correlated with 

urbanization, anthropogenic factors such as stormwater pollution, hardened shorelines, 

development, eutrophication, and boat prop scarring cause direct and indirect damage to the 

nearshore habitats and seagrass resources. In turn, natural factors such as water circulation, 

beach erosion, climate change, and weather events may also cause changes to occur in the 

ecosystem. These interacting environmental issues present a challenge for resource managers to 

develop strategies to protect and sustain the quality of the ecosystem (Meyer, 2008). To protect 

and manage natural resources managers require reliable data (Mumby, 1999). It is therefore 

essential to conduct a monitoring program to gain understanding of the seagrass resource spatial 

distribution and characterization. 

2.1 Study Area 

The study area consists of two regions, Clearwater Harbor/ St. Joseph Sound (CLW/STJS) and 

Boca Ciega Bay (BCB). The northern region of the study area, CLW/STJS, occurs along the 

northwest coastline of Pinellas County (Figure 1). Approximately 30 km north of the mouth of 

Tampa Bay, CLW/STJS consists of open water regions bounded east and west by the coastal 

mainland shoreline and the barrier island chain, respectively. Of the 118 km2 in CLW/STJS, 

expansive seagrass beds cover nearly 60 km2 providing essential habitat for marine flora and fauna 

(Kaufman, 2007). CLW/STJS also encompasses Honeymoon Island and Caladesi Island State 

Parks. The southern region of the study area, BCB, occurs along the southwest coastline of 

Pinellas County (Figure 1). BCB consists of open water and intercoastal regions bounded on the 

west by the coastal mainland and on the east by the barrier island chain. The southern portion of 

BCB connects directly to the Gulf of Mexico near the mouth of Tampa Bay. Of the 91 km2 in BCB, 

seagrass beds cover nearly 36 km2 (Kaufman, 2007). BCB also includes Shell Key Preserve and 

Fort De Soto Park. 

The study area has diverse natural and anthropogenic features. The ecosystem in BCB and 

CLW/STJS provide critical bird nesting areas, sessile algal communities, essential fishery habitats, 

marine mammal and turtle habitats, and numerous recreational opportunities. Anthropogenic 

features in the study area include dredge and fill operations, boat channels, spoil islands, finger 

canal systems, seawalls, and causeways. The complexity of the interacting anthropogenic and 

natural conditions adds to the intricate dynamics of the managing Pinellas County seagrass 

resource. 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 2

 

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 Figure 1. Map of Pinellas County Seagrass Areas 

2.2 Aerial Seagrass Mapping 

To assess the extent of the seagrass resource, Pinellas County participates in a cooperative remote 

sensing project managed by the Southwest Florida Water Management District (SWFMWD). The 

aerial photointerpretation mapping provides acreage estimates for the submerged aquatic 

vegetation (SAV) resource bi-annually. The SAV classification results from the inability of the 

photointerpretation method to discern seagrass from marine algae. The mapping resolution is 0.5 

acres with an 80% ground-truth accuracy. The data can be used to calculate a rate of change 

(ROC) for the SAV: 

 

 SAV ROC = "New Acreage" - "Old Acreage" 

 "Old Acreage" 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 2

 

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In 1950, the estimated SAV acreage in BCB was 10,800 acres as interpreted from single band 

photography. In 1982, the estimate dropped drastically to 5,770 acres (Table 1, Figure 2). From 

1998-2006, the SAV increased to 8,961 acres. The estimated SAV acreage in BCB increased 19% 

from 1996-2006 (Table 2). However, improvements in technology and photointerpretation methods 

may have contributed to the variability. 

The aerial photointerpretation mapping for CLW/STJS took place from 1999-2006. The SAV 

acreage increased from 13,994 to14,982 acres (Table 1, Figure 2.) The overall change in 

estimated SAV acreage increased 8% from 1999-2006 (Table 2). Variation in the SAV acreages 

may include effects from the improvements in technology and photointerpretation methods. 

The aerial photointerpretation mapping project provides an estimate of the geographic extent of the 

SAV in the study area (Figure 3). The trends suggest an increase in the SAV which may be 

positively correlated with an increase in seagrass. To verify these trends resource managers will 

require more detailed information about the seagrass habitat. 

Table 1. SAV acreage calculated from aerial photointerpretation (Kaufman, 2007) 

YEAR BAY 

SEGMENTS 1950 1982 1988 1990 1992 1994 1996 1999 2002 2004 2006

BCB 10,800 5,770 6,258 6,805 6,952 7,116 7,699 7,464 7,673 7,731 8,961 

CLW/STJS 13,994 13,393 14,200 14,982 

Table 2. Change in SAV acreage calculated from aerial photointerpretation (Kaufman, 2007) 

BAY Rates of Change 

SEGMENTS 82-88 88-90 90-92 92-94 94-96 96-99 99-02 02-04 04-06 

BCB 8% 9% 2% 2% 8% -3% 3% 1% 16% 

CLW/STJS -4% 6% 6% 

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

1940 1950 1960 1970 1980 1990 2000 2010

Year

SAV Acreage

Boca Ciega Bay

SJS / Clearwater Harbor

 Figure 2. Estimated SAV acreages calculated from aerial photointerpretation 

 for BCB and CLW/STJS. 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 2

 

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 Figure 3. Submerged Aquatic Vegetation (SAV) mapped in 2006 (Kaufman, 2007).

2.3 Seagrass Habitat Components 

The seagrass monitoring program provides specific information about the species composition, 

abundance, and condition of the resource. In Pinellas County the three prominent species are 

Syringodium filiforme, Thalassia testudinum, and Halodule wrightii (Figure 4) (Deitche and Meyer, 

2003). The common names for the species are manatee, turtle, and shoal grass, respectively. Two 

additional species Ruppia maritina and Halophila engelmanni are occasionally observed in the 

area. In addition to the seagrass species, the SAV includes a variety of marine algae. Figure 5 

shows seven marine algae and an invertebrate common in Clearwater Harbor and St. Joseph 

Sound. Field staff found the marine algae integrated with the seagrass species. The habitat also 

hosts a plethora of invertebrates including the Bay Scallop (Argopecten irradians). 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 2

 

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 Figure 4. Prominent seagrass species in Pinellas County, FL (Meyer 2008) 

 Figure 5. Marine algae found in Clearwater Harbor and St. Joseph Sound, FL. 

 (Meyer, 2008) 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 2

 

In the Tampa Bay area, epibionts, including both epiphytes and epifauna, commonly coexist on 

seagrass blades. The epibionts contribute to the primary production associated with the seagrass 

habitat. While certain epibionts may negatively impact the seagrass, others live symbiotically 

through a mutualistic or commensalistic relationship. Several epibionts found during seagrass 

monitoring include polycheates, attached algae, barnacle spat, coralline algae, and filamentous 

algae (Figure 6). A pilot study by Cho et al (2002) focused on the macroalgal epiphytes on 

Thalassia. The study identified 13 epiphytic species in dense seagrass beds and nine epiphytic 

species in sparse seagrass beds. The epiphytes include green, brown, and red algae with several 

species such as Enteromorpha flexuosa, Sphacelaria rigidula, Ceramium gracillimum var. 

byssoideum, Herposiphonia tenella, Griffithsia, and Stylonema alsidii (Cho et al., 2002). 

 Figure 6. Common epibionts found on seagrass in Pinellas County, FL (A- Spirorbis, a filter-feeding 

 polycheate, B- attached algae, C- barnacle spat, D- encrusting coralline algae, E- Lyngbya, filamentous 

 algae) 

 

2.4 Project Objectives 

This report aims to review and synthesize the monitoring and mapping data from 1998-2007. The 

results will provide an assessment of the seagrass resource in BCB and CLW/STJS. The report is 

separated into two Parts. Part I summarizes the data from the Fixed Transect Monitoring Program 

in BCB and CLW/STJS. Part II summarizes the Stratified Random Transect Program in CLW/STJS. 

An overview of the status of the seagrass resource, issues of concern, comparison of the sampling 

designs, and potential for future studies including the relationship of seagrass to water quality will 

be examined in section 6. 

 7 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

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PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

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3.0 Part I: Fixed Transect Monitoring 

3.1 Methods: Fixed Transect Monitoring 

Pinellas County monitored the fixed seagrass transects during October and November. This period 

marks the end of the growing season when seagrass biomass peaks. A PVC pole, imbedded in the 

bottom, marked the beginning of the transect (0m) and the end of the transect. In most cases the 

end of the transect coincided with the edge of bed. Transects are located using spatial coordinates 

from a Trimble® GPS unit. In most cases, the transects start on or near shore and then continued 

perpendicular to the shoreline (Deitche and Meyer, 2003). 

After arriving on site and locating the transect 0m mark, staff swam along the transect line with a 

meter square frame (quadrat). For transects less than 100m, seagrass abundance was recorded 

every 10m. For transects greater than 100m, only the transect area beyond the 100m was 

recorded in 10m increments; the rest of the transect’s seagrass abundance was recorded at 25m 

increments. 

Seagrass abundance was assessed using the Braun-Blanquet rating system (Braun-Blanquet, 

1965): 

• 0= no coverage 

• 0.1= solitary short shoot 

• 0.5= sparse or less than 1% 

• 1= 1-5% coverage 

• 2= 6-25% 

• 3= 26-50% 

• 4= 51-75% 

• 5= 76-100% 

Due to the stability of the seagrass resource determined by Levy et al (2003) the transects were 

monitoring every other year beginning in 2004. 

 

Other data collected include: water depth, sediment composition, seagrass condition and algae 

occurrence. The sediment composition is qualitatively categorized as sand, sandy mud, mud, 

shelly mud, shelly sand, or hard bottom. The seagrass condition is qualitatively categorized as very 

good, good, fair, poor, or necrotic. Epibiont density on the seagrass blade was assessed using a 

numerical rating scale: 1= clean, 2= light coverage, 3= moderate, 4= heavy. At the transect’s midbed and edge of bed, staff recorded shoot density and canopy height. Three density counts were 

made using either a 10x10cm or 25x25cm square frame. Also, five shoot lengths were recorded to 

the nearest centimeter. Samplers assess each species independently (Deitche and Meyer, 2003). 

Chlorophyll-a, turbidity, Hydrolab®, and LICOR® readings were taken at mid-bed, edge of bed, and 

the 2m depth contour. Chlorophyll-a and turbidity samples were collected using a 125ml Nalgene® 

bottle. The bottles were placed on ice and transferred to COT for analysis. LICOR® readings were 

used to calculate water column photosynthetically active radiation (PAR) values for the transect. 

Since 2003, water samples are analyzed using a transmissometer to complement the LICOR® 

readings to determine relative water clarity and light attenuation. The Hydrolab® provides 

measurements of depth, pH, temperature, salinity, conductivity, and dissolved oxygen (Deitche and 

Meyer, 2003).
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

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3.2 Results: Fixed Transect Monitoring 

In general, the seagrass beds in BCB and CLW/STJS remained stable throughout the monitoring 

program in BCB and CLW/STJS. The species found along the transects were Halodule wrightii,

Thalassia testudinum, Syringodium filiforme, and Halophila engelmanni . The summary results are 

shown in Table 3. The sediment composition ranged from mud to sand with most of the 

observations recorded sandy mud. The seagrass condition ranged from poor-very good with most 

of the observations recorded as good. The epibiont density ranged from light to heavy with the 

most prominent assemblages consisting of attached algae and polycheates. However, in 2002 and 

2003, there was an increase in observations of barnacle spat and bryozoans in the CLW/STJS 

transects. In BCB, the two prominent seagrasses were Halodule and Thalassia. In CLW/STJS, the 

prominent seagrasses were mixed beds composed of Halodule, Thalassia, and Syringodium. The 

species composition varied throughout the monitoring program in several of the transects. The most 

apparent shifts occurred in CLW-08, CLW-10, CLW-11, and CLW-12. In 2001-2005, observers 

recorded an increase in the abundance and occurrence of Syringodium along the middle of the 

transects. The shift transitioned the species composition from Halodule and/or Thalassia to 

Syringodium. The seagrass abundance and length of the bed appeared to increase in BCB-01, 

BCB-04, and CLW-08. The abundance and length of the bed appeared to decrease in CLW-04. 

Overall, the transects in BCB and CLW represent a stable seagrass resource with few temporal 

trends in the data. 

This section summarizes the data collected from 1998-2007 for the fixed transects. The transects 

were grouped by bay segment, BCB (Figure 7) and CLW/STJS (Figure 8). Each transect was 

presented with a summary paragraph, aerial map, transect graphs, epibiont density graph, species 

mean canopy height graph, and species mean density graph. The summary paragraph includes 

the description of the transect along with a brief compilation of the qualitative data and a synopsis of 

the quantitative data. The transect graphs illustrate seagrass abundance by species along the 

transect line by year. The abundance was represented using the Braun-Blanquet rating system. In 

some years, data was not collected from certain points resulting in gaps between readings. The 

epibiont density graph displays the mean density for each year. The density found on each 

seagrass species was ranked on a scale of 1-4 reflecting the categories of clean, light, moderate, 

and heavy, respectively. The mean canopy height and mean density graphs were calculated from 

the readings collected at the mid bed and edge of bed. The results are presented for each 

seagrass species. 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

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PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

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3.2.1 Transect sites in Boca Ciega Bay (BCB)

The fixed transect seagrass monitoring took place from 1998-2007 in Boca Ciega Bay (BCB). 

There are 11 transect locations. The BCB transects are included in the Tampa Bay Estuary 

Program Seagrass Monitoring Program. 

 Figure 7. Location of Boca Ciega Bay fixed transects. 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

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PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

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3.2.1.1 BCB-01

BCB-01 is located on the east side of the Intercoastal Waterway at the northern reach of Boca 

Ciega Bay. The transect extends 300m from the shore of a mangrove island to the edge of the boat 

channel. The depth ranged from 10-120cm. The sediment composition consisted of mud along the 

transect. The prominent seagrass was Halodule. The condition of the seagrass varied from fair to 

good. 

The length of the transect, BCB-01, expanded throughout the monitoring program. In 1998 the data 

indicated the edge of bed at 77m. By 2002, the bed extended to 143m continuing to 223m in the 

2007 survey. The epibiont density decreased slightly over the years to a light/moderate rating 

consisting mainly of attached algae, polycheates, and barnacles. The Halodule canopy height 

remained stable and ranged from 5-25cm. The shoot density ranged from 170-1150 shoots (per 

m2

) with the highest density of nearly 1800 shoots (per m2) reported in 2001. 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

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BCB-01 Transect Graphs 

Halodule

Thalassia

Seagrass Species

Syringodium

Halophila

1998

0

1

2

3

4

5

-17-15

-7-6-5-2

01

10162025303340434550556062657075778090

100110120125130137140150160170180190200210215220223

Braun-Blanquet Rank

1999

0

1

2

3

4

5

-17-15

-7-6-5-2

01

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Braun-Blanquet Rank

2000

0

1

2

3

4

5

-17-15

-7-6-5-2

01

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100110120125130137140150160170180190200210215220223

Braun-Blanquet Rank

2001

0

1

2

3

4

5

-17-15

-7-6-5-2

01

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100110120125130137140150160170180190200210215220223

Braun-Blanquet Rank

2002

0

1

2

3

4

5

-17-15

-7-6-5-2

01

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100110120125130137140150160170180190200210215220223

Braun-Blanquet Rank

2003

0

1

2

3

4

5

-17-15

-7-6-5-2

01

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Braun-Blanquet Rank
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

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2004

0

1

2

3

4

5

-17-15

-7-6-5-2

01

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100110120125130137140150160170180190200210215220223

Braun-Blanquet Rank

2005

0

1

2

3

4

5

-17-15

-7-6-5-2

01

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Braun-Blanquet Rank

2007

0

1

2

3

4

5

-17-15

-7-6-5-2

01

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Distance Along Transect (m)

Braun-Blanquet Rank

BCB-01 Epibiont Density Graph 

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

1996 1998 2000 2002 2004 2006 2008

Year

Epiphyte Density

Halodule

Thalasia

Syringodium
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 18 

BCB-01 Canopy Height Graph 

BCB-01 Canopy Height

0

10

20

30

40

50

60

1996 1998 2000 2002 2004 2006 2008

Year

Canopy Height (cm)

Halodule

BCB-01 Shoot Density Graph 

BCB-01 Shoot Density

0

200

400

600

800

1000

1200

1400

1600

1800

2000

1996 1998 2000 2002 2004 2006 2008

Year

Mean Density per m2

Halodule
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 19 

3.2.1.2 BCB-02

BCB-02 is located on the west side of Veterans Memorial Park in the Intercoastal Waterway. The 

transect extends 230m from the shore to the edge of the boat channel. The depth ranged from 35-

140cm. The sediment composition consisted of mud from 0-100 m; however, the sediment 

transitioned between 100m and 120m to shelly sand then to sand from 120m to 230m. The 

prominent seagrass was Halodule with occurrences of Thalassia between 70m-130m. The 

condition of the seagrass varied from fair to good. 

BCB-02 remained stable throughout the monitoring program. The data indicated that the edge of 

bed varied from 133m to 137m. The observation of Thalassia on the transect varied with a high 

abundance in 2000-2002, less abundance in 2003 and 2004, and rebounding in 2005 and 2006. 

The epibiont density was light in 1999, heavy in 2000, and moderate from 2001 to 2006. The 

epibiont assemblages consisted of attached algae and polycheates with fewer bryozoans and 

barnacles. The canopy height remained stable from 5cm-35cm. The shoot density ranged from 

100-1190 shoots (per m2

) with the highest Halodule density of nearly 4000 shoots (per m2) recorded 

in 2000. 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 20 

BCB-02 Transect Graphs 

Halodule

Thalassia

Seagrass Species

Syringodium

Halophila

1999

0

1

2

3

4

5

0

4.5

56

10202530334050606270717580839095

100102110120125130133134136137

Braun-Blanquet Rank

2000

0

1

2

3

4

5

0

4.5

56

10202530334050606270717580839095

100102110120125130133134136137

Braun-Blanquet Rank

2001

0

1

2

3

4

5

0

4.5

56

10202530334050606270717580839095

100102110120125130133134136137

Braun-Blanquet Rank

2002

0

1

2

3

4

5

0

4.5

56

10202530334050606270717580839095

100102110120125130133134136137

Braun-Blanquet Rank

2003

0

1

2

3

4

5

0

4.5

56

10202530334050606270717580839095

100102110120125130133134136137

Braun-Blanquet Rank

2004

0

1

2

3

4

5

0

4.5

56

10202530334050606270717580839095

100102110120125130133134136137

Braun-Blanquet Rank
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 21 

2005

0

1

2

3

4

5

0

4.5

56

10202530334050606270717580839095

100102110120125130133134136137

Braun-Blanquet Rank

2006

0

1

2

3

4

5

0

4.5

56

10202530334050606270717580839095

100102110120125130133134136137

Distance Along Transect (m)

Braun-Blanquet Rank

BCB-02 Epibiont Density Graph 

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

1998 2000 2002 2004 2006 2008

Year

Epiphyte Density

Halodule

Thalasia

Syringodium

 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 22 

BCB-02 Canopy Height Graph 

BCB-02 Canopy Height

0

10

20

30

40

50

60

1998 1999 2000 2001 2002 2003 2004 2005 2006 2007

Year

Canopy Height (cm)

Halodule

Thalassia

BCB-02 Shoot Density Graph 

BCB-02 Shoot Density

0

1000

2000

3000

4000

5000

6000

7000

1998 1999 2000 2001 2002 2003 2004 2005 2006 2007

Year

Mean Density per m2

Halodule

Thalassia
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 23 

3.2.1.3 BCB-03

BCB-03 is located south of the Bay Pines boat ramp. The transect extends 50m from the mangrove 

shoreline towards the boat channel. The depth ranged from 10cm-90cm. The sediment 

composition was sandy mud along the transect. The prominent seagrass was Halodule. The 

condition of the seagrass varied between poor and fair with a few observations of good. 

BCB-03 remained stable throughout the monitoring program. The data indicated that the edge of 

bed varied from 40m to 44m. The abundance of Halodule varied along the transect. The epibiont 

density ranged from light to moderate with heavy coverage in 2005. The epibiont assemblages 

consisted of attached algae. The canopy height showed an increasing trend from 1998-2002 from 

5cm to 20 cm. In 2004, the canopy height dropped to 5cm, recovered in 2005 to 25-35cm, then 

drastically fell to 2-4cm in 2007. Field comments from 2007 indicated the Halodule was buried 

under sediment. The shoot density ranged from 200-850 shoots (per m2

). The shoot density in 

2001 and 2005 reflected the highest abundance recorded. 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 24 

BCB-03 Transect Graphs 

Halodule

Thalassia

Seagrass Species

Syringodium

Halophila

1998

0

1

2

3

4

5

012

101520253040445060708090

100

Braun-Blanquet Rank

1999

0

1

2

3

4

5

012

101520253040445060708090

100

Braun-Blanquet Rank

2000

0

1

2

3

4

5

012

101520253040445060708090

100

Braun-Blanquet Rank

2001

0

1

2

3

4

5

012

101520253040445060708090

100

Braun-Blanquet Rank

2002

0

1

2

3

4

5

012

101520253040445060708090

100

Braun-Blanquet Rank

2003

0

1

2

3

4

5

012

101520253040445060708090

100

Braun-Blanquet Rank
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 25 

2004

0

1

2

3

4

5

012

101520253040445060708090

100

Braun-Blanquet Rank

2005

0

1

2

3

4

5

012

101520253040445060708090

100

Braun-Blanquet Rank

2007

0

1

2

3

4

5

012

101520253040445060708090

100

Distance Along Transect (m)

Braun-Blanquet Rank

BCB-03 Epibiont Density Graph 

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

1996 1998 2000 2002 2004 2006 2008

Year

Epiphyte Density

Halodule

Thalasia

Syringodium

 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 26 

BCB-03 Canopy Height Graph 

BCB-03 Canopy Height

0

10

20

30

40

50

60

1996 1998 2000 2002 2004 2006 2008

Year

Canopy Height (cm)

Halodule

 

BCB-03 Shoot Density Graph 

BCB-03 Shoot Density

0

200

400

600

800

1000

1200

1400

1600

1800

2000

1996 1998 2000 2002 2004 2006 2008

Year

Mean Density per m2

Halodule
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 27 

3.2.1.4 BCB-04

BCB-04 is located on the south side of Jungle Prada Park on the east edge of the Intercoastal 

Waterway. The transect extends 50m from the shoreline towards the boat channel. The depth 

ranged from 50cm-140cm. The sediment composition shifted between mud and sandy mud. The 

prominent seagrass was Halodule. The condition of the seagrass was good with a few 

observations of fair. 

BCB-04 remained stable and possibly increased throughout the monitoring program. The data 

indicated that the edge of bed varied from 33m in 1998 to 40m in 2005 and 38m in 2006. The 

abundance of Halodule was high along the transect. The epibiont density varied from light 

coverage in 2000 and 2004 to heavy coverage in 2001, 2002, and 2006. The epibiont assemblages 

consisted of attached algae and polycheates. The canopy height ranged from 10cm-45cm with a 

median observation of 30cm. The shoot density ranged from 150 shoots (per m2

) in 1998 to 1800 

shoots (per m2

) in 2004 with no apparent trend. 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 28 

BCB-04 Transect Graphs 

Halodule

Thalassia

Seagrass Species

Syringodium

Halophila

1998

0

1

2

3

4

5

01

101620303336383940

41.2

5060708090

100

Braun-Blanquet Rank

1999

0

1

2

3

4

5

01

101620303336383940

41.2

5060708090

100

Braun-Blanquet Rank

2000

0

1

2

3

4

5

01

101620303336383940

41.2

5060708090

100

Braun-Blanquet Rank

2001

0

1

2

3

4

5

01

101620303336383940

41.2

5060708090

100

Braun-Blanquet Rank

2002

0

1

2

3

4

5

01

101620303336383940

41.2

5060708090

100

Braun-Blanquet Rank

2003

0

1

2

3

4

5

01

101620303336383940

41.2

5060708090

100

Braun-Blanquet Rank
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 29 

2004

0

1

2

3

4

5

01

101620303336383940

41.2

5060708090

100

Braun-Blanquet Rank

2005

0

1

2

3

4

5

01

101620303336383940

41.2

5060708090

100

Braun-Blanquet Rank

2006

0

1

2

3

4

5

01

101620303336383940

41.2

5060708090

100

Distance Along Transect (m)

Braun-Blanquet Rank

BCB-04 Epibiont Density Graph 

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

1996 1998 2000 2002 2004 2006 2008

Year

Epiphyte Density

Halodule

Thalasia

Syringodium
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 30 

BCB-04 Canopy Height Graph 

BCB-04 Canopy Height

0

10

20

30

40

50

60

1996 1998 2000 2002 2004 2006 2008

Year

Canopy Height (cm)

Halodule

 

BCB-04 Shoot Density Graph 

BCB-04 Shoot Density

0

200

400

600

800

1000

1200

1400

1600

1800

2000

1996 1998 2000 2002 2004 2006 2008

Year

Mean Density per m2

Halodule
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 31 

3.2.1.5 BCB-05

BCB-05 is located in the central portion of Boca Ciega Bay. The transect extends 80m towards the 

boat channel and Pasadena Island. The depth ranged from 40cm-120cm. The sediment 

composition was mud from 0-50m then shifted to sand for the remainder of the transect. The 

prominent seagrass was Halodule. The condition of the seagrass was rated as fair to good. 

BCB-05 remained stable with some variation on the nearshore edge and edge of bed. The data 

indicated that the edge of bed fluctuated between 50m in 2002 to 61m in 2007. The abundance of 

Halodule was high along the transect. The epibiont density varied from moderate to heavy with 

assemblages consisting of attached algae, polycheates, barnacles, and bryozoans. The canopy 

height ranged from 5cm to 40cm. The canopy height steadily increased from 15cm in 2000 to 40cm 

in 2006, then dropped to 25cm in 2007. The shoot density ranged from 50 shoots (per m2

) to over 

5000 shoots (per m2

) with most of the recorded density values between 500-2000 shoots (per m2). 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 32 

BCB-05 Transect Graphs 

Halodule

Thalassia

Seagrass Species

Syringodium

Halophila

1998

0

1

2

3

4

5

012

102027283040505254555660617580

Braun-Blanquet Rank

1999

0

1

2

3

4

5

012

102027283040505254555660617580

Braun-Blanquet Rank

2000

0

1

2

3

4

5

012

102027283040505254555660617580

Braun-Blanquet Rank

2001

0

1

2

3

4

5

012

102027283040505254555660617580

Braun-Blanquet Rank

2002

0

1

2

3

4

5

012

102027283040505254555660617580

Braun-Blanquet Rank

2003

0

1

2

3

4

5

012

102027283040505254555660617580

Braun-Blanquet Rank
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 33 

2004

0

1

2

3

4

5

012

102027283040505254555660617580

Braun-Blanquet Rank

2005

0

1

2

3

4

5

012

102027283040505254555660617580

Braun-Blanquet Rank

2006

0

1

2

3

4

5

012

102027283040505254555660617580

Braun-Blanquet Rank

2007

0

1

2

3

4

5

012

102027283040505254555660617580

Distance Along Transect (m)

Braun-Blanquet Rank

BCB-05 Epibiont Density Graph 

y y

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

1996 1998 2000 2002 2004 2006 2008

Year

Epiphyte Density

Halodule

Thalasia

Syringodium
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 34 

BCB-05 Canopy Height Graph 

BCB-05 Canopy Height

0

10

20

30

40

50

60

1996 1998 2000 2002 2004 2006 2008

Year

Canopy Height (cm)

Halodule

 

BCB-05 Shoot Density Graph 

BCB-05 Shoot Density

0

1000

2000

3000

4000

5000

6000

7000

1996 1998 2000 2002 2004 2006 2008

Year

Mean Density per m2

Halodule
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 35 

3.2.1.6 BCB-06

BCB-06 is located near Gulfport just south of the mouth of Clam Bayou. The transect extends 

115m west from the shoreline. The depth ranged from 20cm-140cm. The sediment composition 

shifted between sandy mud and sand throughout the transect. There appeared to be a trend in the 

sediment between 0m-30m from sandy mud to mud. The prominent seagrass was Halodule with 

Thalassia consistent from 70m to 100m. The condition of the seagrass varied greatly from poor to 

good. 

BCB-06 remained relatively stable throughout the monitoring program with the exception of 2000 

when the abundance of seagrass dropped significantly. The data indicated that the edge of bed 

decreased from 107m in 1998 to 100m in 2000 then increased steadily to 115m in 2006. The 

epibiont density varied from light to heavy on the Halodule and Thalassia with assemblages 

consisting mainly of attached algae, polycheates, and bryozoans. The canopy height ranged from 

10cm to 30cm. The shoot density varied greatly from 25 shoots (per m2

) to nearly 7000 shoots (per 

m2

). 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 36 

BCB-06 Transect Graphs 

Halodule

Thalassia

Seagrass Species

Syringodium

Halophila

1998

0

1

2

3

4

5

013

102030405060708090

100103105107108109110115125

Braun-Blanquet Rank

1999

0

1

2

3

4

5

013

102030405060708090

100103105107108109110115125

Braun-Blanquet Rank

2000

0

1

2

3

4

5

013

102030405060708090

100103105107108109110115125

Braun-Blanquet Rank

2001

0

1

2

3

4

5

013

102030405060708090

100103105107108109110115125

Braun-Blanquet Rank

2002

0

1

2

3

4

5

013

102030405060708090

100103105107108109110115125

Braun-Blanquet Rank
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 37 

2003

0

1

2

3

4

5

013

102030405060708090

100103105107108109110115125

Braun-Blanquet Rank

2004

0

1

2

3

4

5

013

102030405060708090

100103105107108109110115125

Braun-Blanquet Rank

2005

0

1

2

3

4

5

013

102030405060708090

100103105107108109110115125

Braun-Blanquet Rank

2006

0

1

2

3

4

5

013

102030405060708090

100103105107108109110115125

Distance Along Transect (m)

Braun-Blanquet Rank

BCB-06 Epibiont Density Graph 

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

Epiphyte Density

1996 1998 2000 2002 2004 2006 2008

Year

Halodule

Thalasia

Syringodium

 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 38 

BCB-06 Canopy Height Graph 

BCB-06 Canopy Height

0

10

20

30

40

50

60

1996 1998 2000 2002 2004 2006 2008

Year

Canopy Height (cm)

Halodule

Thalassia

 

BCB-06 Shoot Density Graph 

BCB-06 Shoot Density

0

1000

2000

3000

4000

5000

6000

7000

1996 1998 2000 2002 2004 2006 2008

Year

Mean Density per m2

Halodule

Thalassia
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 39 

3.2.1.7 BCB-07

BCB-07 is located on the southeast side of the Tierra Verde Bridge. The transect extends north 

200 m from the middle of the seagrass bed towards the boat channel. Strong currents influence the 

north edge of the transect. The depth ranged from 20cm-100cm. The sediment composition varied 

from mud to sand throughout the monitoring program. Boat propeller scars were recorded in the 

comments increasing in frequency throughout the monitoring program. The prominent seagrass 

was Thalassia with occasional Halodule and sparse Syringodium. The condition of the seagrass 

varied from fair to very good. In 2005, the condition of the seagrass appeared necrotic to poor most 

likely due to the combination of heavy epibiont densities, very low tides, and below normal 

temperatures of 40-50 degrees Fahrenheit the week prior to the field survey. 

BCB-07 remained stable throughout the monitoring program. The data indicated that the edge of 

bed was consistently at 193m-194m. The epibiont density was moderate to heavy on the 

Thalassia, and light to moderate on the Halodule and Syringodium with assemblages consisting of 

attached algae, polycheates, bryozoans, and barnacles. In 2005, Lyngbya sp. covered a large 

portion of the seagrass bed. The canopy height ranged from 10cm to 40 cm. The shoot density 

ranged from 100-1000 shoots (per m2

). The shoot density for Thalassia decreased from 1998-2003 

then increased from 2004 to 2007. 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 40 

BCB-07 Transect Graphs 

Halodule

Thalassia

Seagrass Species

Syringodium

Halophila

1998

0

1

2

3

4

5

0

1020253040506070758090

100110120125130140150160170175180190193194200

Braun-Blanquet Rank

1999

0

1

2

3

4

5

0

1020253040506070758090

100110120125130140150160170175180190193194200

Braun-Blanquet Rank

2000

0

1

2

3

4

5

0

1020253040506070758090

100110120125130140150160170175180190193194200

Braun-Blanquet Rank

2001

0

1

2

3

4

5

0

1020253040506070758090

100110120125130140150160170175180190193194200

Braun-Blanquet Rank

2002

0

1

2

3

4

5

0

1020253040506070758090

100110120125130140150160170175180190193194200

Braun-Blanquet Rank

2003

0

1

2

3

4

5

0

1020253040506070758090

100110120125130140150160170175180190193194200

Braun-Blanquet Rank
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 41 

2004

0

1

2

3

4

5

0

1020253040506070758090

100110120125130140150160170175180190193194200

Braun-Blanquet Rank

2005

0

1

2

3

4

5

0

1020253040506070758090

100110120125130140150160170175180190193194200

Braun-Blanquet Rank

2006

0

1

2

3

4

5

01367

1020253040506070758090

100110120125130140150160170175180190193194200

Braun-Blanquet Rank

2007

0

1

2

3

4

5

01367

1020253040506070758090

100110120125130140150160170175180190193194200

Distance Along Transect (m)

Braun-Blanquet Rank

BCB-07 Epibiont Density Graph 

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

1996 1998 2000 2002 2004 2006 2008

Year

Epiphyte Density

Halodule

Thalasia

Syringodium

 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 42 

BCB-07 Canopy Height Graph 

BCB-07 Canopy Height

0

10

20

30

40

50

60

1996 1998 2000 2002 2004 2006 2008

Year

Canopy Height (cm)

Halodule

Thalassia

BCB-07 Shoot Density Graph 

 

BCB-07 Shoot Density

0

200

400

600

800

1000

1200

1400

1600

1800

2000

1996 1998 2000 2002 2004 2006 2008

Year

Mean Density per m2

Halodule

Thalassia
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 43 

3.2.1.8 BCB-08

BCB-08 is located on the east side of the Skyway bridge causeway south of Pinellas Point. The 

transect extends 150m from a sand bar towards the boat channel. The depth ranged from 10cm225cm. The sediment composition was sand. The seagrass species along the transect consisted of 

Halodule, Thalassia, and Syringodium. The condition of the seagrass varied from fair to very good 

for all three species. 

BCB-08 remained stable throughout the monitoring program; however, the distribution of seagrass 

species along the transect fluctuated. The data indicated that the edge of bed decreased from 

150m in 1998 to 100m in 2000 then increased and stabilized at 125m in 2002. The epibiont 

coverage was light to moderate with assemblages consisting of attached algae, bryozoans, and 

polycheates. The canopy height ranged from 20cm to 50 cm. The shoot density ranged from 50-

1400 shoots (per m2

). 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 44 

BCB-08 Transect Graphs 

Halodule

Thalassia

Seagrass Species

Syringodium

Halophila

1998

0

1

2

3

4

5

0

0.5

15

10

18.5

2025304050607075809095

100110117120123125126130138140150

Braun-Blanquet Rank

1999

0

1

2

3

4

5

0

0.5

15

10

18.5

2025304050607075809095

100110117120123125126130138140150

Braun-Blanquet Rank

2000

0

1

2

3

4

5

0

0.5

15

10

18.5

2025304050607075809095

100110117120123125126130138140150

Braun-Blanquet Rank

2001

0

1

2

3

4

5

0

0.5

15

10

18.5

2025304050607075809095

100110117120123125126130138140150

Braun-Blanquet Rank

2002

0

1

2

3

4

5

0

0.5

15

10

18.5

2025304050607075809095

100110117120123125126130138140150

Braun-Blanquet Rank

2003

0

1

2

3

4

5

0

0.5

15

10

18.5

2025304050607075809095

100110117120123125126130138140150

Braun-Blanquet Rank
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 45 

2004

-1

1

3

5

0

0.5

15

10

18.5

2025304050607075809095

Braun-Blanquet Ran

100110117120123125126130138140150

k

2005

0

1

2

3

4

5

0

0.5

15

10

18.5

2025304050607075809095

100110117120123125126130138140150

Braun-Blanquet Rank

2006

0

1

2

3

4

5

0

0.5

15

10

18.5

2025304050607075809095

100110117120123125126130138140150

Braun-Blanquet Rank

2006

0

1

2

3

4

5

0

0.5

15

10

18.5

2025304050607075809095

100110117120123125126130138140150

Distance Along Transect (m)

Braun-Blanquet Rank

BCB-08 Epibiont Density Graph 

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

1996 1998 2000 2002 2004 2006 2008

Epiphyte Density

Year

Halodule

Thalasia

Syringodium
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 46 

BCB-08 Canopy Height Graph 

BCB-08 Canopy Height

0

10

20

30

40

50

60

1996 1998 2000 2002 2004 2006 2008

Year

Canopy Height (cm)

Halodule

Thalassia

Syringodium

 

BCB-08 Shoot Density Graph 

BCB-08 Shoot Density

0

200

400

600

800

1000

1200

1400

1600

1800

2000

1996 1998 2000 2002 2004 2006 2008

Year

Mean Density per m2

Halodule

Thalassia

Syringodium
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 47 

3.2.1.9 BCB09

BCB-09 is located east of the Fort Desoto Bridge and north of the boat channel. The transect 

extends south 500m from the middle of the seagrass bed towards the boat channel. The depth 

ranged from 20cm-120cm. The sediment composition was sandy mud. The prominent seagrass 

species was Thalassia with occasional Halodule. The condition of the seagrass varied from fair to 

good. 

BCB-09 remained stable throughout the monitoring program. The data indicated that the edge of 

bed is consistent at 499m. The epibiont density was moderate to heavy with assemblages 

consisting of attached algae, polycheates, and bryozoans along with hydroids and Lyngbya sp. The 

canopy height ranged from 15cm to 50cm. The shoot density ranged from 50-1400 shoots (per m2

). 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 48 

BCB-09 Transect Graphs 

Halodule

Thalassia

Seagrass Species

Syringodium

Halophila

1998

0

1

2

3

4

5

0

255075

100125150175200225250275300325350375400410420430440450460470480490499500

Braun-Blanquet Rank

1999

0

1

2

3

4

5

0

255075

100125150175200225250275300325350375400410420430440450460470480490499500

Braun-Blanquet Rank

2000

0

1

2

3

4

5

0

255075

100125150175200225250275300325350375400410420430440450460470480490499500

Braun-Blanquet Rank

2001

0

1

2

3

4

5

0

255075

100125150175200225250275300325350375400410420430440450460470480490499500

Braun-Blanquet Rank

2002

0

1

2

3

4

5

0

255075

100125150175200225250275300325350375400410420430440450460470480490499500

Braun-Blanquet Rank

2003

0

1

2

3

4

5

0

255075

100125150175200225250275300325350375400410420430440450460470480490499500

Braun-Blanquet Rank
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 49 

2004

0

1

2

3

4

5

0

255075

100125150175200225250275300325350375400410420430440450460470480490499500

Braun-Blanquet Rank

2005

0

1

2

3

4

5

0

255075

100125150175200225250275300325350375400410420430440450460470480490499500

Braun-Blanquet Rank

2006

0

1

2

3

4

5

0

255075

100125150175200225250275300325350375400410420430440450460470480490499500

Braun-Blanquet Rank

2007

0

1

2

3

4

5

0

255075

100125150175200225250275300325350375400410420430440450460470480490499500

Distance Along Transect (m)

Braun-Blanquet Rank

BCB-09 Epibiont Density Graph 

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

1996 1998 2000 2002 2004 2006 2008

Year

Epiphyte Density

Halodule

Thalasia

Syringodium
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 50 

BCB-09 Canopy Height Graph 

BCB-09 Canopy Height

0

10

20

30

40

50

60

1996 1998 2000 2002 2004 2006 2008

Year

Canopy Height (cm)

Halodule

Thalassia

BCB-09 Shoot Density Graph 

BCB-09 Shoot Density

0

200

400

600

800

1000

1200

1400

1600

1800

2000

1996 1998 2000 2002 2004 2006 2008

Year

Mean Density per m2

Halodule

Thalassia
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 51 

3.2.1.10 BCB10

BCB-10 is located in South Mullet Key Bayou. The transect extends northeast 150m from the 

mangrove shoreline towards the boat channel. The depth ranged from 30cm-140cm. The 

sediment composition was sandy mud. The seagrass bed was a mixture of Halodule and 

Thalassia. The condition of the seagrass varied from fair to good. 

BCB-10 varied in species composition and abundance while maintaining a stable seagrass bed. 

The data indicated that the edge of bed is consistent at 150m throughout the monitoring program. 

In 1998 the prominent seagrass was Halodule. In 1999-2000, Thalassia increased in abundance 

becoming the prominent seagrass. By 2001, Halodule and Thalassia were both prominent species 

along the transect. The abundance of both seagrasses decreased in 2002, and then increased 

slightly through 2003-2004. The abundance of the Halodule increased drastically in 2005-2006. In 

November 2004, the Fort De Soto Recirculation Project restored the connection between the east 

and west side of the causeway. Improved circulation may have contributed to the increase in 

seagrass abundance along the transect. The epibiont density was light to heavy consisting of 

attached algae, polycheates, and barnacles. The canopy height ranged from 15cm-35cm with 

Thalassia consistently higher than the Halodule. The shoot density showed separate trends for the 

species. The Thalassia ranged from 25-200 shoots (per m2

) with a decreasing density. The 

Halodule ranged from 25-1600 shoots (per m2

) with a exponential increase in density from 2004-

2006. 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 52 

BCB-10 Transect Graphs 

Halodule

Thalassia

Seagrass Species

Syringodium

Halophila

1998

0

1

2

3

4

5

0123

152550607075788090

100102110120130140150151160169170175

Braun-Blanquet Rank

1999

0

1

2

3

4

5

0123

152550607075788090

100102110120130140150151160169170175

Braun-Blanquet Rank

2000

0

1

2

3

4

5

0123

152550607075788090

100102110120130140150151160169170175

Braun-Blanquet Rank

2001

0

1

2

3

4

5

0123

152550607075788090

100102110120130140150151160169170175

Braun-Blanquet Rank

2002

0

1

2

3

4

5

0123

152550607075788090

100102110120130140150151160169170175

Braun-Blanquet Rank

2003

0

1

2

3

4

5

0123

152550607075788090

100102110120130140150151160169170175

Braun-Blanquet Rank
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 53 

2004

0

1

2

3

4

5

0123

152550607075788090

100102110120130140150151160169170175

Braun-Blanquet Rank

2005

0

1

2

3

4

5

0123

152550607075788090

100102110120130140150151160169170175

Braun-Blanquet Rank

2006

0

1

2

3

4

5

0123

152550607075788090

100102110120130140150151160169170175

Distance Along Transect (m)

Braun-Blanquet Rank

BCB-10 Epibiont Density Graph 

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

1996 1998 2000 2002 2004 2006 2008

Year

Epiphyte Density

Halodule

Thalasia

Syringodium
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 54 

BCB-10 Canopy Height Graph 

BCB-10 Canopy Height

0

10

20

30

40

50

60

1996 1998 2000 2002 2004 2006 2008

Year

Canopy Height (cm)

Halodule

Thalassia

 

BCB-10 Shoot Density Graph 

BCB-10 Shoot Density

0

200

400

600

800

1000

1200

1400

1600

1800

2000

1996 1998 2000 2002 2004 2006 2008

Year

Mean Density per m2

Halodule

Thalassia
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 55 

3.2.1.11 BCB11

BCB-11 is located on the southeast side of Shell Key. The transect extends 100m from the 

mangrove island towards Shell Key. The area experiences dynamic circulation and sedimentation 

patterns due to the long shore currents and geographic orientation between two significant passes. 

The depth ranged from 5cm-80cm. The sediment composition was sandy mud from 0m-70m. The 

sediment composition shifted to sand from 70m-100m. The prominent seagrass was Halodule. 

The condition of the seagrass varied from fair to good. 

BCB-11 remained stable throughout the monitoring program. The data indicated that the edge of 

bed varied from 70m-77m from 1998-2002 and then increased to 80m-87m in 2003-2005. The 

epibiont density was moderate to heavy with assemblages consisting of attached algae, 

polycheates, and Lyngbya sp. The canopy height ranged from 15cm-30cm. The shoot density 

ranged from 50-3000 shoots (per m2

) averaging near 1000 shoots (per m2). 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 56 

BCB-11 Transect Graphs 

Halodule

Thalassia

Seagrass Species

Syringodium

Halophila

1998

0

1

2

3

4

5

0135

1020304050607075767778808185868790

100

Braun-Blanquet Rank

1999

0

1

2

3

4

5

0135

1020304050607075767778808185868790

100

Braun-Blanquet Rank

2000

0

1

2

3

4

5

0135

1020304050607075767778808185868790

100

Braun-Blanquet Rank

2001

0

1

2

3

4

5

0135

1020304050607075767778808185868790

100

Braun-Blanquet Rank

2002

0

1

2

3

4

5

0135

1020304050607075767778808185868790

100

Braun-Blanquet Rank

2003

0

1

2

3

4

5

0135

1020304050607075767778808185868790

100

Braun-Blanquet Rank

 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 57 

2004

0

1

2

3

4

5

0135

1020304050607075767778808185868790

100

Braun-Blanquet Rank

2005

0

1

2

3

4

5

0135

1020304050607075767778808185868790

100

Distance Along Transect (m)

Braun-Blanquet Rank

BCB-11 Epibiont Density Graph 

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

1996 1998 2000 2002 2004 2006

Year

Epiphyte Density

Halodule

Thalasia

Syringodium
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 58 

BCB-11 Canopy Height Graph 

BCB-11 Canopy Height

0

10

20

30

40

50

60

1996 1998 2000 2002 2004 2006

Year

Canopy Height (cm)

Halodule

 

BCB-11 Shoot Density Graph 

BCB-11 Shoot Density

0

1000

2000

3000

4000

5000

6000

7000

1996 1998 2000 2002 2004 2006

Year

Mean Density per m2

Halodule
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 59 

3.2.2 Transects in Clearwater Harbor and St. Joseph Sound (CLW/STJS) 

The fixed transect seagrass monitoring program took place from 1998-2005 in CLW/STJS. There 

were 14 transect locations. The transect names were abbreviated as CLW-01 through CLW-14. 

Only one transect, CLW-14, was located in STJS. The program was discontinued in 2006 and 

replaced with a different monitoring design to increase geographic coverage. 

 Figure 8. Clearwater fixed transect locations 1998-2005. 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 60 

This page is intentionally blank. 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 61 

3.2.2.1 CLW-01

CLW-01 is located north of the Walsingham Causeway Bridge on the east side of the Intercoastal 

Waterway. The transect extends 200m from the shoreline towards the boat channel. The depth 

ranged from 30cm-110cm. The sediment composition was sandy mud. The prominent seagrass 

was Halodule with occasional Thalassia. The condition of the seagrass was good. 

CLW-01 remained stable throughout the monitoring program. The data indicated that the edge of 

bed fluctuated from 180m-200m. The epibiont density varied from light to heavy with assemblages 

consisting of attached algae, polycheates, barnacles, and tunicates. The canopy height ranged from 

5cm-30cm with an increasing trend from 1998 to 2003. The shoot density ranged from 50-2500 

shoots (per m2

). 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 62 

CLW-01 Transect Graphs 

Halodule

Thalassia

Seagrass Species

Syringodium

Halophila

1998

0

1

2

3

4

5

01

2550707580859095

100110120130140145150160170180181190195200

Braun-Blanquet Rank

1999

0

1

2

3

4

5

01

2550707580859095

100110120130140145150160170180181190195200

Braun-Blanquet Rank

2000

0

1

2

3

4

5

01

2550707580859095

100110120130140145150160170180181190195200

Braun-Blanquet Rank

2001

0

1

2

3

4

5

01

2550707580859095

100110120130140145150160170180181190195200

Braun-Blanquet Rank

2002

0

1

2

3

4

5

01

2550707580859095

100110120130140145150160170180181190195200

Braun-Blanquet Rank

2003

0

1

2

3

4

5

01

2550707580859095

100110120130140145150160170180181190195200

Braun-Blanquet Rank

 2005

0

1

2

3

4

5

01

2550707580859095

100110120130140145150160170180181190195200

Distance Along Transect (m)

Braun-Blanquet Rank
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 63 

CLW-01 Epibiont Density Graph 

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

1996 1998 2000 2002 2004 2006

Year

Epiphyte Density

Halodule

Thalasia

Syringodium

CLW-01 Canopy Height Graph 

CLW-01 Canopy Height

0

10

20

30

40

50

60

1996 1998 2000 2002 2004 2006

Year

Canopy Height (cm)

Halodule

CLW-01 Shoot Density Graph 

CLW-01 Shoot Density

0

1000

2000

3000

4000

5000

6000

7000

1996 1998 2000 2002 2004 2006

Year

Mean Density per m2

Halodule
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 64 

3.2.2.2 CLW-02

CLW-02 is located south of the Belleair Causeway. The transect extends southeast 230m from a 

mangrove island towards the boat channel. The depth ranged from 40cm-110cm. The sediment 

composition varied from sand (0m-25m) to mud (25m-100m) and back to sand (100m-230m). The 

prominent seagrass was Thalassia with Halodule nearshore. The condition of the seagrass was 

good. 

CLW-02 remained stable throughout the monitoring program. The data indicated that the edge of 

bed varied from 125m-139m. The epibiont density varied from heavy to light with a decreasing 

trend from 1998-2003. The epibiont assemblages consisted of attached algae, polycheates, and 

barnacles. The canopy height ranged form 18cm-32cm. The shoot density ranged from 25-600 

shoots (per m2

) with shoot counts over 1200 shoots (per m2) in 2001 and 2003. 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 65 

CLW-02 Transect Graphs 

Halodule

Thalassia

Seagrass Species

Syringodium

Halophila

1998

0

1

2

3

4

5

01

253035404550556065707580859095

100105110115120125128130132135139

Braun-Blanquet Rank

1999

0

1

2

3

4

5

01

253035404550556065707580859095

100105110115120125128130132135139

Braun-Blanquet Rank

2000

0

1

2

3

4

5

01

253035404550556065707580859095

100105110115120125128130132135139

Braun-Blanquet Rank

2001

0

1

2

3

4

5

01

253035404550556065707580859095

100105110115120125128130132135139

Braun-Blanquet Rank

2002

0

1

2

3

4

5

01

253035404550556065707580859095

100105110115120125128130132135139

Braun-Blanquet Rank

2003

0

1

2

3

4

5

01

253035404550556065707580859095

100105110115120125128130132135139

Braun-Blanquet Rank

2005

0

1

2

3

4

5

01

253035404550556065707580859095

100105110115120125128130132135139

Distance Along Transect (m)

Braun-Blanquet Rank
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 66 

CLW-02 Epibiont Density Graph 

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

1996 1998 2000 2002 2004 2006

Year

Epiphyte Density

Halodule

Thalasia

Syringodium

CLW-02 Canopy Height Graph 

CLW-02 Canopy Height

0

10

20

30

40

50

60

1996 1998 2000 2002 2004 2006

Year

Canopy Height (cm)

Halodule

Thalassia

CLW-02 Shoot Density Graph 

CLW-02 Shoot Density

0

200

400

600

800

1000

1200

1400

1600

1800

2000

1996 1998 2000 2002 2004 2006

Year

Mean Density per m2

Halodule

Thalassia
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 67 

3.2.2.3 CLW-03

CLW-03 is located north of the Belleair Causeway Bridge. The transect extends west 260m from 

the boat channel. The depth ranged from 20cm-140cm. The sediment composition was sand with 

a patch of sandy mud near the middle of the transect. The seagrass consisted of Thalassia and 

Halodule. The condition of the seagrass fluctuated from good/fair in 1999 to poor/fair in 2000-2001, 

to good in 2002-2003, and back to poor/fair in 2005. 

CLW-03 remained stable throughout the monitoring program. The Thalassia was consistent along 

the transect and the Halodule decreased in occurrence. The data indicated that the edge of bed 

varied from 227m-238m. In 1999 the edge of bed increased to 253m. The epibiont density was 

moderate to heavy with assemblages consisting of attached algae, polycheates, barnacles, and 

bryozoans. In 1998, the epibiont density on the Halodule was light. The canopy height ranged from 

20cm-40cm with the Halodule typically shorter than the Thalassia. The shoot density ranged from 

25-1850 shoots (per m2

). The Halodule shoot density increased from 1998-2005. 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 68 

CLW-03 Transect Graphs 

Halodule

Thalassia

Seagrass Species

Syringodium

Halophila

1998

0

1

2

3

4

5

-8.7

01

255075

100125150160170175180190200210220227230234237238240250253260

Braun-Blanquet Rank

1999

0

1

2

3

4

5

-8.7

01

255075

100125150160170175180190200210220227230234237238240250253260

Braun-Blanquet Rank

2000

0

1

2

3

4

5

-8.7

01

255075

100125150160170175180190200210220227230234237238240250253260

Braun-Blanquet Rank

2001

0

1

2

3

4

5

-8.7

01

255075

100125150160170175180190200210220227230234237238240250253260

Braun-Blanquet Rank

2002

0

1

2

3

4

5

-8.7

01

255075

100125150160170175180190200210220227230234237238240250253260

Braun-Blanquet Rank

2003

0

1

2

3

4

5

-8.7

01

255075

100125150160170175180190200210220227230234237238240250253260

Braun-Blanquet Rank

2005

0

1

2

3

4

5

-8.7

01

255075

100125150160170175180190200210220227230234237238240250253260

Distance Along Transect (m)

Braun-Blanquet Rank
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 69 

CLW-03 Epibiont Density Graph 

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

1996 1998 2000 2002 2004 2006

Year

Epiphyte Density

Halodule

Thalasia

Syringodium

CLW-03 Canopy Height Graph 

CLW-03 Canopy Height

0

10

20

30

40

50

60

1996 1998 2000 2002 2004 2006

Year

Canopy Height (cm)

Halodule

Thalassia

CLW-03 Shoot Density Graph 

CLW-03 Shoot Density

0

500

1000

1500

2000

2500

3000

3500

4000

1996 1998 2000 2002 2004 2006

Year

Mean Density per m2

Halodule

Thalassia
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 70 

3.2.2.4 CLW-04

CLW-04 is located north of the Belleair Causeway on the east side of the Intercoastal Waterway. 

The transect extends 250m from the shore towards the boat channel. The depth ranged from 

15cm-140cm. The sediment composition changed throughout the monitoring program. In 1998-

2000, the sediment composition was sandy mud from 0m-140m and then changed to sand from 

150m-250m. In 2001, the nearshore area was mud and sandy mud, then transitioned to sand at 

180m. In 2002-2005, the sediment composition was mud from 0m-180m and sand from 190m250m. The field staff noted that the mud was very thick and may have accumulated from the outfall 

of Rattlesnake Creek. The prominent seagrass was Halodule with Thalassia from 160m-235m. The 

condition of the seagrass varied from poor to good and seemed to be correlated with the distance 

from shore, respectively. 

The seagrass abundance along the transect, CLW-04, appeared to decrease slightly throughout the 

monitoring program. The data indicated that the edge of bed varies from 210m-235m. The edge of 

bed decreased from 235m in 1999 to 218m in 2005 with a marked reduction of Thalassia. The 

abundance of Halodule also decreased from 1999-2005 mainly between 150m-200m. The epibiont 

density varied from light to heavy coverage with a decreasing trend from 1999-2005. The epibiont 

assemblages consisted of attached algae and polycheates. The canopy height ranged from 10cm35cm. The shoot density for Thalassia ranged from 20-200 shoots (per m2

). The shoot density for 

Halodule ranged from 20-5200 shoots (per m2

). The shoot density for Halodule decreased abruptly 

from 5200 shoots (per m2

) in 2001 to 1000 shoots (per m2) in 2002 and 2003. In 2004, the shoot 

density for Halodule increased to 2000 shoots (per m2

). 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 71 

CLW-04 Transect Graphs 

Halodule

Thalassia

Seagrass Species

Syringodium

Halophila

1998

0

1

2

3

4

5

-6.8

01

12255075

100110120130140150160170180190200210218220225227230234

Braun-Blanquet Rank

1999

0

1

2

3

4

5

-6.8

01

12255075

100110120130140150160170180190200210218220225227230234

Braun-Blanquet Rank

2000

0

1

2

3

4

5

-6.8

01

12255075

100110120130140150160170180190200210218220225227230234

Braun-Blanquet Rank

2001

0

1

2

3

4

5

-6.8

01

12255075

100110120130140150160170180190

200210218220225227230234

Braun-Blanquet Rank

2002

0

1

2

3

4

5

-6.8

01

12255075

100110120130140150160170180190200210218220225227230234

Braun-Blanquet Rank

2003

0

1

2

3

4

5

-6.8

01

12255075

100110120130140150160170180190200210218220225227230234

Braun-Blanquet Rank

2005

0

1

2

3

4

5

-6.8

01

12255075

100110120130140150160170180190200210218220225227230234

Distance Along Transect (m)

Braun-Blanquet Rank
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 72 

CLW-04 Epibiont Density Graph 

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

1996 1998 2000 2002 2004 2006

Year

Epiphyte Density

Halodule

Thalasia

Syringodium

CLW-04 Canopy Height Graph 

CLW-04 Canopy Height

0

10

20

30

40

50

60

1996 1998 2000 2002 2004 2006

Year

Canopy Height (cm)

Halodule

Thalassia

CLW-04 Shoot Density Graph 

CLW-04 Shoot Density

0

1000

2000

3000

4000

5000

6000

7000

1997 1998 1999 2000 2001 2002 2003 2004 2005 2006

Year

Mean Density per m2

Halodule

Thalassia
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 73 

3.2.2.5 CLW-05

CLW-05 is located near the north end of Sand Key. The transect extends 90m from the middle of 

the seagrass bed towards the boat channel. The area experiences strong currents and heavy boat 

traffic. The depth ranged from 45cm-200cm. The sediment composition was sand with a few 

occurrences of sandy mud. The seagrass consisted of Halodule, Syringodium, and Thalassia. The 

condition of the seagrass was good. 

CLW-05 varied throughout the monitoring program. In 2000-2002, staff found very sparse seagrass 

from 10m-40m. The data indicated that the edge of bed varied from 50m-80m. The epibiont density 

ranged from clean to heavy with assemblages consisting of attached algae, polycheates, and 

bryozoans. The canopy height ranged from 15cm-45cm. The shoot density ranged from 50-1200 

shoots (per m2

). 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 74 

CLW-05 Transect Graphs 

Halodule

Thalassia

Seagrass Species

Syringodium

Halophila

1998

0

1

2

3

4

5

01

10202530405060707580

Braun-Blanquet Rank

1999

0

1

2

3

4

5

01

10202530405060707580

Braun-Blanquet Rank

2000

0

1

2

3

4

5

01

10202530

40

5060707580

Braun-Blanquet Rank

2001

0

1

2

3

4

5

01

10202530405060707580

Braun-Blanquet Rank

2002

0

1

2

3

4

5

01

10202530405060707580

Braun-Blanquet Rank

2003

0

1

2

3

4

5

01

102025304050607075

Braun-Blanquet Rank

2005

0

1

2

3

4

5

01

10202530405060707580

Distance Along Transect (m)

Braun-Blanquet Rank
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 75 

CLW-05 Epibiont Density Graph 

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

1996 1998 2000 2002 2004 2006

Year

Epiphyte Density

Halodule

Thalasia

Syringodium

CLW-05 Canopy Height Graph 

CLW-05 Canopy Height

0

10

20

30

40

50

60

1996 1998 2000 2002 2004 2006

Year

Canopy Height (cm)

Halodule

Thalassia

Syringodium

CLW-05 Shoot Density Graph 

CLW-05 Shoot Density

0

200

400

600

800

1000

1200

1400

1600

1800

2000

1996 1998 2000 2002 2004 2006

Year

Mean Density per m2

Halodule

Thalassia

Syringodium
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 76 

3.2.2.6 CLW-06

CLW-06 is located south of the Clearwater Memorial Bridge. The transect extends 100m from the 

mangrove spoil island. The area experiences strong currents and heavy boat traffic due to its 

proximity to Clearwater Pass. The depth ranged from 5cm-150cm. The sediment composition was 

sand and sandy mud. The seagrass consisted of Halodule from 0m-45m and Thalassia from 45m100m. The condition of the seagrass was good. 

CLW-06 remained stable throughout the monitoring program. The data indicated that the edge of 

bed varied from 60m-100m; however, the orientation or placement of the transect may have been 

adjusted in 1999. The epibiont density was moderate to heavy with the assemblages consisting of 

attached algae and polycheates. The canopy height ranged from 15cm-45cm. The shoot density 

ranged from 100-1000 shoots (per m2

) with Halodule densities of 2000-3000 shoots (per m2) in 

1999 and 2001. 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 77 

CLW-06 Transect Graphs 

Halodule

Thalassia

Seagrass Species

Syringodium

Halophila

1998

0

1

2

3

4

5

-3

01

10203040455060707175809095

100

Braun-Blanquet Rank

1999

0

1

2

3

4

5

-3

01

10203040455060707175809095

100

Braun-Blanquet Rank

2000

0

1

2

3

4

5

-3

01

10203040455060707175809095

100

Braun-Blanquet Rank

2001

0

1

2

3

4

5

-3

01

10203040455060707175809095

100

Braun-Blanquet Rank

2002

0

1

2

3

4

5

-3

01

10203040455060707175809095

100

Braun-Blanquet Rank

2003

0

1

2

3

4

5

-3

01

10203040455060707175809095

100

Braun-Blanquet Rank

2005

0

1

2

3

4

5

-3

01

10203040455060707175809095

100

Distance Along Transect (m)

Braun-Blanquet Rank
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 78 

CLW-06 Epibiont Density Graph 

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

1996 1998 2000 2002 2004 2006

Year

Epiphyte Density

Halodule

Thalasia

Syringodium

CLW-06 Canopy Height Graph 

CLW-06 Canopy Height

0

10

20

30

40

50

60

1996 1998 2000 2002 2004 2006

Year

Canopy Height (cm)

Halodule

Thalassia

CLW-06 Shoot Density Graph 

CLW-06 Shoot Density

0

500

1000

1500

2000

2500

3000

3500

4000

1996 1998 2000 2002 2004 2006

Year

Mean Density per m2

Halodule

Thalassia
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 79 

3.2.2.7 CLW-07

CLW-07 is located between Caladesi Island and the northern end of Clearwater Beach. The 

transect extends west 200m from the mangrove shore towards the boat channel. The depth ranged 

from 40cm-170cm. The sediment composition was sandy mud. The prominent seagrass was 

Halodule with occasional Syringodium in 1999-2001. The condition of the seagrass was 

consistently good. 

CLW-07 remained stable throughout the monitoring program. The data indicated that the edge of 

bed varied from 140m-192m. The epibiont density was light to heavy with assemblages consisting 

of attached algae, polycheates, bryozoans, and barnacles. The canopy height ranged from 15cm35cm. The shoot density ranged from 50-2500 shoots (per m2

). 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 80 

CLW-07 Transect Graphs 

Halodule

Thalassia

Seagrass Species

Syringodium

Halophila

1998

0

1

2

3

4

5

-8

01

25507597

100110120130140142150154160170180184190192200

Braun-Blanquet Rank

1999

0

1

2

3

4

5

-8

01

25507597

100110120130140142150154160170180184190192200

Braun-Blanquet Rank

2000

0

1

2

3

4

5

-8

01

25507597

100110120130140142150154160170180184190192

200

Braun-Blanquet Rank

2001

0

1

2

3

4

5

-8

01

25507597

100110120130140142150154160170180184190192200

Braun-Blanquet Rank

2002

0

1

2

3

4

5

-8

01

25507597

100110120130140142150154160170180184190192200

Braun-Blanquet Rank

2003

0

1

2

3

4

5

-8

01

25507597

100110120130140142150154160170180184190192200

Braun-Blanquet Rank

2005

0

1

2

3

4

5

-8

01

25507597

100110120130140142150154160170180184190192200

Distance Along Transect (m)

Braun-Blanquet Rank
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 81 

CLW-07 Epibiont Density Graph 

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

1996 1998 2000 2002 2004 2006

Year

Epiphyte Density

Halodule

Thalasia

Syringodium

CLW-07 Canopy Height Graph 

CLW-07 Canopy Height

0

10

20

30

40

50

60

1996 1998 2000 2002 2004 2006

Year

Canopy Height (cm)

Halodule

CLW-07 Shoot Density Graph 

CLW-07 Shoot Density

0

500

1000

1500

2000

2500

3000

3500

4000

1996 1998 2000 2002 2004 2006

Year

Mean Density per m2

Halodule
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 82 

3.2.2.8 CLW-08

CLW-08 is located north of the Clearwater Memorial Bridge on the east shore of the Intercoastal 

Waterway. The transect extends west 225m from the shore towards the boat channel. The depth 

ranged from 45cm-150m. The sediment composition was mud from 0m-25m then sandy mud from 

25m-225m. The seagrass species composition was a mixture of Halodule and Thalassia with 

occasional Syringodium and sparse Halophila. The condition of the seagrass was good. 

The length of transect CLW-08 increased throughout the monitoring program. The data indicated 

that the edge of bed increased from 140m to 210m. The Thalassia extended from 50m-80m in 1998 

and to 50m-130m in 2005. In 2002, the field staff recorded Halophila at 170m-175m; however, it fell 

outside within the meter square quadrat and did not appear on the transect graphs. The epibiont 

density varied from light to moderate with assemblages consisting of attached algae and 

polycheates. The epibionts appeared less dense on the Syringodium and Halodule. The canopy 

height ranged from 5cm-30cm for the Halodule and 30cm-50cm for the Thalassia. The shoot 

density ranged from 50-1600 shoots (per m2

). In 2000-2003, the Thalassia shoot density rapidly 

increased from 200 shoots (per m2

) to 1400 shoots (per m2). 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 83 

CLW-08 Transect Graphs 

Halodule

Thalassia

Seagrass Species

Syringodium

Halophila

1998

0

1

2

3

4

5

-10

01

2540506070758090

100110120130140148150160170175180190200207210

Braun-Blanquet Rank

1999

0

1

2

3

4

5

-10

01

2540506070758090

100110120130140148150160170175180190200207210

Braun-Blanquet Rank

2000

0

1

2

3

4

5

-10

01

2540506070758090

100110120130140148150160170175180190200207210

Braun-Blanquet Rank

2001

0

1

2

3

4

5

-10

01

2540506070758090

100110120130140148150160170175180190200207210

Braun-Blanquet Rank

2002

0

1

2

3

4

5

-10

01

2540506070758090

100110120130140148150160170175180190200207210

Braun-Blanquet Rank

2003

0

1

2

3

4

5

-10

01

2540506070758090

100110120130140148150160170175180190200207210

Braun-Blanquet Rank

2005

0

1

2

3

4

5

-10

01

2540506070758090

100110120130140148150160170175180190200207210

Distance Along Transect (m)

Braun-Blanquet Rank
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 84 

CLW-08 Epibiont Density Graph 

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

1996 1998 2000 2002 2004 2006

Year

Epiphyte Density

Halodule

Thalasia

Syringodium

CLW-08 Canopy Height Graph 

CLW-08 Canopy Height

0

10

20

30

40

50

60

1996 1998 2000 2002 2004 2006

Year

Canopy Height (cm)

Halodule

Thalassia

CLW-08 Shoot Density Graph 

CLW-08 Shoot Density

0

200

400

600

800

1000

1200

1400

1600

1800

2000

1996 1998 2000 2002 2004 2006

Year

Mean Density per m2

Halodule

Thalassia
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 85 

3.2.2.9 CLW-09

CLW-09 is located north of the Clearwater Memorial Bridge off the third spoil island. The transect 

extends east 150m from the mangrove island towards the boat channel. The depth ranged from 

40cm-150cm. The sediment composition was sand and sandy mud. The prominent seagrass was 

Halodule with occasional Syringodium. The condition of the seagrass was fair-good. 

CLW-09 remained stable throughout the monitoring program. The data indicated that the edge of 

bed varies between 117m-141m. The epibiont density was moderate with assemblages consisting 

of attached algae, polycheates, and bryozoans. The canopy height ranged from 15cm-45cm. The 

canopy height of the Halodule increased from 1998-2003. The shoot density ranged from 100-2500 

shoots (per m2

). 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 86 

CLW-09 Transect Graphs 

Halodule

Thalassia

Seagrass Species

Syringodium

Halophila

1998

0

1

2

3

4

5

-2.5

01

102030405060708090

100110117120130131135140141

Braun-Blanquet Rank

1999

0

1

2

3

4

5

-2.5

01

102030405060708090

100110117120130131135140141

Braun-Blanquet Rank

2000

0

1

2

3

4

5

-2.5

01

102030405060708090

100110117120130131135140141

Braun-Blanquet Rank

2001

0

1

2

3

4

5

-2.5

01

102030405060708090

100110117120130131135140141

Braun-Blanquet Rank

2002

0

1

2

3

4

5

-2.5

01

102030405060708090

100110117120130131135140141

Braun-Blanquet Rank

2003

0

1

2

3

4

5

-2.5

01

102030405060708090

100110117120130131135140141

Braun-Blanquet Rank

2005

0

1

2

3

4

5

-2.5

01

102030405060708090

100110117120130131135140141

Distance Along Transect (m)

Braun-Blanquet Rank
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 87 

CLW-09 Epibiont Density Graph 

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

1996 1998 2000 2002 2004 2006

Year

Epiphyte Density

Halodule

Thalasia

Syringodium

CLW-09 Canopy Height Graph 

CLW-09 Canopy Height

0

10

20

30

40

50

60

1996 1998 2000 2002 2004 2006

Year

Canopy Height (cm)

Halodule

Syringodium

CLW-09 Shoot Density Graph 

CLW-09 Shoot Density

0

1000

2000

3000

4000

5000

6000

7000

1996 1998 2000 2002 2004 2006

Year

Mean Density per m2

Halodule

Syringodium
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 88 

3.2.2.10 CLW-10

CLW-10 is located north of the Memorial Causeway Bridge on the east side of the Intercoastal 

Waterway. The transect extends west 200m from the shore towards the boat channel. The depth 

ranged from 15cm-150cm. The sediment composition was sandy mud. The prominent seagrass 

was Halodule with increasing Syringodium throughout the monitoring program. The condition of the 

seagrass was good-very good. 

CLW-10 remained stable throughout the monitoring program with most variation occurring between 

110m-200m. The seagrass species composition varied with the appearance of Syringodium from 

75m-160m. The Halodule abundance decreased from 2000-2005. The data indicated that the edge 

of bed increased from 149m in 1998 to 172m in 2005. The epibiont density was light to moderate 

with assemblages consisting of attached algae, polycheates, bryozoans, and barnacles. The 

canopy height ranged from 20cm-40cm. The shoot density ranged from 250-1500 shoots (per m2

) 

with a gradual increasing trend throughout the monitoring program. 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 89 

CLW-10 Transect Graphs 

Halodule

Thalassia

Seagrass Species

Syringodium

Halophila

1998

0

1

2

3

4

5

015

25506070758090

100110120130140142149150157160165170172

Braun-Blanquet Rank

1999

0

1

2

3

4

5

015

25506070758090

100110120130140142149150157160165170172

Braun-Blanquet Rank

2000

0

1

2

3

4

5

015

25506070758090

100110120130140142149150157160165170172

Braun-Blanquet Rank

2001

0

1

2

3

4

5

015

25506070758090

100110120130140142149150157160165170

Braun-Blanquet Rank

2002

0

1

2

3

4

5

015

25506070758090

100110120130140142149150157160165170172

Braun-Blanquet Rank

2003

0

1

2

3

4

5

015

25506070758090

100110120130140142149150157160165170172

Braun-Blanquet Rank

2005

0

1

2

3

4

5

015

25506070758090

100110120130140142149150157160165170172

Distance Along Transect (m)

Braun-Blanquet Rank
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 90 

CLW-10 Epibiont Density Graph 

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

1996 1998 2000 2002 2004 2006

Year

Epiphyte Density

Halodule

Thalasia

Syringodium

CLW-10 Canopy Height Graph 

CLW-10 Canopy Height

0

10

20

30

40

50

60

1996 1998 2000 2002 2004 2006

Year

Canopy Height (cm)

Halodule

Syringodium

CLW-10 Shoot Density Graph 

CLW-10 Shoot Density

0

200

400

600

800

1000

1200

1400

1600

1800

2000

1996 1998 2000 2002 2004 2006

Year

Mean Density per m2

Halodule

Syringodium
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 91 

3.2.2.11 CLW-11

CLW-11 is located north of Clearwater Memorial Bridge on the east side of the Intercoastal 

Waterway. The transect extends west 300m from the shore towards the boat channel. The depth 

ranged from 20cm-150cm. The sediment composition was sandy mud. The prominent seagrass in 

1998-2000 was Halodule; however, by 2003 the prominent species was Syringodium. In 2002 and 

2003 staff also found Halophila. The condition of the seagrass was good. 

CLW-11 remained stable throughout the study; however, the species composition changed. The 

data indicated that the edge of bed increased from 220m-290m. The epibiont density varied from 

light to heavy with the heaviest density in 2005. The epibiont assemblages consisted of attached 

algae, polycheates, bryozoans, and barnacles. The canopy height ranged from 5cm-45cm with an 

increasing trend for Halodule from 1998-2003. The shoot density ranged from 100-1100 shoots 

(per m2

). 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 92 

CLW-11 Transect Graphs 

Halodule

Thalassia

Seagrass Species

Syringodium

Halophila

1998

0

1

2

3

4

5

01

255075

0005000000000000800050047

Braun-Blanquet Ran

10111212131415161718192021222324242526272728292929

k

1999

0

1

2

3

4

5

01

255075

100110120125130140150160170180190200210220230240248250260270275280290294297

Braun-Blanquet Rank

2000

0

1

2

3

4

5

01

255075

100110120125130140150160170180190200210220230240248250260270275280290294297

Braun-Blanquet Rank

2001

0

1

2

3

4

5

01

255075

100110120125130140150160170180190200210220230240248250260270275280290294297

Braun-Blanquet Rank

2002

0

1

2

3

4

5

01

255075

100110120125130140150160170180190200210220230240248250260270275280290294297

Braun-Blanquet Rank

2003

0

1

2

3

4

5

01

255075

100110120125130140150160170180190200210220230240248250260270275280290294297

Braun-Blanquet Rank

2005

0

1

2

3

4

5

01

255075

100110120125130140150160170180190200210220230240248250260270275280290294297

Distance Along Transect (m)

Braun-Blanquet Rank
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 93 

CLW-11 Epibiont Density Graph 

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3.50

4.00

4.50

1996 1998 2000 2002 2004 2006

Year

Epiphyte Density

Halodule

Thalasia

Syringodium

CLW-11 Canopy Height Graph 

CLW-11 Canopy Height

0

10

20

30

40

50

60

1996 1998 2000 2002 2004 2006

Year

Canopy Height (cm)

Halodule

Syringodium

CLW-11 Shoot Density Graph 

CLW-11 Shoot Density

0

200

400

600

800

1000

1200

1400

1600

1800

2000

1996 1998 2000 2002 2004 2006

Year

Mean Density per m2

Halodule

Syringodium
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 94 

3.2.2.12 CLW-12

CLW-12 is located north of the Clearwater Memorial Bridge near the fourth spoil island. The 

transect extends east 300m from the spoil island towards the boat channel. The depth ranged from 

30cm-160cm. The sediment composition was sandy mud. The prominent seagrass species were 

Halodule and Syringodium. The condition of the seagrass was fair-good. 

CLW-12 remained stable throughout the study; however, the species composition changed. The 

frequency of Syringodium increased in abundance along the transect. The data indicated that the 

edge of bed varied from 240m-296m. The epibiont density was light to heavy with increased 

density from 2001-2005. The epibiont assemblages consisted of attached algae, polycheates, 

bryozoans, and barnacles. The canopy height ranged from 10cm-45cm. The shoot density ranged 

from 50-1200 shoots (per m2

). In 2002 and 2003, the Syringodium shoot density was 5333 shoots 

(per m2

) and 3000 shoots (per m2) respectively. 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

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CLW-12 Transect Graphs 

Halodule

Thalassia

Seagrass Species

Syringodium

Halophila

1998

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CLW-12 Epibiont Density Graph 

0.00

0.50

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1.50

2.00

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1996 1998 2000 2002 2004 2006

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Halodule

Thalasia

Syringodium

CLW-12 Canopy Height Graph 

CLW-12 Canopy Height

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Halodule

Syringodium

CLW-12 Shoot Density Graph 

CLW-12 Shoot Density

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Halodule

Syringodium
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

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3.2.2.13 CLW-13

CLW-13 is located southwest of the Dunedin Causeway near the first spoil island. The transect 

extends southeast 450m from the spoil island towards the boat channel. The depth ranged 20cm140cm. The sediment composition was sandy mud. The prominent seagrass was Halodule and 

Syringodium with occasional Thalassia and Halophila. The condition of the seagrass was fair-good. 

CLW-13 remained stable throughout the monitoring program; however, the species composition 

changed. The data suggested that the frequency and abundance of Syringodium increased along 

the transect. The data indicated that the edge of bed varied from 270m-422m. The epibiont density 

varied from light to heavy with assemblages consisting of attached algae and polycheates. The 

canopy height ranged from 20cm-40cm. The shoot density ranged from 100-1500 shoots (per m2

) 

with the lowest density in 2005. 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

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CLW-13 Transect Graphs 

Halodule

Thalassia

Seagrass Species

Syringodium

Halophila

1998

0

1

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Braun-Blanquet Rank
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CLW-13 Epibiont Density Graph 

0.00

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1996 1998 2000 2002 2004 2006

Year

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Halodule

Thalasia

Syringodium

CLW-13 Canopy Height Graph 

CLW-13 Canopy Height

0

10

20

30

40

t (cm)

50

60

1997 1998 1999 2000 2001 2002 2003 2004 2005 2006

Year

Canopy Heigh

Halodule

Thalassia

Syringodium

 CLW-13 Shoot Density Graph 

CLW-13 Shoot Density

0

200

400

600

800

1000

1200

y per m1400

1600

1800

2000

1997 1998 1999 2000 2001 2002 2003 2004 2005 2006

Year

Mean Densit 2

Halodule

Thalassia

Syringodium
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 100 

3.2.2.14 CLW14

CLW-14 is located north of the Dunedin Causeway near the second spoil island. The transect 

extends north 200m from the spoil island towards the boat channel. The depth ranged from 30cm200cm. The sediment composition was sand and sandy mud. The prominent seagrass was 

Syringodium with some Halodule. The condition of the seagrass was good-very good in 1998-

2003. In 2005, the condition was poor-fair. 

CLW-14 remained stable throughout the monitoring program. The transect may have been 

realigned in 2000 accounting for the variation in the length of the seagrass bed. The data indicated 

that the edge of bed varied from 110m-198m. The epibiont density varied from light to heavy with 

assemblages consisting of attached algae and polycheates from 1998-2003. In 2005, the epibionts 

consisted of attached algae, bryozoans, holothuroidians, and tunicates. The shift in epibionts may 

have correlated with the condition of the seagrass. The canopy height ranged from 25cm-50cm with 

the lowest height recorded in 2002. The shoot density ranged from 75-1400 shoots (per m2

). 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

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CLW-14 Transect Graphs 

Halodule

Thalassia

Seagrass Species

Syringodium

Halophila

1998

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1

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CLW-14 Epibiont Density Graph 

0.00

0.50

1.00

1.50

2.00

2.50

3.00

3 0

4. 0

ity

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0

4.50

1996 1998 2000 2002 2004 2006

Year

Epiphyte Dens

Halodule

Thalasia

Syringodium

CLW-14 Canopy Height Graph 

CLW-14 Canopy Height

0

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20

30

40

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60

1997 1998 1999 2000 2001 2002 2003 2004 2005 2006

Year

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Halodule

Syringodium

 CLW-14 Shoot Density Graph 

CLW-14 Shoot Density

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Syringodium
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

 103 

3.3 Discussion: Fixed Transect Monitoring 

The fixed transect monitoring program focused on temporal variation of the seagrass abundance, 

species composition, and condition. Throughout the ten year monitoring program, the data showed 

very few trends that would indicate a change in the seagrass resource. Some of the variation in the 

data may be attributed to natural variability as well as sampling inconsistencies. 

Several factors contributed to the variation in the transect data. The logistics of monitoring fixed 

transects were challenging and resulted in sampling inconsistencies. The placement of the 

transects may have varied between years due to the inability to find the PVC marker stakes and 

bowing of the transect line from currents. In addition, variation may also be attributed to the 

observer. Different field crews conducted the study throughout the monitoring program. Even 

though all the staff attended a training session hosted by the City of Tampa, many of the data 

variables were subjective and/or qualitative in nature. The results were based solely on the data 

recorded within the meter square quadrat recorded incrementally along the transect. This allowed 

d conditions to occur in the vicinity of the transect without being 

reflected in the data. 

Weather patterns, storm events, and other natural and anthropogenic factors may affect the yearto-year results (Deitche and Meyer, 2003). A source of natural variability revolves around the 

placement of the transects near the boat channels. The migration of the boat channels results from 

the natural fluctuations in the tides and currents. This may cause changes to the edge of bed. 

Additionally, the exponential increase in boat traffic may be correlated with a higher frequency of 

propeller scar damage within the seagrass beds. Natural events also prompt variation in the 

seagrass resource. Four hurricane events in 2004 caused an increase in currents, tides, and 

turbidity in the area. These disturbances may be reflected in the lower seagrass abundances on 

some of the transects in 2004 and 2005. 

In summary, the seagrass transects monitored by Pinellas County provided time-series information 

for the transect locations. The data indicated that the seagrass along the transects appeared to be 

in good health and remained stable throughout the monitoring program. 

the possibility of other species an
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 3

 

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PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 4

 

 105 

4.0 Part II: Stratified Random Transect Monitoring 

.1 Methods: Stratified Random Transect Monitoring 

The site selection for this program was based on a probabilistic stratified random sampling design. 

The area was divided into three strata Clearwater Harbor North (CLWN), Clearwater Harbor South 

(CLWS), and St. Joseph Sound (STJS) (Figure 9). The 2004 seagrass map from the aerial 

photointerpretation project was used as a bounda n of sites in the areas 

classified as contiuous or patchy grassbeds. Fifteen percent of the sampling sites were allocated to 

the areas classified as “no grass”. The sites were stratified into depth zones (0-0.5m, 0.51-1.2m, 

 Within each strata and each zone, seven transects were sampled. Fourteen of the 

ansects aligned with the previous fixed transect monitoring sites. In 2006, Pinellas County 

monitored 21 sites in each strata. In 2007, the sampling design was modified to reallocate the 

sampling sites on a seagrass acreage basis. Pinellas County allocated approximately one transect 

per 250 acres of seagrass. The 1:250 ratio resulted in 40 sites in STJS, 17 sites in CLWN, and 10 

sites in CLWS. 

 Figure 9. Map of seagrass strata. 

Transect starting points were located using spatial coordinates from a Trimble® GPS unit. In most 

cases, the transects were oriented north to south, parallel to the shoreline, and perpendicular to the 

depth gradient. After deploying the 30 meter transect and dive flags, staff swam along the transect 

line with a half meter square frame. Starting at the zero meter mark, the seagrass condition was 

recorded at five meter intervals. Seagrass abundance was assessed by estimating the percent of 

coverage within the quadrat evaluating each species independently. At 0, 15, and 30 meter marks 

three shoot density counts and five blade length measurements were also collected for each 

seagrass species present. The density counts were made using the subdivisions of the half meter 

square frame which measure 10cmx10cm. 

4

ry for the stratificatio

and 1.2-2.0m).

tr
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 4

 

 106 

ass appearance, and algae 

erical rating scale: 1= clean, 2= light 

 transmissivity, turbidity, 

AR) 

n of 

Other data collected included: water depth, sediment composition, seagr

occurrence. Epibiont coverage was assessed using a num

coverage, 3= moderate, 4= heavy. Water quality parameters included

Hydrolab®, and LICOR®. Transmissivity samples were collected using a 100ml Nalgene bottle. 

Transmissivity was measured at 660nm to determine relative water clarity. The Hydrolab® 

provided measurements of: depth, pH, temperature, salinity, conductivity, and dissolved oxygen. 

LICOR® readings were used to calculate water column photosynthetically active radiation (P

values for the transects. 

The data analysis included the use of ESRI ArcMap and SAS software. The statistical analyses for

the seagrass abundance and density applied the univariate and general linear model procedures. 

The comparisons included significant differences between strata, depth zone, and the interactio

strata*depth zone. The depth zones for each transect were determined by applying a tide correction 

to the recorded depth. Depth zones A, B, and C represented 0-0.6m, 0.6-1.2m, and >1.2m, 

respectively. The mean submerged aquatic vegetation coverage was calculated by transect from 

the recorded observations. 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 4

 

 107 

e 

ue to 

ence between depth zones (p= 0.0001, alpha= 0.05). The mean 

bundance in depth zone A (77%) was significant different than zone C (37%) (p=0.0007, 

alpha=0.05). 

Halodule was geographically distributed across the study area (Figure 10). Halodule occurred at the 

highest mean abundance in CLWN and the least JS. The highest mean 

abundances were found in depth zones A and B. There was a significant difference in mean 

abundance of Halodule between strata (p=0.0001, alpha = 0.05). The mean abundance in STJS 

(13%) was significantly different than CLWN (42% (p=0.0004, alpha = 0.05). 

Thalassia was geographically distributed throughout the study area (Figure 10). The highest mean 

abundance occurred in STJS and CLWS. There was a significant difference in mean abundance 

between depth zones (p=0.0001, alpha=0.05). The mean abundance in depth zone A (35%) was 

significantly different from zone B (14%)(p=0.0006, alpha= 0.05) and zone C (6%)(p= 0.019, 

alpha=0.05). 

Syringodium was observed in the northern portions of the study area (Figure 10). Syringodium

occurred at the highest mean abundance in STJS and depth zones B and C. There was a 

significant difference in mean abundance between strata (p= 0.0001, alpha = 0.05) and depth 

zones (p= 0.0117, alpha = 0.05). The mean abundance in STJS (29%) was significantly different 

than CLWN (7%)(p=0.0007, alpha =0.05) and CLWS (2%)(p=0.0003, alpha=0.05). The mean 

abundance in depth zone A (7%) was significantly different than zone B (19%) (p=0.0204, 

alpha=0.05). 

 

4.2 Part II- Results: Stratified Random Transect Monitoring 

The sampling design allowed for the comparison between strata and depth zones for several 

parameters; however, the qualitative parameters were only presented with descriptive statistics du

to the subjectivity of the data. The 2006 and 2007 were combined for most of the analyses d

the lack of a significant difference detected between the years. 

4.2.1 Mean Abundance 

The Submerged Aquatic Vegetation (SAV) covered most of the study area (Figure 10). SAV 

occurred at the highest mean abundance in STJS and the least mean abundance in CLWS. The 

highest mean abundances of SAV were found in STJS zone A and the least in CLWS zone C. 

There was a significant differ

a ly

mean abundance in ST

) 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 4

 

 108 

 Figure 10. Spatial representation of the SAV species mean abundance per transect. 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 4

 

 109 

Several marine algae species occurred in the stud area (Figure 11). The marine algae consisted 

of drift algae, rhizophytic algae, and Caluerpa prolifera. The drift algae were recorded throughout 

the study area (Figure 11). The highest mean abundance of drift algae occurred in STJS and 

nearshore in CLWS. The rhizophytic algae constituents (Figure 5) were most abundant in STJS in 

depth zones A and B (Figure 11). Caluerpa prolifera was analyzed separate from the rhizophytic 

algae due to local concerns regarding this species. C. prolifera was most abundant in STJS in 

depth zone A (Figure 11). In addition to the marine algae, staff recorded the presence of bay 

scallops (Argopecten irradians) along the transects (Figure 11). The scallops were most abundant 

in STJS and CLWN and commonly noted in areas with rhizophytic algae. 

y

 Figure 11. Mean abundance of marine algae and the presence of scallops per transect. 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 4

 

 110 

ry 

rred 

ot significantly 

different between years. 

4.2.2 Shoot Density 

The shoot density varied between the seagrass species. The seagrass shoot density did not va

greatly between the 2006 and 2007 sampling events. Halodule had the highest shoot density and 

the greatest variability (Figure 12). The combined mean was 1318 shoots per m2

 (SD= 1124). The

highest shoot density was in CLWS zone A. Thalassia had the lowest combined mean shoot 

density and smallest variability, 555 shoots per m2

 (SD= 365). The highest shoot density occu

in STJS and CLWN in depth zone A. Syringodium had the highest shoot density in strata STJS and

in depth zones A and B. Overall, the shoot densities for each species were n

0

200

400

600

800

1000

1200

1400

1600

1800

2000

2200

2400

2600

Halodule Thalassia Syringodium

Seagrass Species

Shoot Density per m2

2006&2007

2006

2007

Figure 12. Mean shoot density (shoots per m2) by species and year. 

4.2.3 Blade Length 

The mean blade lengths varied by species and by year. The blade lengths tended to be longer in 

2006 than 2007 for all the species (Figure 13). Due to the distribution of the data, the general linear 

model was not calculated for the mean blade length. 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 4

 

 111 

0

5

10

15

20

25

30

35

40

45

ade Length (cm)

50

Halodule Thalassia Syringodium

Seagrass Species

Mean Bl

2006&2007

2006

2007

 Figure 13. Mean blade length for seagrass species. 

4.2.4 Health and Epibionts 

The qualitative assessments of the health and epibiont fouling on the seagrass assisted in the 

determination of the seagrass resource condition. However, there was no previous research to 

support a correlation between seagrass health and epibiont density. Due to the subjective nature of 

these qualitative parameters, only the descriptive statistics are presented. 

The health of the seagrass ranged from very poor to very good. The majority of the resource was 

classified as fair to good throughout the study area (Figure 14). There were a few occurrences of 

poor health. 

The epibiont fouling also contributed to the condit n of the seagrass. The epibiont fouling ranged 

Figure 14) with the majority of the observations from light to moderate. The 

d between seagrass species. Epibiont fouling on Halodule was greatest in 

t fouling on Syringodium varied by strata 

nd depth zone. The epibiont density was greatest in STJS and in depth zone B. Epibiont 

ssemblages consisted of attached algae, barnacles, polycheates, bryozoans, holothuroidians, and 

ydroids. In 2006, staff recorded eggs deposited on the Syringodium and Thalassia blades in strata 

STJS. 

io

from clean to heavy (

epibiont fouling varie

CLWN and zones A and B, and least in STJS and zone C. Epibiont fouling on Thalassia showed 

the most variation between depth zones. The epibiont density on Thalassia was highest in depth 

zone A and CLWS and lowest in STJS zone C. Epibion

a

a

h
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 4

 

 112 

Figure 14. Spatial representation of SAV health, epibiont density, sediment type, and depth for 

seagrass transects. 

the 

he sediment type and depth of the transect may be correlated to the habitat suitability for SAV. 

a, 

a 

4.2.5 Sediment Type and Depth 

T

The sediment type recorded for the transects varied throughout the study area (Figure 14). The 

sediment type of mud commonly occurred in shallow nearshore areas. The majority of STJS 

sediment consisted of sand and shelly sand. Due to the lack of bathymetry data in the study are

the water depth was collected with each transect (Figure 14). The tidal fluctuation in the study are

varied by +/- 1.0 meter during the sampling event. The increased depths required staff to utilize 

SCUBA for data collection. 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 4

 

 113 

.2.6 Water Quality 

ater quality data was collected at each seagrass transect during monitoring (Figure 15). The 

mean dissolved oxygen was highest in STJS (6.41 mg/L) and CLWS (6.44 mg/L). The mean salinity 

was surprisingly lowest in STJS (32.55 ppt). The mean pH was highest in STJS (8.31) and lowest 

in CLWS (8.04). The mean transmissivity, measured at 660nm, was highest in STJS (93.17 %) and 

lowest in CLWS (72.85 %). Overall, the water quality collected on the day of seagrass monitoring 

only provided a brief snapshot and should not be used solely to correlate with seagrass condition. 

4

W

 Figure 15. Mean water quality data collected during seagrass monitoring. 

0

1

2

3

4

5

6

7

8

9

STJS CLWN CLWS

Mean Dissolved Oxygen (mg/L)

0

5

10

15

20

25

30

35

40

STJS CLWN CLWS

Mean Salinity (ppt)

7.4

STJS CLWN CLWS

7.6

7.8

8.2

8.4

8.6

M

8

ean pH

0

STJS CLWN CLWS

10

20

30

40

50

70

80

90

100

Mean Transmissiv @ 660nm)

60

ity (%
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 4

 

 114 

ssion: Stratified Random Transect Monitoring 

S 

fluence of weather patterns, storm events, and other factors that may have affected year-to-year 

results from the transect monitoring. Another factor may be natural events that affected long-term 

water quality but were not reflected in data taken on the day of sampling (Deitche and Meyer, 

2003). The density by year variation may be related to the expansion of the sampling design to 

include deeper areas that may consist of more “patchy” beds. 

The sampling design for this seagrass study diverged from the traditional methods. The goal of the 

design was to increase the geographic extent and statistical defensibility of the seagrass monitoring 

program. 

The increased geographic extent of the program provided an opportunity to characterize a greater 

portion of the resource. Prior to this study, the abundance and extent of the rhizophytic algae in 

STJS and CLWN was unknown. Additionally, the extent of the edge of bed in STJS toward the Gulf 

of Mexico was assumed to be limited to the two meter contour similar to the Tampa Bay ecosystem. 

Findings from this study indicated that the seagrass resource extends in to water depth of 3m-4m. 

This extent has not been represented in the previous monitoring or remote sensing studies for the 

area. Interesting spatial trends arose during the analyses including an apparent ecotone for the 

distribution of Syringodium which rarely occurred in CLWS and increased in frequency heading 

north through the study area into CLWN and STJS. Further examination of the spatial correlation 

between the physical and biological parameters may provide explanation for variation of the 

resource. 

Using a stratified random sampling design allowed for the calculation of statistics to compare the 

seagrass by variables such as year, strata, depth zone, and species. Although the power of the 

design to detect change in the resource has not yet been assessed, the initial information from the 

study has far surpassed the data provided from the previous fixed transect monitoring program for 

the study area. In addition to the random sites, 14 sites remain stationary and coincide with the 

previous fixed transect to maintain backwards compatibility with the existing dataset. This data will 

be analyzed in a subsequent report. 

There is also potential to combine the field survey data from this study with ancillary data from 

water quality and remote sensing studies to provide a more comprehensive evaluation of the 

resource. The results of this study were combined with the results of the 2006 aerial 

 to the limitation of the 

aerial photography to penetrate the water column, seagrass beds growing at depths greater than 

2m may not be visible for mapping. Current studies investigating the mapping of seagrass from 

remote sensing multispectral satellite imagery may provide increased depth penetration to further 

assess the extent of the seagrass resource (Meyer, 2008). 

4.3 Part II- Discu

Overall, the data from this study indicated that the seagrass resource in CLWN, CLWS, and STJ

were stable and in relatively good condition. The abundance and density of seagrass showed little 

variation. The seagrass species spatial distribution indicated a possible ecotone through the study 

area consisting of variation by strata and depth zone. 

Variability in the data may be contributed to a number of issues. Natural variation may include the 

in

photointerpretation mapping study conducted by SWFWMD (Figure 16). Due
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 4

 

 115 

time of seagrass monitoring is not adequate to assess the 

patial and temporal trends of water quality or the response of the seagrass condition. The 

n to 

diment type 

 ground-truthing of maps delineated 

om remote sensing data. 

 Figure 16. Combination of field survey data and 

 SAV map from the aerial photointerpretation 

 study (Kaufman, 2007). 

The water quality data collected at the 

s

integration of ancillary data from the Pinellas County Ambient Water Quality Monitoring Program

(WQMP) enhances the knowledge of the water quality in the study area (Figure 19). In additio

water quality parameters, staff collected environmental habitat information such as se

and seagrass presence/absence for each sampling site (Levy et al, 2008). The data from the 

WQMP also provided additional spatial seagrass data (Figure 17). During the two years of the 

stratified random seagrass monitoring program, 124-30m transects and 216 WQMP sites were 

evaluated. This greatly exceeds the data collected from the previous 14 transect locations. This 

provides a robust independent dataset for the validation and

fr
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 4

 

 116 

Figure 17. The presence/absence of seagrass was collected by the WQMP in 2006 and 2007 (left). 

The WQMP data was combined with the seagrass monitoring data (right). 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 5

 

 117 

.0 Conclusion and Summary 

 summary, the seagrass monitoring activities conducted by Pinellas County Water Resources 

anagement Section suggest that the seagrass resource in Boca Ciega Bay and Clearwater 

arbor/St. Joseph Sound is currently in good health and shows no trends indicating degradation. 

he species found during monitoring included Halodule wrightii, Thalassia testudinum, Syringodium 

liforme, and Halophila engelmanni. Although the seagrass resource is currently stable, many 

atural and anthropogenic factors may threaten the persistence of the resource. Natural concerns 

include weather events such as hurricanes, sea level rise, and climate change. Anthropogenic 

factors include damage from increased boat traffic and propeller scarring, dredging activities, and 

degradation of water quality from stormwater runoff. Throughout the monitoring program, boat prop 

scars have been recorded frequently along the transects and seem to be increasing in frequency. 

During the imagery acquisition in 2007, two boats caused an 800 m propeller scar in the seagrass 

bed adjacent to BCB-01 (Figure 18). Education and enforcement is required to reduce the damage 

to the seagrass resource. 

5

In

M

H

T

fi

n

 Figure 18. Creation of a boat propeller scar through the seagrass 

 monitoring transect. 
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 5

 

 118 

 transect sampling designs provided valuable 

a cluding information on the species composition, 

ng 

pproach may have provided a good balance between the timee scale, geographic extent, and statistical defensibility and power for the evaluation of the 

seagrass resource. 

Future studies to better assess the seagrass resource in Pinellas County will include examining the 

correlation between seagrass and water quality, and interpretation of remote sensing data. The 

County conducts a water quality monitoring program which provides spatial and temporal water 

quality information for the study area (Levy et al, 2008). The design focuses on the ability to detect 

trends in the water quality parameters and allows for spatial interpolation analyses. Parameters 

such as dissolved oxygen, chlorophyll-a concentration, and transmissivity are thought to be 

correlated with the condition and response trends of seagrass resources. The spatial analysis of 

these parameters reveals seasonal trends which may contribute to the seagrass trends. While 

chlorophyll-a concentrations are generally low during the dry season, the concentrations increase 

during the wet season in the southern portion of the study area (Figure 19). The spatial and 

temporal assessment of the water quality may allow the development of a model relating seagrass 

and water quality (Meyer 2008). Fourqurean (2003) used water quality data to develop a response 

model to predict the change in seagrass distribution. This would be a valuable tool to manage the 

seagrass resource. Another tool to assess the seagrass resource applies the interpretation of 

remote sensing satellite imagery to produce coarse scale maps of the resource (Meyer, 2008). 

Detailed habitat maps aid in the assessment and monitoring of changes within the seagrass 

meadows. The ability to integrate field monitoring data with remote sensing methods may be a 

cost-effective method to develop a comprehensive spatial change assessment of the seagrass 

resource. 

Both the fixed transect and stratified random

inform tion concerning the seagrass resource in

health, and condition of the seagrass. However, the most notable difference between the sampli

programs was in the geographic extent and scale of the information. While the fixed transect 

program provided time-series fine scale data, the data proved difficult to examine with statistically 

viable trend analyses. The nature of the fixed transect design severely limited the ability to 

extrapolate the data and conclusions to the rest of the seagrass resource. Additionally, the number 

of fixed transects to monitor the geographic extent of the resource would be cost prohibitive to most

resource management agencies. The stable nature of the Pinellas County seagrass resource in 

STJS, CLWN, and CLWS allowed for the development of a new sampling design. The stratified 

random transect sampling design improved the geographic extent of the monitoring program and 

increases the ability to calculate viable statistical trend analyses. The design maintained the fine 

scale data collection for species composition, biomass, and density estimates; however, it lost the 

specific time-series data. This design encouraged the use of data from complementary monitoring 

programs, such as the WQMP, to further analyze the correlation between physical and biological 

variables. Ideally a hybrid design a

series, fin
PCDEM/WRMS Seagrass Resource Assessment & Monitoring Report Section 5

 

 119 

 

Figure 19. Seasonal Spatial Interpolation 

of the water quality data available in the 

study area for 2004-2006 for the wet 

season (May-September) and the dry 

season (October-April) reproduced from 

Levy et al (2008). The Chlorophyll-a data 

(top left) suggests an increase in 

concentration during the wet season in 

the southern portion of the study area. 

The Dissolved Oxygen data (top right) 

suggests that the concentration is higher 

during the dry season. The transmissivity 

data (bottom left) only shows slight 

variation in the study area between the 

wet and dry seasons. 
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 www.marlin.ac.uk www.sms.si.edu

 www.augsburg.edu ux.brookdalecc.edu