Tampa Bay National Estuary Program 

Technical Publication #07-94 

HARD BOTTOM MAPPING 

OF TAMPA BAY 

FINAL REPORT 

OCTOBER, 1994 
HARD BOTTOM MAPPING 

OF 

TAMPA BAY 

Prepared for: 

Tampa Bay National Estuary Program 

111 Seventh Avenue South 

St. Petersburg, FL 33701 

by 

Daniel M. Savercool 

Roy R. Lewis III 

August 1994 

Revised October 1994 

LEWIS ENVIRONMENTAL SERVICES, INC. 

Post Office Box 20005 

Tampa, FL 33622-0005
INTRODUCTION 

Hard bottom communities are benthic habitats dominated by epifaunal organisms such as 

sponges, hard and soft corals, hydroids, anemones, barnacles, bryozoans, decapod 

crustaceans and gastropods. By nature, these organisms are sessile and most are attached 

directly to the hard substrate. Although hard bottom communities do not dominate 

Florida's estuarine and marine benthos, they are found throughout the central to southern 

coastal regions of the state from Port Canaveral on the east coast to Hernando Beach on 

the west coast. Community composition varies as bottom type varies from the welldocumented coral reefs of southeastern and Keys region of the state to the vermetid and 

coquina reefs of east central Florida and the limestone outcroppings of the west central 

coast. 

Hard bottom community composition typically is defined by the relatively narrow water 

temperature and salinity ranges of the benthos. However, many benthic species are able 

to tolerate the variable environmental conditions present in estuaries. Previous studies 

conducted by Dawson (1953) and Derrenbacker and Lewis (1985) report that hard bottom 

communities are located in Tampa Bay, Florida's largest estuary. Although Dawson first 

reported the hard bottom communities in the bay, it was Derrenbacker and Lewis who 

provided the description of the flora and fauna associated with the hard bottom. Both 

studies located two hard bottom communities within Tampa Bay. The northernmost 

community was located in the central portion of the bay around the Gandy Bridge and the 

other was located south from Bishop Harbor to Terra Ceia Bay in Lower Tampa Bay. 

During recent years, the development of a baywide environmental management plan has 

become a common goal of the local and regional regulatory agencies. Management of 

environmentally sensitive organisms such as those commonly associated with hard bottom 

communities is included in the plan. To effectively manage the hard bottom communities 

and their associated populations, the communities must first be located before detailed 

quantitative studies can be performed. Although only two communities have been located, 

the presence of other benthic communities in Tampa Bay that are associated with hard 

bottoms, such as oyster bars, suggest that others exist. Also, limestone bedrock has 

1 
become exposed through dredging to maintain shipping channels, making habitat 

potentially available for epifaunal benthos. 

In May 1993, Lewis Environmental Services, Inc. was contracted by the Tampa Bay 

National Estuary Program to locate and map existing hard bottom communities in Tampa 

Bay. This report presents the results of aerial photointerpretation, groundtruthing and 

mapping tasks pursuant to that contract. 

METHODS 

True color aerial photography (9" x 9" contact prints) from the 1990 SWIM series for 

Tampa Bay were interpreted to determine approximate locations of areas exhibiting the 

signature of hard bottom communities (Figure 1). These locations were overlaid onto 

NOAA Charts #11414 Ed. #29 and #11413 Ed. #35 to determine location relative to 

latitude and longitude coordinates. Location coordinates were entered into a Magellan 

GPS NAV 5000D. The GPS was used as a navigational aid to locate in the field those 

areas delineated in the photography. 

Each area delineated from the aerial photography was inspected to determine substrate 

type (hard or soft bottom). If the substrate was a hard bottom, the sites were visually 

analyzed to determine dominant species composition, substrate (concrete, limestone or 

oyster shell), water depth, habitat size and updated location. If the water depth was in 

excess of six feet, SCUBA divers or snorkelers were deployed to collect the descriptive 

data. Many sites were photographed using underwater cameras. Upon return to the lab, 

data were tabulated and maps showing hard bottom community locations were updated. 

RESULTS 

Three distinct hard bottom habitat locations were analyzed (Table 1). Two of the three 

were the communities previously described by Derrenbacker and Lewis (1985). The first 

is located from the mouth of Cockroach Bay south to the mouth of Terra Ceia Bay in 

Lower Tampa Bay (Figure 2). The hard bottom community in this area is on native 

2 
Figure 1. Vertical aerial photograph of Little Cockroach Bay, Middle Tampa Bay, February 8, 1994. Hard bottom (HB) is shown 

extending in a linear fashion parallel to the sandbar (SB) jut offshore of the seagrass beds (SG). Also shown are drift algae (A), oyste

bars (OB) and mangroves (M). Photograph by Candy Photography, Inc. 
HARD BOTTOM COMMUNITIES 

1 

INTERPRETED FROM 1990 

1:24,000 TRUE COLOR ! 

VERTICAL AERIAL PHOTOGRAPHY I 

AND GROUNDTRUTHING 

HARD BOTTOM COMMUNITIES 

\ 

4 

FIGURE LEWIS ENVIRONMENTAL 

TAMPA, FT. LAUDERDALE &

SUMMERLAND KEY, FL. 

(813) 889-9684 

SERVICES. INC. MIDDLE & LOWER TAMPA 

BAY 
limestone outcroppings. Much of the limestone has been naturally exposed, with the 

exception of the area in the shipping channel east of the Sunshine Skyway Bridge. Here, 

the limestone has been exposed by dredging operations and has remained exposed through 

the swift tidal currents flowing in the channel. At the hard bottom community in Lower 

Tampa Bay, the dominant epibenthos are sea whip (Leptogorgia virgulata, Figure 3), 

starlet coral (Siderastrea radium), loggerhead sponge (Spheciospongia vesperia), boring 

sponge (Cliona celata) and the alga Sargassum filipendulum (Table 2). This community 

is located in water depths which range from approximately 4' to 22' MSL. 

Table 1. Location and size of verified hard bottom communities by bay segment, Tampa 

Bay, Florida. 

BAY SEGMENT LATITUDE (N) LONGITUDE (W) ACREAGE 

Upper Old Tampa Bay 27o

59'43'' 

27o57'35" 

27o56'40'' 

Subtotal 

Lower Old Tampa Bay 27o

53'29" 

27o52'52" 

Subtotal 

Middle & Lower Tampa Bay 27o

43'00'' 

27o4 1'58" 

27o38 ' 17 " 

27o37'40'' 

27o36'30" 

27o36'38'' 

27o

33 I 1 1 " 

27o32'25'' 

Subtotal 

Tampa Bay Total 

82o39'34" 

82o34'27'' 

82o34'27'' 

82o32'41 " 

82o34'41 " 

82o30'00" 

82o3 1'23" 

82o34'35" 

82o34'50'' 

82o

35' 12'' 

82o38' 14'' 

82o38'14" 

82o35'24" 

65.4 

111.8 

56.0 

233.2 

2.0 

15.4 

17.4 

59.3 

41.4 

2.3 

12.2 

162.9 

185.3 

72.1 

66.2 

60 1.7 

852.3 
Table 2. Lower Tampa Bay hard bottom community species list. 

Porifera Cliona celata boring sponge 

Spheciospongia . vesparia loggerhead sponge 

Cnidaria Leptogorgia virgulata sea whip 

Cerianthopsis americanus tube anemone 

Haloplenella sp. 

Siderastrea radians 

rock anemone 

starlet coral 

Mollusca 

Pol ychaeta 

Crustacea 

Urochordata 

Vertebrata 

Thais haemostoma floridana Florida rock snail 

Dodecacaria concharum boring polychaete 

Alpheus sp. 

Pagurus pollicaris 

snapping shrimp 

flat-clawed hermit crab 

Amaroucium stellatum starred tunicate 

Archosargus probatocephalus sheepshead 

Lagodon rhomboides pinfish 

Haemulon sp. grunt 

Algae Sargassum filipendulum sargassum 

Caulerpa mexicana caulerpa 

The second distinct hard bottom habitat is located in the area of the Gandy Bridge in 

Middle Tampa Bay (Figure 4). Although some of the community is on naturally exposed 

native limestone, much has recruited onto concrete rubble placed within the right-of-way 

during previous bridge construction activities. The dominant species in this area are 

similar to those of the hard bottom of Lower Tampa Bay, with the exception of the 

absence of hard corals and Sargassum (Table 3). This community also supports large 

populations of caprellid amphipods (Caprella spp.) which use their posterior appendages 

to grasp the soft coral surfaces (Lombardo and Lewis 1981; Figures 5 and 6). The water 

depth in this area ranges from approximately 3' to 12' MSL. 
5 

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FIGURE LEWIS ENVIRONMENTAL 

TAMPA ,FT. LAUDERDALE & 

(813) 889-9684

SERVICES. INC. LOWER OLD TAMPA 

SUMMERLAND KEY, FL. BAY 4 

- - ~__ - -~ ~ ~- - ~~~ - 
Table 3. Lower Old Tampa Bay hard bottom community species list. 

Pori fera Cliona celata

Cnidaria Leptogorgia virgulata 

Cerianthopsis americanus 

Bundosoma sp. 

Mollusca Thais haemostoma floridana 

Crustacea Caprella penantis 

Caprella equilibra 

Alpheus sp. 

Pagurus pollicaris 

Urochordata Styela sp. 

Vertebrata Hypleurochilus geminatus 

Syngnathus sp. 

Lagodon rhomboides 

boring sponge 

sea whip 

tube anemone 

burrowing anemone 

Florida rock snail 

caprellid amphipod 

caprellid amphipod 

snapping shrimp 

flat-clawed hermit crab 

sea squirt 

crested blenny 

pipefish 

pinfish 

The third hard bottom habitat, previously unreported, is located in the northern portions of 

Old Tampa Bay off of Booth and Rocky Points (Figure 7). Many hard bottom 

communities within this location are on naturally exposed native limestone, but the 

majority are associated with living oyster reefs. Dominant epifaunal species are the sea 

whip (L virgulata) and American oyster (Crassostrea virginica). Finfish species 

associated with oyster reefs (such as red drum, Sciaenops ocellatus) are also present in 

this area (Table 4). The water depth at this location ranges from approximately 0’ to 9‘ 

MSL. 

DISCUSSION 

When Dawson (1953) first reported the hard bottom communities in Tampa Bay, the 

discovery had little impact on management of the bay because of the lack of 

environmental awareness at the time. Since the advent of environmental regulations in the 

late 1970s, management to protect the bay’s environmental integrity has become an 

important local and regional issue. But when Derrenbacker and Lewis (1985) described 

the hard bottom communities reported by Dawson, environmental regulations still offered 

little assistance towards managing these habitats. Although hard and soft corals are 

9 
Figure 5. Underwater photograph of the orange form of the 

gorgonian, Leptogorgia virgulata,south of the Gandy Bridge, Old 

Tampa Bay. 

10 
Figure 6. Underwater macrophotograph of the surface of a 

gorgonian covered with caprellid amphipods. Two species, 

Caprella penantis and C. equilibru, utilize the soft coral as 

habitat. 

11 
HARD BC TTOM 

INTERPRETED 

COMM UNITI ES 

FROM 1990 

1:24,000 TRUE COLOR 

VERTICAL AERIAL PHOTOGRAPHY 

AND GROUNDTRUTHING 

FIGURE 

7 

UPPER OLD TAMPA 

BAY 

LEWIS ENVIRONMENTAL 

SERVICES. INC. 

TAMPA FT. LAUDERDALE &

(813) 889-9684 

SUMMERLAND KEY, FL 
protected by Florida law, acknowledgement of their presence in Tampa Bay has been 

largely ignored by the various management plans that have been drafted in the past two 

decades. 

Table 4. Upper Old Tampa Bay hard bottom community species list. 

Porifera Cliona celata boring sponge 

Cnidaria Leptogorgia virgulata sea whip 

Cerianthopsis americanus tube anemone 

Mollusca Thais haemostoma floridana Florida rock snail 

Crassostrea virginica American oyster 

Crustacea Caprella penantis 

Caprella equilibra 

Alpheus sp. 

Pagurus pollicaris 

caprellid amphipod 

caprellid amphipod 

flat-clawed hermit crab 

snapping shrimp 

Urochordata Styela sp. sea squirt 

Vertebrata Hypleurochilus geminatus crested blenny 

Syngnathus sp. pipefish 

Lagodon rhomboides pinfish 

Sciaenops ocellatus red drum 

Figures 3, 4 and 7 reflect the location of only those hard bottom communities located in 

water shallow enough to allow detection by visual inspection of aerial photography. It is 

suspected that a far larger hard bottom community is associated with those portions of the 

Tampa Bay ship channel where rock has been dredged and exposed, and in deeper 

portions of the bay not routinely visible in aerial photography. Because of this, any 

proposed disturbance to bay bottom should have a required preliminary live bottom 

survey. An example of this was the benthic survey performed by Mote Marine 

Laboratory related to the possible upgrading of a natural gas pipeline in Old Tampa Bay 

(Mote Marine Laboratory 1993). 

13 
The Tampa Bay National Estuary Program, in its goal to produce a comprehensive 

management plan for the bay, has recognized the unique nature of these habitats in an 

estuary, their implications with respect to water quality, and the importance of their 

protection. Although locating these habitats is an important management tool, further 

quantitative analyses regarding species composition should be conducted. The presence of 

soft corals, a faunal group associated with very clear unpolluted water, in Upper Tampa 

Bay, an area where water quality once was severely degraded, is an indication that efforts 

to improve the bay's water quality are successful. 

LITERATURE CITED

Dawson, C. E., Jr. 1953. A survey of the Tampa Bay area. Fla. State Board Conserv. 

Mar. Lab. Tech Ser. 8. 39 pp. 

Derrenbacker, J. A., Jr. and R. R. Lewis. 1985. Live bottom communities of Tampa Bay. 

Pp. 385-392 in S. Treat, J. L. Simon, R. Lewis and R. Whitman (eds.), 

Proceedings, Tampa Bay Area Scientific Information Symposium [May 1982]. 

Bellwether Press, Minneapolis. 

Lombardo, R. and R. Lewis. 1981. Grasping appendages of Caprella penantis Leach 

(Amphipoda). Fla. Scientist 45( 1):304 (abst). 

Mote Marine Laboratory. 1993. Survey of the benthos along the natural gas pipeline 

corridor from West Gandy Causeway to the Interbay Peninsula, Old Tampa Bay, 

Florida. Technical Rep. No. 330. Sarasota, Fla. 10 pp + figs, tables, app.