Ecological Targets

RESOURCE 

EVALUATION 

REPORT

SFNRC Technical Series

2006:2

for Western Biscayne National Park

National Park Service

U.S. Department of the Interior

South Florida Natural Resources Center

Everglades National Park 
Ecological Targets for 

Western Biscayne National Park 

April, 2006 Department of the Interior 
EXECUTIVE SUMMARY 

National Park Service staff developed descriptive ecological targets based on biological communities in 

Biscayne National Park. We selected biological indicators that include those described by the interagency 

RECOVER team to set environmental targets affected by inflows, primarily as measures of seasonal 

salinity patterns in key areas of the park. Other relevant indicators of bay health derived from previous 

and current studies in the entire Biscayne Bay area are also discussed in support of defining desired 

ecological conditions and the salinities needed to sustain them. The target area for the development of 

ecological and salinity performance measures is a 10,000 acre, primarily softbottom zone in the western 

zone of Biscayne National Park. 

The productivity and richness of the estuarine communities of Biscayne National Park have 

significantly diminished, as have those throughout Biscayne Bay, as a result of channel creation and the 

diversion of water away from the natural systems in south Florida. The quantity of fresh water, the 

seasonal timing of inflows, and the distribution along the coast have been significantly altered, profoundly 

affecting the historic estuarine nature of the western half of the Bay. The alteration of the hydrology of 

south Florida has resulted in the near complete loss of estuarine habitats from the Bay, including Biscayne 

National Park, diminishing the ecological and economic value of this portion of the greater Everglades 

ecosystem. 

This report describes the desired conditions of the park in terms of biology, ecology, and available 

historical record. The “desired condition” takes into account historical information about the ecosystem 

but is not necessarily equivalent to a pre-drainage state because significant portions of the original 

freshwater source area have been irreversibly developed. The desired condition for the Western Bay Zone 

of Biscayne National Park is a range of salinities that is consistently estuarine for support of a productive, 

diverse benthic community based on seagrass. These conditions also support Federally-listed endangered 

species, such as the American crocodile (Crocodylus acutus) and West Indian manatee (Trichechus 

manatus), and create productive nursery habitat that sustains local and regional (Florida Keys) fishery 

resources. 

Considering the needs of many native species including the juvenile stages of crocodiles, gray snapper, 

seatrout, and pink shrimp, and populations of mojarras, pinfish, eastern oyster, and wigeongrass, the 

following salinity characteristics are required: 

• Measured salinities should not exceed 30 ppt. This will be particularly critical to achieve in 

the dry season, from November to June. 

• From March through August (late dry season - early wet season), average monthly salinities 

should range between 15-25 ppt in the Western Bay Zone. 

• In the late wet season (September-October), the Coastal Mangrove Zone should be 

oligohaline (0-5 ppt), and the Western Bay Zone should average less than 20 ppt. 

• Salinity changes should be gradual and reflect changes in coastal inflows that approximate 

those of an unregulated, natural system. 

Flows that achieve these salinity targets will produce stable mesohaline conditions over the 10,000 acre 

nearshore Bay area of Biscayne National Park. 

1
INTRODUCTION 

The purpose of this document is to establish a set of scientifically based ecological and salinity targets in 

the western areas of Biscayne National Park. 

Conservation Designations 

Biscayne National Park comprises the majority of the central and southern portions of Biscayne Bay. It 

was originally designated by Congress in 1968 as Biscayne National Monument and later established as a 

National Park in 1980. Biscayne Bay, its tributaries, and Card Sound are also designated by the state of 

Florida as aquatic preserves, and Card and Barnes Sounds are part of the Florida Keys National Marine 

Sanctuary. Biscayne Bay was designated under the Surface Water Management and Improvement Act of 

1987 as a priority water body by the Florida Legislature. The waters of Biscayne National Park, Biscayne 

Bay Aquatic Preserve, and the two sounds are classified as Outstanding Florida Waters and, as such, are 

subject to the most stringent regulations, including Florida antidegradation policies. Card and Barnes 

sounds are important for the endangered American crocodile because they contain one-third of all 

crocodile nesting in the continental United States, and the east shore of Barnes Sound is included within 

the Crocodile Lakes National Wildlife Refuge. 

All of these areas, including those in the Coastal Mangrove Zone, are Essential Fish Habitat as 

described by a Federal mandate to improve fishery management plans in the United States (NOAA 1996). 

By definition, “essential habitat” incorporates habitat required by the full life cycle of a species, 

recognizing the need for protection of nursery and spawning habitats that are critical to the survival of a 

species. 

Relationship to CERP Processes 

In the drafting of this report, existing performance measures and targets developed through the CERP 

Restoration, Coordination, and Verification (RECOVER) team for Biscayne Bay were used as the basis 

for interim targets for desired conditions. Modifications were made based on results of studies conducted 

in the Bay or similar habitats in south Florida to improve the performance measures. In particular, we 

propose and use a modification of the RECOVER SE-6 performance measure for evaluation of 3,200 

acres to evaluate 10,000 acres of potential seagrass habitat. There is abundant scientific data discussed 

later in this paper to support this expansion. In fact, it is our understanding that RECOVER may be 

considering the expansion of the area in SE-6 to 10,000 acres in response to considerations raised in this 

paper. 

This report describes the desired conditions of the park in terms of biology, ecology, and available 

historical record. The “desired condition” takes into account historical information about the ecosystem 

but is not necessarily equivalent to a pre-drainage state because significant portions of the original 

freshwater source area have been irreversibly developed. Biological indicators that include those 

described by RECOVER are used to set environmental targets affected by inflows, primarily as measures 

of seasonal salinity patterns in key areas of the park. By using target values for salinity, hydrologic targets 

(freshwater inflows and their interaction with precipitation and circulation), can be estimated. Other 

relevant indicators of bay health derived from previous and current studies in Biscayne Bay are also 

discussed in support of defining desired conditions and the salinities needed to sustain them. 

This report provides a description of ecological targets and targets for salinity for the Coastal 

Mangrove Zone and the Western Bay Zone. To do this, we begin with two basic ecological premises: 1) 

healthy seagrass communities are the basis for the support of diverse biological communities, and 2) 

components of the biological community are sensitive to salinity levels and salinity changes. 

2
Area Description 

Biscayne Bay is the largest estuary on the coast of southeast Florida and is continuous with the southern 

Everglades, separated from the Florida Bay system only by a narrow isthmus connecting Key Largo to the 

mainland. Naturally, freshwater flowed into Biscayne Bay from the Everglades through finger glades 

primarily in the wet season and through groundwater seepage year round. 

This report focuses on the portion of Biscayne Bay within Biscayne National Park (Central and South 

Bay (Zone A); Figure 1). Though park waters are the primary concern of this report, similar methodology 

3

Figure 1. Biscayne National Park regional setting and Bay Zone definitions. 
can be applied in northern Biscayne Bay by agencies which are more familiar with conditions there and 

which are responsible for its protection. 

Biscayne Bay has been divided in various ways but the most useful has been based on hydrodynamic 

circulation as used by the Metro-Dade County Planning Department (1986) and used by the South Florida 

Water Management District in the Surface Water Improvement Plan for Biscayne Bay (1994). In this 

report we divide Biscayne Bay into three sections (North Bay, Central Bay, and South Bay) based on 

dominant circulation patterns driven by proximity to oceanic inlets (Wang et al. 2003). These circulation 

patterns strongly influence salinity, and therefore the ecology of the different regions of the Bay. A newer 

and alternate delineation of the Bay was created based on analysis of water quality data by Joe Boyer at 

Florida International University (Boyer 2004). Boyer groups areas based on similarities in water quality 

conditions composed primarily of nitrogen and phosphorus compounds as well as other nutrients. Since 

water quality in Biscayne Bay is largely dependant on canal discharge, which was not present historically, 

we have chosen to use the designation based upon physical circulation patterns. 

These divisions form the basis for oceanographic, geologic, and hydrologic factors that influence 

salinity and therefore ecology. Dominant circulation patterns vary based on local effects within four 

major hydrodynamic regions: 

• North Bay (from Dumfoundling Bay south to Rickenbacker Causeway) 

• Central Bay (from Rickenbacker Causeway south to Black Point) 

• South Bay (from Black Point south to Jewfish Creek) (SFWMD 1995) 

a. The South Bay Section, from Black Point to Mangrove Point, the southwest corner of 

Biscayne National Park (Southern Bay Zone A) 

b. The Extreme Southern Bay Section from Mangrove point to Jewfish creek, (Card Sound 

and Barnes Sound, and the associated bay, Manatee Bay) which are within the boundary of 

the Florida Keys National Marine Sanctuary, and the Biscayne Bay Aquatic Preserve 

(Southern Bay Zone B). 

The general circulation within Central and South Bay (Figure 2) is driven by the large tidal flow in and 

out of the Bay across an area known as the Safety Valve, and modified by the tidal flows through the five 

small creeks bisecting the island chain north of Key Largo and by the large tidal oscillation in and out of 

the enclosed southern basins, Card and Barnes Sounds. Circulation and water exchange in North Bay has 

little to no influence on the circulation in Central Bay. This tidally driven flow pattern is based on 

unpublished salinity monitoring data collected by Biscayne National Park and staff observations. The 

resulting current pattern is consistent with the circulation models developed for Biscayne Bay by the U.S. 

Army Corp of Engineers (Dr. Rob MacAdory) and the University of Miami (Dr. John Wang). Freshwater 

from the mainland enters South Bay directly along the western coastline, and indirectly through Card and 

Barnes Sounds and Central Bay. The net effect is that the western part of the Bay, the area between 

Turkey Point and Black Point, is the area most influenced by freshwater flows. In terms of desired 

conditions for Biscayne National Park, and taking into account all source waters, this area of fresher water 

would extend along the mainland shoreline to the isthmus bounding the southern end of Barnes Sound. 

4
When considering questions related to water management and freshwater flows from the mainland, the 

focus within these regions shifts westward to water and habitats nearest the coast which provide the most 

sensitive indicators of Bay conditions. For the purposes of this report, the focus for development of 

targets for ecological restoration is placed on two areas: the Coastal Mangrove Zone (CMZ) on the 

mainland of Biscayne National Park, and the Western Bay Zone (WBZ), including the seagrass bottom 

which occurs in the western portion of the South Bay Section (Figure 3). 

Figure 2. Biscayne National Park general water circulation and sources. 

5
Western Bay Zone Target Area. RECOVER has developed a performance indicator (SE-6) for CERP 

restoration efforts in Biscayne Bay that describes indicator organisms, salinity conditions, and the 

“nearshore” area in which the performance measure will be applied. The area defined in SE-6 has lost 

historical oyster (Crassostrea virginica) colonies and no longer sustains red drum (Sciaenops ocellatus), 

species that could be restored if habitat conditions were made suitable. Performance measure SE-6 

defines “nearshore” as 250 meters from shore during the dry season and 500 meters from shore during the 

wet season (Figure 3). The definition of these longitudinal bands of estuarine habitat is based on a simple 

consideration of a volume of water entering the bay edge as uniform flow; however, there is no analysis 

in the performance measure that explains why 250 and 500 meters were chosen as target areas. 

Figure 3. RECOVER performance measure focus areas and alternative Western Bay Zone 

focus area based on submerged aquatic vegetation on the bay bottom. 

6
Because the characteristics of the benthic community depend on bottom type, we chose to use existing 

but stable physical characteristics of the Bay bottom to assist in the definition of a target area for 

restoration. Based on benthic mapping and evaluation of abundance and distribution of benthic 

community types, the ecology of Biscayne Bay as a whole is dominated by the soft bottom 

(approximately 64% of the bottom) and hard bottom (17%) benthic communities (NOAA 1996). Soft 

bottom, shallow areas promote seagrass communities, whereas hard bottom areas, which occur where 

sediment is non-existent or very thin over a rocky substrate, are characterized by soft corals (i.e., sea 

fans), sponges, and isolated coral colonies. 

 Examination of geological maps of the Bay bottom shows that areas affected by freshwater inflows 

along the coast of Biscayne National Park comprise a zone of soft bottom seagrass habitat that extends 

from Turkey Point to about 1,000 m off shore at Convoy Point to some 6,500 m off shore at the northern 

mainland boundary of the park (Figure 3). The northern sector of this zone is a mix of both soft and hard 

bottom communities. This zone is bounded by the CMZ at the western shore of central and southern 

Biscayne Bay and by an area of hard bottom that occupies the Middle Bay Zone to the east. This WBZ 

historically received freshwater flow through coastal marshes and creeks and groundwater recharge, 

correlated with the wet and dry seasons. 

The bottom type and location of the WBZ relative to historical freshwater inflows define a target area 

of 10,000 acres of functional, seagrass-based estuarine habitat in Biscayne National Park. In contrast, the 

RECOVER dry season target of 250 meters from shore covers about 1,600 acres, or only 16% of 

functional estuarine habitat that could be restored. The RECOVER wet season target of 500 meters from 

shore covers about 3,200 acres, or less than 1/3 of the estuarine habitat that could be restored. It is our 

understanding that RECOVER may consider revising SE-6 in response to the considerations discussed 

here. 

Our description of desired conditions, and the analyses of ecological and salinity targets in the WBZ 

focus on this 10,000 acre area of submerged aquatic vegetation (SAV) habitat at the western edge of 

Central and South Bay, within Biscayne National Park. Historically, the volume, timing and distribution 

of water flows to Biscayne National Park created natural coastal marsh hydroperiods and provided for 

estuarine salinities in the western part of the Bay. We propose that the ecological requirements of the 

coastal wetlands, and especially the ecological requirements of the estuarine western bay zone, should 

drive the quantity, timing and distribution of water deliveries to this area. This change would reestablish 

high quality nursery habitat for important fish and invertebrates in a band of soft bottom/SAV habitat 

from the northern boundary of Biscayne National Park south to Turkey Point (Figure 3). 

7
ECOLOGICAL TARGETS FOR BISCAYNE NATIONAL PARK 

Historical Conditions 

Coastal Mangrove Zone. What we now call the Coastal Mangrove Zone was formerly composed of 

freshwater marsh species. Historically, fresh surface water flowed to the Bay through natural sloughs, 

rivers, and wetlands, and fresh groundwater flowed through the Biscayne Aquifer (Parker et al. 1955; 

Kohout and Kolipinski 1967; Buchanan and Klein 1976) and seeped into the bay along the coast and 

through the bay bottom. At the southern end of the Miami Rock Ridge, freshwater wetlands in the 

Biscayne Bay watershed occupied extensive coastal marl prairies that were east of the Ridge where it 

curves westward away from the coast. Prior to drainage and land development, these marshes were 

dominated by sawgrass (Cladium jamaicense), spike rush (Eleocharis cellulosa), and other freshwater 

graminoids, including grasses and herbs (Gaiser and Ross 2004). The hydropattern depended on direct 

precipitation, surface flow from the Everglades through breaks in the Ridge called “transverse glades,” or 

rising groundwater when the regional water table was high (Wanless 1976). In a study of the 

paleoecology using soil cores along the coast, Gaiser and Ross (2004) showed that prior to 100 years ago, 

salinities in the coastal wetlands of Biscayne Bay were in the range of 0-10 ppt, whereas at the present 

time the range is about 8-17 ppt. 

The transverse glades and freshwater forests and wetlands drained into a transition zone of coastal 

creeks and a mix of herbaceous freshwater-brackish wetlands, tidal marshes, and mangrove forests on the 

edge of the coast. These supported the Bay ecosystem by spreading freshwater inflow, absorbing excess 

nutrients, and providing habitat—including critical nursery habitat—for fish and shellfish, as well as 

feeding habitat for wading birds. Local rainfall, groundwater seepage, overland sheet flow and small 

coastal rivers fed water to the Bay all along its mainland margins. The flow of fresh water through the 

forested wetlands and fresh water marshes provided dynamic storage of water and a buffer to reduce the 

amplitude of rainfall runoff events, and moderated the transition from fresh water inflows to estuarine and 

marine conditions in the Bay (Wanless 1976; Browder and Wanless 2001). Egler (1952) documents the 

distinct vegetation bands parallel to the coast prior to construction of major drainage canals. He concluded 

that changes in vegetation composition were a result of increases in salinities between freshwater 

wetlands and saline wetlands near the coast. The area was still largely dominated by graminoid freshwater 

wetland, followed by dwarf mangrove scrub, and a narrow band of coastal mangroves in the 1940’s and 

early 1950’s. Kohout and Kolipinski (1997) found a distinct biological zonation of flora and fauna in 

nearshore Biscayne Bay based on salinity in the area around the old Cutler power plant north of the old 

Burger King headquarters site. Ishman et al. (1998) documents increasing salinity with distance offshore 

in predrainage Biscayne Bay. They also compare historical salinities from 1850-1900 to salinities in 1996. 

Gaiser and Ross (2004) also document the historic salinity gradients in the remnant coastal wetlands. 

Average annual mean predrainage salinities were less than 2 ppt and freshwater marshes and associated 

forest units covered 90% of the area, with only a narrow band of mangroves along the coastline. Today 

that same area has a mean salinity of 13.2 ppt, and is 95% covered by mangroves. 

Western Bay Zone. Many different estuarine species flourished in the western part of Biscayne Bay. 

Miami-Dade County was at the core of the American crocodile (Crocodylus acutus) geographic range in 

the U.S. (Kushlan and Mazzotti 1989), with the coastal wetlands along the western shore of Biscayne Bay 

providing important habitat. Oyster reefs and associated fauna could be found in the Bay (Smith 1896; 

Meeder et al. 2001). A large number of fish species could also be found in Biscayne Bay, with Smith 

(1896) listing 95 fish taxa. The presence of several species of drum (family Sciaenidae), which prefer 

brackish conditions, and the description of some of these species as either abundant or common, is 

particularly revealing of more estuarine conditions over 100 years ago (Serafy et al. 2001). 

Recent paleoecological research conducted by the U.S. Geological Survey provided insight into 

predrainage conditions and general trends in Bay salinities since 1900 (Ishman et al. 1998; Wingard et al. 

2003, 2004). Results from sediment cores showed a long-term trend of increasing salinity at virtually all 

sites studied in Biscayne Bay, particularly since 1900. In the vicinity of Black Point these data indicated 

that mid-level mesohaline conditions existed prior to 1900, tending toward more polyhaline conditions 

8
after that time. Sediment core data indicated that since 1950 salinities have increased to mostly polyhaline 

conditions at these sites. Middle Key and Manatee Bay sites to the far south (Barnes Sound area) are 

farthest from the influence of Everglades transverse glades drainage but are under the influence of the 

eastern margin of the Taylor Slough drainage system. Sediment cores from these two sites indicated 

conditions were predominantly fresh water (0 ppt) until about 1900. After that, oligohaline and low-end 

mesohaline conditions appeared, possibly in response to construction of the Flagler railroad, initial land 

drainage activities, and the construction of roadways (Wingard et al. 2004). The final shift occurs around 

the 1960’s to mid-1970’s when marine conditions (30-40 ppt) appear in the sediment record, as evidenced 

by the remains of invertebrate species that can tolerate high salinities in areas that were once estuarine in 

nature. Clearly, since 1900, a significant amount of fresh water inflows to Biscayne Bay have been 

diverted, converting what were once fresh to brackish, estuarine habitats in the nearshore areas to marine 

conditions, with the loss of estuarine productivity and function. 

Current Conditions 

Hydrology has been altered by regional drainage, canal construction and operation, and urban 

development, as well as by construction of roads, levees, and other hydrologic barriers to surface flow. 

The Bay currently receives freshwater inflow as canal flow, with only minor overland flow, and 

occasional groundwater seeps (Kohout and Kolipinski 1967; Buchanan and Klein 1976; SFWMD 1995). 

Freshwater flow to the Card Sound and Barnes Sound section comes only through moderate to light 

discharges from the C-111 Canal, and from overland runoff from extensive freshwater and coastal 

wetlands contiguous with the mainland shoreline of these two basins. 

Coastal Mangrove Zone. The L31E levee and canal run parallel to the coast about 2 km inland and 

intercept the local sub basin drainages and transverse glades that used to discharge water to southern 

Biscayne Bay. As a result, a narrow strip of isolated coastal stream remnants and coastal fringe mangrove 

forest, most of which is within the park, is disconnected from the regional hydrology. The loss of 

freshwater inflows has resulted in the expansion of the fringing mangrove forest to the eastern side of the 

levee system (Ross et al. 2000; Gaiser and Ross 2004). 

Currently, the hydrologic conditions within the CMZ are dependent upon canal stages and local 

rainfall. Because there are no current freshwater deliveries to this area, water levels in the canals 

determine the adjacent water table and, therefore, the water level in the CMZ. Water enters the area as 

groundwater seepage and as rainfall. These changes in surficial drainage have affected surface and 

groundwater hydrology (Parker et al. 1955; Parker 1974), reducing or eliminating coastal creek function 

and productivity. West of the L31E levee, the landscape is drained and compartmentalized by a network 

of mosquito control ditches, wetland drainage ditches, and flood control canals (e.g., Ruiz and Ross 

2004). Although the wetland value of this area has decreased substantially because of increasing salinities 

and drainage, the ecological function of habitat created by the invasion of salinity tolerant coastal 

mangroves remains particularly important to Biscayne Bay (Odum and Heald 1975; Teas 1976). 

The area between Convoy Point and the northern mainland extent of the park covers some 1,500 acres 

of potentially high value fish and wildlife habitat that forms the longest contiguous coastal mangrove 

forest on the east coast of Florida. It is comprised of coastal fringe forest (primarily red mangroves), 

interior transitional forest (red and white mangroves), dwarf mangrove forest (red mangroves), and a 

mosaic of relict stream channels and coastal wetlands. This area provides food, shelter and nursery 

habitat, critical to sustaining the recreational and commercial fisheries in south Florida (Teas 1976; Serafy 

et al. 2003). Salinity fluctuations imposed by water management operations and loss of water to coastal 

creeks that once created brackish conditions in the prop root zone have created impaired fishery habitat 

with impaired nursery function. 

Western Bay Zone. East of the mangroves, the WBZ is dominated by the seagrass (approximately 64% of 

the bottom) and hard bottom (17%) benthic communities (NOAA 1996). Submerged aquatic vegetation 

(SAV) in the Bay is typically a mixed species community that may include shoal grass (Halodule 

wrightii), manatee grass (Syringodium filiforme), turtle grass (Thalassia testudinum), wigeon grass 

9
(Ruppia maritime), and three species of an uncommon SAV Halophila. Freshwater algae (Chara spp.) 

may also be found in low salinity coastal streams, tidal creeks, ponds, and around canal and creek outlets 

where fresher water predominates. The distribution of Chara in the WBZ is limited by its intolerance of 

the marine conditions now common in nearshore areas of the Bay. Currently, the SAV community is 

dominated by turtle grass (Christian et al. 2004), an indicator of true marine conditions because of its low 

tolerance of brackish conditions. 

The CERP Monitoring and Assessment Plan conceptual models identify salinity as the primary stressor 

in the WBZ, affecting biology when conditions deviate from a natural range. Salinity in this area is 

controlled by tidal circulation, which tends to increase salinities toward an offshore level (33-35 ppt), and 

by canal discharge, which is a function of canal operations and introduces freshwater (<1 ppt). To a lesser 

extent, salinity in this zone is affected by local rainfall (SFWMD 1995; Lirman and Cropper 2003; 

Faunce et al. 2003; Serafy et al. 1997). Another stressor is poor-quality water containing nutrients and 

contaminants (SFWMD 1995), carried by the six canals discharging into this zone (Black Creek (C-1), 

Princeton Canal (C-102), Military Canal, and Mowry Canal (C-103), C-111, Snapper Creek (C-2) and the 

Coral Gables Waterway (C-3)). 

Indicator Species: Benthic Community, Endangered Species, and Important Fishery Resources 

Many of the species described in this report are considered to be dependent on estuarine conditions. They 

require a brackish environment or they are reliant on estuarine salinities at specific stages in their life 

cycle. The presence of these species both historically and at present supports the importance of 

maintaining and restoring the estuarine nature of the WBZ. Many of these species are declining 

presumably because of the lack of freshwater currently reaching the bay. Therefore, the salinity range of 

these organisms can be used to define a beneficial salinity range for Biscayne Bay. Many species 

including stone crab, Spanish mackerel, Crevalle jack, grey snapper, and tarpon are either recreationally 

or commercially important within the WBZ fishery. However, historical data and site-specific information 

on preferred salinity ranges are not available for all of these important species. We found more historical 

information and field studies with site-specific information on preferred salinity ranges for six species and 

chose to use these as biological indicators. These species, American crocodile, spotted seatrout, mojarras, 

silver perch, pink shrimp, and eastern oyster, and the specific reasons for their importance, are presented 

in Table 1. 

Organism Zone Importance Source 

American crocodile 

(Crocodylus acutus) 

Mangroves Endangered Species Mazzotti and Cherkiss 1998; Kushlan and 

Mazzotti 1989; Kushlan 1988; Mazzotti 1983 

Spotted seatrout 

(Cynoscion nebulosus) 

Western Bay Zone Commercial value, 

recreational fishing 

Patillo, et al. 1997; Bortone, 2003 

Mojarras 

(Eucinostomus spp.) 

Western Bay Zone Forage base species Serafy, et al., 1997 

Silver perch 

(Bairdiella chrysoura) 

Western Bay Zone Forage base species Serafy, et al., 1997 

Pink shrimp 

(Farfantepenaeus duorarum) 

Western Bay Zone Keystone species, 

commercial value 

Bielsa et al., 1983; Serafy et al., 2001; 

Browder et al., 1999; Gunter et al., 1964 

Eastern oyster 

(Crassostrea virginica) 

Mangroves Commercial value Meeder et al., 2001; Wells, 1961 

Table 1. Fish and wildlife indicators in Biscayne Bay. 

Biscayne National Park’s creel data (based on interviews of anglers when they return from fishing to 

local marinas) has been collected since about 1976. Most of the data pertain to reef fish, since a majority 

of the anglers fish on the reef, and are therefore less useful in this paper, which focuses on the near-shore 

area. The bay species that might be affected by salinity changes near the coast (i.e., snook, spotted sea 

trout, red drum) are now landed infrequently in the areas we survey, making it impossible to identify 

10
trends in population abundance from the creel data. The only species that are affected by salinity changes 

and are frequently reported are snappers and grunts which utilize bayside seagrass beds as juvenile 

habitat. Also, it is impossible to distinguish the effects of salinity changes over time from fishing effects 

over time. For all these reasons, the Biscayne National Park creel data set was used to provide supporting 

evidence of the continued presence of the biological indicator species in the Bay, and was not used for 

more quantitative analyses of the effects of salinity changes. 

The American crocodile (Crocodylus acutus) is primarily found in areas characterized by brackish 

estuarine conditions and average salinities of 14 ppt (Mazzotti 1983; Kushlan 1988; Kushlan and 

Mazzotti 1989). Hatchling crocodiles are particularly reliant on low salinities, generally 0 to 5 ppt 

(Mazzotti and Cherkiss 1998). Mazzotti and Cherkiss also determined that all size classes (hatchlings, 

juveniles and adults) favor water bodies with an 

intermediate salinity of 20 ppt. Juvenile 

crocodiles, in particular, seek out and seem to 

require a mesohaline (<20ppt with an optimum of 

9 ppt) habitat for survival (Mazzotti et al. 2002). 

Eastern oysters (Crassostrea virginica) have 

long been recognized as an indicator of estuarine 

conditions (Dean 1892; Oemier 1894, Ritter 

1896; Grave 1905; Pearse and Wharton 1938; 

Nelson et al. 1991; Estevez 2000; Meeder et al. 

2001). The life cycle of oysters occurs entirely 

within estuaries. Oysters are capable of surviving 

salt concentrations from 5 to 40 ppt, however the 

optimum range for oyster reef growth is 10-20 

ppt (Stenzel 1971; Meeder et al. 2000). This 

allows for oyster reproduction while decreasing 

predation rates (Grave 1905; Gunter 1950; Wells 

1961). 

Spotted sea trout (Cynoscion nebulosus) and 

mojarras (Eucinostomus spp.) are important fish 

species in Biscayne Bay. Serafy et al. (1997) 

found that populations of these two species in 

Biscayne Bay prefer salinities less than 20 ppt. 

They also found that there was a significant 

decline in the abundance of these two species 

from 20 to 30 ppt. A re-examination of these 

data, with the addition of silver perch (Bairdiella 

chrysoura), was conducted to focus on evaluating 

the relationship between salinity and juvenile 

abundance (Figure 4.) A clear pattern of selection 

of salinities less than 20 ppt was observed in the 

data, with significant declines in abundance from 

20 to 30 ppt. The pattern of declining fish density 

with increasing salinity was also observed by 

Campos (1985) in another study conducted in 

Biscayne Bay. 

Pink shrimp (Farfantepenaeus duorarum) 

comprise the most economically important 

fishery in Biscayne Bay as well as being a key 

species in the marine food chain (Bielsa et al. 

1983; Berkley and Campos 1984; Markley and 

Milano 1985; Browder et al. 1999; Serafy et al. 

2001). Estuaries, and the seagrass communities 

found there, are important nursery habitats for 

11

Figure 4. Abundance of key indicator fish 

relative to salinity. (from Serafy et al. 1997) 
pink shrimp and offer the most favorable food and shelter conditions for juvenile and post larval pink 

shrimp (Bielsa et al. 1983; Ault et al. 1999). Young shrimp find their way into the estuary by detecting 

lower salinity and a high amount of organic material (Lindall 1971; Odum and Heald 1975; Ault et al. 

1999). These shrimp spend 2-6 months in estuarine areas before entering offshore water (Costello and 

Allen 1966; Bielsa et al. 1983; Ault et al. 1999). Post-larval pink shrimp are most often found in the 

nearshore seagrass on the western side of the central and southern portions of Biscayne Bay (Ault et al. 

1999). Since this species is critically important to the Bay and the regional fishery, estuarine conditions 

and SAV habitat must be preserved. This can only be accomplished by the stabilization and persistence of 

mesohaline conditions. 

Salinity Characteristics to Support Ecological Communities 

Evidence of the requirements of a number of species presented previously demonstrates that salinity is a 

key habitat factor for the Bay ecosystem. Figure 5 summarizes the optimal salinity ranges for Biscayne 

National Park ecosystem indicators, including primary producers, primary consumers, and predators. The 

majority of these indicator species prefer salinities between 5 and 20 ppt. Based on this observation and 

taking into account that other species (such as seatrout and oysters) may require periods of time with 

slightly higher or lower salinities, we propose the following salinity targets for the CMZ and WBZ of 

Biscayne National Park. 

• At no time should measured monthly salinities exceed 30 ppt. This will be particularly critical 

to measure in the dry season, from November to March. 

o Direct benefit to important fishery species with a life cycle stage that does best at 

estuarine salinities, oysters, fish that serve as sport fish forage, and post larval juvenile 

shrimp that rely on brackish water as a refuge from marine predators. 

o Indirect benefit to recreational and commercial fish species that rely on the forage base 

produced by estuarine conditions, such as adult sea trout, snapper, and grouper fish 

stocks. 

• From March through August (late dry season - early wet season), average monthly salinities 

should range between 15-25 ppt in the WBZ. 

o Direct benefit to spawning habitat for sea trout, adult habitat for forage species (mojarras, 

silver perch), and conditions that foster a healthy and diverse seagrass community that 

can be sustained in a zone that is subject to fresh water runoff. 

o Indirect benefit to nursery habitat for important juvenile fish species (productive seagrass 

beds and an extensive brackish water refuge from marine predators). 

• In the late wet season (September-October), the CMZ should be oligohaline (0-5 ppt), and the 

WBZ should average less than 20 ppt. 

o Direct benefit to juvenile crocodiles that have a physiological requirement for low 

salinity conditions. 

o Direct benefit to important forage fish species in coastal mangroves that do best at 

oligohaline to mesohaline conditions (such as sheepshead minnow, gold-spotted 

killifish). 

o Indirect benefits to all species that consume forage species that support upper trophic 

levels in the mangrove zone, including wading birds, mammals, and crocodiles. 

• Salinity changes should be gradual and reflect changes in hydropattern that approximate a 

natural system. All vegetation, fish, and invertebrate species benefit from gradual changes in 

salinity that avoid physiological stress. 

• Salinity gradients should always consist of lowest salinities near the coast and highest 

salinities in the ocean. 

Restoration of freshwater inflows to reach these salinity targets should result in a highly productive SAV 

community that will support desired ecological characteristics of Biscayne National Park.

12
Figure 5. Optimal salinity ranges (units in ppt) for Biscayne National Park ecosystem indicators. 

Desired Ecological Conditions for Biscayne National Park 

Coastal Mangrove Zone. In the CMZ, these low salinity values will sustain a fully functional tidal 

wetland transition zone, including the estuarine creeks that provide fresh water to the bay, and result in 

stable estuarine conditions for nearshore habitats. Coastal creeks, currently intercepted by the L31E levee, 

should have a normal seasonal hydrograph, with flows in the wet season that are dominated by local 

rainfall, and declining flows in the dry season, dominated by base flows from inland drainage. The level 

of fresh water discharged into Biscayne National Park should support SAV dominated by wigeon grass 

and Chara spp., Emergent vegetation should consist of cord grass (Spartina spp.), salt grass (Distichlis 

spicata), and black rush (Juncus roemerianus). The existing mangrove forest should remain similar to 

what it is now, but consist of a more spatially distinct buttonwood, black mangrove and white mangrove 

transition zone, with red mangroves at the edges of creeks and at the bay’s shoreline. 

The faunal composition in the mangrove zone should be similar to that described in historical 

documentation of pre-drainage conditions, and where it is not detailed, composition should be similar to 

fauna characteristic of less impacted estuarine mangrove forests in south Florida. The desired species are 

those common to coastal streams and inland brackish marsh flats, such as the sailfin molly (Poecilia 

latipinna), gold-spotted killifish, (Floridichthys carpio) sheepshead minnow (Cyprinodon variegatus), 

and eastern mosquitofish (Gambusia holbrooki) (Lorenz 1999; Serafy et al. 2003). 

In the sub tidal area of the CMZ, which is dominated by mangrove prop roots, permanent, healthy 

oyster communities should be common, both on the prop roots and as oyster reefs where the creeks enter 

the bay. Although oysters were once common in the Bay and are characteristic of similar habitats in south 

Florida, they are only found in very low numbers today. Establishment of more natural volumes, timing, 

and distribution of water deliveries will foster the restoration of oyster colonies and the estuarine biota 

associated with them. 

Western Bay Zone. Estuarine conditions in the WBZ will maximize SAV coverage and diversity, a key 

component of critical nursery and juvenile fishery habitats. Under appropriate salinity and water quality 

conditions, it is expected that the WBZ will sustain excellent SAV growth where sediment and water 

depth are appropriate. These salinities should also create a more diverse seagrass community, dominated 

by species that do well under estuarine conditions. Wigeon grass will be the dominant species at the 

mangrove/nearshore ecotone and shoal grass co-dominant with turtle grass throughout the WBZ. 

Maintaining estuarine salinity will sustain larval and juvenile red drum and provide good habitat 

conditions for sustaining a forage base for red drum, including oyster, shrimp, and forage fish 

populations. 

13
In general, water deliveries to Biscayne National Park should not result in damage to natural resources 

including extreme salinity conditions that adversely affect fishery and wildlife resources. The preferred 

salinity ranges for the indicator species presented above help determine freshwater needs and define 

conditions that cause impairment of natural resources. The daily mean salinity for the CMZ should fall 

within the 0-5 ppt in the late wet season (October and November) and average less than 20 ppt annually. 

A natural gradient of salinity should exist between the mangrove zone and the eastern edge of the WBZ 

throughout most of the year. Although the extent and character of the gradient is influenced by a variety 

of factors including the rate of fresh water arrival, evaporation and plant transpiration rate, and tidal 

mixing, water management operations should not result in any unnatural extremes in salinity and should 

approximate natural inflows. The WBZ should have salinities between 5 and 20 ppt throughout the year, 

allowing for only short term excursions (10 days or less) to higher salinities (not exceeding 30 ppt) as a 

result of water management. Longer hypersaline events because of intercepted coastal inflows must be 

avoided, and sustained periods of relatively low salinity are considered essential for sustaining key 

estuarine species. Unnatural pulse discharges of fresh water that cause rapid and significant decreases in 

salinity that damage benthic habitats must also be avoided. 

Summary of Ecological Performance Measures 

The productivity and richness of the estuarine communities of Biscayne National Park have significantly 

diminished, as have those throughout Biscayne Bay, as a result of channel creation and the diversion of 

water from the natural systems in south Florida. The quantity of fresh water, the seasonal timing of 

inflows, and the distribution along the coast have been significantly altered, profoundly affecting the 

historic estuarine nature of the western portion of the Bay. The alteration of the hydrology of south 

Florida has resulted in the near complete loss of estuarine habitats from the Bay, including Biscayne 

National Park, diminishing the ecological and economic values of this portion of the greater Everglades 

ecosystem. 

Additional water losses that may result from future demands for water supply and flood control will 

exacerbate existing impacts. Fresh water inflows during the dry season months are particularly important 

for protection of fish and wildlife resources. Without these fresh water inflows rainfall on the bay is 

insufficient to compensate for evaporation in moderating salinity. Not only has the system become more 

marine in salinity, but the increased frequency and duration of hypersaline events adversely impacts even 

marine biota, most of which have very narrow salinity and temperature tolerances. 

At present, the water that is released to Biscayne National Park provides marginal estuarine benefits, 

far short of those that would result from a more natural, historic hydropattern. The timing of current water 

releases differs significantly from a natural pattern, with large freshwater pulses during the wet season 

that drive salinities too low, and minimal flows in the dry season that allow salinities to greatly exceed the 

predrainage environment. The location of current water deliveries also differs from a natural pattern, in 

that the CMZ no longer receives any significant overland flow, and water inputs to the WBZ arrive as 

point discharge from canals. In short, the quantity, timing, and delivery of water currently arriving at 

Biscayne National Park is not adequate to provide stable estuarine conditions. 

14
DISCUSSION 

Prior to the significant changes in the freshwater flow patterns in south Florida caused by the creation of a 

water control system upon the landscape in the early 20th century, Biscayne Bay was a true estuarine 

system. Significant amounts of fresh water in the form of both surface and ground water were present 

throughout most of the year and supported a wide range of flora and fauna. When these freshwater 

sources were diminished and their distribution altered by water management practices, the vegetation in 

the Bay as well as the juveniles of many fish and invertebrate species were adversely affected, and the 

ecosystem in the Bay changed drastically. The ecosystem that exists today in Biscayne Bay is largely 

marine in nature, as the volume, timing and distribution of the freshwater flows are insufficient to 

maintain an estuarine environment over ecologically-significant temporal and spatial scales. In keeping 

both with the Everglades restoration efforts and the National Park Service mandate to preserve 

unimpaired the nation’s natural resources within the parks, this document provides ecological and 

physical targets for desired conditions in Biscayne National Park, and attempts to quantify the existing 

freshwater flows that are necessary for the protection of fish and wildlife within the park. 

The spatial focus of the discussion of ecologic targets includes the Coastal Mangrove Zone (CMZ) of 

mainland Biscayne National Park in this report and the adjacent Western Bay Zone (WBZ). The shallow 

waters of the WBZ contain thousands of acres of seagrasses as well as a fringing mangrove forest. The 

desired condition, or over arching goal, for the 10,000 acre western zone of Biscayne National Park is the 

existence of stable estuarine conditions that persist through the dry season, to be achieved through more 

natural timing and distribution of freshwater flows. These stable estuarine conditions support a 

productive, diverse benthic community based on seagrass. These conditions will also support endangered 

species and sustain productive nursery habitat for local and regional fishery resources. 

The appropriate restoration area to consider was discussed in this document. The existing RECOVER 

performance measures focus on a narrow (500m) strip of coastline that encompasses 3200 acres of Park 

waters. The alternate approach used here is to focus on existing geomorphological information to define 

an area of soft bottom suitable for seagrasses: this habitat in the WBZ includes roughly 10,000 acres of 

park area. This larger region was chosen as the target area for stable estuarine conditions because it is 

based on Bay geomorphology, a factor that is fundamental to Bay ecology. 

The ecological targets for the WBZ were based upon an approach that includes the benthic community, 

endangered species and important fishery resources in the western bay. Because seagrass is important 

nursery and growth habitat for indicator species, a fundamental resource management and restoration goal 

is to maximize coverage by SAV beds at sustainable levels. Under appropriate salinity and water quality 

conditions, it is expected that this area will support excellent SAV growth where sediment and water 

depth are appropriate for such growth. One explicit restoration target is an increase in the vitality and 

diversity of the WBZ seagrass community, with wigeon grass as the dominant SAV species at the 

mangrove edge within the nearshore ecotone and shoal grass becoming co-dominant with turtle grass 

through much of the rest of the WBZ. Another explicit target is the restoration of the community of 

seagrass-associated fauna which have been largely extirpated from South Bay, and the enhancement of 

habitat for others, such as crocodiles and pink shrimp that will likewise benefit significantly from the 

target salinity conditions. 

These ecological targets require freshwater flows that produce mesohaline conditions throughout most 

of the year at the bottom of the Bay, with salinities ranging from 5 to 20 ppt over the soft bottom areas of 

the WBZ that have the substrate necessary to sustain SAV. In particular, measured dry season salinities 

(November through May) should not exceed 30 ppt anywhere in the zone. The ecological and salinity 

targets that link mesohaline conditions and associated seagrass and faunal communities for this area are 

not currently being met because current freshwater deliveries are insufficient in terms of quantity, timing, 

and distribution. 

This paper has discussed ecological targets for Biscayne National Park. Further analysis is needed to 

develop metrics associated with hydrologic restoration targets for the park. These ecological and 

hydrologic targets will be critical to evaluate potential benefits of restoration projects for Biscayne 

National Park and to assess progress toward ecosystem restoration. We look forward to working with 

SFWMD staff in further developing these performance measures and targets. 

15
LITERATURE CITED 

Ault, J., G. Diaz, S. Smith, J. Luo, and J. Serafy. 1999. An efficient sampling survey design to estimate pink shrimp population 

abundance in Biscayne Bay, Florida. North American Journal of Fisheries Management, 19(3):p. 696-712. 

Bielsa, L., W. Murdich, and R. Labisky. 1983. Species profiles: Life histories and environmental requirements of coastal fishes

and invertebrates (South Florida) - pink shrimp. FWS/OBS-82/11.17. US Fish and Wildlife Service, National Coastal 

Ecosystems Team, Slidell, LA. 21 pp. 

Bortone, S. 2003. Biology of the spotted seatrout. CRC Press, LLC, Boca Raton, FL. 

Boyer, J.N. 2004. South Florida coastal water quality monitoring network. FY 2004 Cumulative Report to the South Florida 

Water Management District (SFWMD Contract C-15397). West Palm Beach, FL. 

Browder, J., V. Restrepo, J. Rice, M. Robblee, and Z. Sein-Eldin. 1999. Environmental influences on potential recruitment of 

pink shrimp, Farfantepenaeus duorarum, from Florida Bay nursery grounds. Estuaries, Vol. 22, No. 2B, June 1999. p. 484- 

499. 

Browder, J.A. and H.R. Wanless. 2001. Science survey team report, pp. 65-230. In: Biscayne Bay Partnership Initiative. Survey 

Team Final Reports. Florida Atlantic University, Joint Center for Environmental and Urban Problems. 307 pp + appendices. 

Buchanan, T. J., and H. Klein (1976) Effects of water management on fresh-water discharge to Biscayne Bay. In: Biscayne Bay: 

Past / Present / Future. A. Thorhaug, and A. Volker, (eds.). Biscayne Bay Symp. I. University of Miami Sea Grant Program 

Spec. Rep. 5. University of Miami, Coral Gables, FL. 271-277. 

Campos, W.L. 1985. Distribution patterns of juvenile epibenthic fishes in south Biscayne Bay, Florida. MS Thesis. University of

Miami, Coral Gables, Florida. 110 p. 

Christian, J., J.F. Meeder, and A. Renshaw. 2004. Nearshore epibenthic vegetative cover in southern Biscayne Bay. Report to the

South Florida Water Management District, West Palm Beach. Southeastern Environmental Research Program, Florida 

International University, Miami, Florida. 60 p+appendices. 

Costello, T.J. and D.M. Allen. 1966. Migrations and geographic distribution of the pink shrimp, Penaeus duorarum, of the 

Tortugas and Sanibel grounds, Florida. U.S. Fish and Wildlife Service, Fishery Bulletin 65: 449-459. 

Dean, Bashford. 1892. The physical and biological characteristics of natural oyster grounds of South Carolina. Bull. U.S. Fish 

Commission 10: 335-362. 

Egler, F.E. 1952. Southeast saline Everglades vegetation, Florida and its management. Veg. Acta Geobot. 3: 213-265. 

Estevez, E. 2000. A review and application of literature concerning freshwater flow management in riverine estuaries. Mote 

Marine Laboratory Technical Report No. 680. South Florida Water Management District, West Palm Beach, FL. 70 pp. 

Faunce, C.H., J.E. Serafy, and J.J. Lorenz. 2003. Density-habitat relationships of mangrove creek fishes within the southeaster

saline Everglades (USA) with reference to managed freshwater releases. Wetlands Ecology and Management 12 :1-18. 

Gaiser, E. and M.S. Ross. 2004. Water flow through coastal wetlands. Annual report to Everglades National Park. Southeast 

Environmental Research Center, Florida International University. Miami, Fl. 59 pp+ figs. 

Grave, C. 1905. Investigations for the promotion of the oyster industry of North Carolina. Pages 247-329 in Report of the U.S. 

Fish Commission for 1903. 

Gunter, G. 1950. Seasonal population changes and distributions as related to salinity, of certain invertebrates on the Texas Coast, 

including the commercial shrimp. Publ. Inst. Mar. Sci. 1(2): 7-51. 

Gunter, G., J.Y. Christmas, and R. Killebrew. 1964. Some relations of salinity to population distributions of motile estuarine 

organisms, with special reference to penaeid shrimp. Ecology 45: 181-185. 

Ishman, S.E., Cronin, T.M, Brewster-Wingard, G-L., Willard, D.A., and D.J. Verardo. 1998. A record of ecosystem change, 

Manatee Bay, Barnes Sound, Florida. Journal of Coastal Research 26: 125-138. 

Kohout, F.A., and Kolipinski, M.C., 1967, Biological zonation related to groundwater discharge along the shore of Biscayne Bay,

Miami, Florida; in G.H. Lauff (ed.), Estuaries: American Association for the Advancement of Science, Publication no. 83, p. 

488-499. 

Kushlan, J. A. 1988. Conservation and management of the American Crocodile. Environmental Management. 12 (6): 777-790. 

Kushlan, J.A. and F.J. Mazzotti. 1989. Historic and present distribution of the American crocodile in Florida. Journal of 

Herpetology 23:1-7. 

Lindall, W. 1973. Alterations of estuaries of South Florida: A threat to its fish resources. Marine Fisheries Review, 35(10):26-33. 

Lirman, Diego, and Wendell P. Cropper Jr. 2003. The influence of salinity of seagrass growth, survivorship and distribution 

within Biscayne Bay, Florida: Field, experimental, and modeling studies. Estuaries. Vol. 26, No. 1, p. 131-141 

Lorenz, J.J. 1999. The responses of fishes to physicochemical changes in the mangroves of northeast Florida Bay. Estuaries 

22:500-517. 

16
Markley, S. and G. Milano. 1985. Biscayne Bay today: A summary report on its physical and biological characteristics. MiamiDade County Department of Environmental Resources Management, Miami, Florida. 78pp. 

Mazzotti, F.J. 1983. The ecology of Crocodylus acutus in Florida. PhD thesis, Pennsylvania State University. 

Mazzotii, F.J., and M.S. Cherkiss. 1998. Status and Distribution of the American Crocodile (Crocodylus acutus) in Biscayne Bay.

Contract No. C-7794. South Florida Water Management District. Everglades Research and Education Center, University of 

Florida. 

Mazzotti, F.J., M.S. Cherkiss, G.S. Cook, and E. McKercher. 2002. Status and conservation of the American crocodile in Florida:

Recovering an endangered species while restoring an endangered ecosystem. Final report to National Park Service, 51 p. 

Meeder, J.F., Harlem, P.W., Ross, M.S., Gaiser, E., Jaffe, R., 2000. Southern Biscayne Bay Watershed Historic Creek 

Characterization (Tasks 1, 2, and 3) Annual Report to the South Florida Water Management District, West Palm Beach. 

Southeast Environmental Research Program, Florida International University, 16 p. 

Meeder, J.F., P.W. Harlem, and A. Renshaw. 2001. Historic creek watershed study, Final Results: Year 1. Report to South 

Florida Water Management District, West Palm Beach, Florida. Southeast Environmental Research Program, Florida 

International University. 

Nelson, D., E. Irlandi, L. Settle, M. Monaco and L. Coston-Clements. 1991. Distribution and abundance of fishes and 

invertebrates in southeast estuaries. ELMR Rep. No. 9. NOAA/NOS Strategic Env. Assess. Div., Silver Spring, MD. 167 pp. 

NOAA. 1996. Mangusen-Stevens Fishery Conservation and Management Act, as amended through October 11, 1996. National 

Ocean and Atmospheric Administration Technical Memo. NMFS-F/SPO-23. 121 pp. 

Oemier, A. 1894. The past, present and future of the oyster industry in Georgia. Bulletin of the U.S. Fish Commission 13: 263-

272. 

Odum,W.E. and E.J. Heald. 1975. The detritus-based food web of an estuarine mangrove community. Pp. 265-286 in L. Cronin 

(ed), Estuarine Research. Academic Press, New York. 

Pattillo, M., T. Czapla, D. Nelson and M. Manaco 1997. Distribution and abundance of fishes and invertebrates in Gulf of 

Mexico estuaries. Volume II: Species life history summaries. ELMR Rep. No. 11. NOAA/NOS Strategic Env. Assess. Div., 

Silver Spring MD. 377 pp. 

Parker, G.G. 1974. Hydrology of the predrainage system of the Everglades in southern Florida. Pp. 18-27 in P.J. Gleason (ed), 

Environments of South Florida: Past, Present, and Future. Miami Geological Society, Mem. 2. 

Parker, G. G., G. E. Ferguson, and S. K. Love. 1955. Water resources of southeastern Florida with special reference to the 

geology and groundwater of the Miami area. Water Supply Paper 1255, U. S. Geological Survey, U. S. Government Printing 

Office Washington D.C. 965pp. 

Pearse, A.S. and G.W. Wharton. 1938. The oyster “leech,” Stylochus inimicus Palombi, associated with oysters on the coasts of 

Florida. Ecological Monographs 8: 605-655. 

Ritter, H.P. 1896. Report of a reconnaissance of the oyster beds of Mobile Bay and Mississippi Sound, Alabama. Bulletin of the 

U.S. Fish Commission 15: 325-340. 

Ross, MS., J.F. Meeder, J.P. Sah, P.I Ruiz and G.J. Telesnicki. 2000. The southern saline Everglades revisited: a half-century of 

coastal vegetation change. Jour. Veg. Sci. 11:101-112. 

Ruiz, J.F. and M.S. Ross. 2004. Hydrologic Restoration of the Biscayne Bay Coastal Wetlands: Mosquito and Drainage Ditch 

Inventory and Recommendations. Final Report. Southeast Environmental Research Program, Florida International 

University, 13p. 

Serafy, J.E. and J.S. Ault, P. Ortner, and R. Curry. 2001. Coupling Biscayne Bay’s natural resources and fisheries to 

environmental quality and freshwater inflow management, pp. 163-174. In: Biscayne Bay Partnership Initiative. Survey Team 

Final Reports. Florida Atlantic University, Joint Center for Environmental and Urban Problems. 307 pp + appendices. 

Serafy, J.E., K.C. Lindeman, T.E. Hopkins, and J.S. Ault. 1997. Effects of canal discharge on fish assemblages in a subtropical

bay: field and laboratory observations. Marine Ecology Progress Series 160:161-172. 

Serafy, J.E., C.H. Faunce, and J.J. Lorenz. 2003. Mangrove shoreline fishes of Biscayne Bay, Florida. Bull. of Mar. Science 

72:161-180. 

SFWMD. 1995. An Update of the Surface Water Improvement Management Plan for Biscayne Bay, Florida. Technical 

Supporting Document and Appendices. South Florida Water Management District. 3301 Gun Club Road West Palm Beach 

Florida. 

Smith, H.M. 1896. Notes on Biscayne Bay, Florida, with reference to its adaptability as the site of a marine hatching and 

experiment station. Report of the Commissioner [U.S. Commission of Fish and Fisheries] for the year ending June 30, 1895. 

21. Pp 169_191. 

Stenzel, H.B. 1971. Treatise on invertebrate paleontology. In: Moore, R.C. and C. Teichert (eds.), Part N. Volume 3 (of 3), 

Mollusca 6, Bivalvia. Oysters. Geological Society of America Inc. and the University of Kansas Press, Lawrence, Kansas. 

Pp. N953-N1224. 

Teas, H.J. 1976. Productivity of mangroves in Biscayne Bay. Pp. 103-112. In: Thorhaug, A., and A. Volker (Eds). Biscayne Bay: 

Past, Present and Future. Sea Grant Special Report No. 5. University of Miami, Florida. 315 p. 

17
18

Wang, J.D., J. Luo, and J. S. Ault. 2003. Flows, salinity, and some implications for larval transport in south Biscayne Bay, 

Florida, Bull. Mar. Sci. 72:311-329. 

Wanless, H.R., 1976a. Geologic setting and recent sediments of the Biscayne Bay region. p. 1-32, In: Thorhaug, A., and Volker, 

A. (Eds). Biscayne Bay: Past, Present and Future. Sea Grant Special Report No. 5. University of Miami, Florida. 315 p. 

Wells, H.W. 1961. The fauna of oyster beds, with special reference to the salinity factor. Ecological Monographs 31(3): 239-66 

Wingard, G.L., T.C. Cronin, G.S. Dwyer, S.E. Ishman, D.A. Willard, C.W. Holmes, C.E. Bernhardt, C.P. Williams, M.E. Marot, 

J.B. Murray, R.G. Stamm, J.H. Murray, and C. Budet. 2003. Ecosystem history of southern and central Biscayne Bay: 

summary report on sediment core analysis. Open File Report 03-375. U.S. Geological Survey. 

Wingard, G.L., T.M. Cronin, C.W. Holmes, D.A. Willard, G. Dwyer, S.E. Ishman, W. Orem, C.P. Williams, J. Albietz, C.E. 

Bernhardt, C.A. Budet, B. Landacre, T. Lerch, M. Marot, and R.E. Ortiz. 2004. Ecosystem history of southern and central 

Biscayne Bay: Summary report on sediment core analyses – Year Two. Open File Report 2004-1312. U.S. Geological 

Survey.