A summary of Coral Reef Evaluation and Monitoring Project (CREMP) site selection and monitoring methods.

Site Selection

Florida Keys National Marine Sanctuary Coral Reef Evaluation and Monitoring Project

The Florida Keys National Marine Sanctuary Coral Reef Evaluation and Monitoring Project (FKNMS CREMP) sampling sites and stations were selected and installed in 1995. Originally 40 sites and 160 stations were selected for monitoring. The original 40 CREMP sampling sites were selected using a stratified, or layered, random sampling procedure based on the U.S. Environmental Protection Agency's (EPA) Environmental Mapping and Assessment Program (EMAP). Stratification, or the arrangement of the layers, was based on habitat type, with four main habitat types defined: nearshore hardbottom, patch reefs, offshore shallow reefs (roughly 10 to 20 feet of depth), and offshore deep reefs (about 30 or 50 feet deep). While sampling sites were selected in a random matter, stations were installed with the intention of monitoring specific aspects of the selected habitats. In 1999 three sites totaling 12 stations were installed and sampled in the Dry Tortugas as part of the FKNMS CREMP monitoring, for a total of 43 sites and 172 stations.

Of the three Dry Tortugas sites, one site with four stations is located in the northern Dry Tortugas Ecological Reserve and two sites with eight stations are located within the Dry Tortugas National Park. These sites and stations were selected as representative samples of coral reefs in the Dry Tortugas.

Prior to sampling in 2001 statistical analysis of previous CREMP data indicated that sampling effort could be reduced without significantly affecting the outcome of analyses; 55 stations and three sites were removed from the survey. One additional site with two stations was dropped prior to each of the 2006 and 2008 sampling events. At least two stations are surveyed at the remaining survey sites.

For FKNMS CREMP there are currently 38 sites with a total 113 stations. There are two nearshore hardbottom sites with seven stations, 11 patch reef sites with 33 stations, 12 offshore shallow reef sites with 39 stations and 13 offshore deep reef sites with 34 stations. FKNMS CREMP sites are represented by black triangles on the map below.

In 2008 there will be an additional six sites with two stations each installed and surveyed at patch reefs within Hawk Channel, several kilometers offshore, in order to provide additional monitoring for this diverse area. Hawk Channel sites will be selected as representative samples of their specific areas.

Southeast Florida Coral Reef Evaluation and Monitoring Project

The Southeast Florida Coral Reef Evaluation and Monitoring Project (SECREMP) survey sites are monitored by the National Coral Reef Institute at Nova Southeastern University Oceanographic Center.

Off the coast of southeast Florida there are three linear reef structures running parallel to shore; an inner reef tract (at a depth of nearly 10 feet), a middle reef tract (about 35 feet deep), and an offshore reef tract (roughly 50 feet below the surface). Inside of the inner reef tract is a fairly continuous nearshore hardbottom community. The three reef tracts are separated by sand flats roughly 2,000 feet wide.

SECREMP sampling sites were selected as representative samples of the three reef tracts located off of southeast Florida. Station installation and the first surveys of these sites occurred in 2003. For Miami-Dade and Broward counties, one site was chosen from each of the three reef tracts, totaling six sites and 24 stations. In Palm Beach County the inner and middle reef tracts are less defined. Two sites totaling eight stations were selected from the offshore reef tract, and one site with four stations was selected from the inner tract/hardbottom habitat. An additional site, four stations, was set up off of Palm Beach County with the intention of monitoring the Acropora Cervicornis thickets that exist there.

In 2005, three additional survey sites were selected off of Martin County. The Martin County reef area is limited and generally found along one track parallel to shore. Two sites with eight stations were installed to conduct surveys using standard CREMP protocols and one additional site was installed with the intention of monitoring individual coral colonies, fate-tracking.

SECREMP survey stations were set up parallel at each survey site. There are currently 12 sites with 48 stations as part of SECREMP, and one additional site in Martin County setup for coral colony fate tracking. SECREMP sites are represented by blue diamonds on the map below.

Dry Tortugas Coral Reef Evaluation and Monitoring Project

The Dry Tortugas is an area of well-developed and varied reef structures, located some 60 miles west of Key West. The Dry Tortugas Coral Reef Evaluation and Monitoring Project (DRTO CREMP) is a survey of coral reefs located within the Dry Tortugas National Park, which covers about 100 square miles (1002) of marine habitat.

The first CREMP stations installed in the Dry Tortugas National Park were installed in 1999 as part of the FKNMS CREMP monitoring project. Of the three sites installed in 1999, two were are located within the National Park boundaries and are also included as part of the DRTO CREMP. One site with four stations is an offshore deep reef (in 40 feet of water) and the other, also with four stations, is considered a patch reef habitat

The DRTO CREMP was initiated in 2004 to provide a better understanding of temporal changes, or changes that take place through time, in reef communities occurring within the Dry Tortugas National Park. DRTO CREMP sites and stations were selected as representative samples of the coral reefs of the Dry Tortugas and with the intention of targeting certain coral species. Four sites totaling 13 stations were installed and first surveyed in 2004. All four of these sites are considered patch reef habitats for the purpose of CREMP. Two sites totaling five stations are shallow water habitats focused on monitoring acroporid stands, while the other two sites, four stations each, are located in slightly deeper water farther from shore.

One additional nearshore patch reef was added during each of the 2005 and 2006 surveys. In 2005 a two-station site was added off the southeast side of Loggerhead Key that focused on an Acropora cervicornis stand. In 2006 a site was added off the northwest side of Loggerhead Key. Because of extremely shallow depths this site it is not surveyed using standard CREMP methods. There are currently seven sites with a total of 23 stations surveyed as part of the DRTO CREMP, and one additional site surveyed using modified methods. DRTO CREMP sites are represented by red circles on the map below.

CREMP sampling sites

Survey Station Installation/Setup Methods

The CREMP survey station is a permanently marked area that allows for the same section of coral reef habitat to be surveyed year after year. A number of experimental and logistical aspects were considered when selecting the location of CREMP survey stations. At locations with large areas of habitat, CREMP stations are generally set up in parallel formations, several meters apart. However, at some locations the habitat area is limited and station placement is dependant on finding areas with enough space to accommodate the survey area that is 22- by 2-meters long. In areas characterized by spur and groove reefs, stations were set up on separate but adjacent reef spurs. A number of station locations were chosen with the intent of monitoring specific aspect of the selected habitat type.

Once a location is selected for station installation a hole is drilled into the substrate using an underwater hydraulic drill (Figure 4). A steel marker is then placed into the hole and cemented in place. These markers are permanent and are used to relocate the survey station as well as provide an anchor for station setup.

CREMP scientists installing a survey stake CREMP scientists installing a survey stake

Figure 4: The substrate is drilled using the underwater hydraulic drill.

 

The CREMP Survey Station (Figure 5)

A CREMP survey station is marked by two steel stakes that are cemented into the hard substrate at either side of the station approximately 22 meters apart. Steel poles two meters in length are placed over the stakes and fiberglass measuring tapes are extended between the ends and the middle of the two steel poles. Lightweight plastic chains are then laid over the substrate using the fiberglass tapes as a guide. The result is a station that has three transects and encompasses an area of 44 meters squared (44m2).

CREMP sampling station

CREMP station setup

CREMP station setup

Figure 5. The CREMP survey station (left). Station setup; CREMP divers extend fiberglass tapes between the steel poles at either end of the station (above right). Station setup; CREMP divers lay chain over the substrate using fiberglass tapes as a guide (below right).

Core Monitoring/Assessment Methods

Sampling at the original 40 sites, 160 stations (four stations per site), began in 1996 with the collection of video transect data and species richness counts. Monitoring of clionid sponges began in 2001. All CREMP stations are surveyed using these core methods unless otherwise specified above.

Video Transect Survey (Figure 6)

CREMP uses a video transect survey to determine the benthic substrate coverage of various coral species and various taxonomic groups (such as octocorals, macroalgae, sponges, etc...). First, a clapper board with all of the necessary site and station information is recorded. Then a diver swims the length of all three transects of the survey station starting from the same side of the station each time. The camera is held at a distance of 40 centimeters (cm) off the substrate using a convergent laser system. The area filmed is 40-cm wide and about 22-meters (m) long for each transect resulting in a total area of approximately 26.4 m2 for each survey station. Still images are later taken from the video and analyzed using custom software, Coral Point Count 99, developed by Phil Dustan at the University of Charleston. This software package randomly places points over the still images. The substrate cover under those points is then identified. For a single survey station, three transects, approximately 2,000 points are counted. This method allows for a large, detailed dataset to be collected at each station within the limited time allotted by SCUBA.

CREMP video transect survey station

CREMP video transect survey

Figure 6. The area of a CREMP survey station covered during filming of video transects (left). A diver films a video transect while holding camera at a constant distance of 40cm from the substrate (right).

Species Inventory Survey (Figure 7)

The species inventory survey is simply a count of all the stony coral species within the area of a station (44 meters-squared). Two divers closely examine the substrate for all stony coral species for no longer than 15 minutes and then compare observations to insure that all species are counted. The presence or absence of disease and bleaching, and the species affected is also noted. The number of long-spined sea urchins (Diadema antillarum) within the station area is also counted.

CREMP species inventory survey station

CREMP species inventory survey

Figure 7. The area of a survey station covered during the species inventory survey (left). Two divers examine the area of a survey station for stony coral species and disease or bleaching conditions (right).

Clionid Sponge Survey (Figure 8)

For the clionid sponge survey a diver examines the area within one-half meter of each transect, creating a one-meter wide belt transect, for the bio-eroding sponges Cliona delitrix, C. varians, C. lampa and C. carribaea. When any of these species are encountered the surface area of the sponge within the belt transect is measured using a 0.3- by 0.3-meter quadrat that is separated into 5- by 5-centimeter sections. A total of 66 meters-squared is examined for clionid sponges. The total surface area of each species is recorded as centimeter-squared by meter-squared (cm2/m2).

CREMP clionid sponge survey station

CREMP clionid sponge survey

Figure 8. The total area of a survey station covered during the clionid sponge survey (left). A diver conducts the clionid sponge survey using a meter stick to create a belt transect centered around one of the survey station transects (right).

Additional Survey Methods

Several additional surveys are conducted at a number of the CREMP sites. Many of these surveys are designed to monitor or address concerns identified by previously gathered CREMP data.

FKNMS CREMP (four current)

On-site Temperature Data
In 2002, temperature loggers, which are instruments used to record water temperatures, were installed on station markers at 12 sites in the lower and middle Florida Keys in order to have a detailed record of temperature changes throughout the year. Later, temperature loggers were installed at four sites in the Dry Tortugas. At these 16 sites sea water temperature is recorded hourly near the reef substrate all year.

Acropora palmata Fate-tracking Survey
Over the last decade, 80-90 percent of the cover by the iconic branching elk horn coral, Acropora palmata, has been lost in the Florida Keys. In 2007, this formerly common coral was added to the U.S. Endangered Species List. This survey uses existing CREMP survey stakes to locate, relocate and monitor the condition of A. palmata colonies on an annual basis starting in 2008.

A. palmata colonies are located and mapped at all offshore shallow reef sites where it is present using the bearing and distance from existing CREMP survey stakes. Once colonies are located they are photographed and observations on the colonies' size, morphology, or structure, and positioning are gathered. In following years each colony's location will be revisited and the presence, absence and condition of the colonies will be noted. In addition, the presence of new colonies will be recorded.

Montastrea annularis species complex Fate-tracking Survey and Health Sampling
M. annularis
is a boulder coral that can reach massive sizes and is a major framework builder on many of Florida's coral reefs. In the late 1990s this species suffered major declines in coverage. This survey uses existing CREMP survey stakes to locate, relocate and monitor the condition of M. annularis colonies on an annual basis starting in 2007.

M. annularis colonies are located at nine previously selected survey sites (one patch reef, one offshore shallow reef, and one offshore deep reef from each region such as the upper, middle, and lower Florida Keys) using the bearing and distance from existing CREMP survey stakes. Once located, each colony is photographed and qualitative data on the colonies condition is recorded (including the percent of living tissue, number of discrete living areas, presence and coverage of bleaching and disease conditions). There are currently 140 colonies of various sizes being monitored as part of this survey.

The fate-tracking survey of M. annularis is accompanied by the collection of coral tissue and mucus samples to determine baseline health of targeted M. annularis colonies affected with black band disease. The tissue sampling is conducted at only one fate-tracking station in each region.

Tissue samples are taken for histology, or study of tissue structure, using both light and transmission electron microscopes. Mucus samples are collected to study bacteria and samples are also taken for microalgal analysis. Healthy samples will be compared to diseased samples and differences in the microbiological and microalgal communities will be analyzed over time to aid in determining baseline health versus a diseased state. Transmission electron microscopy will aid in understanding the mechanism of black band disease pathology and allow for identifications of the cyanobacteria present in diseased coral tissue.

A Survey of the Barrel Sponge Xestopongia muta
Sponges play many important roles in the reef ecosystem: filtering bacteria and nutrients from the water column, binding corals to the substrate, aid in reef regeneration, and providing a food source. Xestospongia muta is commonly found on coral reefs typically at depths greater than 10 meters. This sponge contributes greatly to overall sponge biomass and habitat and is an important indicator of reef health.

CREMP monitors X. muta at all offshore deep stations. A belt transect method similar to that used for the Clionid Sponge Survey is used to locate X. muta colonies. Volume is measured as an indicator of sponge abundance and population health for each X. muta colony. The presence and absence of disease and bleaching is also recorded for each sponge colony. These data will help to explain the population dynamics, community structure, and health of these important and often understudied reef organisms.

In the past, several surveys have been completed or discontinued. For information on these surveys please refer to the CREMP Discontinued Operating Procedures

SECREMP (one current)

Coral Colony Fate-Tracking at Martin County Site 3 (MC3)
Because of the low coverage of stony coral off of Martin County, this alternate method is used to monitor the condition of coral colonies at one site. Forty-nine colonies of six stony coral species were mapped using the distance and bearing from installed marker stakes. Just as in the fate-tracking studies listed above, these colonies are revisited every year. Their sizes (length and width) are measured, their condition (including disease, bleaching, etc.) is recorded and they are photographed. Photographs of the planar, or two-dimensional, view of the colonies are then used to determine living or damaged tissue areas using custom software, Coral Point Count with Excel Extensions (CPCe), developed by Kevin Kohler of the National Coral Reef Institute.

DRTO CREMP (two current)

Octocoral Abundance Survey
Octocoral abundance is monitored at one survey site, Mayer's Peak, in the Dry Tortugas using 20 randomly placed one meter-square quadrats. Octocorals are identified to genera because it is difficult to distinguish different octocoral species in the field. This survey is conducted to provide baseline data on octocoral abundance.

Modified Sampling at Little Africa
At Little Africa, a survey site located just offshore to the northwest of Loggerhead Key, depths are too shallow to use CREMP core methods for monitoring coral reef communities. Scleractinian Species Inventories and Bioeroding Sponge Surveys are not conducted. Rather than filming video transects to determine benthic coverage, a still photography method is used. Ten transects are used, each 25-meters long. Photos are taken every half-meter along the each transect. These photos are then analyzed using the same methods as still images taken from video.

For more information regarding CREMP site selection and methods please contact the corals group at Corals@MyFWC.com

Additional information on the coral reef tracts of southeast Florida is available at the SECREMP Web page at the National Coral Reef Institute

Additional information on the coral reef resources of the Dry Tortugas is available at the National Park Service: Dry Tortugas Web page.

Additional information on the Coral Point Count w/ Excel Extensions Software is available at the CPCe Web page at the National Coral Reef Institute

 



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