U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2006-5287

Gulf of Mexico Program

Seagrass Status and Trends in the Northern 

Gulf of Mexico: 1940–2002

U.S. Environmental Protection Agency 855-R-04-003
Cover:  Background, seagrass through surface of water (Tommy Michot, U.S. Geological

Survey). Left, seagrass sampling (Tommy Michot, U.S. Geological Survey). Center, oblique

aerial photograph of seagrass (Tommy Michot, U.S. Geological Survey). Right, manatees in

seagrass habitat (Sirenia Project, U.S. Geological Survey).
Seagrass Status and Trends in the Northern 

Gulf of Mexico: 1940–2002

Edited by L. Handley, D. Altsman, and R. DeMay

U.S. Environmental Protection Agency 855-R-04-003

Scientific Investigations Report 2006–5287

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

DIRK KEMPTHORNE, Secretary

U.S. Geological Survey

Mark D. Myers, Director 

U.S. Geological Survey, Reston, Virginia: 2007

For product and ordering information:

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U.S. Government.

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

reproduce any copyrighted materials contained within this report.

Suggested citation:

Handley, L., Altsman, D., and DeMay, R., eds., 2007, Seagrass Status and Trends in the Northern Gulf of Mexico: 

1940-2002: U.S. Geological Survey Scientific Investigations Report 2006-5287 and U.S. Environmental Protection 

Agency 855-R-04-003, 267 p.
iii

Preface

The Gulf of Mexico Program (GMP) is a network of citizens dedicated to promoting the economic 

health of the region by managing and protecting the gulf’s resources. Although administered by 

the U.S. Environmental Protection Agency (EPA), the GMP engages many organizations across 

the Gulf of Mexico coastal region to implement and lead restoration and conservation projects 

that are environmentally and economically sound. The GMP includes representatives from State 

and Federal agencies, nonprofit organizations, the scientific community, business and industry, 

and an organized citizens group. These members are appointed by the five State governors along 

the gulf coast. The GMP focuses on three ecological issues: (1) public health, (2) excess nutrient 

enrichment, and (3) habitat degradation and loss, including the introduction of nonindigenous 

species.

The GMP has long recognized that seagrasses, estuaries, and coastal wetlands are vital in 

providing food and shelter for plants and animals, improving water quality, sediment filtration, 

and flood and erosion control. In 1999, the GMP’s Habitat Focus Team set a goal to restore, 

enhance, or protect 20,000 acres of important coastal habitats of the gulf by 2009. The Habitat 

Team, recognizing that seagrass beds are some of the most productive habitats in nearshore 

waters, set a goal to produce this summary report on gulfwide seagrass status and trends. 

The purpose of the summary report is to provide current baseline information on the status of 

seagrasses in the Gulf of Mexico.

To produce this report, the GMP’s Habitat Team formed a subcommittee, consisting of over 30 

gulf coast seagrass scientists and environmental managers. Committee members provided 

data on seagrass maps, seagrass status and trends, causes of change in seagrass acreage, 

monitoring activities, and restoration efforts important to seagrass areas along the gulf coast. 

The U.S. Geological Survey’s (USGS) National Wetlands Research Center provided extensive 

support in the production of data, maps, writing, and editing for this summary. 

Lastly, Seagrass Habitat in the Northern Gulf of Mexico: Degradation, Conservation, and 

Restoration of a Valuable Resource, written in lay terms and developed for the general public, 

legislators, and Gulf of Mexico stakeholders, is meant to be a companion to this summary 

report. For example, nomenclature of seagrasses in the summary report follows this outreach 

document. Additional information will be available on the USGS National Wetlands Research 

Center’s Web site at http://www.nwrc.usgs.gov and the GMP Web site at 

http://www.epa.gov/gmpo/.
iv

Acknowledgments

The U.S. Geological Survey, National Wetlands Research Center, and the U.S. Environmental 

Protection Agency, Gulf of Mexico Program partnership would like to thank the following scientists and environmental managers for reviewing the Gulf of Mexico seagrass status and trends. 

Your dedication, time, and expertise are greatly appreciated.

Ron Boustany, U.S. Department of Agriculture, Natural Resources Conservation Service

Dr. Ken Dunton, University of Texas

Dr. Steve Jordan, U.S. Environmental Protection Agency

Dr. Michael Lewis, U.S. Environmental Protection Agency

Randy Roach, U.S. Fish and Wildlife Service

Frank Sargent, Florida Department of Environmental Protection, Southwest Florida

Water Management District

Dr. Judy Stout, University of South Alabama

Dr. Sandy Wyllie-Echeverria, University of Washington

Dr. Judy Stout, University of South Alabama

Captain David Yeager, Mobile Bay National Estuary Program

Personnel from the USGS National Wetlands Research Center who played a key role in the 

production of this document included

Pete Bourgeois, cartography

Helena Schaefer, peer review coordination

Blaire Hutchison, data compilation
v

Contents

Preface ..........................................................................................................................................................iii

Acknowledgments .......................................................................................................................................iv

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

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

References Cited ...........................................................................................................................................6

Statewide Summary for Texas

Background ....................................................................................................................................................7

Statewide Status and Trends Data .............................................................................................................9

Galveston Bay System .........................................................................................................................9

Texas Coastal Bend Region ................................................................................................................9

Laguna Madre System ......................................................................................................................11

Causes of Change .......................................................................................................................................11

Natural Process Changes .................................................................................................................11

Human-induced Changes .................................................................................................................11

Gaps in Data Coverage ..............................................................................................................................12

Bay Systems Lacking Inventories ............................................................................................................12

Data Limitations and Future Needs .................................................................................................12

Overview of Seagrass Restoration Efforts ..............................................................................................13

Seagrass Conservation Plan and Resource Management Needs ............................................13

Overview of Monitoring, Restoration, and Enhancement Opportunities ...........................................13

Monitoring for Seagrass Ecosystem Health ..................................................................................13

References Cited .........................................................................................................................................14

Galveston Bay System

Background ..................................................................................................................................................17

Scope of Area ..............................................................................................................................................17

Methodology Employed To Determine and Document Current Status ..............................................17

Methodology Employed To Analyze Historical Trends ..........................................................................19

Status and Trends ........................................................................................................................................19

Upper Galveston Bay and Trinity Bay..............................................................................................19

West Galveston Bay ...........................................................................................................................21

Christmas Bay .....................................................................................................................................21

Causes of Change........................................................................................................................................21

Upper Galveston-Trinity Bays ...........................................................................................................21

West Galveston Bay ...........................................................................................................................23

Christmas Bay System .......................................................................................................................24

Species Information ....................................................................................................................................24

Monitoring for Seagrass Health ...............................................................................................................24
vi

Mapping and Monitoring Needs ..............................................................................................................25

Restoration and Enhancement Opportunities ........................................................................................25

References Cited .........................................................................................................................................26

Laguna Madre

Background ..................................................................................................................................................29

Scope of Area ..............................................................................................................................................29

Methodology Employed To Determine and Document Current Status ..............................................29

Methodology Employed To Analyze Historical Trends ..........................................................................31

Status and Trends ........................................................................................................................................31

Lower Laguna Madre ........................................................................................................................31

Upper Laguna Madre ........................................................................................................................33

Laguna Madre as a Whole ...............................................................................................................36

Causes of Change........................................................................................................................................36

Lower Laguna Madre ........................................................................................................................36

Upper Laguna Madre ........................................................................................................................37

Monitoring for Seagrass Health................................................................................................................38

Mapping and Monitoring Needs ...............................................................................................................38

Restoration and Enhancement Opportunities.........................................................................................39

Acknowledgments.......................................................................................................................................39

References Cited .........................................................................................................................................40

Texas Coastal Bend

Background ..................................................................................................................................................41

Scope of Area ..............................................................................................................................................41

Redfish Bay..........................................................................................................................................41

Harbor Island.......................................................................................................................................43

Mustang Island ...................................................................................................................................43

Nueces Bay .........................................................................................................................................43

Methodology Employed To Determine and Document Current Status ..............................................43

Classification Scheme .......................................................................................................................43

Methodology Employed To Analyze Historical Trends ..........................................................................45

Status and Trends ........................................................................................................................................46

System Summary ................................................................................................................................46

Status Summary..................................................................................................................................46

Trends Summary .................................................................................................................................46

Causes of Change .......................................................................................................................................52

Redfish Bay .........................................................................................................................................52

Harbor Island ......................................................................................................................................54

Mustang Island ...................................................................................................................................54

Nueces Bay .........................................................................................................................................54

Species Information ....................................................................................................................................55

Monitoring for Seagrass Health ...............................................................................................................55

Mapping and Monitoring Needs ...............................................................................................................56

Restoration and Enhancement Opportunities ........................................................................................56
vii

Propeller Scar Restoration ...............................................................................................................56

Designation of State Scientific Areas .............................................................................................56

Signage and Boater Education Activities.......................................................................................57

Seagrass Restoration Through Beneficial Use Projects ............................................................57

Coastal Bend Bays and Estuaries Program Outreach Strategies ..............................................57

References Cited .........................................................................................................................................58

Statewide Summary for Louisiana

Background ..................................................................................................................................................60

Statewide Status and Trends ....................................................................................................................60

Reference Cited ...........................................................................................................................................60

Chandeleur Islands

Background ..................................................................................................................................................62

Scope of Area ..............................................................................................................................................62

Methodology Employed To Determine and Document Current Status ...............................................62

Methodology Employed To Analyze Historical Trends ..........................................................................64

Status and Trends ........................................................................................................................................64

Causes of Change........................................................................................................................................64

Species Information ....................................................................................................................................66

Monitoring for Seagrass Health................................................................................................................66

Mapping and Monitoring Needs ...............................................................................................................66

Restoration and Enhancement Opportunities.........................................................................................71

References Cited .........................................................................................................................................71

Statewide Summary for Mississippi

Background ..................................................................................................................................................72

Statewide Status and Trends ....................................................................................................................72

Causes of Change Statewide ....................................................................................................................72

Gaps in Data Coverage ...............................................................................................................................74

Overview of Seagrass Restoration Efforts ..............................................................................................74

Overview of Monitoring, Restoration, and Enhancement Opportunities ...........................................74

References Cited .........................................................................................................................................74

Mississippi Sound and the Gulf Islands

Background ..................................................................................................................................................76

Scope of Area ..............................................................................................................................................78

Methodology Employed To Determine and Document Current Status ...............................................78

Methodology Employed To Analyze Historical Trends ..........................................................................80

Status and Trends ........................................................................................................................................80

Causes of Change........................................................................................................................................80

Seagrass Health...........................................................................................................................................83

Species Information ....................................................................................................................................84

Monitoring, Restoration, and Enhancement Opportunities ..................................................................84

References Cited .........................................................................................................................................84
viii

Statewide Summary for Alabama

Background ..................................................................................................................................................86

Natural Environment ..........................................................................................................................86

Context of Human Influences ...........................................................................................................88

Scope of Area...............................................................................................................................................90

Historical Documentation ..........................................................................................................................90

Statewide Status and Trends.....................................................................................................................90

Historical Surveys ..............................................................................................................................90

Methodology Employed To Determine and Document Current Status .....................................91

Current Status and Changes ............................................................................................................91

Causes of Change........................................................................................................................................93

Seagrass Health ..........................................................................................................................................93

Species Information ....................................................................................................................................93

Monitoring, Restoration, and Enhancement Opportunities ..................................................................94

References Cited .........................................................................................................................................94

Statewide Summary for Florida

Background ..................................................................................................................................................98

Species Information ....................................................................................................................................98

Scope of Area ............................................................................................................................................100

Methods Used To Determine Current Status of Seagrasses in the State of Florida ......................100

Status and Trends .....................................................................................................................................100

Causes of Change .....................................................................................................................................105

Mapping and Monitoring Problems and Information Needs .............................................................107

Data Problems ..................................................................................................................................107

Monitoring Needs.............................................................................................................................109

Assessment, Protection, Recovery, and Restoration Opportunities ................................................109

Acknowledgments ....................................................................................................................................111

References .................................................................................................................................................111

Perdido Bay

Background ................................................................................................................................................114

Scope of Area ............................................................................................................................................116

Upper Perdido Bay ...........................................................................................................................116

Middle Perdido Bay..........................................................................................................................116

Lower Perdido Bay ...........................................................................................................................116

Methodology Employed To Document Current Status ........................................................................116

Methodology Employed To Analyze Historical Trends ........................................................................118

Status and Trends ......................................................................................................................................118

Upper Perdido Bay ...........................................................................................................................118

Middle Perdido Bay .........................................................................................................................118

Lower Perdido Bay ...........................................................................................................................118

Entire Study Area..............................................................................................................................118

Causes of Change......................................................................................................................................124

Upper/Middle Perdido Bay .............................................................................................................124
ix

Lower Perdido Bay ...........................................................................................................................124

Species Information ..................................................................................................................................124

Monitoring for Seagrass Health .............................................................................................................125

Mapping and Monitoring Needs .............................................................................................................125

Restoration and Enhancement Opportunities ......................................................................................125

References .................................................................................................................................................126

Oral and Written Communication ...........................................................................................................126

Pensacola Bay

Background ................................................................................................................................................128

Scope of Area ............................................................................................................................................128

Escambia Bay....................................................................................................................................130

East Bay..............................................................................................................................................130

Pensacola Bay ..................................................................................................................................130

Big Lagoon ........................................................................................................................................130

Santa Rosa Sound ............................................................................................................................130

Methodology Employed To Determine and Document Current Status .............................................130

Methodology for Historical Trend Mapping ..........................................................................................132

Status and Trends ......................................................................................................................................132

Escambia Bay....................................................................................................................................132

East Bay..............................................................................................................................................134

Pensacola Bay ..................................................................................................................................134

Big Lagoon and Santa Rosa Sound ...............................................................................................134

Causes of Change......................................................................................................................................134

Species Information ..................................................................................................................................136

Monitoring for Seagrass Health .............................................................................................................136

Epiphytic Coverage ..........................................................................................................................138

Water-quality Monitoring ................................................................................................................138

Light-attenuation Monitoring..........................................................................................................138

Mapping and Monitoring Needs .............................................................................................................138

Restoration and Enhancement Opportunities ......................................................................................140

References Cited .......................................................................................................................................140

Choctawhatchee Bay

Background ................................................................................................................................................142

Scope of Area ............................................................................................................................................144

Western Choctawhatchee Bay ......................................................................................................144

Middle Choctawhatchee Bay .........................................................................................................146

Eastern Choctawhatchee Bay........................................................................................................146

Methodology Employed To Determine and Document Current Status .............................................146

Methodology Employed To Analyze Historical Trends ........................................................................146

Status and Trends ......................................................................................................................................147

Western Choctawhatchee Bay ......................................................................................................147

Middle Choctawhatchee Bay .........................................................................................................148

Eastern Choctawhatchee Bay........................................................................................................148
x

Causes of Change......................................................................................................................................148

Western Choctawhatchee Bay ......................................................................................................148

Middle Choctawhatchee Bay .........................................................................................................150

Eastern Choctawhatchee Bay........................................................................................................150

Species Information ..................................................................................................................................150

Western Choctawhatchee Bay ......................................................................................................150

Middle and Eastern Choctawhatchee Bay ..................................................................................150

Monitoring for Seagrass Health .............................................................................................................151

Mapping and Monitoring Needs ............................................................................................................151

Restoration and Enhancement Opportunities ......................................................................................151

References Cited .......................................................................................................................................152

St. Andrew Bay

Background ................................................................................................................................................154

Scope of Area ............................................................................................................................................154

St. Andrew Bay Segment ...............................................................................................................156

West Bay Segment ..........................................................................................................................156

North Bay Segment .........................................................................................................................156

East Bay Segment ............................................................................................................................156

St. Andrew Sound Segment ...........................................................................................................156

Methodology Employed To Determine and Document Current Status ............................................156

Methodology Employed To Analyze Historical Trends ........................................................................158

Status and Trends ......................................................................................................................................158

Entire Study Area .............................................................................................................................158

St. Andrew Bay Segment ...............................................................................................................158

East Bay Segment ............................................................................................................................159

North Bay Segment .........................................................................................................................159

West Bay Segment ..........................................................................................................................159

St. Andrew Sound Segment ...........................................................................................................159

Causes of Change .....................................................................................................................................160

Entire Study Area .............................................................................................................................160

St. Andrew Bay Segment ...............................................................................................................160

East Bay Segment ............................................................................................................................160

North Bay Segment .........................................................................................................................165

West Bay Segment ..........................................................................................................................165

St. Andrew Sound Segment ...........................................................................................................166

Species Information ..................................................................................................................................166

Monitoring for Seagrass Health .............................................................................................................166

Mapping and Monitoring Needs ............................................................................................................166

Restoration and Enhancement Opportunities ......................................................................................167

References Cited .......................................................................................................................................167

Florida Big Bend

Background ................................................................................................................................................170

Scope of Area ............................................................................................................................................172
xi

Methodology Employed To Determine and Document Current Status ............................................172

Methodology Employed To Analyze Historical Trends ........................................................................174

Status and Trends .....................................................................................................................................174

Regionwide Mapping Studies ........................................................................................................175

Other Subregional Mapping Studies ............................................................................................176

Causes of Change .....................................................................................................................................179

Hydrologic Alteration of Watersheds ...........................................................................................179

Nutrient Enrichment of Estuaries and Nearshore Coastal Waters .........................................179

Species Information ..................................................................................................................................180

Monitoring for Seagrass Health .............................................................................................................182

Mapping and Monitoring Needs .............................................................................................................182

Restoration and Enhancement Opportunities ......................................................................................185

References Cited .......................................................................................................................................185

Tampa Bay and Saint Joseph Sound

Background.................................................................................................................................................188

Scope of Area.............................................................................................................................................188

Methodology Employed To Determine and Document Current Status .............................................188

Methodology Employed To Analyze Historical Trends ........................................................................190

Status and Trends .....................................................................................................................................190

Tampa Bay .........................................................................................................................................190

Clearwater Harbor and Saint Joseph Sound ..............................................................................192

Causes of Change .....................................................................................................................................192

Monitoring for Seagrass Health .............................................................................................................193

Species Information ..................................................................................................................................194

Restoration and Enhancement Opportunities ......................................................................................194

The Tampa Bay Nitrogen Management Strategy .......................................................................194

Reduction of Seagrass Scarring ...................................................................................................202

References .................................................................................................................................................202

Sarasota Bay

Background ................................................................................................................................................206

Scope of Area ............................................................................................................................................206

Methodology Employed To Determine and Document Current Status ............................................206

Status and Trends .....................................................................................................................................208

Upper Sarasota Bay in Manatee County ......................................................................................208

Upper Sarasota Bay in Sarasota County ......................................................................................208

Roberts Bay .......................................................................................................................................208

Little Sarasota Bay ...........................................................................................................................210

Blackburn Bay...................................................................................................................................210

Causes of Change......................................................................................................................................210

Monitoring for Seagrass Health .............................................................................................................216

Species Information ..................................................................................................................................216

Restoration and Enhancement Opportunities ......................................................................................216

References .................................................................................................................................................217
xii

Charlotte Harbor

Background ................................................................................................................................................218

Scope of Area ............................................................................................................................................218

Methodology Employed To Determine and Document Current Status ............................................221

Southwest Florida Water Management District .........................................................................223

South Florida Water Management District ..................................................................................223

Methodology Employed To Analyze Historical Trends .......................................................................224

Status and Trends .....................................................................................................................................233

Causes of Change .....................................................................................................................................233

Monitoring for Seagrass Health .............................................................................................................236

Species Information .................................................................................................................................237

Mapping and Monitoring Needs ............................................................................................................237

Restoration and Enhancement Opportunities ......................................................................................238

References .................................................................................................................................................239

Oral and Written Communication ...........................................................................................................240

Florida Bay

Background ................................................................................................................................................242

Scope of Area ............................................................................................................................................244

Methodology Employed To Analyze Historical Trends .......................................................................244

Aerial Photography and Interpretation ........................................................................................244

Field Investigations ..........................................................................................................................246

Current Seagrass Change—Florida Bay Fisheries Habitat Assessment Program ........................246

Methods .............................................................................................................................................246

Status and Trends .....................................................................................................................................249

Restoration Opportunities ........................................................................................................................249

References Cited .......................................................................................................................................252

Conclusions 

Importance of Gulf of Mexico Seagrasses ...........................................................................................254

Seagrass Losses .......................................................................................................................................254

Seagrass Decline Leads to Economic and Aesthetic Losses ...........................................................257

Resource Management and Monitoring ...............................................................................................258

Field of Dreams or Empty Meadows: If You Build It, Will They Come? ............................................259

Conservation Is a Necessary and Proactive Management Tool ......................................................259

Towards Restoration and Conservation Success ...............................................................................259

References Cited .......................................................................................................................................260

Appendix 

Appendix 1. .................................................................................................................................................265

References Cited .......................................................................................................................................266
Background

Perdido River and Perdido Bay form the western 

boundary of Escambia County, Fla., as well as the Florida/

Alabama State line. Coastal Alabama and northwest Florida 

are currently experiencing rapid growth and development 

similar to historical boom years in south Florida. It is likely 

that unless there are conscious efforts to apply growth 

management lessons learned from mistakes made in southern 

Florida, similar costly mistakes may be repeated. Current 

expansions associated with the Perdido River and Bay 

watersheds (fig. 1) provide an opportunity to apply “smart 

growth” principles to restore and protect their water bodies.

Although Perdido Bay covers approximately 130 km2 (50 

mi2), its watershed encompasses over 3,238 km2 (1,250 mi2) of 

land, tributaries, lagoons, and bayous in Florida and Alabama. 

Perdido Bay is connected to the Gulf of Mexico through 

Perdido Pass, and the Gulf Intracoastal Waterway (GIWW) 

passes through the southern portion of the bay. Perdido 

Bay includes areas along the coastal and inland sections of 

Escambia County in Florida, and Baldwin and Escambia 

Counties in Alabama. Because of its small size, Perdido Bay 

features rapid changes in water quality in response to rainfall, 

wind, and tide (Perdido Ecosystem Restoration Group, 1998).

Because Perdido Bay includes oligohaline, mesohaline, 

and euryhaline systems, this estuary possesses high species 

diversity. Seagrasses in Perdido Bay provide spawning, 

nursery, and adult habitat for many commercially and 

recreationally important catches such as shrimp (Penaeus sp.), 

crabs (Callinectes sp.), scallops (Argopecten sp.), speckled 

trout (Cynoscion sp.), redfish (Sciaenops sp.), and mullet 

(Mugil sp.). Increased shoreline and watershed development, 

stormwater runoff, septic tanks, wastewater treatment plant 

effluent, industrial discharges, agriculture, silviculture, and 

natural occurrences (e.g., hurricanes) have all contributed 

to the degradation of water quality and the resulting loss 

of seagrasses in Perdido Bay. Hurricane Frederick, for 

example, which made landfall at Mobile Bay in 1979, did 

considerable damage to Perdido Bay seagrasses (Perdido 

Ecosystem Restoration Group, 1998). Seagrass monitoring 

efforts in Perdido Bay have shown that from 1940 to 1992, 

approximately 90% of the historical continuous seagrass 

coverage has been lost (table 1). Wolf Bay, the largest tributary 

to southwestern Perdido Bay, has undergone decreasing water 

quality because of nitrate and phosphate runoff (Livingston, 

2001). Eutrophication of Wolf Bay has been attributed to an 

increase in agricultural land use, which is just one example 

of a nutrient source within the Perdido Bay watershed 

(Livingston, 2001).

Two-thirds of Escambia County, Fla., residents live 

within 16 km (10 mi) of a major waterway. Like most 

Florida surface waters, Perdido Bay is threatened by human 

activities. Most residential stormwater sources are located in 

the southern portions of the watershed, particularly the highly 

developed Ono Island and Perdido Key areas. Recent statistics 

reveal that in the years 1997–99, nearly 5,000 new singlefamily housing units and over 1,400 new multifamily housing 

units were permitted in Escambia County. Census results 

indicate that the population of Escambia County increased 

nearly 13% between 1990 and 2000 (University of 

Florida, 2000). 

Upper Perdido Bay is impacted by runoff from 

agricultural and silvicultural lands. In 1998, it was determined 

that 75% of the basin in Baldwin County, Alabama; 70% of 

the basin in Escambia County, Ala.; and 85% of the basin 

in Escambia County, Fla., were used for timber production 

(Perdido Ecosystem Restoration Group, 1998). 

Perdido Bay 

By Taylor (Chips) Kirschenfeld,1 Robert K. Turpin,2 and Lawrence R. Handley3

1 Senior Water Quality Scientist, Escambia County, Fla.

2 Chief, Marine Resources Division, Escambia County, Fla.

3 U.S. Geological Survey.

Table 1. Perdido Bay seagrass values in hectares (acres) 

from 1940 to 2002.

Seagrasses 1940 1979 1987 1992 2002

Continuous 365

(880)

38 

(94)

124 

(307)

40 

(99)

Patchy 114 

(282)

171 

(423)

103 

(255)

74 

(183)

Present 112 

(277)
65 

10 

R ive r S ty x

Mobile 

Pensacola 

Ferry Pass 

Blackwater R iver

Pe rd

di o R i ver

Gulf of Mexico

Perdido

Bay

Perdido Bay 

Watershed boundary 

City 

Interstate highway 

River 

Gulf Intracoastal 

Waterway 

County line 

5 0 km 10 15 20 

6 3 0 mi 9 12 

N

Figure 1. Watershed for Perdido Bay.

116 Seagrass Status and Trends in the Northern Gulf of Mexico: 1940–2002
The most significant point source discharge into Perdido 

Bay is a paper mill. The mill discharges approximately 

0.92 m3/s (21 million gal/d) of kraft process effluent into 

Elevenmile Creek (Perdido Ecosystem Restoration Group, 

1998). In addition, effluent from other industrial and domestic 

wastewater treatment plants increase nutrient levels in the 

bay. Much of Perdido Bay has been included on the 303(d) 

list of impaired waters because of low dissolved oxygen 

and high nutrient levels. As a result of citizen concerns 

about water quality in Perdido Bay, in July 1998 the 

Perdido Ecosystem Restoration Group, Florida Department 

of Environmental Protection (FDEP), National Oceanic 

and Atmospheric Administration (NOAA), and Florida 

Department of Community Affairs (DCA) published “Perdido 

Ecosystem Management Strategies.” This publication outlines 

management policies, action plans, and best management 

practices for the Perdido Bay watershed.

Scope of Area

Perdido Bay is oriented approximately perpendicular to 

the Gulf of Mexico, with a length of 53 km (33 mi) and an 

average width of 4 km (2 mi). Average water depth in the bay 

is approximately 2 m (7 ft) (Livingston, 2001). Perdido Bay 

can be divided into three segments: Upper, Middle, and 

Lower (fig. 2).

The Perdido River, designated by the State of Florida an 

“Outstanding Florida Water,” is a characteristic blackwater 

stream and the major freshwater tributary of Perdido Bay. 

The river is also the State boundary between Alabama and 

Florida. Much of the adjacent lands are used for silviculture. 

The majority of land along the river is owned by only two 

corporations. In contrast, the River Styx, which converges with 

the Perdido River from the west, has experienced substantial 

residential development.

Upper Perdido Bay

Upper Perdido Bay begins at the mouth of the Perdido 

River and extends south past the mouths of Elevenmile Creek 

and Bayou Marcus to Cummings Point. Although a substantial 

portion of the watershed remains forested, residential 

development is increasing.

Middle Perdido Bay

Extending southwest from Cummings Point to Innerarity 

Point, Middle Perdido Bay is the largest segment of the bay. 

Located on the eastern side of the bay, Tarkiln Bayou is one 

of the last remaining pristine bayous in northwest Florida. 

Tarkiln Bayou State Preserve and the Perdido Pitcher Plant 

Prairie (prioritized for preservation by Escambia County, Fla., 

and the State of Florida) surround Tarkiln Bayou.

Lower Perdido Bay

Lower Perdido Bay extends from Innerarity Point 

southward to the Gulf of Mexico and includes Wolf Bay, 

Cotton Bayou, Old River, and the GIWW eastward to the Theo 

Baars Bridge. The Lower Perdido Bay watershed includes 

Innerarity Point and Perdido Key in Florida, and Ono Island 

and Gulf Shores in Alabama. Although highly developed, 

with extensive residential and resort areas, this portion of the 

watershed also includes three State parks, as well as Gulf 

Islands National Seashore.

Methodology Employed To Document 

Current Status

The most current mapping study of seagrass coverage 

for the Perdido Bay area was conducted more than 10 yr ago 

by the U.S. Geological Survey (USGS) National Wetlands 

Research Center (NWRC) by using natural-color aerial 

photography taken in 1992 at a 1:24,000 scale as part of the 

northeastern Gulf of Mexico seagrass mapping project.

The mapping protocol consisted of stereoscopic 

photointerpretation, cartographic transfer, and digitization in 

acccordance with strict mapping standards and conventions. 

Other important aspects of the protocol included the 

development of a classification system, groundtruthing, quality 

control, and peer review.

The information derived from the photography was 

subsequently transferred using a zoom transfer scope onto a 

stable medium overlaying USGS quadrangle basemaps. In 

those cases where the data were inadequate or incomplete, 

contemporary supplemental data were acquired from other 

sources and used to complete the photographic coverage.

The seagrass classification system (see appendix for full 

discussion) used consists of two classes of open water—RIV 

(riverine, fresh water) and EST (estuarine or marine open 

water)—and five classes of seagrass habitats. One class is 

continuous seagrass, CSG, for which no density distinction 

was made, and the other four classes of patchy seagrass are 

based on percent ground cover of patches and in increments of 

5%—PSG1 (0%–10% very sparse), PSG2 (15%–40% sparse), 

PSG3 (45%–70% moderate), and PSG4 (75%–95% dense).

The groundtruthing phase included the participation 

of field staff from Gulf Islands National Seashore, U.S. 

Fish and Wildlife Service (USFWS), Dauphin Island Sea 

Lab, Mississippi State University, Alabama Department of 

Conservation and Natural Resources, and Florida Department 

of Environmental Protection. Draft maps were sent to the 

aforementioned agencies and staff for review and comments. 

All comments received were incorporated into the final maps 

prepared and delivered.

Methodology Employed To Document Current Status 117
Gulf of Mexico

Elevenmile

Spring Branch

Colton Creek

Highway 98 bridge

Perdido River

Blackwater River

 Perdido Bay

Inerarity Point

Tarkiln Bayou

Alabama

Perdido Key

Florida

Gulf Shores

Orange Beach

Soldier Creek

Palmetto Creek Tarkiln Bayou State Preserve

Cummings Point

3

2

1

Wolf

Bay

Creek

 6

 6

4

4

2

2 0

0

km

mi

2

3

Upper Perdido Bay

Middle Perdido Bay

Lower Perdido Bay Segment

GulfIntracoastalWaterway

1

Study area

N

Florida

Alabama

BayouMarcus

Bon Secour Bay

Figure 2. Scope of area for the Perdido Bay seagrass vignette.

118 Seagrass Status and Trends in the Northern Gulf of Mexico: 1940–2002
Methodology Employed To Analyze 

Historical Trends

To produce a trend analysis for Perdido Bay, in 1988 and 

1989, the NWRC produced a series of historical seagrass maps 

for the USFWS’s Panama City Ecological Services Office and 

the U.S. Environmental Protection Agency’s (EPA) Region IV 

Near Coastal Waters Program. Black and white photography 

from 1940–41 (1:20,000 scale), color infrared photography 

from 1979 (1:65,000 scale), and color infrared photography 

from 1987 (1:65,000 scale) was used to develop the trend 

analysis. Each date of aerial photography was analyzed with 

stereoscopic visual equipment, and seagrasses were delineated 

onto Mylar® overlays by using a zoom transfer scope with 

USGS 1:24,000 scale topographic quadrangles as the base 

maps. The overlays were digitized by using the Wetland 

Analytical Mapping System (WAMS) and converted into Arc 

format files. All dates of photography were of good to high 

quality for delineating seagrasses.

For consistency, classification of the seagrass for the 

trend analysis followed the same protocol as was used in the 

development of the Northeastern Gulf of Mexico seagrass 

mapping using the 1992 aerial photography. The seagrass 

classification system used consists of the same two classes 

of open water and five classes of seagrass habitats used to 

document current seagrass status.

Draft maps were sent out to the USFWS for review and 

comments. All comments received were incorporated into the 

final maps prepared and delivered. Although groundtruthing of 

the 1987 seagrass delineations was performed by NWRC, no 

groundtruthing took place for the 1940–41 or 1979 historical 

seagrass delineations.

The NWRC currently holds the aerial photography, the 

interpreted overlays, and the Mylar® overlays for the 1940–

41, 1979, and 1987 maps.

Status and Trends

Seagrass monitoring efforts in 1940 (fig. 3), 1979 (fig. 4), 

1987 (fig. 5), 1992 (fig. 6), and 2002 (fig. 7) have documented 

the decline of seagrass in Perdido Bay (table 1). In the 52-yr 

period from 1940 to 1992, Perdido Bay lost 355 ha (877 

acres), or 74%, of its seagrass coverage. In the 10-yr period 

from 1992 to 2002, it appears that the rate of seagrass loss 

may have declined, but Perdido Bay still continued to lose 

an additional 3 ha (7 acres), or 2.6%, of its seagrass coverage 

during this 10-yr period. Total loss of seagrass coverage from 

1940 to 2002 was 358 ha (885 acres), or 76%. 

Upper Perdido Bay

The 1940 data (fig. 3) show only 0.4 ha (0.9 acres) of 

seagrass in Upper Perdido Bay. By 1979 (fig. 4), the seagrass 

coverage in this segment of the bay had apparently increased 

to 4.5 ha (11 acres), and the 1987 (fig. 5) data show 4.3 ha (11 

acres) of seagrass. By 1992 (fig. 6), the seagrass coverage in 

Upper Perdido Bay had decreased to 1.3 ha (3 acres). By 2002, 

data showed no seagrass present in Upper Perdido Bay. 

Middle Perdido Bay

Middle Perdido Bay showed seagrass coverage of 46.1 ha 

(114 acres) in 1940 (fig. 3). The majority of this coverage was 

located at the mouths of Soldier Creek and Palmetto Creek on 

the west side of the bay. By 1979, (fig. 4) seagrass coverage 

was greatly reduced to only 1.5 ha (4 acres), and by 1987, 

it had declined to 0.5 ha (1 acre). The 1992 data showed no 

seagrass present in Middle Perdido Bay, while the 2002 data 

shows 0.3 ha (0.7 acres).

Lower Perdido Bay

Since 1940, the majority of seagrass in Perdido Bay has 

been documented in the lower segment. Data show 434 ha 

(1,072 acres) of seagrass in Lower Perdido Bay in 1940 (fig. 

3) and 209.7 ha (518 acres) in 1979 (fig. 4). By 1987 (fig. 5), 

seagrass coverage was 233.9 ha (578 acres). Photography from 

1992 (fig. 6) shows 122.9 ha (304 acres) of seagrass in Lower 

Perdido Bay, while 2002 data indicate 121.1 ha (299 acres).

Entire Study Area

In 1940 (fig. 3), total Perdido Bay seagrass coverage was 

480 ha (1,186 acres). As in subsequent years, most of this 

acreage (>90%) was located in Lower Perdido Bay. Seagrass 

maps from 1979 (fig. 4) showed total Perdido Bay seagrass 

coverage of 215.7 ha (533 acres). By 1987 (fig. 5), the total 

seagrass coverage in the bay was 239 ha (590 acres); by 1992 

(fig. 6), it was 124.2 ha (307 acres); and by 2002, it was 121.3 

ha (300 acres).

U.S. Geological Survey seagrass maps from 1987 (fig. 

5) indicate that, in the 47-yr period between 1940 and 1987, 

approximately 50% of the total seagrass in Perdido Bay had 

been lost (figs. 3–5). Seagrass acreage decreased from 480 ha 

(1,186 acres) in 1940 (fig. 3) to 239 ha (590 acres) in 1987 

(fig. 5), a loss of 241 ha (596 acres) baywide. Assuming a 

relatively steady rate of decline, the average rate of seagrass 

loss over this 47-yr period was approximately 5 ha (12 acres) 

per year, or just over 1% per year. Middle Perdido Bay lost 

about 45 ha (111 acres) of seagrass, or 98% of its 1940 total. 

Lower Perdido Bay lost 199 ha (492 acres) of seagrass, or 

46% of its 1940 total. Upper Perdido Bay actually showed an 

increase of about 4 ha (10 acres) of seagrass during this time 

period. The decline of seagrass in Lower Perdido Bay was the 

greatest acreage loss, accounting for 199 ha (492 acres) of the 

total 241 ha (596 acres) lost baywide.

Status and Trends 119
Water

km 0 1 2 3 4

mi 0 0.5 1 1.5 2 2.5

N Gulf of Mexico

Seagrass, patchy 

Seagrass, continuous 

Land

Figure 3. Distribution of seagrass in Perdido Bay, 1940.

120 Seagrass Status and Trends in the Northern Gulf of Mexico: 1940–2002
Water 

Seagrass, patchy 

Seagrass, continuous 

Land 

Gulf of Mexico

43210km

mi 0.50 1 21.5 2.5

N

Figure 4. Distribution of seagrass in Perdido Bay, 1979. 

Status and Trends 121
Water 

Seagrass, patchy 

Seagrass, continuous 

Land 

Gulf of Mexico

43210km

mi 0.50 1 21.5 2.5

N

Figure 5. Distribution of seagrass in Perdido Bay, 1987.

122 Seagrass Status and Trends in the Northern Gulf of Mexico: 1940–2002
Water 

Seagrass, patchy 

Seagrass, continuous 

Land 

Gulf of Mexico

43210km

mi 0.50 1 21.5 2.5

N

Figure 6. Distribution of seagrass in Perdido Bay, 1992.

Status and Trends 123
43210km

mi 0.50 1 21.5 2.5

Water 

Seagrass, present 

Land 

Gulf of Mexico

N

Figure 7. Distribution of seagrass in Perdido Bay, 2002.

124 Seagrass Status and Trends in the Northern Gulf of Mexico: 1940–2002
U.S. Geological Survey seagrass maps from 1992 (fig. 

6) show that total seagrass coverage in Perdido Bay was 

approximately 124 ha (306 acres). The percentage of seagrass 

lost in the 5-yr period from 1987 to 1992 was 48% (figs. 5 and 

6). Total Perdido Bay seagrass acreage decreased from 239 ha 

(591 acres) to 124 ha (306 acres) during this time period. The 

average rate of seagrass loss during this 5-yr period was 141 

ha (348 acres) per year, or almost 10% per year. Only about 

1.2 ha (3 acres) of seagrass remained in Upper Perdido Bay, 

and only about 122 ha (301 acres) remained in Lower Perdido 

Bay. Unlike the 1940 (fig. 3) and 1987 (fig. 5) data, the 1992 

(fig. 6) data indicated that no seagrass remained in Middle 

Perdido Bay. Seagrasses that were present at Palmetto and 

Soldiers Creeks had been lost by 1992.

In the 52-yr period from 1940 to 1992 (figs. 3–6), 

Perdido Bay lost 355 ha (877 acres), or 74%, of its seagrass 

coverage. The greatest loss of seagrasses occurred in Lower 

Perdido Bay where 310 ha (766 acres) of these 355 ha (877 

acres) were lost. The lower section of Perdido Bay is the area 

that experienced the greatest developmental pressure during 

this 52-yr time period. Most of this development was related to 

vacation home construction and tourism.

It appears that during the 1992 to 2002 period, the rate of 

seagrass loss has declined. Data show a loss of 3 ha (7 acres), 

or 2.6%, during this recent 10-yr period, which equates to an 

estimated rate of decline of less than 0.3% per year.

Causes of Change

Upper/Middle Perdido Bay

Waters in Upper/Middle Perdido Bay are greatly 

influenced by the Perdido River, Elevenmile Creek, Bayou 

Marcus, Soldier Creek, Palmetto Creek, and numerous smaller 

tributaries. Wastewater and paper mill effluent are major point 

sources of pollution that can contain high levels of nutrients. 

Nonpoint pollution sources within the watershed include 

agricultural and silvicultural runoff that also can contribute 

high levels of nutrients to Perdido Bay. Other tributaries of 

Middle Perdido Bay (e.g., Palmetto Creek, Soldier Creek, and 

Bayou Garcon) have been residentially developed. Residential 

runoff (e.g., fertilizers, pesticides, and herbicides) also may 

affect water quality. Although primarily used for silviculture, 

lands surrounding Middle and Upper Perdido Bay and Perdido 

River are vulnerable to future residential development.

Lower Perdido Bay

Lower Perdido Bay has been greatly affected by 

accelerated residential, resort, and marine development. 

Numerous homes, condominiums, hotels, and marinas have 

crowded the coastline resulting in increased impervious 

surfaces and increased stormwater runoff, which usually cause 

increased nutrient enrichment, increased turbidity, decreased 

water clarity, decreased light penetration, and loss of seagrass. 

Ono Island and Perdido Key are approaching the maximum 

limits of development. Increased impervious surfaces 

generally contribute to greater amounts of urban stormwater 

running off into surrounding surface waters and transporting 

various pollutants such as fertilizers, pesticides, hydrocarbons, 

metals, and other toxins. Numerous marinas and residential 

docks, with associated vessels and activities, can provide 

additional stress to water quality and seagrasses. 

Throughout Florida, the primary cause of water 

quality degradation is eutrophication Florida Department 

of Environmental Protection, 2000. Eutrophication has 

been blamed for seagrass losses in Florida and elsewhere 

(Cambridge and others, 1986; Tomasko and others, 1996). 

Loss of Perdido Bay seagrasses may be due to the result of 

decreased light, which is likely caused by increased turbidity 

and eutrophication. The degradation of water quality in 

the bay has occurred over time in proportion to population 

growth, increased land use, and development within the 

watershed. Over the past 10 yr, there has been a steady 

increase in population and development in the watershed and a 

concomitant loss of seagrasses. 

Nutrient input is reported to be a major factor in 

Perdido Bay’s water quality problems (Livingston, 2001). 

Residential and agricultural runoff are likely nutrient sources, 

as are domestic wastewater treatment facilities and paper 

mill discharges. Excess nutrients cause the reduction of 

light available to seagrass for photosynthesis in two general 

ways: (1) epiphytic growth, stimulated by nutrients, directly 

shade seagrass photosynthetic pigments; (2) nutrients cause 

phytoplankton blooms that absorb photosynthetically active 

radiation (PAR) in the water column. 

 Long-term trends are often viewed as gradual change 

over time; however, natural events such as hurricanes may 

cause large magnitude changes in a short time period. For 

example, the 1979 (fig. 4) seagrass maps were developed 

from data collected several months after a major hurricane 

(i.e., Frederick) heavily impacted Perdido Bay. Thus, when 

analyzing long-term trends, caution should be used when 

viewing short-term fluctuations in seagrass coverage that are 

to the result of isolated events.

Species Information

Three species of seagrasses have been found in Perdido 

Bay: wigeon grass (Ruppia maritima), shoal grass (Halodule 

wrightii), and turtle grass (Thalassia testudinum). Although 

not a true seagrass, the freshwater species water celery 

(Vallisneria americana) has been reported as the dominant 

submerged aquatic vegetation in the shallow, oligohaline 

waters of Upper Perdido Bay (Davis and others, 1999). Less 

frequently, wigeon grass occurs in shallow waters of Upper 

Species Information 125
Perdido Bay (Kirschenfeld and Turpin, personal observation). 

In contrast, euhaline species, shoal grass and turtle grass, are 

predominantly found in Lower Perdido Bay (Kirschenfeld and 

Turpin, personal observation).

Monitoring for Seagrass Health

Perhaps because of greater attention given to the larger 

Pensacola Bay System in Florida, or Weeks Bay and Mobile 

Bay in Alabama, management of Perdido Bay water quality 

and marine resources (e.g., seagrasses) has not been given 

adequate attention.

In 1991, the USFWS prepared a report on the changes 

in submerged vegetation coverage in Perdido Bay from 

1940 to 1987 by analyzing and interpreting historical maps 

developed from aerial photography (U.S. Fish and Wildlife 

Service, 1991). In this report, a distinction was made between 

the true seagrasses and submerged vegetation, the latter of 

which additionally includes water celery. While no new field 

monitoring or water quality data were collected, the map 

analysis concluded that there was a loss of 235.5 ha (582 

acres) of submerged vegetation, or a 48% net loss, from 1940 

to 1987 (figs. 3–5).

Several transplanting efforts involving wigeon grass 

and water celery in upper Perdido Bay have indicated that 

water quality may be suitable for seagrass restoration efforts 

(Davis and others, 1999; Davis and Kirschenfeld, 

personal observation).

Weekly and monthly water quality monitoring data have 

been collected in Perdido Bay by biologists at the FDEP office 

in Pensacola. Measured parameters include nutrient levels, 

chlorophyll a, turbidity, Secchi depth, fecal bacteria, dissolved 

oxygen, temperature, and conductivity/salinity. In addition, 

Livingston (2001) published an extensive collection of many 

years of phytoplankton and nutrient data that was the result 

of studying the effects of pulp mill effluent on the Perdido 

Bay ecology.

Mapping and Monitoring Needs

As existing data show, the rate of seagrass loss in Perdido 

Bay appears to have increased from a loss rate of about 1% 

per year, from 1940 to 1987 (figs. 3–5), to a loss rate of 

about 10% per year, from 1987 to 1992 (figs. 5 and 6). More 

recently, however, from 1992 to 2002, it appears that the loss 

rate of seagrass in Perdido Bay has declined to less than 0.3% 

per year. Efforts should be undertaken to determine what 

activities and what best management practices have been 

implemented in Perdido Bay from 1992 to 2002 because data 

show an apparent successful effort to reduce the rate of decline 

of seagrass in the bay. Other estuarine systems could benefit 

from this information. If seagrass loss is still continuing, as 

historical trends indicate, additional seagrass preservation 

efforts and water quality improvements will be required in 

order to reverse this downward trend in seagrass coverage. 

The continued loss of seagrass, and the continued loss of its 

important intrinsic functions and values, will result in the 

further degradation of the ecology of Perdido Bay. 

Restoration and Enhancement 

Opportunities

A seagrass monitoring effort and development of a 

seagrass management plan have recently been completed 

for nearby Big Lagoon and Santa Rosa Sound (Florida 

Department of Environmental Protection, 2001). Efforts such 

as this one should be expanded to include Perdido Bay.

In 1991, EPA biologists transplanted water celery in 

several different planting configurations in Upper Perdido Bay 

(Davis and others, 1999). In 1997, EPA and FDEP biologists 

successfully transplanted water celery and wigeon grass 

in Upper Perdido Bay (Davis and Kirschenfeld, personal 

observation). These results suggested that seagrass transplant 

efforts may be successful. 

In recent years, there has been an elevated public 

awareness of environmental concerns in Escambia County, 

Florida, including water quality deterioration and loss of 

seagrasses. In 1998, the Pensacola FDEP office, in association 

with the Perdido Ecosystem Restoration Group (1998), led an 

effort to organize stakeholder meetings, develop action plans 

and management strategies, and publish Perdido Ecosystem 

Management Strategies. This document highlighted the 

public’s concerns with poor water quality in Perdido Bay 

and the need for coordinated restoration efforts. In 1999, 

a special State of Florida Grand Jury issued a report on 

air and water quality concerns in Escambia County, which 

included 27 recommendations. These recommendations 

called for increased water quality monitoring efforts, more 

stringent water quality rules and regulations, reduced point 

and nonpoint sources of pollution, and the protection and 

preservation of environmentally sensitive lands. Perdido 

Bay has been classified as an Outstanding Florida Water, 

which means that there are more restrictive permit conditions 

required for developmental activities in this area.

Local efforts have been made to improve the water 

quality of Perdido Bay. Routine water quality monitoring 

by volunteers and publication of the data in the local 

newspaper (Pensacola News Journal) have heightened the 

public’s environmental awareness. Citizens’ efforts to reduce 

fertilization of lawns and reduce the use of pesticides and 

herbicides will help improve water quality. Local government 

efforts to reduce stormwater runoff and retrofit old storm 

drains will also help to improve water quality. The major 

industrial source of pollution to Perdido Bay is currently 

improving its process to improve the quality of its 0.92 m3/s 

(21 million gal/d) of kraft mill effluent that is discharged into 

Elevenmile Creek and Perdido Bay. The cumulative positive 

126 Seagrass Status and Trends in the Northern Gulf of Mexico: 1940–2002
effects of these efforts should be documented for positive 

reinforcement that these improvements and efforts 

are worthwhile.

Additional development will surely occur along the 

coast, but more stringent State and local regulations could be 

implemented to minimize negative environmental impacts. 

Improving the water quality of Perdido Bay, implementing 

coastal growth management plans, and continuing seagrass 

restoration efforts could reverse the trend of declining 

seagrass abundance.

References

Bortone, S.A., and Turpin, R., 2000, Tape grass life history 

metrics associated with environmental variables in a 

controlled estuary, in Bortone, S.A., ed., Seagrasses. 

Monitoring, ecology, physiology, and management: Boca 

Raton, Fla., CRC Press, p. 65–79.

Cambridge, M.L., Chiffings, A.W., Britton, C., Moore, L., 

and McComb, A., 1986, The loss of seagrass in Cockburn 

Sound, Western Australia: possible causes of seagrass 

decline: Aquatic Botany, v. 24, p. 269–285. 

Davis, W.P., Davis, M.R., and Flemer, D.A., 1999, 

Observations of the regrowth of subaquatic vegetation 

following transplantation: a potential method to assess 

environmental health of coastal habitats, in Bortone, S.A., 

ed., Seagrasses. Monitoring, ecology, physiology, and 

management: Boca Raton, Fla., CRC Press, p. 295–307. 

Florida Department of Environmental Protection, 2001, 

Seagrass management plan for Big Lagoon and Santa 

Rosa Sound: Pensacola, Fla., Florida Department of 

Environmental Protection.

Hotchkiss, N., 1972, Common marsh, underwater, and 

floating-leaved plants of the United States and Canada: New 

York, Dover Publications, Inc.

Livingston, E., 1988, A Florida development manual: a guide 

to sound land and water management: Tallahassee, Fla., 

Florida Department of Environmental Regulation. 

Livingston, E., McCarron, E., Scheinkman, M., and Sullivan, 

S., 1989, Florida nonpoint source management plan, volume 

2: Tallahassee, Fla., Florida Department of Environmental 

Regulation, Bureau of Surface Water Management, 

Nonpoint Source Management Section.

Livingston, R.J., 2001, Eutrophication processes in coastal 

systems: origin and succession of plankton blooms and 

effects on secondary production in Gulf Coast estuaries: 

Boca Raton, Fla., CRC Press.

Perdido Ecosystem Restoration Group, 1998, Perdido 

ecosystem management strategies: Pensacola, Fla., Florida 

Department of Environmental Protection.

Tomasko, D.A., Dawes, C.J., and Hall, M.O., 1996, The 

effects of anthropogenic nutrient enrichment on turtle grass 

(Thalassia testudinum) in Sarasota Bay, Florida: Estuaries, 

v. 19, p. 448–456.

U.S. Fish and Wildlife Service, 1991, Changes in submerged 

vegetation in Perdido Bay, 1940–1987: Panama City, Fla.

U.S. Geological Survey, 2002, Aerial photography and 

photointerpretation of seagrass coverage in Perdido Bay: 

1940, 1987, 1992: Lafayette, La., U.S. Geological Survey, 

National Wetlands Research Center, http://sabdata.cr.usgs.

gov/sabnet_pub/pub_sab_app.aspx?prodid=789.

University of Florida, 2000, Florida Statistical Abstract 

2000: Gainesville, Fla., Bureau of Economic and Business 

Research, Warrington College of Business Administration, 

University of Florida.

Oral and Written Communication

Davis, W.P., and Kirschenfeld, T., 2002, Personal observation: 

Gulf Breeze, Fla., U.S. Environmental Protection Agency.

Kirschenfeld, T., and Turpin, R., 2002, Personal observation: 

Pensacola, Fla., Escambia County Neighborhood and 

Environmental Services Department.

Oral and Written Communication 127