Background

The Gulf of Mexico coastline within the State of Florida 

(also known as the Florida gulf coast) extends approximately 

1,000 km (over 600 mi) from the Alabama State line to the 

Dry Tortugas. Along this coast, Florida State waters and 

adjacent Federal waters include the two largest contiguous 

seagrass beds in the continental United States: the Florida 

Keys and the Florida Big Bend regions. The exact sizes of 

these two beds have not been determined because it is difficult 

to map deepwater seagrass beds dominated by paddle grass 

(Halophila decipiens); however, Sargent and others (1995) 

estimated that Florida State waters contained approximately 

1,076,500 ha (2,660,000 acres) of seagrass, of which 55% 

(587,600 ha, or 1,451,900 acres) occurred in the Florida Keys 

and Florida Bay. An additional 334,600 ha (826,800 acres, 

31% of statewide total seagrass area) occurred in the Big Bend 

region. The remaining seagrass area, 154,300 ha (381,200 

acres), was distributed in estuaries and lagoons throughout 

the State. If seagrasses in adjacent Federal waters, including 

deepwater Halophila beds, are included, however, the total 

seagrass area in State and Federal waters is more than 1.2 

million ha (3 million acres). 

Florida’s extensive estuarine and nearshore seagrass 

beds have developed as the result of the unique and stable 

geological history, climate, and circulation patterns along the 

Florida peninsula since the last ice age. The broad, shallow, 

and nearly flat continental shelf along the Florida gulf coast is 

larger (150,000 km2

, or 57,915 mi2) than the land area of the 

Florida peninsula (139,700 km2, or 54,000 mi2). The shallow 

slope of the west Florida shelf, less than 20 cm/km (1 ft/mi), 

results in several million hectares of shallow bottom where 

sufficient light reaches the bottom for seagrass to survive. 

Nevertheless, Florida’s seagrass resources are at risk, as 

human impacts over the past 100 yr have caused significant 

seagrass losses in all of the estuaries described in the 

following vignettes. At present, coastal development, nutrient 

loads caused by humans, and hydrological modifications 

threaten estuarine and nearshore seagrass beds along the entire 

Florida gulf coast (fig. 1).

Species Information

Although the climatic gradient results in significant 

variation in seagrass productivity, the same six seagrass 

species are found along the entire length of the Florida gulf 

coast (Phillips, 1960; Zieman and Zieman, 1989). Turtle grass 

(Thalassia testudinum), shoal grass (Halodule wrightii), and 

manatee grass (Syringodium filiforme) are the most abundant 

species in estuarine and nearshore waters of the Florida gulf 

coast (Phillips, 1960). Star grass (Halophila engelmanii) is 

locally abundant in turbid estuarine environments, and paddle 

grass, although diminutive, covers large areas of the west 

Florida shelf at depths from 9 to more than 30 m (30 to over 

100 ft) (Continental Shelf Associates Inc., 1989). Because 

of its broad salinity and temperature tolerances, wigeon 

grass (Ruppia maritima) is also widely distributed in Florida 

estuaries. Water celery (Vallisneria americana) is a freshwater 

aquatic plant which occurs in the oligohaline reaches of many 

Florida tidal rivers, but it is not considered a seagrass because 

of its very low salinity tolerance.

Because seagrasses are very sensitive to water column 

transparency, their depth, distribution, and survival are 

primarily determined by water clarity. In areas with extremely 

clear water (the offshore areas of Big Bend and the Florida 

Keys, for example), seagrasses grow to depths greater than 

20 m (65 ft) (Iverson and Bittaker, 1986). In turbid waters 

found in many Florida estuaries, however, seagrass beds are 

sometimes limited to depths less than 1 m (3.3 ft). If water 

column transparency at a particular site declines over time, 

seagrasses in deeper water die. As noted by Tomasko and 

Greening (Tampa Bay vignette), Tampa Bay seagrass cover 

declined 46% between 1950 and 1982, primarily as the result 

of declines in water column transparency resulting from 

human-caused nutrient loading, phytoplankton blooms, and 

resuspended sediment.

The climate along the Florida gulf coast ranges from 

temperate continental in the Florida panhandle to oceanic 

subtropical in the Florida Keys. Although Pensacola has a 

mean monthly minimum air temperature of 6°C (43°F) in 

January, the January mean sea-surface temperature is 12.5°C 

(approximately 58°F). At the very southern tip of the State, 

mean monthly minimum air temperature at Key West in 

January is 16°C (61°F), and the February mean sea-surface 

temperature is 23°C (73°F). Mean maximum air temperatures 

Statewide Summary for Florida

By Paul R. Carlson, Jr., and Kevin Madley1

1

 Florida Fish and Wildlife Conservation Commission.
75

95

4

75

Tallahassee

Dothan

Pensacola

St. Petersburg

Sarasota

Gainesville Panama City

Tampa

10 65

Mobile

Orlando

Port Charlotte

Fort Myers

Port Saint Lucie

West Palm Beach

Fort Lauderdale

Miami

Gulf of Mexico

Watersheds

Big BendCharlotte HarborChoctawhatchee BayFlorida BayPensacola BayPerdido BaySarasota BaySt. Andrew BayTampa Bay 

Study Areas

Big BendCharlotte HarborChoctawhatchee BayFlorida BayPensacola BayPerdido BaySarasota Bay St. Andrew BayTampa Bay 

City

Gulf IntracoastalWaterwayInterstate highwayState boundary

N

1209060300km

806040200mi

Fort Walton Beach

Figure 1. Watershed for the Gulf of Mexico coast of Florida.

100 Seagrass Status and Trends in the Northern Gulf of Mexico: 1940–2002
for Pensacola (32°C, or 90°F) and Key West (33°C, or 91°F) 

are very similar, and monthly mean sea-surface temperatures 

for both cities are 30°C (86°F). The timing and volume of 

rainfall also vary along the Florida gulf coast. The Florida 

panhandle and north Florida receive considerably more winter 

rainfall than the southwest Florida and Florida Keys regions. 

The entire Florida gulf coast also receives a significant amount 

of rainfall during the wet season (June through October). 

Annual rainfall ranges from 160 cm (63 inches) at Pensacola, 

to 120 cm (47 inches) at Cedar Keys, to 130 cm (51 inches) at 

Saint Petersburg and Naples, and to 100 cm (39 inches) at Key 

West. Rainfall, in general, and El Niño events, in particular, 

have a very strong effect on seagrasses along the Florida gulf 

coast. For example, during the strong El Niño of 1997–98, 

there was heavy rain throughout Georgia and Florida. As a 

result, monthly mean discharge of the Suwannee River at 

Wilcox, Fla., in March 1998 was 1,160 m3/s (40,960 ft3/s), 

the highest monthly mean discharge for the month of March 

measured during the 60-yr period of record for the gage. Thick 

phytoplankton blooms occurred throughout winter, spring, and 

early summer 1998 in west Florida estuaries and the adjacent 

shelf, causing declines in seagrass density and health at 

several sites along the west coast of Florida (Carlson and 

others, 2003).

Scope of Area 

Previous estimates of seagrass cover for the entire State 

of Florida (Sargent and others, 1995) divided the State into 

five regions: Panhandle, Big Bend, Gulf Peninsula, South 

Florida, and Atlantic Peninsula. For this document, we have 

divided the 24 Florida counties along the Gulf of Mexico 

among the Panhandle, Big Bend, Gulf Peninsula, and South 

Florida regions (fig. 2). To provide an areal estimate for the 

south Florida coast, four subregions have been extracted from 

the region described by Sargent and others (1995): (1) Ten 

Thousand Islands, which includes Collier County and the 

mainland portion Monroe County; (2) Florida Bay, including 

parts of Dade and Monroe Counties; (3) the gulfside Florida 

Keys, which extend from Long Key to the Tortugas; and (4) 

the southwest Florida shelf, which is a roughly rectangular 

region bounded by Cape Romano on the north side, the Dry 

Tortugas on the west, and the Florida Keys on the south (fig. 

3). Vignettes have been prepared for Perdido Bay, Pensacola 

Bay, Choctawhatchee Bay, St. Andrew Bay, the Florida Big 

Bend region, Tampa Bay and St. Joseph Sound, Sarasota 

Bay, Charlotte Harbor, and Florida Bay. Areas outside the 

vignette regions—St. Joe Bay, Ten Thousand Islands, and 

gulfside Florida Keys—are described only in this statewide 

summary. The estuarine or nearshore systems described in 

the vignettes range from moderately healthy and stable (Big 

Bend) to severely degraded but improving (Tampa Bay). In 

most systems, the principal human threats are nutrient loading 

and degraded water quality, which decrease water column 

transparency and light available for seagrasses. In Florida 

Bay, however, hydrologic modification of The Everglades is 

probably the principal human impact on seagrass distribution 

and community structure.

Methods Used To Determine Current 

Status of Seagrasses in the State of 

Florida

Seagrass cover estimates for the State of Florida have 

been based on photointerpretation of aerial photography. Some 

seagrass aerial photography was flown at 1:48,000 scale, but 

most of the photography used for trend analysis has been 

flown at 1:24,000 scale. As part of a study to determine the 

impact of propeller scarring in seagrass beds, Sargent and 

others (1995) made the first effort to summarize seagrass cover 

data for the entire State of Florida using photography flown 

between 1982 and 1990 (table 1). To update areal estimates, 

Madley and others (2003) constructed new statewide seagrass 

maps using data produced from aerial photography acquired 

from 1987 through 1999 (table 1). Note that seagrass area 

estimates are reported to the nearest acre or hectare in 

accompanying tables; however, we have rounded estimates in 

the following text to the nearest 100 acres or hectares.

Status and Trends

The most recent estimate of seagrass cover which has 

been mapped in Florida State waters (Madley and others, 

2003) is approximately 910,980 ha (2,251,000 acres; table 2). 

This estimate is limited to State jurisdictional boundaries on 

both the Atlantic and Gulf of Mexico coasts, but considerable 

amounts of seagrass lie outside State waters in the gulf and 

are excluded from this estimate. As noted earlier, inclusion of 

deepwater paddle grass beds in the Big Bend region and the 

southwest Florida shelf could raise the total area of seagrass 

in Florida gulf coast estuaries and on the west Florida shelf to 

over 3 million ha (7.4 million acres).

Of the statewide total seagrass area estimate, 

approximately 74% (678,681 ha, or 1.7 million acres) occurs 

in the Gulf of Mexico between the Dry Tortugas and the 

Florida/Alabama State line and in adjacent estuaries. Along 

the Gulf of Mexico coast, the Big Bend region has the largest 

total seagrass area of 207,206 ha (612,000 acres), followed by 

the Florida keys, including the Marquesas and Dry Tortugas, 

with 220,156 ha (544,000 acres). Florida Bay contains 

147,715 ha (365,000 acres) of seagrass, and the gulf peninsula 

region, stretching from Cape Sable to Anclote Key, contains 

43,343 ha (107,100 acres). The Panhandle region contains 

17,483 ha (43,200 acres) of seagrass (table 2).

Recent estimates of Florida statewide seagrass cover 

range from 910,575 to 918,669 ha (2.25 million to 2.27 

Status and Trends 101
Panhandle

Big Bend

Gulf Peninsula

South Florida

Study boundaries for counties

Regions 

N

Gulf of Mexico 

Atlantic Ocean 

Escambia

Santa Rosa 

Okaloosa 

Walton 

Gulf 

Bay

Franklin 

Wakula 

Jefferson 

Taylor 

Dixie 

Levy 

Citrus 

Hernando 

Pasco 

Hillsborough 

Pinellas 

Manatee 

Sarasota 

Charlotte 

Lee 

Collier 

Dade 

Monroe

Figure 2. Florida counties along the Gulf of Mexico coast.

102 Seagrass Status and Trends in the Northern Gulf of Mexico: 1940–2002
1995 Data 2002 Data

County Year Scale Source(s) Year Scale Source(s)

Panhandle

Escambia 1982–85 1:24,000 EPA/USFWS 1992 1:24,000 USGS

Santa Rosa 1982–85 1:24,000 EPA/USFWS 1992 1:24,000 USGS

Okaloosa 1982–85 1:24,000 EPS/USFWS 1992 1:24,000 USGS

Walton 1982–85 1:24,000 EPA/USFWS 1992 1:24,000 USGS

Bay 1982–85 1:24,000 EPA/USFWS 1992 1:24,000 USGS

Gulf 1982–85 1:24,000 EPA/USFWS 1992 1:24,000 USGS

Franklin 1982–85 1:24,000 EPA/USFWS 1992 1:24,000 USGS

Big Bend

Wakulla 1982–85 1:24,000 EPA/USFWS 1992 1:24,000 USGS

Jefferson 1983 1:40,000 MMS 1992 1:24,000 USGS

Taylor 1983 1:40,000 MMS 1992 1:24,000 USGS

Dixie 1983 1:40,000 MMS 1992 1:24,000 USGS

Levy 1983 1:40,000 MMS 1992 1:24,000 USGS

Citrus 1983 1:40,000 MMS 1992 1:24,000 USGS

Hernando 1983 1:40,000 MMS 1992 1:24,000 USGS

Pasco 1983 1:40,000 MMS 1992 1:24,000 USGS

Gulf Peninsula

Pinellas 1992 1:24,000 SWFWMD 1999 1:24,000 SWFWMD

Hillsborough 1992 1:24,000 SWFWMD 1999 1:24,000 SWFWMD

Manatee 1992 1:24,000 SWFWMD 1999 1:24,000 SWFWMD

Sarasota 1992 1:24,000 SWFWMD 1999 1:24,000 SWFWMD

Charlotte, north 1992 1:24,000 SWFWMD 1999 1:24,000 SWFWMD

Charlotte, south 1982, 1987 1:24,000 FDOT, FDEP 1999 1:24,000 SFWMD

Lee 1982, 1987 1:24,000 FDOT, FDEP 1999 1:24,000 SFWMD

South Florida

Collier 1982, 1987 1:40,000 MMS, FWRI 1987 1:24,000 SFWMD

Monroe 1982, 1987 1:40,000 MMS, FWRI 1987 1:24,000 SFWMD

Dade- Florida Bay 1982–86 1:40,000 MMS 1992/1994 1:24,000 NOAA, FWRI

Monroe-Fla. Keys 1982, 1987 1:40,000 MMS, FWRI

Table 1. Seagrass aerial photography datasets used for Florida statewide seagrass cover estimates by Sargent and others (1995) and 

Madley and others (2003).

[EPA = U.S. Environmental Protection Agency, USFWS = U.S. Fish and Wildlife Service, USGS = U.S. Geological Survey, MMS = Minerals Management 

Service, SWFWMD = Southwest Florida Water Management District, FDOT = Florida Department of Transportation, FDEP = Florida Department of 

Environmental Protection, SFWMD = South Florida Water Management District, FWRI = Fish and Wildlife Research Institute, NOAA = National 

Oceanic and Atmospheric Administration]

Status and Trends 103
Figure 3. Four subregions of the south Florida coast.

N

Gulf of Mexico

Atlantic Ocean 

Southwest Florida shelf

Ten Thousand Islands

Florida Bay

Gulfside Keys

104 Seagrass Status and Trends in the Northern Gulf of Mexico: 1940–2002
Table 2. Recent and current estimates of seagrass cover in Florida State waters.

[FWRI = Fish and Wildlife Research Institute]

FWRI Seagrass Continuous Seagrass Patchy Seagrass Total Seagrass

Data File Hectares Acres Hectares Acres Hectares Acres

Statewide estimates

Madley and others, 2003 402,563 994,733 510,476 1,261,387 913,039 2,256,120

Sargent, 2000 399,916 988,192 520,046 1,285,034 919,962 2,273,226

Sargent and others, 1995 N/A N/A N/A N/A 1,075,783 2,658,260

Regional estimates (Madley and others, 2003)

Panhandle 7,191 17,768 10,283 25,409 17,474 43,178

Big Bend 28,508 70,443 219,090 541,372 247,598 611,815Gulf Peninsula 29,974 74,066 13,349 32,985 43,323 107,051Atlantic Peninsula 27,413 67,737 2,357 5,823 29,769 73,560South Florida* 309,478 764,719 265,398 655,798 574,875 1,420,517

* Includes significant seagrass area on Atlantic side of Florida Peninsula in Dade County. Complete seagrass surveys of Broward County have not been performed, so that area is represented with a zero 

value in the calculations for these projects.

Florida gulf coast (within State jurisdictional boundaries) (Madley and others, 2003)

1. Panhandle 7,191 17,768 10,283 25,409 17,474 43,178

2. Big Bend 28,508 70,443 219,090 541,372 247,598 611,815

3. Gulf Peninsula 29,974 74,066 13,349 32,985 43,323 107,051

4. Ten Thousand Islands** 0 0 3,085 7,623 3,085 7,623

5. Florida Bay 109,550 270,698 38,063 94,054 147,613 364,752

6. Gulfside Keys 90,730 224,193 129,658 320,384 220,388 544,579

Gulf coast total 265,953 657,168 413,528 1,021,827 679,481 1,678,998

Florida gulf coast (area of benthic habitat less than 18 m (60 ft) deep, including Federal waters and deepwater Halophila beds

This is a measure of potential seagrass habitat based on depth, not actual mapped seagrass) (Madley and others, 2003)

7. Big Bend 1,415,028 3,496,534

8. Southwest Florida shelf 1,433,127 3,541,254

Gulf coast total (equals 1, 3, 4, 5, 6, 7, 8 because 2 is within 7) 3,279,524 8,103,704

**Ten Thousand Islands seagrass was originally reported as presence/absence values. For this analysis we categorized all seagrass of the Ten Thousand Islands as patchy.

Status and Trends 105
million acres). Although the 2003 estimate of statewide 

seagrass cover is 15% lower than the 1995 estimate of Sargent 

and others (about 1 million ha, or 2.6 million acres), the 

difference results in part from differences in the spatial extent 

of aerial photography and mapping coverage. The spatial 

extent of the geographic information system (GIS) data used 

by Sargent and others (1995) for the Big Bend region, in 

particular, was greater than that of the 1992 GIS data used in 

more recent estimates. Differences in habitat classification 

schemes and accuracy of alternate methods also contributed 

to the differences in seagrass area estimates. For example, the 

Minerals Management Service (MMS) 1982–87 photography 

for south Florida was flown at 1:40,000 scale and mapped at a 

coarser level of accuracy than the 1992–94 National Oceanic 

and Atmospheric Administration (NOAA) photography. 

Therefore, attempts to interpret trends in seagrass gains or loss 

on a statewide scale must acknowledge the variation among 

datasets being compared.

Several of the vignettes in this document focus on 

smaller areas of Florida where consistent mapping scales and 

classification schemes make trend analysis more reliable. 

In 7 of the 11 estuaries described in the following vignettes, 

significant seagrass loss has occurred. No measurable change 

in seagrass cover occurred in northern Charlotte Harbor, 

and seagrass cover in Tampa Bay increased 24% between 

1982 and 1996, after declining 46% between 1950 and 1982. 

Seagrass cover in Sarasota Bay increased by 19% between 

1988 and 1996 after declining by 30% between the 1950s and 

1988. Therefore, significant seagrass loss has occurred in 10 

of the 11 systems. In the two estuaries where seagrass cover 

has increased since the 1980s, recent gains have not offset 

historical losses.

Causes of Change

Several human activities have caused direct or indirect 

losses of seagrasses in Florida, and many of the Florida 

vignettes describe similar scenarios of seagrass loss. 

Significant amounts of seagrass were lost in many Florida 

estuaries as the result of dredging operations in the 1950s 

and 1960s. Propeller scarring impacts by commercial and 

recreational boats have also increased dramatically in the 

past decade (Sargent and others, 1995) as the total number of 

boats registered in Florida has risen to over 900,000. Seagrass 

losses caused by thermal effluent from powerplants have 

been documented in Biscayne Bay and St. Joseph Sound. 

Herbicides, metals, and hydrocarbons might also have caused 

seagrass loss in some Florida estuaries, acting alone or along 

with other stressors, but their distribution and impact on 

seagrasses in Florida have received little attention. Paper 

mills, known to discharge dioxins and organic compounds 

with high biological oxygen demand, nutrients, and color, 

have also caused significant loss of seagrass in several west 

Florida estuaries. For example, Livingston and others (1998) 

estimated that paper mill effluent has caused the loss of 

seagrasses over a large area at the mouth of the Fenholloway 

River. The greatest single cause of seagrass loss to date in 

Florida, in the Gulf of Mexico, and throughout the world, 

however, has been water-quality degradation. Along the 

west coast of Florida, the principal cause of water-quality 

degradation has been eutrophication resulting from domestic, 

agricultural, and industrial wastes. Several vignettes address 

the role of nutrients in seagrass losses as well as nutrient load 

reductions and corresponding recovery of seagrasses. Despite 

concerted efforts to improve water quality and restore lost 

seagrasses in Florida, losses might occur in the future as the 

result of groundwater contamination, freshwater removal from 

estuarine tributaries, and a shift in the dominance of humancaused nutrient impacts from point sources to less manageable 

nonpoint sources.

Dredge and fill operations for navigation and 

development have been strictly controlled in Florida since the 

early 1970s, but prior dredging caused significant direct and 

indirect losses of seagrasses. Dredging for navigation purposes 

along the Florida gulf coast began in the late 1890s, when the 

Federal Government authorized construction of channels from 

Tampa Bay to Sarasota and from Sarasota to Venice (Alperin, 

1983). By 1936, the Gulf Intracoastal Waterway (GIWW) was 

complete between the Apalachicola River and New Orleans. 

The GIWW segment which extends 245 km (152 mi) from 

the Caloosahatchee River to the Anclote River was dredged 

between 1960 and 1967. Congress also authorized, but never 

funded, a dredged channel in Florida between St. Marks 

and the Anclote River to connect the two GIWW segments. 

Navigation channels were dredged in Tampa Bay in the early 

1900s, and Lewis and Estevez (1988) determined that 34 km2

(13 mi2

) of bay bottom in Tampa Bay had been dredged or 

filled for residential and navigational purposes. Navigation 

channels dredged through shallow seagrass beds caused the 

immediate loss of the seagrass removed from the channel, 

burial of adjacent seagrass by deposition of dredged material, 

as well as continuing losses due to turbidity created by 

resuspended fine sediments, and turbulent scour caused by the 

wakes of large ships. Several dredging projects created fingerfill residential developments in Tampa Bay and Sarasota Bay. 

In 1924, D.P. Davis dredged Hillsborough Bay, a subestuary of 

Tampa Bay, to create residential developments which still bear 

his name. Dredging for residential development continued 

into the 1950s and 1960s, and Taylor and Saloman (1968) 

estimated that residential dredging in Boca Ciega Bay alone 

filled in approximately 1,400 ha (3,460 acres) of mangrove 

and seagrass habitat.

Propeller scar impacts are an increasing problem for 

shallow seagrass beds in Florida. Propeller scars typically 

require several years to recover (Zieman, 1976; Dawes and 

others, 1997), and many scars become scoured by currents 

or wave action and fail to recover (Precht and Gelber, 2003). 

Prior to 1995, when the Florida State Constitution was 

amended to prohibit gill net fishing in Florida State waters, 

many propeller scars were created by commercial fishing 

106 Seagrass Status and Trends in the Northern Gulf of Mexico: 1940–2002
boats circling schools of fish. Since 1995, however, the 

number of commercial fishing boats has declined dramatically, 

and the number of recreational boats has increased to almost 

1 million, making recreational boaters responsible for most 

propeller scars. Sargent and others (1995) made the first 

comprehensive inventory of propeller scarring of seagrass 

beds in Florida. They determined that approximately 70,000 

ha (173,000 acres) of Florida seagrass beds had some degree 

of propeller scarring. Moderate and severe propeller scarring 

was most prevalent in the Florida Keys, Charlotte Harbor, and 

Tampa Bay. A demonstration project at Fort Desoto County 

Park in Pinellas County found that additional signage (above 

and beyond navigation markers), speed restriction zones, and 

motor exclusion zones reduced the number and severity of 

propeller scars (Stowers and others, 2002).

Although dredging and propeller scarring have had 

serious impacts on seagrasses, degraded water quality has 

been responsible for most of the declines in the distribution 

and abundance of Florida seagrasses and submerged aquatic 

vegetation, echoing trends throughout the Gulf of Mexico 

(Lewis and others, 1982; Pulich and White, 1991), the United 

States (Orth and Moore, 1983), and the world (Cambridge and 

others, 1986) over the past 50 yr. Seagrasses are particularly 

vulnerable to declines in water column transparency resulting 

from human activities because all seagrasses require light for 

photosynthesis and because they possess nonphotosynthetic 

belowground tissues (roots and rhizomes) which require 

photosynthetically produced oxygen to survive. Reduced water 

column transparency, in turn, results from a number of natural 

and human factors. Turbidity can result from suspended 

sediment particles or phytoplankton cells, and any particles 

in the water column, living or dead, reduce light penetration 

(Gallegos, 1994; McPherson and Miller, 1994; Gallegos and 

Kenworthy, 1996). Suspended sediment can result from wind 

and wave action, boat wakes, dredging, and river runoff. In 

some gulf estuaries, dissolved organic matter also reduces 

light penetration through the water column (McPherson and 

Miller, 1994; Livingston and others, 1998). The principal 

cause of light attenuation in nearshore and estuarine waters 

of the Florida gulf coast, however, is phytoplankton blooms 

driven by nutrient runoff from urban, residential, agricultural, 

and industrial sources.

Seagrasses in many estuaries have also demonstrated 

the capability to recolonize and spread in areas where water 

quality has improved, and Tampa Bay provides a model for 

seagrass recovery in response to water-quality management 

(see Tampa Bay vignette). Lewis and others (1999) estimated 

that seagrass area in Tampa Bay declined from over 30,000 

ha (74,000 acres) in the late 1800s, to 16,500 ha (41,000 

acres) in 1950, and to 8,700 ha (21,500 acres) in 1982. Lowest 

seagrass cover coincided with high nutrient and chlorophyll 

concentrations in Tampa Bay. With implementation of 

advanced wastewater treatment at the City of Tampa sewage 

treatment plant and the subsequent development of a public 

and private nutrient management consortium, seagrass cover 

increased steadily in Tampa Bay and Hillsborough Bay 

between 1982 and 1996. For the entire Tampa Bay, Tomasko 

and Greening (Tampa Bay vignette) reported a 24% increase 

in seagrass cover during this period. Seagrass cover in 

Sarasota Bay also increased by 19% during the same period as 

the result of nutrient load reductions (Sarasota Bay vignette).

Although increases in seagrass cover have occurred 

in response to improved water quality, current trends in the 

volume, form, and spatial delivery pattern of Tampa Bay 

nutrient loads raise questions about the recovery potential 

of seagrasses in Tampa Bay and other Florida estuaries. In 

the mid-1970s, when Tampa Bay water quality was poorest, 

point sources accounted for 68% of the total nitrogen load 

of 8,437 Mg/yr (9,300 ton/yr) entering the bay (Zarbock and 

others, 1994). By the year 2010, even though total nitrogen 

loads are forecast to drop to 4,264 Mg/yr (4,700 tons/yr), 

nonpoint source nitrogen is projected to make up 84% of the 

total nitrogen load. Increasing dominance of nonpoint source 

nutrient inputs is cause for concern because the diffuse spatial 

pattern of nonpoint loads makes them difficult and expensive 

to control. Furthermore, the rate of seagrass recovery in 

Tampa Bay has slowed recently, suggesting that more stringent 

conditions might be required for seagrass reestablishment than 

for maintenance of existing beds.

The 1997–98 El Niño episode demonstrated the 

vulnerability of Florida gulf coast seagrasses to nonpoint 

nutrient loading. As noted earlier, Tampa received more than 

50 cm (20 inches) of “extra” rainfall between December 1997 

and April 1998 (Ross and others, 1998). Baywide seagrass 

cover declined by 7.7% from 10,900 ha (26,900 acres) in 

1996 to 10,060 ha (24,900 acres) in 1999. One subbasin, Old 

Tampa Bay, lost 24% of its seagrass cover between 1996 and 

1999. Sarasota Bay seagrass cover declined by approximately 

10% during the same period, demonstrating the regional scale 

impact of El Niño rainfall and runoff. No data are available 

for seagrass losses in the Big Bend region during El Niño 

episodes, but SeaWiFS satellite imagery from the NOAA for 

spring 1998 showed extensive phytoplankton blooms along 

the Florida gulf coast, and seagrass cover and health declined 

at monitoring sites in the Big Bend and gulf peninsula regions 

(Carlson and others, 2003). Poe and others (2003) estimated 

that average-annual nonpoint source nitrogen loads for 

Tampa Bay were 3,151 tons N/yr during the 1995–98 El Niño 

period compared with 1,723 tons N/yr in 1992–94, driven by 

runoff values of 2,083 million cubic meters in 1995–98 and 

1,161 million cubic meters in 1992–94. Increases in nitrogen 

loading driven by El Niño rainfall were most pronounced in 

Old Tampa Bay and Hillsborough Bay, the two Tampa Bay 

segments with the greatest rates of seagrass loss. High rainfall 

in 2003 has also been implicated as a factor slowing seagrass 

recovery in the Feather Sound portion of Old Tampa Bay 

(Greening and others, 2004).

 These data suggest that estuarine and nearshore seagrass 

cover for the Florida gulf coast might be strongly affected 

by rainfall and associated nonpoint source nutrient loads. 

Controlling nonpoint nutrients is generally more expensive 

and difficult than controlling point sources, and different 

Causes of Change 107
strategies will be required for different regions of the Florida 

gulf coast. Urbanized estuaries, such as Tampa Bay and 

Sarasota Bay, have limited space and capacity to intercept and 

treat storm water. By comparison, effective control of nonpoint 

source nutrients in the Big Bend region requires management 

of land use in the Suwannee River watershed, making up 

almost 25,900 km2

 (10,000 mi2) in Florida and Georgia.

Because human-caused nutrient loads to estuaries and 

the nearshore Gulf of Mexico increase as coastal populations 

grow, population density, urban development patterns, and 

land-use changes are the most important factors affecting 

seagrass distribution and survival along the west coast of 

Florida. In 2001, the human population of Florida was 

estimated to be 16.4 million, of which more than 12 million 

lived in coastal counties (Florida Office of Economic and 

Demographic Research, 2004). Eight coastal counties of 

southwest Florida (Monroe, Collier, Lee, Charlotte, Sarasota, 

Manatee, Pinellas, and Hillsborough) contained 3.4 million 

people, or 21% of the State total. Seven coastal counties of 

the Panhandle (Escambia, Santa Rosa, Okaloosa, Walton, 

Bay, Gulf, and Franklin) contained 835,000 people, and 

three counties along the “Springs Coast” (Citrus, Hernando, 

and Pasco) contained 601,000 people. In contrast, five 

counties of the Big Bend region (Wakulla, Jefferson, Taylor, 

Dixie, and Levy) contained only 108,000 people in 2001. 

Not surprisingly, coastal counties with the largest human 

populations, such as Pinellas, Hillsborough, Manatee, and 

Sarasota Counties, have experienced the greatest amounts of 

seagrass loss.

As populations continue to grow in Florida coastal 

counties, especially those in the Gulf Peninsula, Panhandle, 

and Big Bend regions, the potential for seagrass loss will also 

increase. Pinellas County, the most densely settled county in 

Florida, has limited space for additional development, so the 

population is forecast to increase by only 6% between 2000 

and 2010. Predicted rates of population growth for Collier, 

Lee, Charlotte, Pasco, Hernando, Citrus, and Levy Counties, 

however, range from 17% to 20% during the same period. As 

population growth, urbanization, and land-use changes occur 

in coastal counties, additional seagrass losses will occur unless 

concerted efforts are made to control point and nonpoint 

source nutrient loads. Other contaminants, such as herbicides, 

metals, and hydrocarbons, that enter nearshore waters from 

point sources and nonpoint source runoff might also affect 

seagrass growth and survival.

Mapping and Monitoring Problems and 

Information Needs

Data Problems

Data problems associated with seagrass mapping are 

not unique to the State of Florida. Typical problems include 

lack of standardization in habitat classification systems, 

scale of photography and mapping, absence of frequent and 

synoptic coverage, use of different projections for benthic 

habitat mapping and GIS data, and seasonal differences in 

seagrass cover (see discussion of phenology below). Uniform 

classification systems for seagrass mapping are currently 

being adopted by the Florida Fish and Wildlife Conservation 

Commission (FWC) and other State, Federal, and local 

agencies; however, many historical seagrass data have used 

differing classification systems. The NOAA Coastal Services 

Center has provided specifications and guidance for seagrass 

aerial photography and mapping, and those standards are often 

used as guidelines for projects nationwide (Finkbeiner and 

others, 2001).

Rescue and preservation of seagrass aerial photography 

are also important data problems and needs for the State of 

Florida. Although water management districts have carried out 

seagrass aerial photography along much of the Florida gulf 

coast since the late 1980s, portions of the coastline are still not 

flown on a regular basis, availability of earlier photography 

is spotty, and original photographs are being lost because 

no systematic program exists to locate, rescue, archive, and 

catalog historical aerial photography. For example, the earliest 

seagrass aerial photography reported in table 1 was flown in 

1982 by NOAA and by MMS. Although the FWC’s Fish and 

Wildlife Research Institute (FWRI) has archived some MMS 

photography, efforts to locate the original negatives have been 

unsuccessful, emphasizing the need for data rescue. 

Other significant data problems affecting seagrass 

resource management are errors or biases associated with 

seagrass photointerpretation and mapping which sometimes 

overestimate, and sometimes underestimate, seagrass cover. 

For example, with current manual photointerpretation 

techniques, seagrass beds in aerial photographs are classified 

as patchy or continuous, and minimum mapping unit (MMU) 

sizes for 1:24,000 aerial photography are generally set at 

108 Seagrass Status and Trends in the Northern Gulf of Mexico: 1940–2002
0.1 ha (0.25 acres) or larger, ignoring smaller seagrass beds. 

Seagrass cover can also be overestimated because patchy beds 

include substrate with seagrass cover as low as 10%. From a 

resource management standpoint, the most serious concern 

is that potentially significant declines in seagrass cover 

could occur undetected within polygons classified as patchy 

seagrass, compromising our ability to recognize and correct 

water-quality problems in a timely manner.

Digital, multispectral imagery and supervised software 

classification techniques provide opportunities to improve 

estimates of seagrass area and density by decreasing MMU 

size and increasing the number of seagrass cover classes. 

Costs for digital imagery acquisition and turnaround time 

for digital imagery processing and interpretation are also 

expected to decrease. These factors will enhance our ability 

to visualize seagrass changes and take management action in 

a timely manner. Despite improvements in seagrass mapping 

techniques, however, monitoring with field work is, and will 

continue to be, a necessary adjunct to aerial photography for 

seagrass assessment and management.

Seagrass phenology—seasonal changes in seagrass 

growth and senescence—is an important yet often 

overlooked data problem for seagrass aerial photography. 

Seagrasses along the Florida gulf coast grow during spring 

and summer, generally reaching peak biomass in early 

fall. When cold fronts begin to cool water temperatures in 

October and November, seagrass cover begins to decline. 

Between December and March, cold fronts and lunar tidal 

forces generate very low tides during daytime hours, which 

frequently causes shallow seagrasses to desiccate and 

defoliate, rendering them invisible to aerial photography 

at 1:24,000 scale. The decline and loss of seagrass cover 

occur earlier in fall and persist longer in spring in north 

Florida than in south Florida and the Florida Keys, creating 

potential problems within datasets and in comparing data 

from different times. Along the west coast of Florida, seagrass 

aerial photographs taken in December and January might 

show significantly less shallow seagrass cover than would 

photographs taken in November, especially for shoal grass 

(Halodule wrightii). Because, over the past 14 yr, Tampa Bay 

aerial photography documenting seagrasses has been flown 

once in October, twice in December, three times in January, 

once in February, and once in April, areal estimates of shallow 

seagrass might vary considerably.

Phenology is often overlooked or considered a secondary 

criterion because of overriding concerns about cloud cover and 

water clarity. Ideal conditions for seagrass aerial photography 

occur infrequently because they include sun angle, cloud 

cover, wind, and water clarity criteria. During summer in 

Florida, cloud cover is generally too great. For much of the 

Florida peninsula, runoff and associated phytoplankton and 

turbidity create unacceptable water clarity for seagrass aerial 

photography into late fall and early winter. As a result, many 

seagrass aerial photography projects are currently flown in late 

fall and winter to take advantage of low cloud cover, low tides, 

and better water clarity.

Spring months (March and April in south Florida 

and April and May in north Florida), however, have more 

cloud-free days than do December, January, and February. 

In typical years, water clarity is excellent in spring, and 

seagrasses have begun to grow again, creating a spring 

window of opportunity for aerial photography. The St. Johns 

River Water Management District (SJWMD), one of the first 

agencies in the State of Florida to develop a comprehensive 

seagrass mapping and monitoring program, flies seagrass 

aerial photography in spring (Virnstein and Morris, 1996), 

although the Southwest Florida Water Management District 

(SWFWMD) flies aerial photography between October and 

January for much of the west-central Florida coast. To obtain 

the best possible seagrass photography, the fall “window” 

should be shortened to avoid winter defoliation, and a spring 

“window” should be considered. Because photointerpretation 

costs are much greater than aerial photography costs alone, 

resource management agencies might consider acquiring 

photography in spring and fall and then using the best set or 

portions of each set to create the most complete, accurate 

assessment of seagrass cover. At a minimum, an effort should 

be made to determine the amount of seagrass cover “missing” 

in winter photography.

Because several factors (seagrass phenology, sun angle, 

cloud cover, haze, wind, and water clarity) affect the quality 

and interpretability of seagrass imagery, several sets of Florida 

seagrass imagery have been partly or totally unusable. The 

cost and effort of mobilizing aircraft and staff for aerial 

photography projects sometimes result in photography under 

less than optimal conditions. Large areas often require several 

days for complete photography, and changing conditions can 

affect imagery quality. To avoid costly mistakes acquiring 

imagery of poor quality, there are two relatively new resources 

available for seagrass aerial imagery planning: MODIS 

satellite imagery and real-time cloud cover data. MODIS 

imagery is downloaded daily by the University of South 

Florida Institute for Marine Remote Sensing, and the center 

maintains a Web site with a library of current and recent 

MODIS imagery for the Florida peninsula 

(http://modis.marine.usf.edu). Turbidity from resuspended 

sediments, as well as color resulting from dissolved organic 

matter and phytoplankton blooms, is readily apparent in 

MODIS imagery. Large seagrass beds are also visible. The 

daily frequency of the imagery allows rapid and frequent 

assessment of water clarity, cloud cover, and approaching 

weather systems. Real-time cloud cover maps are available 

from several National Weather Service Web sites, enabling 

users to hourly select cloud-free areas for aerial photography.

Another important information gap is the area of the 

west Florida shelf covered by deepwater paddle grass and 

star grass. Paddle grass meadows are not easily mapped by 

aerial photography because they frequently occur in water 

depths greater than 10 m (33 ft) and because the plants are 

small. Continental Shelf Associates, Inc. (1989) found that 

paddle grass covered 1.2 million ha (3 million acres), or 31% 

of their study area, on the southwest Florida continental shelf. 

Mapping and Monitoring Problems and Information Needs 109
Paddle grass occurred to depths of 37 m (122 ft) with greatest 

biomass at depths from 21 to 27 m (70 to 90 ft). Continental 

Shelf Associates, Inc. (1985) also reported extensive beds of 

paddle grass in the Florida Big Bend region. In table 2, we 

have made a conservative estimate of potential paddle grass 

cover on the west Florida shelf, and the inclusion of paddle 

grass beds raises our estimate of seagrass area to about 3 

million ha (7.4 million acres). The accurate assessment of area 

of paddle grass beds on the west Florida shelf is an important 

data gap to fill because of the potential trophic importance of 

these communities and their vulnerability to nutrification of 

the nearshore Gulf of Mexico. Because aerial photography 

is not useful for mapping paddle grass beds, other mapping 

techniques (acoustics and video transects, for example) should 

be used.

Monitoring Needs

Monitoring of seagrasses in the Big Bend region is one 

of the most urgent needs for the State of Florida because 

increasing nutrient loads to nearshore waters of the Florida 

gulf coast jeopardize extensive seagrass resources (Mattson 

and others, Florida Big Bend vignette, this report). In some 

springs of the Suwannee River drainage basin, groundwater 

nitrate concentrations have risen thirtyfold in the past 40 yr 

(Katz and others, 1997). SeaWiFS chlorophyll imagery in 

spring 1998 showed extensive and persistent phytoplankton 

blooms in the northeastern Gulf of Mexico resulting from 

El Niño runoff and increasing nutrient loads in west Florida 

rivers. Given the large size of offshore seagrass beds and the 

shallow slope of the west Florida shelf, a 50-cm (20-inch) 

decrease in seagrass compensation depth resulting from small 

increases in turbidity and/or phytoplankton biomass would 

eliminate thousands of acres of seagrass. In the absence of 

good mapping and monitoring for offshore seagrasses, we 

would be unaware of the losses. With funding from the U.S. 

Environmental Protection Agency Gulf of Mexico Program, 

FWC and Suwannee River Water Management District are 

developing a seagrass monitoring program for the Big Bend 

region, and FWC is also working with NOAA on Halophila

beds of the southwest Florida shelf. Additional effort and 

funding will be required, however, to design and implement a 

seagrass monitoring program for the west Florida shelf.

Seagrass assessment programs incorporating aerial 

photography and mapping as well as fixed-site or probabilistic 

monitoring are evolving throughout Florida, and FWRI is 

developing an integrated and statewide seagrass mapping and 

monitoring program. The primary goals of this program are 

seagrass mapping and monitoring on a schedule that balances 

cost and the need for timely information for management 

decisions. Mapping and monitoring are complementary tools 

because they operate on different spatial and temporal scales. 

For example, in an integrated program such as that developed 

by the SJWMD (Virnstein and Morris, 1996), seagrass cover 

in the Indian River Lagoon is mapped every 2 or 3 yr from 

aerial photography. Groundtruthed data for aerial photographs 

and more frequent and detailed information on seagrass 

species composition, canopy height, and density are collected 

every summer from 80 fixed transects along the lagoon. Costs 

for aerial photography and photointerpretation of the Indian 

River Lagoon are approximately $428/acre, and costs for 

annual monitoring of 80 seagrass transects are approximately 

$60,000/yr (Virnstein, personal commun.). Similar integrated 

mapping and monitoring programs have been developed 

for Tampa Bay, Sarasota Bay, and Charlotte Harbor. Better 

integration of mapping and monitoring data is needed, and the 

merits of probabilistic sampling versus fixed transects should 

be evaluated. In the short term, however, we hope to collect 

data from all seagrass mapping and monitoring programs in 

Florida, producing annual monitoring reports and mapping 

reports every 6 yr.

For nearshore seagrass beds in the Big Bend shelf, 

southwest Florida shelf, and the gulfside Florida Keys, the 

sheer size of the areas involved and water depths will require 

mapping and monitoring programs of a different scale and 

frequency. Much of the initial offshore survey work was done 

to provide background information for potential oil and gas 

exploration and extraction. Lacking that economic incentive, 

we need to find other sources of funding to map, monitor, and 

manage these resources.

Assessment, Protection, Recovery, and 

Restoration Opportunities

Several agencies participate in seagrass monitoring and 

management along the Florida gulf coast, including the FWC, 

Florida Department of Environmental Protection (FDEP), 

Northwest Florida Water Management District, Suwannee 

River Water Management District, SWFWMD, and South 

Florida Water Management District. Tampa Bay and Charlotte 

Harbor have active estuary programs, and there are two 

national estuarine research reserves along the Florida gulf 

coast: Apalachicola Bay and Rookery Bay. Several counties 

also have environmental monitoring programs. These agencies 

focus on seagrass protection by coordinating mapping and 

monitoring activities, by providing information on seagrass 

management and restoration to managers, and by making 

efforts to protect and improve water quality.

The FDEP also has jurisdiction over submerged lands 

in State waters and administers several aquatic preserves 

along the Florida gulf coast. There are three national wildlife 

refuges along the Florida gulf coast (Lower Suwannee, 

Chassahawitzka, and St. Marks) and one national park 

(Everglades). The combined jurisdiction of State aquatic 

preserves, national wildlife refuges, and Everglades National 

Park provides statutory protection for much of the nearshore 

seagrass beds in the Big Bend and Ten Thousand 

Islands regions.

110 Seagrass Status and Trends in the Northern Gulf of Mexico: 1940–2002
Protection of existing seagrasses and the maintenance or 

restoration of water quality are the most cost-effective seagrass 

management tools available because seagrass restoration 

plantings are extremely expensive, and the success of 

restoration plantings varies considerably. Fonseca and others 

(1998) reported that published costs for seagrass plantings 

ranged from $25,000/ha to $50,000/ha. They suggested that 

total costs were likely closer to $500,000/ha (approximately 

$200,000/acre), excluding costs for donor material collection 

or purchase. If that cost estimate is combined with the estimate 

by Lewis and others (1999) of seagrass loss in Tampa Bay 

between 1950 and 1982 (over 8,000 ha, or 20,000 acres), 

the cost of restoring the lost seagrass would be over $4 

billion. Tomasko (2003) reported that, between 1982 and 

1996, less than 1% of the seagrass recovery that occurred in 

Tampa Bay resulted from seagrass restoration plantings. The 

remaining 99% of seagrass recovery during that time period 

(approximately 2,130 ha, or 5,262 acres) resulted from natural 

expansion and recolonization of seagrasses within the bay 

in response to improved water clarity. The improved water 

clarity, in turn, resulted from a public-private partnership to 

manage nitrogen loading to Tampa Bay (Lewis and 

others, 1999).

Given the potential for natural recovery in response 

to water quality management, the best role for restoration 

plantings might be for mitigating unavoidable losses and for 

restoration of direct impacts such as vessel groundings and 

propeller scars. Even in that context, however, additional 

information is needed on development of reliable sources 

and methods to cultivate seagrass transplant material for 

restoration, mechanical and hand planting techniques, and 

techniques to stimulate regrowth of seagrass in propeller scars. 

For example, current restoration and mitigation programs rely 

on donor material from intact seagrass beds or on salvage 

material from beds which are being destroyed. Donor bed 

impacts are unavoidable in the former case. Alternatives to 

using donor seagrass material from healthy seagrass beds 

include micropropagation and seagrass nurseries. At present, 

complete micropropagation techniques have been developed 

and field tested for wigeon grass. Some success has been 

achieved with laboratory culture of shoal grass but not with 

turtle grass or manatee grass. Seagrass Recovery, Inc. in 

Ruskin, Fla., has successfully propagated shoal grass in 

brackish pond culture, a process that considerably reduces 

donor bed impacts.

In addition to problems with obtaining seagrass 

transplants, restoration plantings are also very labor intensive. 

Mechanical seagrass transplanting techniques are currently 

being tested and might provide a cost-effective method for 

restoration plantings. Propeller scar restoration techniques 

which are currently being tested by FWC staff and industry 

partners are sediment tubes and sediment amendments 

which might stimulate seagrass growth into propeller scars. 

Propeller scar recovery is particularly important because of the 

increasing number of recreational boats and the long recovery 

time (over 7 yr) of propeller scars measured in Tampa Bay 

(Dawes and others, 1997).

Florida seagrass scientists and resource managers 

have invested considerable effort in collecting and sharing 

information on seagrass biology, ecology, and management. 

The Tampa Bay Estuary Program has sponsored two 

conferences related to seagrass management in the past 3 yr: 

“Seagrass Management: It’s Not Just Nutrients” was held in 

St. Petersburg, Fla., in August 2000, followed by “Submerged 

Aquatic Habitat Restoration in Estuaries: Issues, Options, 

and Priorities,” held in Sarasota, Fla., in March 2003. Print 

copies of proceedings for both conferences are available from 

the Tampa Bay Estuary Program, and electronic copies of the 

presentations are posted on the Tampa Bay Digital Library 

Web site created by the U.S. Geological Survey (USGS) 

(http://gulfsci.usgs.gov/library/ ). The Tampa Bay Estuary 

Program and the U.S. Environmental Protection Agency have 

also collaborated to update Zieman and Zieman’s (1989) 

report The Ecology of the Seagrass Meadows of the West 

Coast of Florida: A Community Profile. The updated report 

by Dawes, Phillips, and Morrison (2004) titled Seagrass 

Communities of the Gulf Coast of Florida: Status and Ecology

is available as a digital document from the Tampa Bay Estuary 

Program Web site (http://www.tbeptech.org/TechPubs/

t0304.pdf).

The FWC and other resource management agencies also 

provide online access to seagrass GIS data. Statewide GIS data 

are available from the FWRI Marine Resources GIS Internet 

Map Server (http://ocean.floridamarine.org/mrgis/viewer.htm). 

The SWFWMD also offers downloadable GIS coverages for 

their biennial seagrass surveys in the Tampa Bay, Sarasota 

Bay, Lemon Bay, and Charlotte Harbor regions 

(http://www.swfwmd.state.fl.us/data/gis/libraries/swim.htm). 

Maps of Tampa Bay seagrass cover based on SWFWMD aerial 

photography and GIS data are available from the Tampa Bay 

Estuary Program (http://www.tbeptech.org/html/sg_maps.html). 

Metadata for FWRI and SWFWMD GIS data that is compliant 

with guidelines by the Federal Geographic Data Committee 

can be downloaded from their respective Web sites.

In a partnership, the FWRI, USGS, Tampa Bay Estuary 

Program, and the SWFWMD have created a Web site that 

provides digital imagery, digital nautical charts, seagrass data, 

and other relevant GIS data for the Tampa Bay area. This Web 

site (http://ocean.floridamarine.org/tbep) contains rectified 

and georeferenced time series aerial photography that allows 

users to view and overlay aerial photographs from 1928 

through 2002. A set of easy-to-use but powerful tools allows 

any user to assess temporal changes in seagrass cover and 

construction throughout the Tampa Bay region. It is hoped that 

this Web site will serve as a model, providing intuitive access 

to complex data for a variety of users, and FWRI is making 

a concerted effort to rescue, preserve, digitize, and distribute 

historical seagrass aerial photography, surveys, and monitoring 

data from around the State. 

Assessment, Protection, Recovery, and Restoration Opportunities 111
Three relevant reports and databases have been 

developed by FWC’s Florida Marine Research Institute. 

The Florida Seagrass Conservation Information System 

(www.floridamarine.org/seagrass) provides descriptive and 

contact information for a number of seagrass-related projects 

in Florida, including education, protection, restoration, 

mapping/monitoring, and research. Narrative project 

summaries are available. Users can query the online database 

to identify projects according to several key fields of interest, 

including project type, location, and principal investigator. 

Search results are arranged in print-friendly reports, and new 

projects can be submitted for inclusion in the database by 

completing online forms. Because this is a dynamic database 

with continuous update ability, it is hoped that acceptance 

and use of this system will promote up-to-date information 

exchange among seagrass scientists and managers.

The Florida Seagrass Manager’s Toolkit is also available 

on the FWC Web site (http://www.floridamarine.org/features/

view_article.asp?id=23202). The toolkit provides practical 

information for resource managers and other professionals 

directly involved in seagrass management, as well as for 

interested citizens. The ecological importance of Florida’s 

seagrass habitats and the need for effective management are 

summarized. A basic problem-solving model that can be used 

to develop appropriate management responses is presented, 

and the importance of spatial and temporal scale in seagrass 

management and monitoring is addressed. Tools available 

for mapping and monitoring, protection and restoration, 

and replanting and repair of damage are described, and 

emerging issues of potential future interest to seagrass 

managers are discussed.

Finally, FWC has developed a framework for a statewide 

seagrass management program. Titled Conserving Florida’s 

Seagrass Resources: Developing a Coordinated Statewide 

Management Program, the report is also available at http://

www.floridamarine.org/features/view_article.asp?id=23185. 

This report is intended to serve as a nontechnical planning 

document that provides a conceptual framework for 

development of a coordinated statewide seagrass management 

initiative while also recognizing supporting and building upon 

the accomplishments of local, community-based programs. 

Effective local seagrass management programs are currently 

underway in several areas of Florida. In addition, a number 

of Federal and State agencies provide programs for the 

protection, mapping, and monitoring of seagrass habitats 

within their jurisdictions. This report recommends a series of 

steps that could be taken to initiate a coordinated, cooperative, 

multiagency program. A primary purpose of the statewide 

program should be to provide increased support for, as well 

as greater statewide consistency in the implementation of, the 

various components of seagrass management. 

One key component of this plan is adoption of 

measurable goals for seagrass protection and recovery and 

a program to monitor seagrass status and trends throughout 

the State. With impetus from the U.S. Commission on Ocean 

Policy Ocean Initiative, the Florida Ocean Initiative has begun 

development of a statewide seagrass mapping and monitoring 

program. The Florida Department of Environmental Protection 

and Fish and Wildlife Conservation Commission are 

partnering in this effort. It is hoped that, by building on current 

seagrass mapping efforts by water management districts within 

the State of Florida and by adopting standardized monitoring 

protocols, onground assessments will be performed annually 

and complete statewide seagrass mapping will be performed 

every 6 yr.

Acknowledgments

We thank Jesse Lewis and Jim Krolick for GIS analysis 

of seagrass data. Bill Sargent and David Crewz provided 

information on FWC Web publications and restoration 

technique development, respectively. Laura Yarbro and Penny 

Hall provided valuable editorial comments on early drafts. 

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