OCS Study 

MMS 2003-031 

Long-Term Monitoring at the 

East and West Flower Garden Banks 

National Marine Sanctuary, 1998-2001 

Final Report

U.S. Department of the Interior

Minerals Management Service 

Gulf of Mexico OCS Region 
U.S. Department of the Interior 

Minerals Management Service 

Gulf of Mexico OCS Region 

OCS Study 

 MMS 2003-031 

Long-Term Monitoring at the 

East and West Flower Garden Banks 

National Marine Sanctuary, 1998-2001 

Final Report 

Authors 

Quenton R. Dokken 

Ian R. MacDonald 

John W. Tunnell, Jr. 

Terry Wade 

Kim Withers 

Suzanne J. Dilworth 

Thomas W. Bates 

Carl R. Beaver 

Christopher M. Rigaud 

Prepared under MMS Contract 

1435-01-98-CT-30905 

by 

Center for Coastal Studies 

Texas A&M University, Corpus Christi 

6300 Ocean Drive 

Corpus Christi, Texas 78412 

Published by 

New Orleans

July 2003 
iii

DISCLAIMER 

This report was prepared under contract between the Minerals Management Service 

(MMS), the National Oceanic and Atmospheric Administration (NOAA) and the Center for 

Coastal Studies (CCS), Texas A&M University-Corpus Christi, and the Geological and 

Environmental Research Group (GERG), Texas A&M University-College Station. This report 

has been technically reviewed by MMS and NOAA, and approved for publication. Approval 

does not signify that the contents necessarily reflect the views and policies of MMS and NOAA, 

nor does the mention of trade names or commercial products constitute endorsement or 

recommendation for use. It is, however, exempt from review and compliance with MMS 

editorial standards. 

REPORT AVAILABILITY 

Extra copies of this report may be obtained from the Public Information Office (Mail 

Stop 5034) at the following address: 

U.S. Department of the Interior 

Minerals Management Service 

Gulf of Mexico OCS Region 

Public Information Office (MS 5034) 

1201 Elmwood Park Boulevard 

New Orleans, Louisiana 70123-2394 

Telephone: (504) 736-2519 or 

 1-800-200-GULF 

CITATION 

Suggested citation: 

Dokken, Q.R., I.R. MacDonald, J.W. Tunnell, Jr., T. Wade, K. Withers, S.J. Dilworth, T.W. 

Bates, C.R. Beaver, and C.M. Rigaud. 2003. Long-Term Monitoring at the East and 

West Flower Garden Banks, 1998-2001: Final Report. U.S. Dept. of the Interior, 

Minerals Management Service, Gulf of Mexico OCS Region, New Orleans, Louisiana. 

OCS Study MMS 2003-031. 90 pp. 

NOTE TO READER 

Information contained within this synthesis report takes precedence over all data reported 

in Dokken et al. 1996-1999. Advanced analysis and enhanced calculations make this data more 

robust and comprehensive. 
v

ACKNOWLEDGMENTS 

Project personnel and their major responsibilities: 

1. Quenton R. Dokken Project Manager, Co-Principal Investigator 

2. Ian R. MacDonald Scientist, Co-Principal Investigator 

3. John W. Tunnell, Jr. Scientist, Co-Principal Investigator 

4. Terry Wade Scientist/Data Analysis 

5. Kim Withers Scientist/Data Analysis 

6. Suzanne J. Dilworth Scientist/Logistics/Data Analysis/Field Management 

7. Thomas W. Bates Scientist/Data Analysis/Field Management 

8. Carl R. Beaver Scientist/Data Analysis/Field Management 

9. Christopher M. Rigaud Scientist/Data Analysis 

Project Divers 

Suzanne Dilworth 

Susan Childs 

Ian MacDonald 

Mike Fredericks 

Amy Koltermann 

David Gray 

Tannika Engelhard 

Thomas Bates 

Carl Beaver 

Kerry DeHart 

Al Oswalt 

Addie Frets 

Jennifer Davidson 

Rick Maxey 

Quenton Dokken 

Jay Gardner 

Omar Guerra 

David Hicks 

Jason Jones 

Kyle Klootwyk 

Christopher Rigaud 

Chris Ledford 

Noe Barrera 

Mark MacNamara 

Tomas Oberding 

Jennifer Pearce 

Individual authors/contributors and the tasks they performed are listed below. 

REPORT Task/Analysis Author/Contributor 

Project Management, 

Discussion, Conclusions, 

Recommendations, Editorial 

Management 

Quenton R. Dokken 

Ian R. MacDonald 

John W. Tunnell, Jr. 

Introduction 

Study Site 

Methods 

Suzanne J. Dilworth 

Quenton R. Dokken 

Kim Withers 

John W. Tunnell, Jr. 

Ian R. MacDonald 

Random Photographic 

Transects 

Christopher Rigaud, Aimee Cunningham, 

and Kim Withers 

Encrusting Growth Stations Thomas W. Bates and Kim Withers 

Repetitive Quadrats Thomas W. Bates and Kim Withers 

Sclerochronology Carl Beaver and Kim Withers 

Water Chemistry Terry Wade 

Insolation Ian R. MacDonald and Norman Guinasso 

Temperature Thomas W. Bates and Suzanne J. 

Dilworth 

Urchin Surveys Suzanne J. Dilworth 

LONG-TERM MONITORING AT 

THE EAST AND WEST FLOWER 

GARDEN BANKS, 1998-2001 

(MMS/NOAA FUNDED PROJECT) 

Document Layout & 

Preparation 

Suzanne J. Dilworth
vii

EXECUTIVE SUMMARY 

During the 1998 - 2001 monitoring period analysis of monitoring data indicated that the 

Flower Garden Banks (FGB) were healthy and productive. Relative to other coral reef systems 

of the Gulf of Mexico and Caribbean Sea, the FGB have low diversity of stony corals and high 

coral cover, generally ~ 50%. Located 193 and 172 km (East and West Flower Garden Bank, 

respectively), offshore from Galveston, Texas, the FGB are relatively isolated from terrestrial 

based impacts when compared to reef systems such as those of the Florida Keys and southern 

Gulf of Mexico. Although afforded a measure of protection from shore side development and 

watershed drainage impacts, within the FGB there is potential for habitat damage from industrial 

and recreational activities occurring in the near vicinity such as marine shipping, oil/gas 

production, and sport diving. Prior to designation as a National Marine Sanctuary in 1992, 

substantial anchor damage was observed. Some anchor damage has occurred since Sanctuary

designation. No significant impact from oil/gas production activity has been documented

after Sanctuary designation.

Based on the results of the random transect data, cover of the Montastraea annularis 

complex (M. annularis, M. faveolata, and M. franksi; Weil and Knowlton, 1994) at the EFGB 

increased. A concurrent loss of reef rock, M. cavernosa and Diploria strigosa was indicated, but 

the data is inconclusive and these results may be an artifact of methodology. Algal cover 

increased in 1999, but then declined. Reef rock was also negatively correlated with algal cover. 

It appeared that M. annularis complex and algae colonized more of the non-living surfaces of the 

bank. The significant positive correlation between algae and total coral suggested that algae 

were not expanding at the expense of coral cover. 

Increases in the cover of the M. annularis complex at the WFGB was less than at the 

EFGB. The correlations between the M. annularis complex, D. strigosa, M. cavernosa and total 

coral cover were indicative of the fact that these three species are the predominant corals on the 

bank. The same negative correlation between reef rock and algae recorded at the EFGB was also 

seen at the WFGB. Consistent with the EFGB, algae primarily colonized non-living surfaces 

(i.e. reef rock). Unlike the EFGB, the M. annularis complex did not appear to be expanding into 

areas of non-living substrate. In addition, there were no significant correlations between the M. 

annularis complex and D. strigosa or M. cavernosa or algae and total cover as seen at the 

WFGB. The coral community at the WFGB remained stable throughout the monitoring period 

despite the increase in algal cover. 

Random photographic transects were completed outside the boundaries of the designated 

100 m2

 study area to test whether or not the study area remained representative of the reef 

habitat. No inconsistencies between the reef character outside the designated study area and the 

study area were evident (Appendix 1). 

Variability of accretionary growth and encrusting growth was the rule. Annual 

accretionary growth of Montastraea faveolata at the East Flower Garden Bank (EFGB) averaged 

7.5 mm/year (range = 6.12-8.23). At the West Flower Garden Bank (WFGB) annual 

accretionary growth ranged from 4.49 to 6.64 mm/year and averaged 5.37 mm/year. No 

significant long-term upward or downward trends in growth rates were evident, and no 

correlations of growth to environmental parameters could be ascertained. Rates of coral growth 
viii

at the Flower Garden Banks were in the mid to upper range of growth rates of corals at various 

Caribbean Sea reefs. Encrusting growth, measured on colonies of Diploria strigosa, was also 

variable over time, but appeared balanced (i.e. gain versus loss of tissue). No significant longterm trends in encrusting growth were evident. 

Habitat characters such as degree of bleaching and percent cover of algae and bare reef 

rock varied annually from 1998 to 2001. However, as with the growth data, no trends were 

evident and no change appeared to be long term. Disease was a minor component of the FGB 

ecosystem dynamics with no apparent significant impact. 

 Light intensity in the water column indicated that the water clarity of the Flower Garden 

Banks National Marine Sanctuary was between that of the clearest coastal waters and clearest 

oceanic waters. Periodic changes in water clarity reflected changes in cloud cover and 

concentrations of suspended particles and plankton. It was speculated that changing current 

patterns affected the transmissivity of the water column. 

 The temperature regime for 1998 and 2001 was consistent with historical patterns with 

temperatures staying within normal parameters. With the peak temperature less than 30o

C, 

bleaching was not a major event with the exception of the Millepora alcicornis colonies, which 

were particularly susceptible. 

 Ancillary efforts to the monitoring program by visiting scientists produced an expanded 

catalog of flora and fauna. Combined, Fredericq et al. (2001) (University of Louisiana at 

Lafayette) and Lehman and Albert (2001) (Center for Coastal Studies, Texas A&M UniversityCorpus Christi) produced a list of 72 species of algae, and Barrera and Tunnell (2001) (Center 

for Coastal Studies, Texas A&M University-Corpus Christi) added 100 new species to the 

catalog of molluscs found at the FGB. Dunton and Miller (2001) (University of Texas at Port 

Aransas) used stable nitrogen isotopes to describe a food web structure and macroalgal primary 

production. Nutrients at the Flower Garden Banks were derived primarily from local benthic 

cyanobacterial mats rather than from coastal zones. Nipper and Carr (2001) (Center for Coastal 

Studies, Texas A&M University-Corpus Christi and U.S. Geological Survey-Biological 

Resources Division Marine Ecotoxicology Research Station, respectively) tested the pore waters 

of the Flower Garden Banks substrates and described the pore water quality as good in all 

parameters. 

The Minerals Management Service and Flower Garden Banks National Marine Sanctuary 

made substantial progress in implementing many of the recommendations of past reports. The in 

situ water quality monitoring instrumentation was upgraded; and the 2002 and 2003 monitoring 

program, as specified within the published RFP will include: 

1) Expanded algal studies, nutrient flows, and nutrient concentration measurements; 

2) More rigorous laboratory measurements of potential contaminants; 

3) Continued analysis of population densities of the herbivore, Diadema antillarium; 

4) Deep water stations will be established and monitored; and 

5) Fish censuses will be conducted. 
ix

These actions will not only expand our knowledge and understanding of the Flower Garden 

Banks ecosystem, but will also improve the foundation from which management decisions are 

made. 
xi

TABLE OF CONTENTS 

ACKNOWLEDGMENTS....................................................................... v

EXECUTIVE SUMMARY...................................................................... vii

LIST OF FIGURES.............................................................................. xiii

LIST OF TABLES................................................................................ xv

1.0 INTRODUCTION............................................................................ 1

1.1 OVERVIEW......................................................................... 1

1.1.1 Habitat Description...................................................... 1

2.0 METHODS.................................................................................... 5

2.1 FIELD LOGISTICS.................................................................. 5

2.2 STUDY SITES........................................................................ 5

2.3 RANDOM TRANSECTS.......................................................... 5

2.3.1 Field Methods and Data Capture........................................ 5

2.3.2 Data Presentation and Statistical Analysis............................ 9

2.4 SCLEROCHRONOLOGY......................................................... 10

2.4.1 Field Methods and Data Capture........................................ 10

2.4.2 Data Presentation and Statistical Analysis............................. 10

2.5 ENCRUSTING GROWTH......................................................... 11

2.5.1 Field Methods and Data Capture....................................... 11

2.5.2 Data Presentation and Statistical Analysis............................ 11

2.6 REPETITIVE QUADRATS....................................................... 12

2.6.1 Field Methods and Data Capture....................................... 12

2.6.2 Data Presentation and Statistical Analysis............................ 14

2.7 VIDEO TRANSECTS.............................................................. 14

2.8 WATER QUALITY/INSOLATION/TEMPERATURE........................ 15

2.8.1 Water Quality............................................................... 15

2.8.2 Insolation................................................................... 15

Li Cor Data Loggers.................................................... 15

YSI Data Sondes and OSP Installation............................... 15

Estimating Light Attenuation........................................... 16

2.8.3 Temperature............................................................... 17

2.9 SEA URCHIN SURVEYS........................................................ 17

3.0 RESULTS..................................................................................... 19

3.1 RANDOM TRANSECTS............................................................ 19

3.1.1 East Bank – Community Composition and Structure............... 21

3.1.2 East Bank – Comparisons Among Years.............................. 19
xii

3.1.3 West Bank – Community Composition and Structure............... 23

3.1.4 West Bank – Comparisons Among Years............................. 24

3.2 SCLEROCHRONOLOGY......................................................... 29

3.2.1 East Bank.................................................................. 29

3.2.2 West Bank.................................................................. 30

3.3 ENCRUSTING GROWTH STATIONS.......................................... 32

3.4 REPETITIVE QUADRATS........................................................ 35

3.4.1 East Bank – Species Composition and Cover......................... 35

3.4.2 West Bank – Species Composition and Cover........................ 38

3.5 VIDEO TRANSECTS............................................................... 41

3.6 WATER QUALITY/INSOLATION/TEMPERATURE..................... 41

3.6.1 Water Quality.............................................................. 41

3.6.2 Insolation................................................................... 42

3.6.3 Temperature............................................................... 47

3.7 SEA URCHIN SURVEYS......................................................... 47

4.0 DISCUSSION................................................................................. 51

4.1 GENERAL............................................................................. 51

4.2 CORAL GROWTH AND CONDITION......................................... 52

4.3 INSOLATION/TEMPERATURE/WATER QUALITY....................... 56

4.4 BIODIVERSITY..................................................................... 56

5.0 RECOMMENDATIONS................................................................... 59

6.0 CONCLUSION............................................................................... 61

7.0 LITERATURE CITED..................................................................... 63

8.0 APPENDIX 1................................................................................. 69

8.1 EAST BANK – COMMUNITY COMPOSITION, STRUCTURE, AND 

 TRENDS............................................................................... 69

8.2 WEST BANK – COMMUNITY COMPOSITION, STRUCTURE, AND 

 TRENDS.............................................................................. 69

9.0 APPENDIX 2................................................................................. 77

10.0 APPENDIX 3................................................................................. 79
xiii

LIST OF FIGURES 

1.1.1.1 Location map of the East and West Flower Garden Banks in relation to 

the continental shelf and other topographic features of the northwestern 

Gulf of Mexico (from Gittings et al. 1992)...................................... 2

2.2.0.1. Map of East Flower Garden Bank 100 x 100 m study site showing 

relative positions of permanent stations, mooring bolt and other 

conspicuous features................................................................ 6

2.2.0.2. Map of West Flower Garden Bank 100 x 100 m study site showing 

relative positions of permanent stations, mooring bolt and other 

conspicuous features................................................................ 7

2.3.0.1. Diver with random transect camera framer...................................... 8

2.5.0.1. Diver photographing a permanent encrusting growth station................. 12

2.6.0.1. Diver photographing a permanent repetitive photographic station and 

example of station post............................................................ 13

2.8.2.1 Ocean Sentinel Platform with YSI 6000 Data Sonde and light diffuser 

installed at the East and West Flower Garden Banks.......................... 16

3.1.1.1. Bray-Curtis community similarity dendrogram for random transects from 

1996-2001 for the East Flower Garden Bank................................... 21

3.1.3.1. Bray-Curtis community similarity dendrogram for random transects from 

1996-2001 for the West Flower Garden Bank. ................................. 26

3.2.1.1. X-ray images of two coral cores taken at the East Flower Garden Bank, 

September 2001 (uppermost layer of core includes some growth from 

collection year)...................................................................... 29

3.2.2.1. X-ray image of the coral core taken at the West Flower Garden Bank, 

April 2002 (uppermost layer of core includes some growth from 

collection year)...................................................................... 31

3.3.0.1. Encrusting growth station percent cover changes for the East Flower 

Garden Bank from 1998-2001..................................................... 34

3.3.0.2. Encrusting growth station percent cover changes for the West Flower 

Garden Bank from 1998-2001..................................................... 34

3.6.2.1. Irradiance at the HI389 platform: Upper panel shows mean hourly 

irradiance from April 1997 to February 2000. Lower panel shows mean 

hourly irradiance from March 2000 to November 2001; instrument was 

intermittent........................................................................... 43
xiv

3.6.2.2. Irradiance at the East Flower Garden Bank: Upper panel shows mean 

hourly irradiance from April 1997 to February 2000. Lower panel shows 

mean hourly irradiance from March 2000 to November 2001; note scale 

change, instrument was intermittent.............................................. 44

3.6.2.3. Irradiance at the West Flower Garden Bank: Upper panel shows mean 

hourly irradiance from April 1997 to February 2000. Lower panel shows 

mean hourly irradiance from June 2000 to August 2001...................... 45

3.6.2.4 Total insolation at the East Flower Garden Bank (upper) and at the West 

Flower Garden Bank (lower) monitoring stations (23.8 m water depth) 

April 1997 to March 2000......................................................... 46

3.6.2.5 Complete data record of environmental parameters from YSI probe 

installed at East Flower Garden Bank seafloor station, September 2001-

February 2002....................................................................... 48

3.6.2.6 Complete data record of environmental parameters from YSI probe 

installed at West Flower Garden Bank seafloor station, September 2001-

October 2002........................................................................ 49

3.6.3.1. Mean seawater temperatures for the East and West Flower Garden Banks 

from September 1999 to April 2000 (A) and November 2000 to 

September 2001 (B)................................................................ 50

8.1.0.1 Bray-Curtis community similarity dendrogram for outside random 

transects from 1998-2001 for the East Flower Garden Bank................. 72

8.2.0.1 Bray-Curtis community similarity dendrogram for outside random 

transects from 1998-2001 for the West Flower Garden Bank................ 75

 

 

 
xv

LIST OF TABLES 

3.1.1.1. Percent cover data from 1996-2001 for the East Flower Garden Bank 

random transects..................................................................... 20

3.1.1.2. Diversity (H’, base 10), evenness (J’), dominance (Berger-Parker) of the 

coral community using average % cover by year on the East Flower 

Garden Bank ....................................................................... 21

3.1.2.1. Results of analysis of variance among years on reef components on the 

East Flower Garden Bank using % cover data ................................ 22

3.1.2.2. Non-parametric correlation (Spearman’s rho, 2-tailed) between percent 

cover of major reef components of the East Flower Garden Bank ......... 23

3.1.2.3. Results of non-parametric runs test using median percent cover of coral 

species, total coral, algae, and sponge as the cutoff value for the East 

Flower Garden Bank............................................................... 24

3.1.3.1. Percent cover data from 1996-2001 for the West Flower Garden Bank 

random transects.................................................................... 25

3.1.3.2. Diversity (H’, base 10), evenness (J’), dominance (Berger-Parker) of the 

coral community using average % cover by year West Flower Garden 

Bank ................................................................................ 26

3.1.4.1. Results of one-way analysis of variance and Tukey’s HSD among years 

on reef components on the West Flower Garden Bank using % cover 

data ................................................................................. 27

3.1.4.2. Non-parametric correlation (Spearman’s rho, 2-tailed) between % cover 

of major reef components of the West Flower Garden Bank ............... 28

3.1.4.3. Results of non-parametric runs test using median percent cover of coral 

species, total coral, algae, sponge and reef rock as the cutoff value for 

the West Flower Garden Bank................................................... 28

3.2.1.1. Mean annual growth (mm) with standard deviation for 1985 to 2001 

determined from measurements of accretionary growth bands in cores 

from Montastraea faveolata, East Flower Garden Bank..................... 

30

3.2.2.1. Mean annual growth (mm) with standard deviation for 1985 to 2001 

determined from measurements of accretionary growth bands in cores 

from Montastraea faveolata, West Flower Garden Bank.................... 

32

3.3.0.1. Number of encrusting growth stations of Diploria strigosa and average 

gain (+), loss (−), or no change (=) in percent cover of coral tissue at the 

East and West Flower Garden Banks, 1998-2001............................. 33
xvi

3.4.1.1. Mean percent cover of coral species and total coral with standard 

deviation in 8 m2

 repetitive quadrats at the East Flower Garden Bank, 

2000-20011......................................................................... 35

3.4.1.2. Mean percentage of points falling on areas of bleaching, disease, etc. by 

station with standard deviation, maximum percentage for all stations and 

frequency (%) of occurrence for 8 m2 repetitive quadrats at the East 

Flower Garden Bank.............................................................. 

 

36

3.4.1.3. Percentage of colonies exhibiting bleaching1

 by species at the East 

Flower Garden Bank for 2000-2001............................................ 36

3.4.1.4. Overall percentage of points falling on areas of colonies exhibiting 

bleaching, disease etc. at the East Flower Garden Banks, 1998-2001...... 37

3.4.2.1. Mean percent cover of coral species and total coral with standard 

deviation in 8 m2

 repetitive quadrats at the West Flower Garden Bank, 

2000-2001. ......................................................................... 38

3.4.2.2. Mean percentage of points falling on areas of bleaching, disease, etc. by 

station with standard deviation, maximum percentage for all stations and 

frequency (%) of occurrence for 8 m2 repetitive quadrats at the West 

Flower Garden Bank.............................................................. 39

3.4.2.3. Percentage of colonies exhibiting bleaching1 by species at the West 

Flower Garden Bank for 2000-2001............................................ 40

3.4.2.4. Overall percentage of points falling on areas of colonies exhibiting 

bleaching, disease etc. at the East Flower Garden Banks, 1998-2001...... 40

3.6.1.1. Semi-Permeable Membrane Device (SPMD) sampling periods for the 

East and West Flower Garden Banks, 2000-2001............................. 41

3.6.1.2. Semi-Permeable Membrane Device (SPMD) deployed at the East Flower 

Garden Bank during drilling activities on HI-389 (courtesy of W&T 

Offshore, Inc.), May-September 2001.................................. 42

3.7.0.1. Average number of Diadema antillarium per meter square on the East 

and West Flower Garden Banks from 1996-2001............................. 47

8.1.0.1 Mean cover (%) with standard deviation in parenthesis from outside 

random transects, East Flower Garden Bank................................... 70

8.1.0.2 Shannon diversity (H’, base 10), evenness (J’) and Berger-Parker 

dominance (d), outside study area at the East Flower Garden Bank......... 71
xvii

8.1.0.3 Results of non-parametric Mann-Whitney U comparing inside transects 

to outside transects for major reef components, East Flower Garden 

Bank.................................................................................. 71

8.2.0.1 Mean cover (%) with standard deviation in parenthesis from outside 

random transects, West Flower Garden Bank.................................. 73

8.2.0.2 Shannon diversity (H’, base 10), evenness (J’) and Berger-Parker 

dominance (d), outside study area at the West Flower Garden Bank....... 74

8.2.0.3 Results of non-parametric Mann-Whitney U comparing inside transects 

to outside transects for major reef components, West Flower Garden 

Bank.................................................................................. 74
1

1.0 INTRODUCTION 

1.1 OVERVIEW 

The Flower Garden Banks National Marine Sanctuary (FGBNMS; designated 1992) 

includes deepwater coral habitats associated with two topographic high points located on the 

outer continental shelf in the northwestern Gulf of Mexico. The East Flower Garden Bank 

(EFGB) is located about 193 km southeast of Galveston, Texas (27o 54.5’ N, 93o 36.0’ W), 

and the West Flower Garden Bank (WFGB), about 20 km west of EFGB, is located about 

172 km southeast of Galveston (27o 52.4’ N, 93o 48.8’ W; Figure 1.1.1.1). The Flower 

Garden Banks (FGB) are found in the most active offshore oil/gas exploration and 

production area in the world. Approximately 4,000 production platforms are located in the 

northern Gulf of Mexico and are concentrated in the northwestern quadrant where the FGB 

are located. Two kilometers east of the EFGB, a production platform has been producing 

natural gas since its installation in 1982. Currently, there are no data suggesting that oil and 

gas production in the vicinity has been detrimental to the coral communities of the FGB 

(Dokken et al. 1999, 2001). The purpose of the long-term monitoring efforts on the coral 

reefs of the FGB that began in 1989 (Gittings et al. 1992) is to provide relevant and timely 

environmental data to those charged with managing the resources of the FGBNMS and

oil/gas exploration and production in the vicinity of the coral reefs. The objectives of the 

monitoring program are: 

1. to document long-term changes in community composition of reef-building 

coral and associated communities; 

2. to document long-term natural variation in reef growth; 

3. to stimulate ancillary research efforts and coordinate monitoring activities by 

other agencies and institutions; and 

4. to evaluate and synthesize monitoring data and other research in order to 

assess the impact of change and provide recommendations to managers. 

1.1.1 Habitat Description 

The FGB are part of a widely dispersed, discontinuous arc of reef environments along 

the outer continental shelf of the Gulf of Mexico (Rezak et al. 1985). The FGB are 

topographic features created when sedimentary rock was uplifted by underlying salt domes of 

Jurassic, Louann origin (Rezak 1981). The crests of these topographic highs extended into 

the intense photic zones of the surface waters providing the necessary habitat for overgrowth 

of scleractinian corals and other calcareous and sessile marine organisms. Environmental 

conditions on the northern Gulf’s outer continental shelf are generally favorable for 

development of hermatypic scleractinian coral species. Salinities range from 34 to 36 ppt. 

Water temperatures range from a low of ~ 20o

C (mid-February) to a high of ~ 30oC (August). 

Water clarity permits an average 75% per meter of water transmission of white light with 

40% to 50% of surface light reaching to 37 m (McGrail et al. 1982). 
2

Figure 1.1.1.1. Location map of the East and West Flower Garden Banks in relation to the continental shelf and 

topographic features of the northwestern Gulf of Mexico (from Gittings et al. 1992).
3

 These coral banks are the largest charted calcareous banks in the northwestern Gulf of 

Mexico (Bright et al. 1985) and the northernmost coral reefs on the continental shelf of North 

America (Bright et al. 1984). Although non-coral communities exist on neighboring banks 

(e.g., Stetson Bank), the reefs at Cabo Rojo, about 100 km south of Tampico, Mexico, are the 

closest extensively developed coral reefs in the Gulf of Mexico. 

The coral cap ranges in depth from approximately 18 to 44 m. The pear-shaped 

EFGB, encompassing about 67 km2, slopes from the crest at roughly 20 m to a seabed plane 

of terrigenous muds at a depth of 100-120 m. The eastern and southern edges of the bank 

slope steeply whereas the area north and west of the coral cap slopes more gently. The 

WFGB is slightly more than twice as large (137 km2) as the EFGB. Its major features are 

three crests aligned along an east-west axis. The middle crest rises from a depth of 100 – 150 

m to within 18 m of the surface and supports coral reef habitat. Diversity of the coral 

community at both banks is depauperate with only 20 species of hermatypic corals (Bright et 

al. 1984), whereas up to 67 species can be found on some Caribbean reefs. Acroporid 

branching scleractinians (e.g., Acropora palmata) and shallow water gorgonians are absent 

from the FGB reefs. 

Three biological zones have been delineated at the FGB (Rezak et al. 1985). In the 

shallowest areas of the banks (depths <36 m) is the Montastraea-Diploria-Porites Zone, with 

16 coral species. The Stephanocoenia-Millepora Zone extends from 36 – 52 m and contains 

13 coral species. Coral cover in both zones is interrupted by areas of bare reef rock and 

patches of biogenic sands. The Algal-Sponge Zone is found between ~ 46 – 88 m. Lower 

portions of this depth range are characterized by antipatharians that grade into a soft bottom 

composed of coarse carbonate sands below ~ 88 m. 

The Montastraea annularis species complex (Montastraea annularis, M. faveolata, 

and M. franksi; Weil and Knowlton 1994) represents the dominant scleractinian taxa in the 

Montastraea-Diploria-Porites Zone, followed by Diploria strigosa, M. cavernosa, Porites 

astreoides, and Colpophyllia natans. Total live coral cover averages ~ 45–52% (Dokken et 

al. 1999, 2001). Nine genera of crustose coralline algae have been identified in this zone and 

calcareous green algae are also common. In addition, over 350 species of invertebrates, 

including more than 225 molluscan species (Bright and Pequenat 1974; Dokken et al. 2001) 

and 177 species of fishes (Pattengill 1998) have been recorded. 

 In the Stephanocoenia-Millepora Zone, along the narrow depth gradient between 36 

and 46 m, the scleractinian Stephanocoenia intersepta and the hydrozoan Millepora 

alcicornis dominate. In addition, 11 other species of scleractinians are present including 

Diploria strigosa, M. cavernosa, Colpophyllia natans and Agaricia sp. (Bright and Pequenat 

1974). 

The EFGB study site was initially established in 1989 by Texas A&M University 

during early MMS-funded monitoring efforts (Gittings et al. 1992). The WFGB study site 

was originally established by Continental Shelf Associates (CSA) in 1988 and incorporated 

into the MMS monitoring efforts by Texas A&M University (Gittings et al. 1992). Both 

sites are located in the coral habitats of the Diploria-Montastraea-Porites Zone. 
5

2.0 METHODS 

2.1 FIELD LOGISTICS 

 Sampling cruises were conducted aboard the M/V Fling during 27 September - 1 

October 1998, 12-16 September 1999, 17-22 September 2000, and 16-21 September 2001. 

Weather conditions were excellent during the 1998 cruise; however, conditions during the 

September 1999 cruise were marginal, forcing delay of one contracted task (core extraction). 

Core extraction was eventually performed in February 2000. For 2000 and 2001 cruises, 

weather and currents prevented ancillary deepwater studies, however, all other tasks were 

completed. 

2.2 STUDY SITES 

 For all years, sampling was conducted within the previously established 100 x 100 m 

study sites on both the EFGB and WFGB. Subsurface buoys attached to stainless steel 

eyebolts cemented into the reef rock mark the four corners of each study site. During each 

sampling effort, graduated, color-coded polypropylene lines were extended between each 

corner eyebolt to mark the boundaries of the study sites and aid in diver navigation and 

location of individual monitoring stations. Boundary lines were removed at the end of each 

sampling effort. Each dive team was supplied with detailed underwater maps depicting 

relative positions of repetitive stations in relation to boundary lines and major topographical 

features (Figures 2.2.0.1 and 2.2.0.2). A master map on the surface was updated after each 

dive with the relative positions of new or renumbered stations. During spring, summer, and 

fall a large surface buoy is secured to a mooring line that is attached to a stainless steel u-bolt 

permanently cemented into the reef rock within each site. The buoys are owned by the 

FGBNMS and maintained by contract with Buoy Services, Inc. of Freeport, Texas. The 

buoys served as mooring sites for the research vessel during monitoring missions. 

2.3 RANDOM TRANSECTS 

 The purpose of random transects was to determine reef community composition and 

structure. A minimum of 14 transects ~10 m long, that consisted of at least 17 nonoverlapping photographs were performed within the boundaries of the study site on each 

bank during each monitoring cruise (Gittings et al. 1992; Hagman and Gittings 1992; 

Dokken et al. 1999, 2001). In addition, three transects consisting of 14 non-overlapping 

photographs were taken outside the boundaries of the study area at each bank during 1998-

2001 cruises to determine if the coral community within the study area was representative of 

the banks as a whole (Appendix 1). 

2.3.1 Field Methods and Data Capture 

Divers were equipped with Nikonos V cameras with a 28 mm lens and dual Nikonos strobes 

mounted on a rectangular aluminum or stainless steel camera frame that holds the camera 1 

m above the reef surface (Figure 2.3.0.1). The bottoms of the frames were wrapped in closed 

cell foam to protect the reef from damage. Cameras were loaded with Kodak Ektachrome 

100, 36-exposure color slide film and set for f-11 and a distance of 0.8 m; strobes were set on 

TTL and slave. This system produces color positive images of reef substrate approximately 

44 x 63 cm (0.2772 m2

). 
6

Figure 2.2.0.1. Map of East Flower Garden Bank 100 x 100 m study site showing 

relative positions of permanent stations, mooring bolt and other 

conspicuous features. 

43

33

106

110 3

2

8

4

5

116

11

10

122

116

83

34

12 115

2

1

22

34

3

32

69

58

143

27

55

17

19

18

185

145

79

84

82

190

63

13 21

170

22 49

60 186

32

119

98

93

99

188

29

193

37

28

27 26

130

168

92

44

6

73 184

181

74

183

21

12

15

149

13 11

64

57 187

191

195

178

176

192

179

189

39

40

177

194

Sand

Sand

Cement 

Block

Mooring 

#2

100m

100m 100m

100m

0 m 0 m

0 m

0 m

NW

SE

SW

NE

East Flower Garden Bank 100 x 100m Study Site

= Lateral Growth Station

= Repetitive Quadrat Station Updated Sept. 2001

13

44

71

3

30

169

30

154

146

67

61

34

148

150

180

142

165

162

171

164

163

127

166 175

= Missing / Not Found

43

33

106

110 3

2

8

4

5

116

11

10

122

116

83

34

12 115

2

1

22

34

3

32

69

58

143

27

55

17

19

18

185

145

79

84

82

190

63

13 21

170

22 49

60 186

32

119

98

93

99

188

29

193

37

28

27 26

130

168

92

44

6

73 184

181

74

183

21

12

15

149

13 11

64

57 187

191

195

178

176

192

179

189

39

40

177

194

Sand

Sand

Cement 

Block

Mooring 

#2

100m

100m 100m

100m

0 m 0 m

0 m

0 m

NW

SE

SW

NE

East Flower Garden Bank 100 x 100m Study Site

= Lateral Growth Station

= Repetitive Quadrat Station Updated Sept. 2001

13

44

71

3

30

169

30

154

146

67

61

34

148

150

180

142

165

162

171

164

163

127

166 175

= Missing / Not Found
7

Figure 2.2.0.2. Map of West Flower Garden Bank 100 x 100 m study site showing relative 

positions of permanent stations, mooring bolt and other conspicuous 

features. 

129

13

30

117 134 147

133

32

31

135

33

11

36 125

13 123

5

107

21

4 2

3

18

20

23

16

17

8

103

14 11

45

28

9

124

108 25

121

8

32

10

69

15

52

132

43

44

19

7 1

139

18

4 3

53

55

73

102

61

51 56

57

120

105

101

41

38

37

53

46

45

44

112

113

52

54

49

56

27

62

57

26

138

36

38

43

51

31

33

60

64

140

30 SW

NW

NE

SE

100m

100m

100m

100m 0 m

0 m

0 m

0 m

Mooring 

#5

Cement 

Block

Barrel

West Flower Garden Bank 100 x 100m Study Site

= Lateral Growth Station

= Repetitive Quadrat Station Updated Sept. 2001

55

62

= Missing / Not Found

37

23

141

200

198

150

136

196

128

126

199

68

129

13

30

117 134 147

133

32

31

135

33

11

36 125

13 123

5

107

21

4 2

3

18

20

23

16

17

8

103

14 11

45

28

9

124

108 25

121

8

32

10

69

15

52

132

43

44

19

7 1

139

18

4 3

53

55

73

102

61

51 56

57

120

105

101

41

38

37

53

46

45

44

112

113

52

54

49

56

27

62

57

26

138

36

38

43

51

31

33

60

64

140

30 SW

NW

NE

SE

100m

100m

100m

100m 0 m

0 m

0 m

0 m

Mooring 

#5

Cement 

Block

Barrel

West Flower Garden Bank 100 x 100m Study Site

= Lateral Growth Station

= Repetitive Quadrat Station Updated Sept. 2001

55

62

= Missing / Not Found

37

23

141

200

198

150

136

196

128

126

199

68
8

 

 Figure 2.3.0.1. Diver with random transect camera framer. 

Before entering the water, divers were assigned two sets of two random numbers. 

The first number of each set was a compass heading and the second was the number of fin 

kicks. Divers descended to the reef surface and proceeded to an assigned quadrant (i.e. 

northeast, northwest, southeast, southwest) to minimize the potential for transect overlap 

within the study area. At this point the diver swam in the designated compass heading for the 

specified number of fin kicks for transect beginning. Transects continued in the same 

direction until seventeen, non-overlapping photographs were taken. The diver then used the 

next set of random numbers to move to the starting point of the second transect. Each diver 

completed two transects (1 roll of film) during each dive. All quadrants of the study site 

were photographed at least once. 

 Slides were developed and digitally recorded on CD-ROM media. Areal coverage of 

coral species and other reef components was acquired using a Wacom serial graphics tablet 

and Jandel Scientific Sigma Scan Pro 4.0 software. The projection of the digitized images on 

the computer screen was calibrated to equal the actual area (cm2

) of the substrate represented 

by the slide. Coral colonies and other reef components were outlined using the serial graphics 

pen and areal coverage was automatically calculated. The following species or cover 

categories were used: coral species and total coral (1996-2001), filamentous algae (2000-
9

2001), crustose coralline algae (2000-2001), Dictyota sp. (2000-2001), total algae (1996-

2001), total sponge (1996-2001), FA: Serpulidae (2000-2001), other (e.g., fish, disease; 

2000-2001), reef rock (1998-2001), sand (1996-2001), artifacts (e.g., hand, SCUBA gauge; 

2000-2001); and not identified (included all non-living categories except sand, other 

biological and the unidentifiable portions of slides 1996-1997; all non-living categories 

except sand and reef rock, other biological and the unidentifiable portions of slides 1998-

1999; only the unidentifiable portions of slides in 2000-2001). 

2.3.2 Data Presentation and Statistical Analysis 

Mean percent cover and standard deviation for each year and bank were calculated 

for coral species and other cover categories. The areas of each species or category delineated 

in each slide taken along a transect were summed and divided by the sum of the areas of all 

slides taken along the transect (1 slide = 2,772 cm2). The numbers of slides per transect 

varied slightly (minimum 17, maximum 22) as did the number of usable transects (minimum 

of 10 in 1996 on EFG; maximum of 19 on EFG in 2001). Data are presented separately for 

inside and outside transects. 

For each bank and year, Shannon diversity (H’, base 10), evenness (J’), and BergerParker dominance (d) were calculated for the coral community using mean percent cover of 

each coral species. Bray-Curtis cluster analysis of community similarity (complete link) was 

used to evaluate coral community similarity among years. Data are presented separately for 

inside and outside transects. 

Using data from the study site transects only, one-way analysis of variance was used 

to determine significant differences (p < 0.05) in percent cover among years within each 

bank for the following: coral species (except rare Agaricia fragilis), total coral, total algae, 

total sponge and reef rock. Percent cover data for each species or category within each bank 

were tested for normality using the Kolmogorov-Smirnoff test and arcsine transformed if 

necessary. The general linear model was used since the design was unbalanced (numbers of 

transects per year varied). Where significant differences were found, Tukey’s HSD was used 

to delineate homogenous subsets of years. 

Using mean percent cover data for each species or category analyzed with analysis of 

variance (including data reported from previous monitoring by Gittings et al. (1992) and 

Continental Shelf Association (1996) in Dokken et al. (2001), as well as the data presented 

here), a non-parametric runs test was performed. Runs tests are used to determine whether 

or not events occur in a random sequence or whether the probability of a given event is a 

function of the outcome of a previous event. Additionally, this analysis is used for 

dichotomized data for which it tests the random sequence of a series of observations (Sokal 

and Rohlf, 1995). For the random transect data, runs tests were used to establish if data 

varied randomly or exhibited a systematic trend. 

To determine if the study areas were representative of the remainder of the high 

diversity living coral reef at each bank, the Mann-Whitney U test (the non-parametric 

equivalent of a t-test) was used. Percent cover data for each shared coral species and cover 

category were tested for significant differences between inside and outside transects using 

mean cover for each year when both types of data were collected. 
10

2.4 SCLEROCHRONOLOGY 

Sclerochronology is the determination of annual growth rates through the measurement 

of the width of accretionary growth bands in coral core samples. In accordance with NOAA 

permit FGBNMS-11-99, one or two cores were extracted from Montastraea faveolata

colonies at each bank only during the current contract period, when sea state and weather 

conditions allowed. Cores were extracted from EFGB during February 2000 and September 

2001 and from WFGB during February 2000 and April 2002. 

2.4.1 Field Methods and Data Capture 

The M. faveolata colonies chosen for coring exhibited the following characteristics: 

upright growth with a non-scoured base, no evidence of abnormal growth patterns resulting 

from the colony toppling after the base had eroded, no obvious holes caused by boring 

organisms, and no overgrowth by algae or sponges. Cores were extracted using a pneumatic 

drill attached to a compressed air scuba cylinder. Coral heads were drilled perpendicularly to 

the water’s surface on the top of the coral’s head to obtain the most accurate and continuous 

growth information. Cores were 60 mm in diameter and were drilled to a depth of at least 

100 mm to ensure at least 10 years of growth were represented. The hole left from core 

extraction was plugged with a preformed concrete plug inscribed with the date of core 

extraction. 

Cores were longitudinally sectioned into 3-4 mm thick slabs using a dual-blade 

diamond impregnated rock saw. Coral slabs were arranged on Kodak brand Industrix 400 xray film and exposed to x-rays (100 mA, 20 KV for 1.25 seconds) to reveal annual density 

bands. A machined metal scale was included as a length standard in each x-ray image to 

insure precise measurement of growth bands. Measurement standards were included in each 

x-ray, so that when film negatives were scanned into a computer and enlarged for growth 

band analysis the image’s scale was not compromised. 

One annual growth increment is defined as the combination of one low-density band 

and its adjacent high-density band (Knutson et al. 1972). The area between the upper 

boundaries of two sequential high-density growth bands was considered an annual growth 

increment. Scanned images were enlarged by a factor of ten and the first complete set of 

high and low density bands were used as the starting point for growth analysis. An objectoriented drawing program was used to place measurement lines at three separate locations on 

each annual growth band parallel to the growth axis. The program automatically displayed 

each line length in millimeters after it was drawn. Measurement data was corrected using the 

scale included in each x-ray. 

2.4.2 Data Presentation and Statistical Analysis 

Overall mean growth rates with standard deviation were calculated for each bank and 

year (1985-2000) based on all available data. Data are presented for each year in tabular. 

Nonparametric runs tests were used to determine if growth rates varied systematically or 

randomly. 
11

2.5 ENCRUSTING GROWTH 

 During previous studies (Continental Shelf Associates, 1996; Gittings et al., 1992), 

60 colonies of Diploria strigosa on each bank were established as permanent stations to 

assess coral margin growth rates. Rates of coral advance (tissue gain) and retreat (tissue loss) 

were determined through photographic analysis of these stations. 

2.5.1 Field Methods and Data Capture 

Growth stations were set up on colonies of D. strigosa along a margin of live coral 

growth adjacent to bare reef rock. These stations were established by permanently 

embedding two pins in the reef rock in such a manner that the growth margin of the coral 

would bisect a repeatable close-up photograph of the station. A uniquely numbered plastic 

tag secured to one of the pins was used to identify each station. 

Divers were equipped with a Nikonos V camera with a 28 mm lens, Nikonos close-up 

kit and strobe, and loaded with Kodak Ektachrome 100, 36-exposure slide film. The camera 

was set at f-22 and a distance of infinity, and the strobe was set to TTL. This setup produces 

13.3 x 19.7 cm (262.01 cm2

) photographic images. To take the slide, the inside lower edge 

of the camera framer was placed against the two pins, producing a repeated image of the 

station (Figure 2.5.0.1). Each station was photographed and the station and frame number 

recorded on an underwater slate. The information was transferred to the permanent data log. 

All images were digitized and stored on CD-ROM digital media. Images of each 

station taken during previous monitoring cruises were matched by ridge position of the 

corals. The area of the D. strigosa contained within slides was traced on a Wacom serial 

graphics tablet using Jandel Scientific SigmaScan Pro 4.0 to determine total coral tissue 

cover (cm2

) for each station.

2.5.2 Data Presentation and Statistical Analysis 

Percent cover of tissue was calculated by subtracting the area measured for each 

station for the current year from the area measured during the previous year to determine 

advance, retreat, or no change. Percent cover changes were calculated by determining the 

amount of area gained or lost and dividing by the total photograph area (262.01 cm2

). At this 

time, these data are used for descriptive purposes only because the pins and markers denoting 

stations are constantly being lost, rendering the data unsuitable for repeated measures 

analysis of variance. In addition, at stations that are found, the loss of one pin often results in 

error due to problems orienting the camera exactly as it was the year before. We are working 

to find better methods for marking stations and ensuring correct camera orientation. 
12

 Figure 2.5.0.1. Diver photographing a permanent encrusting growth station. 

2.6 REPETITIVE QUADRATS 

Repetitive photographic stations were established to monitor the frequency and 

occurrence of tissue growth in the coral community as a whole as well as tissue loss due to 

bleaching, disease, replacement, and other causes. 

2.6.1 Field Methods and Data Capture 

Forty permanent, repetitive photographic stations were established on each bank and 

identified by securing a numbered plastic tag to a stainless steel post inserted into the reef 

rock (Figure 2.6.0.1). Each station was photographed during each cruise using an aluminum 

T-shaped camera frame mounted with a Nikonos V camera loaded with Kodak Ektachrome 

100, 36-exposure slide film and a 15 mm lens (distance = 2 m, f-stop = 8). Two Ikelite 225 

watt-second strobes were mounted on the ends of the horizontal bar and set on TTL and slave 

(Gittings et al. 1992). Consistent orientation of the camera was achieved by using a compass 

and bubble level mounted on the horizontal bar of the frame. Stations were photographed 

after placing the vertical bar of the frame against the steel post, orienting the compass to 

magnetic north and leveling the horizontal bar. This setup produces a slide that represents 8 

m

2

 of reef surface. 
13

Figure 2.6.0.1. Diver photographing a permanent repetitive photographic station and 

example of station post. 

Percent cover of coral species and extent of tissue loss or gain was estimated using point 

counts. Categories of tissue loss or gain were: paling (considerably lighter in color that than 

in previous years but has not yet reached a stark white color; a possible precursor of 

bleaching) (Kleppel et al. 1989), bleaching (with and without mortality), disease (with or 

without mortality and new), replacement (algae, sediment, or combination), other tissue loss 

(fish biting, competition, unexplained), and growth (infilling or marginal). Slides were 

projected onto a flat surface to produce an image 25.2 x 37.9 cm (955.09 cm2

) and each was 

overlain with three sets of 100 randomly positioned markers. Cover estimates were based on 

the total number of markers that intersected live coral tissue. This same procedure was used 

to estimate the extent of bleaching or tissue loss resulting from disease or other processes. 

The percentages calculated from each overlay were averaged to determine final percentages. 
14

At stations where tissue growth and/or loss or replacement was observed, slides from the 

previous year were examined to attempt to determine the cause. In addition, the numbers of 

colonies of each species exhibiting bleaching were counted. 

2.6.2 Data Presentation and Statistical Analysis 

Overall mean percent cover and standard deviation of each species or cover category 

was determined for each bank and compared with random transect data to determine if 

repetitive photo stations reflect overall community composition at each bank. No statistical 

comparisons were made between data generated from random transects and data generated 

from repetitive quadrats since both the method (actual areal coverage vs point counts) and the 

scale/resolution of photos (0.28 m2

 vs 8 m2) are different and any differences found could be 

artifacts of methods rather than true differences. 

Mean percentage of points per station with standard deviation and maximum 

percentage of points for all stations at each bank and each year falling onto coral areas with 

growth and tissue loss processes were determined. Frequency of occurrence (number of 

photos containing corals exhibiting a category/total number of photos) was also determined 

for each category on each bank and for each year. Growth/retreat ratios were calculated for 

each year and each bank. At this time, no statistical analysis has been attempted on this data. 

Percentage of colonies exhibiting bleaching or identifiable disease were determined 

from photos by counting the number of colonies of each species that were affected and 

dividing by the total number of colonies observed. Since disease data were only collected in 

this manner during 2000-01 and because this analysis returns an absolute value rather than a 

mean with standard deviation, statistical analysis is not possible at this time. 

2.7 VIDEO TRANSECTS 

Similar to the three previous studies (Gittings et al. 1992; Continental Shelf 

Associates 1996; Dokken et al. 1999), diver-held video transects were recorded to establish a 

permanent record of visual observations at the study sites. Two transects were performed on 

each bank using identical techniques as in previous studies. A Hi-8 video camcorder in an 

underwater housing was “flown” across the bottom by a diver at an angle of approximately 

45°. A target height of 2 m above bottom was maintained by using a weighted, 2 m plumbline attached to the camera housing. This resulted in a transect width of 3.5 m on the 

videotape when viewed at the center of the television monitor. Each 100 m transect 

represented a total area of 350 m2

. The transect areas videoed at the EFGB site were the 

northern boundary line (from west to east) and the eastern boundary line (from north to 

south). At the WFGB site the transect areas were the southern boundary line (from east to 

west) and the western boundary line (from south to north). 

In addition to the two 100 m boundary line transects at each bank, a 360° circularview video was performed at each of six corner markers (three on each bank marking the 

ends of two adjacent boundary lines). Using the corner markers as a center point, the video 

camera was held nearly horizontal and low to the reef (dependent upon topography of reef) 

and panned slowly in a full circle. This technique was useful for observing detail and gross 

changes to the areas of the reef around each corner marker. Prior to performing the video 

transects, the transect lines were pulled tight between anchor points, to insure the best chance 
15

of obtaining transect data that matched previous efforts. No data analyses were performed on 

video transects; they were simply archived for future reference. 

2.8 WATER QUALITY/INSOLATION/TEMPERATURE 

2.8.1 Water Quality 

 Semi-Permeable Membrane Devices (SPMD) were deployed on both banks to 

monitor the presence of hydrocarbons and other analytes in the water column. The SPMDs 

were installed in special housings and anchored to the sea floor near the surface and mooring 

bolt. The SPMDs were sent to Environmental Sampling Technologies in St. Joseph, 

Missouri for dialyses. The Geochemical and Environmental Research Group (GERG) at 

Texas A&M University, College Station, performed the purification and analyses. Three 

sample sets were analyzed. 

All SPMDs were dialyzed, and diasylates for each site were combined and evaporated 

to 2 ml or less, sealed in an ampule, and shipped to GERG. At GERG, the samples and field 

blanks were purified using gel permeation chromatography (HPLC with Phenogel) to remove 

triolein. The sample extracts and field blanks, as well as laboratory quality control samples 

(procedural blank, spike blank, and spike blank duplicate), were analyzed for pesticides/PCB 

or PAH by standard GERG procedures. 

 2.8.2 Insolation 

Li Cor Data Loggers - Two underwater Li Cor spherical light sensors were used to 

monitor irradiance in the optimum photosynthetic wave lengths (photosynthetically active 

radiation, PAR) at the EFGB and WFGB. Both sensors were deployed at 23.8 m depth. A 

reference sensor was also deployed on the HI-389 oil and gas production platform to monitor 

sea-surface irradiance. All instruments were configured to record hourly averages in units of 

μM s-1

 m

2

. From 1997 through November 2001, data from the sensors were recorded in Li1000 data loggers. 

YSI Data Sondes and OSP Installation - On September 12-13, 2001, two semipermanent platforms were installed with new water quality monitoring instruments at 

National Marine Sanctuary sites in the EFGB and WFGB (Figure 2.8.2.1). The installations, 

known as Ocean Sentinel Platforms or OSPs, were designed to provide a secure attachment 

point for monitoring instruments. The design for the OSPs employs eight angle-iron struts 

welded to a galvanized train wheel. The frame for the datalogger is stainless steel and 

includes TBT anti-fouling collars to protect the sensors and the light diffuser from 

bioaccumulation. Although not part of this contract, a third OSP was installed at Stetson 

Bank in support of NOAA’s monitoring objectives. 
16

Figure 2.8.2.1. Ocean Sentinel Platform with YSI 6000 Data Sonde and light diffuser 

installed at the East and West Flower Garden Banks. 

The first instrument installed was a YSI 6000 Data Sonde. The sonde logs data from 

sensors 30 minute intervals. The sensor suite installed in the sondes includes pressure 

(depth), temperature, salinity (conductivity), light in the range of PAR, dissolved oxygen, 

pH, and turbidity. 

Estimating Light Attenuation - The attenuation coefficient for light transmission 

through water, k, is a parameter in the equation (1): 

 Id = I0 e

-kd (1) 

where I0 and Id are light intensities at the surface and some depth, d, in meters 

(Parsons et al. 1984). Rearranging this equation (2), 

 ln(Id/I0)/-d = -k (2) 

it is possible to calculate the measured light attenuation in the water column at the two 

monitoring stations by comparing synoptic values to the reference sensor on the HI389 

Platform. These estimates of -k were calculated from the accumulated daily irradiance at 

each sensor where full-day values were available for the reference and the underwater 

sensors. 

The two underwater Li Cor sensors were set to record values during daylight hours by 

setting a minimum threshold value in the data logger configuration. All instruments were 

configured to record hourly averages in units of μM s-1

m

-2. Values were converted to Mh1

m

2

. 

Data were recovered from the data loggers during the monitoring cruises in 1998 and 1999 

(Appendix 2). Beginning in 1998, sensor units were fitted with TBT-impregnated collars to 

inhibit algae growth on sensor surfaces. Sensors units were recalibrated at least every year. 

Several sensors were found broken on recovery following a measurement interval, resulting 
17

in data loss and necessitated replacement with new sensors. Problems that resulted in data 

loss from the sensors are summarized in Appendix 2. 

2.8.3 Temperature 

 

 Temperature readings were collected at each bank to detect relationships between 

temperature and biological changes at the FGB during the monitoring period. One HOBOTemp recording thermograph (Onset Instruments, Pocasset, Massachusetts), sealed in a 

watertight container, was attached to a bottom structure near the light meters at each study 

site. Thermographs were set to record water temperature at 20-minute intervals. 

Temperature data was supplemented with Sea Surface Temperature (SST) data retrieved 

from data buoys (National Data Buoy Center No. 42019 located at 27o

92.0’ N, 95 o 35.0’ W). 

2.9 SEA URCHIN SURVEYS 

To monitor changes in sea urchin, Diadema antillarium, abundance, urchins were 

counted approximately 1.5 hours after sunset. Using the lines that marked the boundary of 

the study area as a belt transect, divers counted all sea urchins within 1 m of the lines. This 

resulted in 4 belt transects that encompassed an area of 100 m2 each. Because very few 

urchins were observed during any monitoring period, only descriptive data are presented. 
19

3.0 RESULTS 

3.1 RANDOM TRANSECTS 

3.1.1 East Bank - Community Composition and Structure 

Mean percent cover of the Montastraea annularis complex increased between 1996-

2001 (Table 3.1.1.1). Total coral cover increased by 20% between the highest (2001) and 

lowest (1997) years. Some of the increases in mean estimates of both Montastraea annularis

complex as well as total coral may be due to increasing numbers of transects, thus more of 

the coral cap within the study area was sampled. However when standard deviations (±1 SD) 

are examined there is a great deal of variability in cover estimates for Montastraea annularis 

complex (ranging from a low estimate of 7.1% in 1996 to a high estimate of 57.7% in 2001) 

as well as total coral cover. These increases also coincide with generally decreasing 

percentages of cover assigned to the unidentifiable category, suggesting that at least some of 

the increase may be due to better photographs that allowed for better and more reliable 

identification of Montastraea annularis complex in later years of the study. In fact, the 

increase in number of usable transects (transects were classified as unusable due to 

photographic insufficiencies such as under- or overexposure) through time reinforces this 

explanation. 

Total algal cover was greatest in 1999 then fell in both 2000 and 2001. Diploria 

strigosa was also highest during 1999 and likewise declined in both 2000 and 2001. 

Although a minor component, cover of Siderastrea sp. was highest (1.8%) in 1996 and fell to 

less than 1% in all-successive years. Cover of the remaining coral species as well as sponges 

remained relatively stable throughout the monitoring period. Cover of reef rock was highest 

in 1998, the year before algal cover peaked, then declined. 

Diversity and evenness declined from 1996-2001 as dominance increased reflecting 

increasing coverage by the M. annularis complex (Table 3.1.1.2). Although overall 

community similarity among years was approximately 70%, the rise in dominance by the M. 

annularis complex is seen in the dendrogram as the separate clustering of 2000-2001 (Figure 

3.1.1.1). 

3.1.2 East Bank – Comparisons Among Years 

The ANOVA indicates there were significant differences among years for 5 of the 13 

coral species as well as total coral, total algae and reef rock (Table 3.1.2.1). Three 

overlapping, homogenous subsets of years were delineated for the M. annularis complex. 

The primary difference was between the two years with highest cover, 2000 and 2001 and the 

two years with lowest cover, 1996 and 1997. Total coral, with four overlapping subsets, 

exhibits a similar pattern due to the dominance of the M. annularis complex in the 

community. Cover of other coral species tended to overlap greatly with primary differences 

between the years of highest and lowest cover. Algal cover in 1999 was significantly higher 

than all other years and cover in 2000-2001 was significantly greater than 1996-1998. Reef 

rock was significantly higher than other years in both 1998 and 1999. 

 
20

Table 3.1.1.1. 

Percent cover data1 from 1996-2001 for the East Flower Garden Bank random transects. 

 Standard deviations are in parentheses. 

*Montastraea annularis complex is comprised of M. annularis, faveolata, and franksi. 1Percent cover data for the synthesis report was calculated using total area sampled for each transect (see methods). 2Prior to 2000, algae were not separated into species or groups, so only total algal cover is available. 3 In 1996 and 1997 only living coral was identified; this category contains reef rock, other, artifacts, serpulids and the unidentifiable portions of 4 In 1998 and 1999, serpulids, other, artifacts, and the unidentifiable portions of slides were grouped into this category. 5In 20002 and 2001, only the unidentifiable portions of slides (shadows, out of focus etc.) were grouped into this category. 

Species 1996 1997 1998 1999 2000 Agaricia agaricites 0.4 (0.2) 0.5 (0.4) 0.4 (0.4) 0.2 (0.2) 0.2 (0.2Agaricia fragilis 0.005 (0.02) 0 0 0 Colpophyllia natans 0.8 (1.4) 0.8 (1.3) 2.1 (2.7) 3.6 (2.9) 2.6 (3.3Diploria strigosa 10.1 (7.1) 5.1 (4.4) 8.3 (3.7) 12.4 (6.0) 6.2 (2.8Montastraea annularis complex* 21.3 (14.2) 21.6 (8.1) 30.4 (11.1) 28.2 (11.7) 39.5 (9.6Montastraea cavernosa 3.7 (5.3) 4.7 (4.9) 3.5 (2.9) 2.4 (2.8) 4.8 (5.7Scolymia sp. 0.009 (0.01) 0.02 (0.02) 0.004 (0.008) 0.02 (0.02) 0.01 (0.02Stephanocoenia michilini 0.5 (0.9) 0.4 (0.6) 0.5 (0.9) 0.02 (0.09) 0.1 (0.2Mussa angulosa 0.1 (0.4) 0.02 (0.04) 0.1 (0.2) 0.08 (0.2) 0.2 (0.4Madracis sp. 0.4 (0.7) 0.8 (1.4) 0.6 (1.1) 0.3 (0.6) 0.8 (2.3Porites astreoides 3.6 (1.5 ) 5.3 (3.0) 4.2 (3.0) 3.4 (1.7) 2.6 (1.7Porites porites 0.005 (0.02) 0.1 (0.4) 0 0.005 (0.02) 0.04 (0.08Siderastrea sp. 1.8 (4.0) 0.2 (0.4) 0.2 (0.9) 0.6 (1.0) 0.03 (0.1Millepora sp. 0.9 (1.0) 1.9 (2.3) 1.3 (1.2) 1.6 (1.8) 1.3 (1.5Total Coral 43.7 (12.0) 41.6 (8.3) 51.6 (8.3) 53.0(9.0) 58.3 (6.7Filamentous algae 15.6 (4.9Crustose coralline algae 1.2 (0.8Dictyota sp. 0.5 (0.6Total Algae2 6.1 (5.2) 0.5 (0.6) 3.2 (2.6) 24.7 (13.2) 17.3 (4.9Total Sponge 0.9 (1.0) 1.1 (1.7) 0.5 (0.9) 0.7 (0.9) 0.7 (0.8Serpulidae 0.05 (0.04Other 0.03 (0.09Reef rock3 27.6 (5.9) 11.1 (8.2) 4.3 (1.7Sand 0.1 (0.2) 0.0 0.4 (1.0) 0.1 (0.3) 0.02 (0.07Artifacts 1.4 (3.8No ID3;4 43.7 (12.0) 56.8 (8.2) 16.8 (2.8) 10.3 (12.3) 17.8 (4.6Number of transects 10 14 14 14 1

20
21

Table 3.1.1.2. 

Diversity (H’, base 10), evenness (J’), dominance (Berger-Parker) of the coral community 

using average % cover by year on the East Flower Garden Bank. 

1996 1997 1998 1999 2000 2001 

Diversity 0.70 0.67 0.60 0.60 0.52 0.47 

Evenness 0.65 0.61 0.58 0.55 0.46 0.42 

Dominance 0.41 0.52 0.59 0.53 0.68 0.72 

Figure 3.1.1.1. Bray-Curtis community similarity dendrogram for random transects from 

1996-2001 for the East Flower Garden Bank. 

0% Similarity 50 100
22

Table 3.1.2.1. 

Results of analysis of variance among years on reef components on the East Flower Garden 

Bank using % cover data. Data for all components except Montastraea annularis 

were arcsine transformed prior to analysis to normalize distribution. 

Component df F p Homogenous Subsets 

 

Montastraea annularis

complex* 

5, 83 10.949 0.0001 97 96 99 98 00 01 

 

Agaricia agaricites 5, 83 3.148 0.0120 99 00 96 98 01 97 

Colpophyllia natans 5, 83 2.306 0.0520 No homogenous subsets delineated 

Diploria strigosa 5, 83 7.076 0.0001 01 97 00 98 96 99 

Madracis sp. 5, 83 0.645 0.6660 No homogenous subsets delineated 

 

Montastraea cavernosa 5, 83 0.538 0.7470 No homogenous subsets delineated 

Millepora sp. 5, 83 0.795 0.5570 No homogenous subsets delineated 

Mussa angulosa 5, 83 0.634 0.6750 No homogenous subsets delineated 

 

Porites astreoides 5, 83 2.639 0.0290 00 99 96 98 01 97

 

Porites porites 5, 83 0.891 0.4910 No homogenous subsets delineated 

 

Scolymia sp. 5, 83 2.653 0.0280 No homogenous subsets delineated 

Siderastrea sp. 5, 83 2.526 0.0350 00 01 97 98 99 96 

Sponge 5, 83 0.511 0.7670 No homogenous subsets delineated 

Stephanocoenia mechelinii 5, 83 1.713 0.1410 No homogenous subsets delineated 

Total coral 5, 83 11.415 0.0001 97 96 98 99 00 01 

Total algae 5, 83 28.060 0.0001 97 98 96 01 00 99 

 

Reef rock1 3, 61 64.760 0.0001 00 01 99 98 

*

Montastraea annularis complex is comprised of M. annularis, faveolata, and franksi. 1 Was not a separate category until 1998. 
23

There were significant negative correlations between cover of the M. annularis

complex, reef rock and D. strigosa as well as between reef rock and total algal cover (Table 

3.1.2.2). There were significant positive correlations between the M. annularis complex and 

total coral cover reflecting the increase of its cover and dominance in the coral community. 

In addition, there was a significant positive correlation between algal cover and total coral 

cover. Runs tests indicated no significant trends, only random variability in cover of any 

species or reef component (Table 3.1.2.3). 

Table 3.1.2.2. 

Non-parametric correlation (Spearman’s rho, 2-tailed) between percent cover of major reef 

components of the East Flower Garden Bank. Ma = Montastraea annularis complex; Ds = 

Diploria strigosa; Mc = Montastraea cavernosa; TALG = total algae; RR = reef rock; 

TCOR = total coral. Bold indicates significant correlations. 

Ds Mc TALG RR TCOR 

Ma Correlation Coefficient -0.371 -0.209 0.156 -0.398 0.768

 Sig. (2-tailed) 0.0001 0.049 0.1430 0.0010 0.0001

 N 89 89 89 65 89

Ds Correlation Coefficient 0.053 0.050 0.196 0.016

 Sig. (2-tailed) 0.620 0.644 0.1180 0.881

 N 89 89 65 89

Mc Correlation Coefficient -0.038 0.007 0.083

 Sig. (2-tailed) 0.725 0.953 0.441

 N 89 89 89

TALG Correlation Coefficient -0.291 0.227

 Sig. (2-tailed) 0.0180 0.032

 N 65 89

RR Correlation Coefficient -0.483

 Sig. (2-tailed) 0.0001

 N 65

3.1.3 West Bank - Community Composition and Structure 

Cover of the Montastraea annularis complex and total coral increased slightly 

between 1996-2001 (Table 3.1.3.1). Total algal cover increased dramatically between 1997 

(lowest) and 2001 (highest). Although a minor component, cover of Millepora sp. was 

highest in 1997 and fell to less than 1% in each successive year. Also a minor component, 

Siderastrea sp. cover generally increased from 1996 to 2000 then dropped precipitously in 

2001, the lowest value recorded. Cover of the remaining coral species as well as sponges 

remained relatively stable throughout the monitoring period. Cover of reef rock was highest 

in 1998 and 1999, declining by about 50% in each subsequent year. 
24

Diversity was relatively stable between 1996 and 1999, increasing slightly in 2000 

then decreasing to a low in 2001 (Table 3.1.3.2). Evenness and dominance were fairly stable 

throughout the study period. Overall community similarity was 85% (Figure 3.1.3.1). Year 

clusters corresponded to years of highest algal cover (1999-2001) and lowest algal cover 

(1996-1998). 

Table 3.1.2.3. 

Results of non-parametric runs test using median percent cover of coral species, total coral, 

algae, and sponge as the cutoff value for the East Flower Garden Bank. 

 *

Montastraea annularis complex is comprised of M. annularis, faveolata, and franksi.

3.1.4 West Bank – Comparisons Among Years 

Only one coral, Madracis sp. a minor component of the coral community, exhibited 

significant differences among years (Table 3.1.4.1). In 1999, the year when Madracis sp. 

cover was highest, was significantly higher than all other years except 2000. There were also 

significant differences among years in algae cover and reef rock with the delineated 

homogenous subsets representing the years of highest and lowest cover. 

There were significant positive correlations between total coral cover and cover of the 

M. annularis complex, D. strigosa, and M. cavernosa (Table 3.1.4.2). Cover of reef rock 

was significantly negatively correlated with algal cover. Runs tests indicated no significant 

trends only random variation in deviations above or below median for any species or reef 

component (Table 3.1.4.3). Runs tests were not performed on reef rock since a minimum of 

five data points are necessary. 

Component Cases < mean > mean Runs Z Significance

Montastraea annularis

complex* 9 4 5 4 -0.683 0.495

Agaricia agaricites 9 4 5 5 0.000 1.000

Colpophyllia natans 9 4 5 5 0.000 1.000

Diploria strigosa 9 4 5 5 0.000 1.000

Madracis sp. 9 4 5 6 0.040 0.968

Montastraea cavernosa 9 4 5 6 0.040 0.968

Millepora sp. 9 4 5 7 0.763 0.445

Mussa angulosa 9 3 6 6 0.408 0.683

Porites astreoides 9 4 5 5 0.000 1.000

Porites porites 9 4 5 4 -0.683 0.540

Scolymia sp. 9 4 5 3 -1.406 0.160

Siderastrea sp. 9 4 5 6 0.040 0.968

Sponge 9 4 5 8 1.486 0.137

Stephanocoenia mechelinii 9 4 5 4 -0.683 0.495

Total coral 9 4 5 4 -0.683 0.495

Total algae 9 4 5 5 0.000 1.000
25

Table 3.1.3.1. 

Percent cover data1 from 1996-2001 for the West Flower Garden Bank random transects. 

 Standard deviations are in parentheses. 

*Montastraea annularis complex is comprised of M. annularis, faveolata, and franksi.

1Percent Cover Data for the synthesis report was calculated using total area sampled for each transect (see methods). 

2Prior to 2000, algae were not separated into species or groups, so only total algal cover is available. 3 In 1996 and 1997 only living coral was identified; this category contains reef rock, other, artifacts, serpulids and the unidentifiable portions of 4In 1998 and 1999, serpulids, other, artifacts, and the unidentifiable portions of slides were grouped into this category. 5In 20002 and 2001, only the unidentifiable portions of slides (shadows, out of focus etc.) were grouped into this category. 

Species 1996 1997 1998 1999 2000 Agaricia agaricites 0.4 (0.9) 0.3 (0.3) 0.2 (0.2) 0.2 (0.2) 0.3 (0.2Agaricia fragilis 0 0 0 0 0.007 (0.03Colpophyllia natans 1.3 (1.8) 1.3 (1.6) 1.7 (2.7) 0.7 (1.7) 3.6 (4.3Diploria strigosa 7.9 (3.5) 9.1 (5.9) 9.6 (4.8) 10.9 (7.8) 8.1 (6.Montastraea annularis complex* 27.2 (8.3) 27.7 (9.9) 28.4 (11.9) 31.7 (8.6) 30.9 (11.6Montastraea cavernosa 1.5 (2.2) 4.3 (4.2) 2.6 (2.4) 2.4 (3.5) 5.8 (11.7Scolymia sp. 0.02 (0.03) 0.02 (0.02) 0.007 (0.02) 0.003 (0.02) 0.01 (0.02Stephanocoenia mechelinii 0.9 (2.1) 0.5 (1.3) 0.6 (1.1) 0.01 (0.04) 0.9 (0.9Mussa angulosa 0.06 (0.1) 0.1 (0.1) 0.07 (0.1) 0.2 (0.4) 0.3 (0.6Madracis sp. 0.08 (0.2) 0.1 (0.2) 0.03 (0.07) 0.5 (0.6) 0.2 (0.4Porites astreoides 2.5 (1.4) 2.7 (2.3) 2.4 (2.0) 2.7 (1.9) 2.5 (1.6Porites porites 0 0 0 0 0.1 (0.6Siderastrea sp. 0.1 (0.4) 0.2 (0.3) 1.7 (5.8) 1.4 (4.5) 2.0 (4.0Millepora sp. 1.9 (4.8) 1.5 (2.0) 0.7 (1.1) 0.8 (0.8) 0.7 (0.8Total Coral 46.5 (12.3) 47.9 (13.9) 48.5 (12.7) 51.5 (8.1) 51.6 (13.7Filamentous algae 16.4 (9.1Crustose Coralline algae 2.3 (0.8Dictyota sp. 0.09 (0.4Total Algae2 4.5 (2.9) 0.1 (0.1) 2.3 (1.3) 18.8 (6.2) 22.6 (14.0Total Sponge 1.0 (1.0) 0.9 (1.3) 0.6 (0.6) 0.6 (0.7) 0.6 (0.8Serpulidae 0.04 (0.06Other 0.009 (0.03Reef rock3 20.7 (11.2) 21.1 (9.8) 8.5 (3.7Sand 0.0 0.0 0.0 1.3 (3.3) 0.9 (2.1Artifacts 0.3 (0.6No ID3; 4 51.7 (9.5) 47.9 (13.9) 28.4 (15.9) 6.7 (1.8) 14.3 (4.7Number of transects 15 13 14 13 1

25
26

Table 3.1.3.2. 

 Diversity (H’, base 10), evenness (J’), dominance (Berger-Parker) of the coral community 

using average % cover by year West Flower Garden Bank. 

1996 1997 1998 1999 2000 2001 

Diversity 0.56 0.60 0.58 0.54 0.64 0.49 

Evenness 0.52 0.55 0.53 0.50 0.56 0.49 

Dominance 0.62 0.58 0.59 0.61 0.56 0.66 

Figure 3.1.3.1. Bray-Curtis community similarity dendrogram for random transects from 

1996-2001 for the West Flower Garden Bank. 

0% Similarity 50 100
27

Table 3.1.4.1. 

Results of one-way analysis of variance and Tukey’s HSD among years on reef components 

on the West Flower Garden Bank using % cover data. Data for all components 

except Montastraea annularis, Diploria strigosa, total coral and algae were 

arcsine transformed prior to analysis to normalize distributions. 

Component df F p Homogenous Subsets 

 

Montastraea annularis complex* 5, 81 1.222 0.7870 No homogenous subsets delineated 

 

Agaricia agaricites 5, 81 0.748 0.5900 No homogenous subsets delineated 

Colpophyllia natans 5, 81 2.356 0.0480 No homogenous subsets delineated 

Diploria strigosa 5, 81 0.485 0.7870 No homogenous subsets delineated 

 

Madracis sp. 5, 81 4.104 0.0030 98 01 96 97 00 99 

Montastraea cavernosa 5, 81 1.165 0.3340 No homogenous subsets delineated 

 

Millepora sp. 5, 81 0.825 0.5360 No homogenous subsets delineated 

Mussa angulosa 5, 81 1.095 0.3700 No homogenous subsets delineated 

 

Porites astreoides 5, 81 0.328 0.8950 No homogenous subsets delineated 

 

Porites porites 5, 81 0.914 0.4770 No homogenous subsets delineated 

 

Scolymia sp. 5, 81 1.872 0.1080 No homogenous subsets delineated 

Siderastrea sp. 5, 81 1.025 0.4090 No homogenous subsets delineated 

Sponge 5, 81 0.617 0.6870 No homogenous subsets delineated 

Stephanocoenia mechelinii 5, 81 1.067 0.3850 No homogenous subsets delineated 

Total coral 5, 81 0.666 0.6500 No homogenous subsets delineated 

 

Total algae 5, 81 34.439 0.0001 97 98 96 99 00 01

Reef rock1 3, 55 18.300 0.0001 01 00 98 99

 

*

Montastraea annularis complex is comprised of M. annularis, faveolata, and franksi. 1

Was not a separate category until 1998. 
28

Table 3.1.4.2. 

Non-parametric correlation (Spearman’s rho, 2-tailed) between % cover of major reef 

components of the West Flower Garden Bank. Ma = Montastraea annularis complex; 

Ds = Diploria strigosa; Mc = Montastraea cavernosa; TALG = total algae; 

RR = Reef rock; TCOR = total coral. Bold indicates significant correlations. 

Table 3.1.4.3. 

Results of non-parametric runs test using median percent cover of coral species, total coral, 

algae, sponge and reef rock as the cutoff value for the West Flower Garden Bank. 

Component Cases > mean < mean Runs Z1 Significance

Montastraea annularis complex* 9 4 5 4 -0.683 0.4950

Agaricia agaricites 9 4 5 3 -1.406 0.1600

Colpophyllia natans 9 4 5 4 0.000 1.000

Diploria strigosa 9 4 5 6 0.040 0.9680

Madracis sp. 9 4 5 4 -0.683 0.4950

Montastraea cavernosa 9 4 5 5 0.000 1.000

Millepora sp. 9 3 6 4 -0.408 0.6830

Mussa angulosa 9 3 6 6 0.408 0.6830

Porites astreoides 9 4 5 7 0.763 0.4450

Scolymia sp. 9 4 5 3 -1.406 0.1600

Siderastrea sp. 9 4 5 6 0.040 0.968

Sponge 9 4 5 5 0.000 1.0000

Stephanocoenia mechelinii 9 4 5 8 1.486 0.1370

Total coral 9 4 5 4 -0.683 0.4950

Total algae 9 4 5 5 0.000 1.0000

1 Non-parametric equivalent of the F statistic, i.e. distribution of data along a bell curve *

Montastraea annularis complex is comprised of M. annularis, faveolata, and franksi.

Ds Mc TALG RR TCOR 

Ma Correlation Coefficient -0.116 -0.121 0.067 -0.091 0.677

 Sig. (2-tailed) 0.2870 0.2650 0.5340 0.4930 0.0001

 N 87 87 87 59 87

Ds Correlation Coefficient -0.086 -0.032 -0.103 0.304

 Sig. (2-tailed) 0.4280 0.7660 0.4370 0.0040

 N 87 87 59 87

Mc Correlation Coefficient -0.133 0.035 0.229

 Sig. (2-tailed) 0.2190 0.7950 0.0330

 N 87 59 87

TALG Correlation Coefficient -0.438 0.044

 Sig. (2-tailed) 0.0010 0.6850

 N 87 87

RR Correlation Coefficient -0.217

 Sig. (2-tailed) 0.0980

 N 59
29

3.2 SCLEROCHRONOLOGY 

3.2.1 East Bank 

Two cores of Montastraea faveolata were taken from the EFGB in 2001 (Figure 

3.2.1.1). Estimated growth (mm/year) of M. faveolata ranged from 5.05 − 11.19 mm, with 

an overall mean of 7.50 mm ±1.02 (1 SD). Lowest overall mean growth occurred in 1986 

and highest occurred in 2000 (Table 3.2.1.1.). The nonparametric runs test on median annual 

growth was not significant (median = 7.45; n= 16; cases < median = 8; cases > median = 8; 

runs = 8; Z = -0.259; asymptotic significance [2-tailed] = 0.796) indicating that there was no 

systematic or cyclic variability occurring in the values; variability in growth rates appears to 

be occurring randomly. 

Figure 3.2.1.1. X-ray images of two coral cores taken at the East Flower Garden Bank, 

September 2001 (uppermost layer of core includes some growth from 

collection year). 

Core 1 Core 2 2000

1999

1998

1997

1996

1995

1994

1993

1992

1991

1990

1989
30

Table 3.2.1.1. 

Mean annual growth (mm) with standard deviation for 1985 to 2001 determined from 

measurements of accretionary growth bands in cores from Montastraea faveolata, East 

Flower Garden Bank. Mean and SD were calculated from three measurements of each set of 

high and low density bands in each core; overall growth rate was calculated from the means 

of all data. 

Years Coral Cores Taken 

2001 1999 Coral Core Years 

Marked on X-rays Core 1 Core 2 Core 1 

Overall 

1985 6.25 (0.58) 6.25 (0.58) 

1986 6.12 (0.61) 6.12 (0.61) 

1987 7.40 (0.20) 7.40 (0.20) 

1988 7.36 (0.67) 7.36 (0.67) 

1989 7.56 (0.16) 7.84 (0.13) 7.70 (0.21) 

1990 7.84 (0.86) 5.32 (0.23) 6.58 (1.49) 

1991 7.67 (0.35) 7.97 (0.70) 7.00 (0.23) 7.55 (0.60) 

1992 8.51 (0.42) 9.92 (1.13) 5.76 (0.28) 8.06 (1.93) 

1993 7.44 (0.25) 8.13 (0.81) 7.58 (0.48) 7.72 (0.58) 

1994 7.85 (0.67) 7.82 (0.41) 6.38 (0.40) 7.40 (0.85) 

1995 7.55 (0.47) 8.90 (0.96) 7.54 (0.99) 8.05 (1.03) 

1996 8.46 (0.39) 7.92 (0.47) 6.13 (0.68) 7.50 (1.14) 

1997 7.84 (0.59) 6.95 (0.64) 6.64 (0.54) 7.14 (0.74) 

1998 7.95 (0.70) 7.62 (0.23) 6.45 (0.41) 7.34 (0.80) 

1999 7.78 (0.35) 7.31 (0.32) 8.20 (0.89) 7.76 (0.63) 

2000 8.28 (0.98) 8.18 (0.44) 8.23 (0.68) 

3.2.2 West Bank 

The two cores taken at the WFGB during the 2001 monitoring cruise were unusable 

due to burrowing mollusc holes throughout both cores. In April 2002, another core was 

taken at the WFGB that was usable (Figure 3.2.2.1). Estimated growth (mm/year) of 

Montastraea faveolata ranged from 3.88 − 8.01 mm, with an overall mean of 5.37 mm ± 0.79 

(1 SD). Lowest overall mean growth was in 1986 and highest was in 2000 (Table 3.2.2.1). 

The nonparametric runs test on median annual growth (mm) was not significant (median = 

5.29; n= 15; cases < median = 7; cases > median = 8; runs = 6; Z = -1.059; asymptotic 

significance [2-tailed] = 0.290) indicating that variability in growth rates is random with no 

systematic or cyclic pattern of variability. 
31

Figure 3.2.2.1. X-ray image of the coral core taken at the West Flower Garden Bank, April 

2002 (uppermost layer of core includes some growth from collection year). 

2001

2000

1999

1998

1997

1996

1995

1994

1993

1992

1991
32

Table 3.2.2.1. 

Mean annual growth (mm) with standard deviation for 1985 to 2001 determined from 

measurements of accretionary growth bands in cores from Montastraea faveolata, West 

Flower Garden Bank. Mean and SD were calculated from three measurements of each set of 

high and low density bands in each core; overall growth rate was calculated from the means 

of all data. 

Years Coral Cores Taken 

Core 1 Core 1 Coral Core Years 

Marked on X-rays 1999 2002 

Overall 

1985 5.43 (0.44) 5.43 (0.44) 

1986 4.60 (0.28) 4.60 (0.28) 

1987 5.37 (0.05) 5.37 (0.05) 

1988 4.99 (0.20) 4.99 (0.20) 

1989 4.80 (0.40) 4.80 (0.40) 

1990 4.49 (0.75) 4.49 (0.75) 

1991 5.94 (0.47) 5.68 (0.55) 5.80 (0.48) 

1992 5.01 (0.24) 5.56 (0.43) 5.29 (0.43) 

1993 5.56 (0.33) 4.83 (0.10) 5.19 (0.45) 

1994 4.73 (0.75) 5.11 (0.51) 4.92 (0.61) 

1995 4.89 (0.78) 5.34 (0.26) 5.11 (0.58) 

1996 5.18 (0.54) 5.68 (0.26) 5.43 (0.47) 

1997 5.98 (0.72) 4.77 (0.34) 5.37 (0.83) 

1998 5.36 (0.42) 7.61 (0.43) 6.49 (1.29) 

1999 4.63 (0.09) 6.41 (0.10) 5.52 (0.98) 

2000 6.64 (0.17) 6.64 (0.17) 

2001 4.94 (0.00) 4.94 (0.00) 

3.3 ENCRUSTING GROWTH STATIONS 

 Throughout the 1998-2001 monitoring period, a large number of encrusting growth 

stations had become unsuitable for analysis either by loss of pins or advance or retreat of the 

coral margin beyond the area of the close-up camera frame. New stations were established to 

replace those no longer useable. Subsequently, this caused a reduced number of stations that 

could be compared from year to year for coral growth. This reduction is particularly 

noticeable in the 2000-2001 data, in which 13 (EFGB) and 25 (WFGB) stations are 

compared in 2000 and 29 (EFGB) and 24 (WFGB) stations are compared in 2001. 

 There was a high degree of variability between advance/retreat percentages among 

years for both the EFGB and WFGB (Table 3.3.0.1,). At EFGB, there appeared to be a net 

loss of Diploria strigosa from 1998-2000. Growth and loss were approximately equal during 

2001. Net loss was also noted at EFGB during 1998-1999 but net gains were noted during 

2000-2001 (Figure 3.3.0.1). Additionally, there was a net overall gain at WFGB (Figure 

3.3.0.2). Although some of these changes accurately assess growth and retreat of coral 

tissue, a more likely explanation for the differences is camera positioning at each station 

from year to year. Due to pin loss, breakage, etc., some stations had only one pin for camera 

placement making it difficult to replicate the same picture year after year. However, the 
33

technique has become better over the years, which is reflected in the lower and more similar 

percentages of growth and retreat at each bank in 2000 and 2001. Appendix 2 shows the data 

for each station for each year and its respective coral coverage. 

Table 3.3.0.1. 

Number of encrusting growth stations of Diploria strigosa and average 

gain (+), loss (−), or no change (=) in percent cover of coral tissue at the 

East and West Flower Garden Banks, 1998-2001. 

EFGB WFGB 

# of Changes % cover # of Changes % cover 

1998 1998 

21 (+) 9.55% 19 (+) 14.07% 

14 (−) 27.41% 14 (−) 18.42% 

11 (=) 1.27% 6 (=) 0.26% 

 

1999 1999 

27 (+) 13.59% 17 (+) 17.38% 

12 (−) 29.51% 22 (−) 24.52% 

11 (=) 0.85% 8 (=) 0.46% 

 

2000 2000 

 5 (+) 10.55% 9 (+) 5.49% 

 3 (−) 13.95% 10 (−) 1.89% 

 5 (=) 0.37% 6 (=) 0.35% 

 

2001 2001 

 6 (+) 7.72% 14 (+) 10.93% 

11 (−) 7.78% 4 (−) 3.36% 

12 (=) 0.25% 6 (=) 0.12% 
34

Figure 3.3.0.1. Encrusting growth station percent cover changes for the East Flower Garden 

Bank from 1998-2001. 

Figure 3.3.0.2. Encrusting growth station percent cover changes for the West Flower Garden 

Bank from 1998-2001. 

1998 1999 2000 2001

-40

-30

-20

-10

0

10

20

Increase 

Decrease 

No Change 

Net Change 

% Cover

Year

1998 1999 2000 2001

-30

-20

-10

0

10

20

Increase 

Decrease 

No Change 

Net Change

% Cover

Year
35

3.4 REPETITIVE QUADRATS 

3.4.1 East Bank – Species Composition and Cover 

In general, the species composition and percent cover of the coral community in the 8 

m

2

 repetitive quadrats is similar to that found in the analysis of the random inside transects at 

EFGB (Table 3.4.1.1). Overall, mean coral cover was about 7% lower than the inside 

random transects in 2000 and 10% in 2001; mean cover of the Montastraea annularis

complex was also 2-7% lower. Diploria strigosa mean cover was higher than the inside 

transects in both years. The mean cover of the remaining species was somewhat lower than 

that found in the inside transects, and four uncommon species, Agaricia agaricites, A.

fragilis, Scolymia sp., and Siderastrea sp., were not found in the analysis of the 8 m2

repetitive quadrats. These differences are likely due to the differences in photographic 

analysis techniques (point counts vs determination of actual areal coverage) and differences 

in photographic resolution (8 m2

 vs 0.28 m2) rather than any substantial differences in the 

coral communities. All analyzed species fell within the same range of cover based on ± 1 SD. 

Because of the differences in photographic analysis methods and the fact that percent cover 

data for repetitive quadrats were only collected during 2000-2001, no statistical comparisons 

between cover estimates from repetitive quadrat data and random transects were made. 

Table 3.4.1.1. 

Mean percent cover of coral species and total coral with standard deviation 

in 8 m2 repetitive quadrats at the East Flower Garden Bank, 2000-20011. Twenty-six stations 

were photographed in 2000; 32 stations were photographed in 2001. 

Species 2000 2001 

Montastraea annularis complex* 37.5 (16.8) 37.0 (17.8)

Montastraea cavernosa 3.0 (4.7) 2.8 (5.0)

Diploria strigosa 7.3 (8.8) 6.3 (7.6)

Colpophyllia natans 1.9 (3.4) 2.9 (4.1)

Porites astreoides 2.2 (2.1) 1.7 (1.9)

Stephanocoenia mechelinii 0.04 (0.2) 0.03 (0.1)

Mussa angulosa 0.03 (0.1) 0.0

Millepora sp. 0.8 (1.5) 0.8 (1.0)

Madracis sp. 0.2 (0.6) 0.3 (1.0)

Porites porites 0.04 (0.1) 0.1 (0.4)

Total Coral 53.1 (13.2) 51.6 (15.3) 1 Percent cover can only be calculated for 2000-2001 data. *Montastraea annularis complex is comprised of M. annularis, faveolata, and franksi. 

Mean percentages of points falling on areas of paling (the possible precursor of 

bleaching; Kleppel et al. 1989), bleaching, disease, and retreat per station were essentially 

stable between 2000-2001 (Table 3.4.1.2). The maximum percentage of points falling on 

areas of bleaching without mortality was stable, but declined on areas of bleaching followed 

by mortality. Frequency of samples exhibiting paling increased slightly from 2000 to 2001; 

frequency of bleaching with or without mortality declined during the same period. The total 

percentage of colonies exhibiting bleaching increased from 2000 to 2001 (Table 3.4.1.3), and 

most species exhibited slightly increased percentages of bleached colonies. However, the 
36

majority of the overall increase appears to be due to bleaching of substantially greater 

numbers of Millepora sp. colonies. 

Table 3.4.1.2. 

Mean percentage of points falling on areas of bleaching, disease, etc. 

by station with standard deviation, maximum percentage for all stations and 

frequency (%) of occurrence for 8 m2 repetitive quadrats at the East Flower Garden Bank. 

2000 – based on 26 stations and 1551 colonies. 2001 – based on 32 stations and 1581 

colonies. 

Mean percent/station 

(SD) 

Maximum 

percent/any station 

Frequency of 

Observation occurrence 

2000 2001 2000 2001 2000 2001 

Paling 1.2 (2.0) 1.3 (1.5) 31 42 61.5 68.7 

Bleaching followed by mortality 1.2 (3.4) 0.3 (0.9) 31 10 34.6 21.9 

Bleaching not followed by mortality 0.5 (1.0) 0.4 (0.8) 14 14 46.2 37.5 

Disease followed by mortality 0.0 0.02 (0.1) 0 1 0 3.1 

Disease not followed by mortality 0.0 0.0 0 0 0 0 

Algal-replacement 1.4 (1.6) 1.2 (2.4) 36 40 80.8 68.7 

Sediment-replacement 0.1 (0.3) 0.07 (0.2) 4 2 19.2 12.5 

Algal/sediment- replacement 0.2 (0.4) 0.1 (0.3) 5 3 26.9 15.6 

Tissue loss due to competition 0.0 0.0 0 0 0 0 

Tissue loss due to fish biting 0.0 0.0 0 0 0 0 

Unexplained tissue loss 0.7 (1.3) 0.9 (1.2) 20 30 65.4 68.7 

Growth-infilling 0.2 (0.5) 0.2 (0.3) 6 6 23.1 31.2 

Growth-marginal 0.7 (1.0) 1.0 (1.0) 18 31 69.2 81.2 

New disease 0.05 (0.3) 0.05 (0.3) 1 2 3.8 3.1 

Table 3.4.1.3. 

Percentage of colonies exhibiting bleaching1 by species at the East Flower Garden Bank 

for 2000-2001. 

Species 2000 2001 

Montastraea annularis complex* 1.1 1.5 

Montastraea cavernosa 0.0 0.2 

Diploria strigosa 0.8 1.1 

Colpophyllia natans 0.06 0.2 

Porites astreoides 0.06 0.2 

Stephanocoenia mechelinii 0.0 0.06 

Mussa 0.0 0.06 

Millepora sp. 0.4 1.1 

Madracis sp. 0.06 0.2 

Total percent 2.6 4.4 

Total colonies 1551 1581 1 Data from which percentages could be calculated was only collected in 2000-2001. *Montastraea annularis complex is comprised of M. annularis, faveolata, and franksi.
37

Very little disease was noted, and only one point fell on an area of mortality due to 

disease. Only 1 or 2 points fell on areas exhibiting new disease (Table 3.4.1.4). There was 

no loss of tissue due to competition or fish biting; however, the percentage of points falling 

on areas of unexplained tissue loss increased. The mean percentage of points falling on areas 

of algal replacement per station declined slightly whereas the maximum percentage increased 

by 4% from 2000 to 2001. However, frequency of algal-replacement declined substantially. 

Sediment-replacement and , algal/sediment-replacement both declined. 

Table 3.4.1.4. 

Overall percentage of points falling on areas of colonies exhibiting bleaching, disease, etc. at 

the East Flower Garden Banks, 1998-2001. 

Observation 1998 1999 2000 2001 

Paling1 N/A N/A 1.2 1.3

Bleaching followed by mortality 0.0 0.1 1.2 0.3

Bleaching not followed by mortality 0.02 0.06 0.5 0.4

Disease followed by mortality 0.0 0.0 0.0 0.03

Disease not followed by mortality 0.0 0.03 0.0 0.0

Algal- replacement 2.3 1.4 1.4 1.2

Sediment- replacement 0.8 0.3 0.1 0.06

Algal/sediment- replacement 0.06 0.1 0.2 0.09

Tissue loss due to competition 0.03 0.0 0.0 0.0

Tissue loss due to fish biting 0.0 0.0 0.0 0.0

Unexplained tissue loss 0.3 0.7 0.8 0.9

Growth-infilling 0.3 0.5 0.2 0.2

Growth-marginal 4.5 2.3 0.7 1.0

New disease1 N/A N/A 0.03 0.06

Overall growth 4.8 2.8 0.9 1.2

Overall retreat, mortality & tissue loss 3.5 2.6 3.7 2.6

Approximate Growth:Loss Ratio 5:3 1:1 1:4 1:3

Number of stations 33 33 26 32 1

 These categories were added in 2000. 

Infilling growth was stable during the 2000-2001 monitoring period but marginal 

growth increased in 2001 (Table 3.4.1.4). The majority of stations contained corals that 

exhibited growth during this monitoring period. Overall, there were greater percentages of 

tissue loss or retreat than growth in both years of the most recent monitoring period (Table 

3.4.1.4). During 1998-2001, the overall percentage of points falling on areas of tissue loss 

and/or retreat as well as rates of loss remained relatively stable, but the percentage of points 

falling on areas of growth declined. Growth/loss ratios suggest a slowing of growth 

processes from 1998 to 1999, and increase in loss processes in 2000. Loss appeared to slow 

in 2001, but was still greater than growth. 
38

3.4.2 West Bank – Species Composition and Cover 

The species composition and percent cover of the coral community in the 8 m2

repetitive quadrats is generally the same as that found in analysis of random inside transects 

(Table 3.4.2.1). Although estimates of total coral cover and the cover of most species is 

lower than the random inside transects, these differences are likely due to differences in 

photographic analysis rather than substantial differences in the coral community. All 

analyzed species fell within the same range of cover based on ±1 SD. Four uncommon 

species, Agaricia agaricites, A. fragilis, Porites porites, and Scolymia sp., found in the inside 

random transects, were not found in the 8 m2 quadrats. Because of the differences in 

photographic analysis methods and the fact that percent cover data for repetitive quadrats 

were only collected during 2000-2001, no statistical comparisons between cover estimates 

from repetitive quadrat data and random transects were done. 

Table 3.4.2.1. 

Mean percent cover of coral species and total coral with standard deviation 

 in 8 m2 repetitive quadrats at the West Flower Garden Bank, 2000-2001. Thirty-one stations 

were photographed in 2000; 36 stations were photographed in 2001. 

Species 2000 2001 

Montastraea annularis complex* 32.3 (13.2) 31.3 (13.0)

Montastraea cavernosa 3.9 (6.7) 3.8 (7.1)

Diploria strigosa 6.4 (5.8) 6.2 (5.7)

Colpophyllia natans 1.5 (2.2) 1.8 (3.0)

Porites astreoides 2.2 (2.1) 2.6 (2.0)

Stephanocoenia mechelinii 0.3 (1.0) 0.4 (1.1)

Mussa angulosa 0.06 (0.1) 0.1 (0.3)

Millepora sp. 0.8 (1.0) 1.1 (1.3)

Madracis sp. 0.1 (0.3) 0.1 (0.6)

Siderastrea siderea 1.0 (4.1) 0.9 (3.6)

Total Coral 50.0 (9.6) 48.3 (10.2) 1 Data from which percent cover can be calculated was only collected in 2000-2001. *Montastraea annularis complex is comprised of M. annularis, faveolata, and franksi.

Mean percentages of points that fell on areas of bleaching followed by mortality, 

disease followed by mortality, algal-replacement retreat, sediment- replacement retreat, tissue 

loss due to competition, unexplained tissue loss, and new disease per station were essentially 

stable between 2000-2001 (Table 3.4.2.2). Mean percentage of points falling on areas of 

bleaching without mortality per station declined substantially as did the frequency at which it 

occurred. Percentage of points falling on areas of all the remaining categories increased, 

although only slightly for most. Frequency of bleaching followed by mortality, algalreplacement retreat, algal/sediment replacement retreat, and tissue loss due to competition 

increased substantially; frequency of unexplained tissue loss nearly doubled. Mean 

percentage of points falling on areas of paling as well as its frequency, increased fairly 

dramatically. The total percentage of colonies exhibiting bleaching doubled between 2000-

2001, with all species except Colpophyllia natans and Mussa angulosa contributing to the 

increase (Table 3.4.2.3). 
39

Very little disease was noted with only one point falling on an area of mortality due to 

disease in 2001 (Table 3.4.2.2). Although the mean percentage of points falling on areas of 

new disease was stable during the monitoring period, the frequency at which it occurred 

nearly doubled. 

Infilling growth increased during the 2000-2001 monitoring period and marginal 

growth was stable (Table 3.4.2.2). Most stations contained corals that exhibited growth 

during the most recent monitoring period. However, tissue loss was still greater than growth 

in both years (Table 3.42.4). From 1998 to 2000, the overall percentage of points falling on 

areas of tissue loss and/or retreat declined, with a small increase in 2001; the percentage of 

points falling on areas of growth has declined substantially since 1998. Growth/loss ratios 

suggest a slowing of growth from 1998-1999, near equivalence of these processes during 

1999 and 2000 and increasing loss processes in 2001. 

Table 3.4.2.2. 

Mean percentage of points falling on areas of bleaching, disease, etc. by station with standard 

deviation, maximum percentage for all stations and frequency (%) of occurrence for 8 m2

repetitive quadrats at the West Flower Garden Bank. 2000 – based on 34 stations and 1627 

colonies. 2001 – based on 33 stations and 1591 colonies 

Mean percent/station 

(SD) 

Maximum percent/ 

any station 

Frequency of 

Observation occurrence 

2000 2001 2000 2001 2000 2001 

Paling 0.3 (0.5) 0.8 (2.4) 2 13 32.3 39.4 

Bleaching followed by mortality 0.05 (0.2) 0.07 (0.2) 1 1 2.9 12.1 

Bleaching not followed by mortality 1.3 (2.2) 0.3 (0.6) 11 1 52.9 27.3 

Disease followed by mortality 0.0 0.04 (0.2) 0 1 0 3.0 

Disease not followed by mortality 0.02 (0.1) 0.0 1 0 2.9 0 

Algal- replacement 0.5 (0.1) 0.8 (1.0) 3 3 55.9 66.7 

Sediment- replacement 0.08 (0.3) 0.06 (0.2) 2 1 8.8 9.1 

Algal/sediment- replacement 0.03 (0.2) 0.2 (0.6) 1 2 2.9 15.1 

Tissue loss due to competition 0.03 (0.1) 0.05 (0.1) 1 1 5.9 12.1 

Tissue loss due to fish biting 0.0 0.0 0 0 0 0 

Unexplained tissue loss 0.3 (0.5) 0.4 (0.4) 2 1 26.5 54.5 

Growth-infilling 0.06 (0.2) 0.2 (0.5) 1 2 11.8 24.2 

Growth-marginal 0.6 (0.7) 0.6 (1.1) 3 4 55.9 45.4 

New disease 0.4 (1.5) 0.3 (0.8) 8 4 8.8 15.1 
40

Table 3.4.2.3. 

Percentage of colonies exhibiting bleaching1 by species at the 

West Flower Garden Bank for 2000-2001. 

Species 2000 2001 

Montastraea annularis complex* 0.2 0.6 

Montastraea cavernosa 0.06 0.3 

Diploria strigosa 0.4 0.6 

Colpophyllia natans 0.06 0.0 

Porites astreoides 0.06 0.3 

Mussa angulosa 0.06 0.0 

Millepora sp. 0.4 0.6 

Total percent 1.2 2.4 

Total colonies 1627 1591 1 Data from which percentages could be calculated was only collected in 2000-2001. *Montastraea annularis complex is comprised of M. annularis, faveolata, and franksi.

Table 3.4.2.4. 

Overall percentage of points falling on areas of colonies exhibiting bleaching, disease etc. at 

the East Flower Garden Banks, 1998-2001. 

Observation 1998 1999 2000 2001 

Paling1 N/A N/A 0.3 0.8

Bleaching followed by mortality 0.2 0.1 0.05 0.06

Bleaching not followed by mortality 0.3 0.06 1.3 0.06

Disease followed by mortality 0.03 0 0 0.03

Disease not followed by mortality 1.2 0.03 0.03 0

Algal- replacement 1.7 1.4 0.5 0.9

Sediment- replacement 0.8 0.3 0.09 0.06

Algal/sediment- replacement 0.06 0.1 0.03 0.2

Tissue loss due to competition 0.03 0 0.03 0.06

Tissue loss due to fish biting 0 0 0 0

Unexplained tissue loss 0.3 0.7 0.3 0.4

Growth-infilling 0.3 0.5 0.06 0.2

Growth-marginal 4.3 2.1 0.6 0.6

New disease1 N/A N/A 0.4 0.3

Overall growth 4.6 2.6 0.7 0.8

Overall retreat, mortality & tissue loss 3.1 2.6 1.0 1.7

Approximate Growth:Loss Ratio 5:3 1:1 1:1 1:2

Number of Stations 35 35 34 33 1

 These categories were added in 2000. 
41

3.5 VIDEO TRANSECTS 

Following the established protocol for video documentation, linear transects were 

recorded following the perimeter boundary lines at each bank. The images collected appear 

consistent with the results of the encrusting, quadrat, and random photographic samples. The 

most notable observations at the EFGB were an area of increased algal cover on the south 

transect approximately 03:31 (mm:ss) into taping and a few noted instances of what appeared 

to be bleaching on the west transect. On the WFGB, some bleaching was seen on the 

Montastraea annularis complex and M. cavernosa, as well as several areas of parrot fish 

biting/marks on the north transect. On all transects, Millepora sp. appeared to be bleaching 

in almost all instances. 

3.6 WATER QUALITY/INSOLATION/TEMPERATURE 

3.6.1 Water Quality 

 One SPMD was deployed at each bank during the 2000 and 2001 monitoring cruises 

(Table 3.6.1.1). Upon retrieval of the 2000 SPMD canisters, it was discovered that the 

membranes were torn and many postlarval crustaceans were residing within the metal 

housing. Therefore, the SPMDs could not be sent in for dialyzation. The 2001 SPMDs were 

also not analyzed because they could not be located. 

Table 3.6.1.1. 

Semi-Permeable Membrane Device (SPMD) sampling periods for the 

East and West Flower Garden Banks, 2000-2001. 

Deployment Retrieval Date Analyzed 

2000

EFGB 13-Sept-00 10-Nov-00 Not sent for analysis, 

membrane torn 

WFGB 11-Sept-00 11-Nov-00 Not sent for analysis, 

membrane torn 

2001

EFGB 19-Sept-01 * Not Found 

WFGB 17-Sept-01 * Not Found 

* searched for SPMDs in November 2001 

However, during the period of 12 June – 20 Sept 2001, SPMDs were deployed at 

EFGB to monitor for impacts from a nearby oil/gas drilling project. W&T Offshore Inc, 

New Orleans granted permission to report the data on concentrations of polycyclic aromatic 

hydrocarbons (PAH) collected (Table 3.6.1.2). Concentrations of PAH ranged from 0-135.6 

ng (parts per trillion) during this period. 
42

Table 3.6.1.2. 

Semi-Permeable Membrane Device (SPMD) deployed at the East Flower Garden Bank 

during drilling activities on HI-389 (courtesy of W&T Offshore, Inc.), May-September 2001. 

ESSI Label Deployed Retrieved Status Total PAH 

Level (ng) 

EFGB 05/27/01 05/27/01 -- Lost in Field -- 

EFGB 06/12/01 06/12/01 07/08/01 Analyzed 0 

EFGB 07/09/01 07/09/01 07/19/01 Analyzed 0 

EFGB 07/19/01 07/19/01 07/31/01 Analyzed 135.6 

EFGB 07/31/01 07/31/01 09/06/01 Analyzed 11.1 

EFGB 09/06/01 09/06/01 09/20/01 Analyzed 0 

EFGB 09/20/01 09/20/01 -- Lost in Field -- 

3.6.2 Insolation 

This report presents all available data collected since February 1997. Portions of the 

1997 data sets have been previously described in earlier reports (Dokken et al. 1999) and are 

summarized here for completeness. The mean PAR irradiance and corresponding values for 

-k were lower at the WFGB than at the EFGB during 1997-1999; however, it does not appear 

that these differences are statistically significant. Beginning in March 2000, and continuing 

through November 2001, the instruments in use at the HI-389 platform and the WFGB 

station became erratic. Accurate comparisons of irradiance between the EFGB and WFGB 

were not possible for that period. Lack of reference irradiance measurements made it 

impossible to estimate -k. 

Seasonal variation in light levels was clearly evident in the plot of PAR values 

recorded at the HI-389 Platform (Figure 3.6.2.1). Higher frequency variability is caused by 

weather patterns that periodically increase cloud cover. During 1999, a transient problem 

with the instrument resulted in three data gaps (Figure 3.6.2.1). PAR levels were recorded 

during these gaps, but the levels were unacceptably low and were rejected as bad data. The 

cause of these events is under investigation, but may have been due to mechanical shading of 

the sensor during platform operations. The sensor was recalibrated, but failed to respond. 

Consequently, there were no reference data from which to calculate extinction rates. 

Seasonal variation in PAR was present, but less coherent for values recorded by the 

instruments at the EFGB and WFGB (Figures 3.6.2.2 and 3.6.2.3). For example, PAR doses 

recorded at the EFGB instrument during summer of 1997 and 1999, show distinct decreases 

during month-long episodes that are not reflected in values recorded at HI-389. The cause of 

these deviations is presumably change in the transmission characteristics of the water at the 

site. Decreased transmissivity could result from presence of more turbid coastal water 

masses, increases in phytoplankton production over the site, or both. Direct comparison of 

PAR dosage and water column attenuation was made for the 405 days when synoptic values 

were available for both underwater sensors (Figure 3.6.2.4). 
43

Figure 3.6.2.1. Irradiance at the HI389 platform: Upper panel shows mean hourly irradiance 

from April 1997 to February 2000. Lower panel shows mean hourly 

irradiance from March 2000 to November 2001; instrument was intermittent. 

Areas marked E, F, and G represent gaps in the data, see Appendix 2. 

HI389 Platform Irradiance

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

Apr-97May-97Jul-97Aug-97Sep-97Oct-97Nov-97Dec-97Jan-98Feb-98Mar-98Apr-98May-98Jun-98Jul-98Aug-98Sep-98Oct-98Nov-98Dec-98Jan-99Feb-99Mar-99Apr-99May-99Jun-99Jul-99Aug-99Sep-99Oct-99Nov-99Dec-99Jan-00Feb-00

Month-Year

Irradiance (M/ sq. m)

E F G

HI389 Irradiance 00-01

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

Mar-00Mar-00Apr-00May-00Jun-00Jul-00Aug-00Sep-00Oct-00Nov-00Dec-00Jan-01Feb-01Mar-01Apr-01May-01Jun-01Jul-01Aug-01Sep-01Oct-01Nov-01Dec-01Jan-02

Month- Year

Irradiance (M /sq. m)
44

Figure 3.6.2.2. Irradiance at the East Flower Garden Bank: Upper panel shows mean hourly 

irradiance from April 1997 to February 2000. Lower panel shows mean 

hourly irradiance from March 2000 to November 2001; note scale change, 

instrument was intermittent. Areas marked A, B, and C represent gaps in the 

data, see Appendix 2. 

East Bank Irradiance 97-99

0

200

400

600

800

1000

1200

Apr-97May-97Jun-97Jul-97Aug-97Sep-97Oct-97Nov-97Dec-97Jan-98Feb-98Mar-98Apr-98May-98Jun-98Jul-98Aug-98Sep-98Oct-98Nov-98Dec-98Jan-99Feb-99Mar-99Apr-99May-99Jun-99Jul-99Aug-99Sep-99Oct-99Nov-99Dec-99Jan-00Feb-00Mar-00

Month-Year

Mean Irradiance (μM/sq. m/s)

A B C

East Bank Irradiance 00-01

0

200

400

600

800

1000

1200

1400

Mar-00Apr-00May-00Jun-00Jul-00Aug-00Sep-00Oct-00Nov-00Dec-00Jan-01Feb-01Mar-01Apr-01May-01Jun-01Jul-01Aug-01Sep-01Oct-01Nov-01

Month-Year

Mean Irradiance (μM/ sq. m/s)
45

Figure 3.6.2.3. Irradiance at the West Flower Garden Bank: Upper panel shows mean hourly 

irradiance from April 1997 to February 2000. Lower panel shows mean 

hourly irradiance from June 2000 to August 2001. Areas marked “r” 

represent gaps in the data, see Appendix 2. 

West Bank Irradiance 00-01

0

50

100

150

200

250

300

350

400

Mar-00Mar-00Apr-00May-00Jun-00Jul-00Aug-00Sep-00Oct-00Nov-00Dec-00Jan-01Feb-01Mar-01Apr-01May-01Jun-01Jul-01Aug-01Sep-01Oct-01

Month -Year

Mean Irradiance(μM/sq m/s)

West Bank Irradiance 97-98

0

50

100

150

200

250

300

Apr-97May-97Jun-97Jul-97Aug-97Sep-97Oct-97Nov-97Dec-97Jan-98Feb-98Mar-98Apr-98May-98Jun-98Jul-98Aug-98Sep-98Oct-98Nov-98Dec-98Jan-99Feb-99Mar-99Apr-99May-99Jun-99Jul-99Aug-99Sep-99Oct-99Nov-99Dec-99Jan-00Feb-00Mar-00

Month-Year

Mean irradiance (μM/sq. m/s)

D G
46

Figure 3.6.2.4 Total insolation at the East Flower Garden (upper) and at the West Flower 

Garden Bank (lower) monitoring stations (23.8 m water depth) April 1997 to 

March 2000. Areas marked A, B, C, D, E, F, and G represent gaps in the 

data, see Appendix 2. 

East Bank Attenuation 97-99

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

Apr-97May-97Jun-97Jul-97Aug-97Sep-97Oct-97Nov-97Dec-97Jan-98Feb-98Mar-98Apr-98May-98Jun-98Jul-98Aug-98Sep-98Oct-98Nov-98Dec-98Jan-99Feb-99Mar-99Apr-99May-99Jun-99Jul-99Aug-99Sep-99Oct-99Nov-99Dec-99Jan-00Feb-00Mar-00

Month-Year

-k

A B C

West Bank Attenuation 97-99

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

0.18

Apr-97May-97Jun-97Jul-97Aug-97Sep-97Oct-97Nov-97Dec-97Jan-98Feb-98Mar-98Apr-98May-98Jun-98Jul-98Aug-98Sep-98Oct-98Nov-98Dec-98Jan-99Feb-99Mar-99Apr-99May-99Jun-99Jul-99Aug-99Sep-99Oct-99Nov-99Dec-99Jan-00Feb-00Mar-00

Month-Year

-k

D E F G
47

Between 23 September 2001-8 February 2002, salinity, turbidity, dissolved oxygen 

and pH, in addition to temperature and PAR, were continuously measured. During this 

period, salinity at EFGB declined from 38 ppt to about 32 ppt; at WFGB salinity remained 

relatively stable at 35-36 ppt. Turbidity at both banks was relatively stable, but was greater 

at EFGB. There was a brief, but dramatic increase in turbidity during mid-October at WFGB 

and there were numerous short-lived turbidity spikes at EFGB. DO concentrations at EFGB 

were generally higher than at WFGB. Both DO and pH increased through the period as 

would be expected with observed seasonal decline in water temperature. The complete 

record for YSI data collected (salinity, depth, dissolved oxygen, pH, temperature, turbidity, 

and PAR) at the EFGB and WFGB seafloor stations is shown in Figures 3.6.2.5 and 3.6.2.6. 

3.6.3 Temperature 

Seawater temperatures obtained from the Hobo-Temp recording thermographs (Onset 

Instruments, Pocasset, Massachusetts) deployed near the mooring bolt. Data indicate an 

overall mean minimum temperature of 20.3oC in February of 2001 and a mean maximum of 

29.8oC in August of 2001 (Figures 3.6.3.1). Due to equipment failure, no data was recorded 

from April 2000 to November 2000; instruments were replaced in November 2000. 

3.7 SEA URCHIN SURVEYS 

Sea urchin surveys for Diadema antillarium were conducted on both the 2000 and 

2001 monitoring cruises. Results from those surveys are in Table 3.7.0.1. 

Table 3.7.0.1. 

Average number of Diadema antillarium per meter square on the East and West Flower 

Garden Banks from 1996-2001. 

Year EFGB WFGB 

1996 No counts made 

due to sea conditions 0.0033 m2

1997 No counts made 

 due to sea conditions 0.0038 m2

1998 0.023 m2 No counts made 

 due to sea conditions 

1999 No counts made 

 due to sea conditions 

No counts made 

 due to sea conditions 

2000 0.018 m2 0.030 m2

2001 0.005 m2 0.050 m2
48

03:01 19:37 12:13 04:49 21:25 

8.2408.2968.3528.4088.4648.520

pH

03:01 19:37 12:13 04:49 21:25 

4.505.506.507.508.509.50

DO Conc(mg/L) 

03:01 19:37 12:13 04:49 21:25 

21.7022.2422.7823.3223.8624.40

Depth(m)

03:01 19:37 12:13 04:49 21:25 

31.032.433.835.236.638.0

Salinity(ppt)

03:01 19:37 12:13 04:49 21:25 

8.2408.2968.3528.4088.4648.520

03:01 19:37 12:13 04:49 21:25 

4.505.506.507.508.509.50

03:01 19:37 12:13 04:49 21:25 

21.7022.2422.7823.3223.8624.40

03:01 19:37 12:13 04:49 21:25 

31.032.433.835.236.638.0

)

DateTime(M/D/Y)

09/23/01 10/20/01 11/17/01 12/15/01 01/11/02 

East Bank

Figure 3.6.2.5. Complete data record of environmental parameters from YSI probe installed at East Fl

Garden Bank seafloor station, September 2001-February 2002.
49

19:00 05:06 15:12 01:18 11:24 

8.2708.3148.3588.4028.4468.490

pH

19:00 05:06 15:12 01:18 11:24 

5.405.766.126.486.847.20

DO Conc(mg/L) 

19:00 05:06 15:12 01:18 11:24 

27.0027.3427.6828.0228.3628.70

Depth(m)

19:00 05:06 15:12 01:18 11:24 

34.0034.5035.0035.5036.0036.50

Salinity(ppt) 

DateTime(M/D/Y)

09/23/01 09/29/01 10/04/01 10/10/01 10/15/01 

West Bank

Figure 3.6.2.6. Complete data record of environmental parameters from YSI probe installed at West Fl

Garden Bank seafloor station, September 2001-October 2002.
50

Figure 3.6.3.1. Mean seawater temperatures for the East and West Flower Garden Banks 

from September 1999 to April 2000 (A) and November 2000 to September 

2001 (B). 

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

Nov-00 Dec-00 Jan-01 Feb-01 Mar-01 Apr-01 May-01 Jun-01 Jul-01 Aug-01 Sep-01

Date

Temperature (oC)

EFGB

WFGB

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

Sep-99 Oct-99 Nov-99 Dec-99 Jan-00 Feb-00 Mar-00 Apr-00

Date

Temperature (oC)

WFGB

EFGB

A

B
51

4.0 DISCUSSION 

4.1 GENERAL 

Through the 2001 monitoring period, the Flower Garden Banks (FGB) appeared to be 

healthy and productive. Dokken et al. (1999) described the character of the FGB coral reefs 

with comparisons to other coral reef systems of the Gulf of Mexico and Caribbean Sea. 

Relative to these other coral reef systems, the FGB have low diversity of stony corals and 

high coral cover, generally ~ 50%. Located approximately 180 km from the nearest 

landmass, the FGB are relatively isolated from terrestrial based impacts when compared to 

reef systems such as those of the Florida Keys (FMRI 1997; Lapointe 1997; Porter et al. 

2002), southern Gulf of Mexico (Tunnell 1992; Chavez and Tunnell 1993), Netherlands 

Antilles (Bak and Nieuwland 1995), and the Caribbean Sea of Central America (Cortés 

1997). 

Although afforded a measure of protection from shore side development and 

watershed drainage impacts, within the FGB there is potential for habitat damage from 

industrial and recreational activities occurring in the near vicinity such as anchoring and oil 

spills. Prior to designation as a National Marine Sanctuary in 1992, substantial anchor 

damage was observed. Since designation, no damage from these activities has been 

documented. No significant impact from oil/gas activity has been documented before or after 

Sanctuary designation. Lang et al. (2001) characterized the FGB as “...near excellent in the 

spectrum of possible reef conditions.” The results reported herein are in general agreement. 

Management of the FGB began in the early 1980’s with the application for a drilling/ 

production permit in the High Island 389 lease block by Mobil Exploration and Production 

U.S. Inc. The proposed drill site was approximately 1.5 km east of the East Flower Garden 

Bank. The High Island A389 production platform was required to shunt all permitted 

discharges to within 10 m of the seabed (~120 m) and a monitoring program was established 

to track trends in the health of the coral reef. Management primarily focused on prevention 

of negative impacts from oil and gas operations in the area. In 1992, with the designation of 

the Flower Garden Banks as a national marine sanctuary, the potential for impacts from other 

human activities was recognized and additional management guidelines were instituted. 

Buffer zones were established around the banks that exclude oil and gas activity and the 

banks were deemed no anchoring zones. To eliminate anchor damage, mooring buoys were 

installed to allow access to the FGB by recreational divers and their support vessels. Fishing 

guidelines allowed for single hook and line fishing, but no spearfishing or multiple hook, 

traps, or net type commercial equipment. These guidelines are still in effect as of October 

2002. 

The number of recreational divers visiting the FGB annually is not known precisely, 

but it is believed that about 3,000 recreational divers make at least 9,000 dives on the FGB 

each year. The impact of this activity is not known, and the monitoring strategy does not 

produce data that would clearly distinguish and document the impact of recreational diving. 

The FGB continue to be dominated by Montastraea spp. and Diploria strigosa, which 

according to the findings of Hughes and Jackson (1985), would indicate the relatively stable 

environment favored by the more robust and massive species of corals. Understanding of 

chronic versus catastrophic mortality (Bythell et al. 1993) at the FGB is virtually nil. 
52

Hurricanes routinely pass through the area (e.g. Hurricane Andrew 1992, Hurricane Georges 

1998), but no attributable impact has been recorded. In addition, tropical storms and winter 

high-pressure fronts force surface conditions above the FGB to sea states > 5 m several times 

each year. The depth of the FGB is likely the most important contributing factor to 

minimizing impact from storms. Chronic mortality from predation (Simpson 1979), disease 

(Bruckner and Bruckner 1998, 2000) and competition occurs continuously as indicated by 

the monitoring data, but it is balanced by growth. Bythell et al. (1993) postulated that due to 

inherent morphological and physical differences between M. annularis and D. strigosa, the 

population dynamics of M. annularis may be more controlled by chronic mortality events 

and D. strigosa more influenced by events of catastrophic mortality. 

4.2 CORAL GROWTH AND CONDITION 

Dokken et al. (1999; 2001) reported annual variability of accretionary growth within 

banks and between banks (Tables 3.3.1.1 and 3.3.2.1), which is consistent with the data 

reported herein for 2000 and 2001. No significant long-term upward or downward trends in 

growth rates were evident. These conclusions are consistent with the reports of Gittings et al. 

(1992) and Continental Shelf Associates (1996). Between 1985 and 2001, Montastraea 

faveolata growth at the EFGB ranged from 6.12 to 8.23 mm/yr. Accretionary growth at the 

WFGB ranged from 4.49 to 6.64 mm/yr. There is no clear explanation of why M. faveolata

generally accretes faster at the EFGB. Random transect data also indicated that the M. 

annularis complex grew faster at the EFGB. Rates of coral growth at the Flower Garden 

Banks were in the mid to upper range of growth rates of corals at various Caribbean Sea reefs 

(Dokken et al. 2001). 

Interpretation of repetitive quadrat data was problematic because rather than 

recording the numbers of colonies exhibiting the characteristic, the number of points 

contacted on the random point intercept mask was recorded, consistent with the historical 

methodology. The frequencies for the last two years at EFGB suggest that all causes of loss 

except unexplained tissue loss declined (Table 3.5.1.2). However, the percentage of colonies 

exhibiting bleaching increased (Table 3.5.1.3). Thus, at EFGB, the frequencies may not be 

providing a clear picture of the extent to which these processes are occurring or exist. On the 

other hand, at WFGB, frequencies of nearly all causes of loss increased between 2000-2001 

(Table 3.5.2.2) and the percentage of colonies exhibiting bleaching also increased (Table 

3.5.2.3). Data compilation of the last four years suggested that the overall percent cover of 

“new growth” declined fairly dramatically, however, since the same point mask was not used 

on the same photo every year, this may or may not be the case. However, since these are 

measures of “relative” growth and loss, then it is possible that the percent of area affected by 

loss processes, although it has fluctuated up and down by about 1% over the last four years, 

is relatively stable, whereas the percentage of the area exhibiting growth is declining. The 

growth:loss ratios suggested that the processes were essentially in equilibrium during 1998-

1999, but that loss processes affected more area during 2000-2001, with the greatest loss 

occurring during 2000. Still, the long-term picture suggested stability. 

Growth/loss ratios estimated from repetitive quadrat data at EFGB seem somewhat 

contradictory in light of the large apparent increases in Montastraea annularis and total coral 

cover seen in the random transects. However, the cover estimates from the random transect 

data are not directly comparable to the cover estimated for the 8 m quadrats due to 

differences in both slide scale and data capture technique. There was a very slight decline in 
53

percent cover of M. annularis complex, Diploria strigosa, and total coral in the repetitive 

quadrat stations (see Table 3.5.1.1) that seems in line with the growth/loss ratios. In addition, 

net loss of D. strigosa was noted at encrusting stations for 1998-2000; growth and loss were 

approximately equal during 2001. Frequencies of paling, bleaching and disease followed by 

mortality, replacement (all), tissue loss due to competition, unexplained tissue loss, and new 

disease increased between 2000-2001 as did infilling growth. Frequencies of bleaching 

without mortality, disease without mortality, and marginal growth declined. These changes 

indicate that, at least at repetitive quadrat stations, loss processes are outpacing growth 

processes and this is reflected in the growth/loss ratios. 

At the WFGB, decreased growth was also seen between 1998-1999. Growth/loss 

were essentially equivalent in 1999-2000, then increased substantially in 2001. Again, the 

percent cover estimates generated from the random transect data is not directly comparable to 

those from the repetitive quadrats for the same reasons cited above. However, unlike the 

EFGB, only moderate increases in cover of M. annularis complex were seen at the WFGB, 

so the growth/loss ratios do not seem to be quite as contradictory. Like the EFGB, cover of 

the M. annularis complex and total coral cover declined slightly in the repetitive quadrats 

which is also in line with the increased loss seen in 2001. Frequencies of nearly all causes of 

loss increased from 2000 to 2001 whereas frequencies of both growth processes declined. 

Habitat characters such as degree of bleaching and percent cover of algae and bare 

reef rock varied annually from 1996 - 2001. Although no significant trends were evident and 

no change appeared to be long term, there was a substantial increase in the M. annularis

complex at the EFGB. Based on the results of the random transect data, cover of the M. 

annularis complex at the EFGB appeared to be increasing at the expense of reef rock, M. 

cavernosa and D. strigosa (correlations), but only more data will allow a definitive answer. 

Runs tests do not indicate trends, only natural or random variability. Algal cover increased 

in 1999, but this appeared to be a very short-term condition based on casual observations 

approximately four weeks after the monitoring cruise. Reef rock was also negatively 

correlated with algal cover. It appeared that the M. annularis complex and algae colonized 

more of the non-living surfaces of the bank. The significant positive correlation between 

algae and total coral suggested that algae were not expanding at the expense of coral cover. 

In using random photographic methods to collect the data on which these correlations 

have been founded, there are two possible sources for error: 1) randomness of the 

photographic transects and 2) laboratory measurement and analysis of the data contained in 

the photographs. The potential for subjective error is minimized by increasing transect 

replicates and using the same personnel and technology to complete the laboratory analysis 

each year, but it cannot be eliminated all together. Although we are confident in the 

conclusion that the M. annularis complex did expand in area coverage, we are less confident 

in stating that the coverage of M. annularis doubled (110% increase) from 1996 to 2001 

(Table 3.1.1.1). There are three key considerations in understanding how the data could 

indicate a 110% increase: 1) standard deviations, 14.2% in 1996 and 12.9% in 2001, show 

substantial overlap in the ranges, 2) the increase in number of transects, 10 in 1996 to 19 in 

2001, and 3) the reduction in “No ID” category from > 43% in 1996 and 1997 to < 18% in 

1998, 1999, 2000, and 2001. Also, in 1996 a transition was made to a computer-based 

technology for delineating the content of transect photographs and calculating relative 

percentages of each component. 
54

 Expansion of the M. annularis complex at the WFGB showed a more moderate 

increase (29%) from 1996 to 2001 (Table 3.1.3.1). As at the EFGB, standard deviations 

muted any statistical significance and the “NO ID” category declined from > 51% in 1996 to 

< 16% in 2001. In contrast the number of usable transects remained consistent with the 

number ranging from 13 to 16 transects. 

The correlations between the M. annularis complex, D. strigosa, M. cavernosa and 

total coral cover were indicative of the fact that these three species are the predominant 

corals on the bank. The same negative correlation between reef rock and algae recorded at 

the EFGB was also seen at the WFGB. It appeared that like the EFGB, algae primarily 

colonized non-living surfaces (i.e. reef rock). Unlike the EFGB, the M. annularis complex 

did not appear to be expanding into areas of non-living substrate. In addition, there were no 

significant correlations between the M. annularis complex and D. strigosa or M. cavernosa

or algae and total cover as seen at the EFGB. It appeared that the coral community at the 

WFGB remained relatively stable throughout the monitoring period. 

Random photographic transects were completed outside the boundaries of the 

designated 100 m2 study area to test whether or not the study area remained representative of 

the reef habitat. No inconsistencies between the reef character outside the designated study 

area and the study area were evident. The study area continued to be representative of the 

reef habitat at each bank. 

 

Disease was a minor component of the FGB ecosystem dynamics with no apparent 

significant impact (Dokken et al. 2001; Oberding 2002). This was in contrast to near shore 

Gulf and Caribbean reefs such as the Florida Keys (Porter et al. 2001) where “dramatic” 

increases in the occurrence of disease (404% increase) and the number of coral species 

affected by diseases (218% increase) occurred in recent years. Garzόn-Ferreira et al. (2001) 

reported on the increase in coral diseases on coral reefs of Colombia (i.e. southwestern 

Caribbean). Black band disease was common with corals of the Montastraea spp. and 

Diploria sp. commonly infected. Richardson et al. (2001) stated, “A second overwhelming 

threat, yet to be documented, is the role of coral diseases in initiating phase shifts on coral 

reefs.” There is no evidence of a phase shift at the FGB, but research and monitoring 

programs should be alert to such an event should it occur. 

Oberding reported black band disease, ridge mortality, yellow blotch, plaque disease, 

and neoplasia in the corals of the FGB with black band being the most common disease 

condition primarily affecting M. annularis, D. strigosa, and M. caveronsa. He also reported 

“conditions of unknown or undeterminable diseases.” It must noted that Oberding’s disease 

identifications were made strictly with the use of photographic guides. Staff members of the 

FGBNMS question his conclusions of “black band being the most common.” Further 

investigations are needed to further clarify the identification of disease conditions at the 

FGB. To date there are no clear indications that disease conditions at the FGB have changed 

appreciably from historical conditions. This is not surprising since the increase of disease in 

near shore reef habitats has been in part attributed to anthropogenic stresses (Peters 1997; 

Green and Bruckner 2000; Acosta 2001); and the FGB are considered to be relatively free of 

land based anthropogenic stresses. As described by Bruckner and Bruckner (1998, 2000) 

there was evidence of coral loss to feeding patterns/habits of Sparisoma viride. A review of 

private archived photographs (Q. Dokken) provided evidence that this condition existed prior 

to 1996. 
55

Bleaching at the FGB was observed most commonly in 1997-98 (Dokken et al. 1999, 

2001) but not as a threatening event. The hydrocoral, Millepora alcicornis, and to a lesser 

extent the scleractinian coral, Montastraea cavernosa, were most susceptible to this 

condition. Consistent with the reports of Gittings et al. (1992) and Hagman and Gittings 

(1992), bleaching correlated strongly with temperature, most commonly occurring when 

seawater temperatures at the coral surface exceeded 30°C. Bleaching events were of short 

duration, but because of the sampling schedule dictated, one time per year, bleaching as an 

annual event is poorly understood at the Flower Garden Banks. But, to date bleaching does 

not appear to be a significant threat. However, bleaching events should be monitored with 

the understanding that bleaching stressed corals may be more susceptible to coral disease 

pathogens (Harvell et al. 2001). 

In 1999 a bloom of filamentous algae was present during the time of monitoring 

cruise (Dokken et al. 2001). The bloom occupied bare reef rock, but based on subsequent 

anecdotal observations, was short lived. Over the duration of this monitoring program it was 

difficult to draw firm conclusions regarding fluctuations in algal densities. Although algal 

densities increased at the time of the annual monitoring expeditions, the absence of 

monitoring data throughout the year and of nutrient data to which to possibly correlate 

changes left questions of algal fluctuations unanswered. The grazing patterns and relative 

impacts of herbivorous fish and urchins have not been studied at the FGB with the exception 

of Gittings and Bright (1987). Urchin densities at the WFGB tended to be greater than at the 

EFGB (Table 3.8.0.1) and there was an increase from 1996 to 2001 at the WFGB, but based 

on a one time per year census conducted during the time of the September monitoring cruise 

Diadema antillarum populations have not made an appreciable recovery since the 1983-84 

mass mortality event (Lessios 1988). It is also noted that anecdotal observations (Q. 

Dokken) suggest the possibility that urchin densities vary throughout the year and may be 

greater in the spring and summer months prior to September. Systematic quantitative 

surveys need to be conducted to determine the validity of this observation. Surveying 80 reef 

sites in the Florida Keys between August and December 1999, Chiappone et al. (2002) 

reported minimal recovery of D. antillarum. No urchins were recorded in 69 of the sampled 

sites, and all total, only 16 individuals were recorded from all 80 sites. 

Dunton and Miller (2001 in Dokken et al. 2001) concluded that nutrients at the FGB 

are produced autochthonously by benthic cyanobacterial mats rather than transported into the 

system from coastal zones. Dodge and Lang (1983) demonstrated correlations of coral 

growth to flooding events in southern Louisiana suggesting that the FGB may not be as 

isolated from coastal zone impacts as one would assume. Subsequently, the reason for algal 

blooms is not clearly understood. In contrast, Lapointe (1997) described external sources of 

nitrogen as facilitating the habitat shift of coral dominance to algae dominance on the reefs of 

southern Florida. Lapointe’s conclusions were challenged by Hughs et al. (1999) who 

maintained that a reduction in the herbivory was the primary cause of the coral to macroalgae 

shift. In the lagoon systems of Belize, McClanahan et al. (1999) point to a combination of 

factors, temperature, nutrients, and fishing, causing a phase shift from coral to macroalgae. 

Aronson and Precht (2000) suggest changes in the herbivore populations as the primary 

factor for the phase shift in Discovery Bay, Jamaica. Although population densities of 

Diadema antillarum were low during the monitoring sampling periods, no such phase shifts 

occurred at the FGB. 
56

4.3 INSOLATION/TEMPERATURE/WATER QUALITY 

 Comparison of data from the underwater light sensors to the reference station clearly 

showed the effect of probable overcast conditions on light availability at depth. Although 

light levels were much lower at depth, the highs and lows of sunny and overcast days match 

closely through the records. Additionally, seasonal changes can also be discerned in the 

general trends of light level for the underwater and reference sensors. Abrupt shifts in the 

measured light intensity at depth, e.g. between 16 and 17 July 1996 (see Figure 3.7.2.1, 

lower), which are not mirrored by the reference values, indicated changes in the light 

transmission properties of the water column. 

 The estimates of the attenuation coefficient, k, provided information on the water 

column characteristics. Overall, the k values were in the range that Parsons et al. (1984) 

suggested falls between the clearest coastal water (k = 0.15) and the clearest oceanic waters 

(k = 0.033). The robust growth rates that have generally been reported for hermatypic corals 

at the Flower Garden Banks probably reflect these clear water column conditions. 

Monitoring light levels is therefore an important means for gauging the physical conditions 

that maintain coral health in this marine sanctuary. Previous reports of light intensity levels 

at the monitoring sites (CSA 1996), give only the daily averages in graphic form. The raw 

data from this study should be reviewed and re-processed to calculate attenuation values. 

 The temperature regime for 2000 and 2001 was unremarkable with temperatures 

staying within normal parameters. Seawater temperatures typically range from ~18°C in 

February to 30°C in August. From May through November temperatures generally stay at or 

above 25°C and only during the months of January, February and March do temperatures 

approach the lower limits. The months of April and December are transition months with 

temperatures rising and falling, respectively. During July and August 1997 temperatures 

exceeded 30°C and subsequently increased bleaching was observed during this time period. 

 The utilization of Semipermeable Membrane Devices (SPMD) to collect information 

on the chemical quality of the water column proved problematic. Specifically, the SPMD 

were suitable for short-term (i.e. < 30 days) deployment only. Beyond this deployment 

duration the SPMD “ribbons” became fouled with sessile growth and juvenile crustaceans 

took up residence in the housing and tore holes in the ribbons as they fed on the sessile 

growth. The water quality at the FGB was deemed good based on the SPMD data collected, 

a conclusion supported by the work of Nipper and Carr (2001 in Dokken et al. 2001) in their 

assessment of the toxicity of the interstitial water of the sediments on the reef cap. 

Concentrations of polycyclic aromatic hydrocarbons (PAH) were very low, < 1,150 ng (parts 

per trillion) and usually < 500 ng. Likely sources were condensate oil seepage and ship fuels. 

Along with PAH, pesticides and PCBs were detected at concentrations < 100 ng. At the 

miniscule concentrations recorded it was not possible to conclusively attribute impact by 

these compounds, but based on the growth and health measured, we would logically 

conclude that they had no influence on the corals. 

4.4 BIODIVERSITY 

 Dokken et al. (1999) reported the lack of information on biodiversity as a gap in the 

knowledge and management foundation of the FGB. To initiate efforts to close this gap, 

Dokken et al. (2001) included as attachments reports by Fredericq et al., Lehman and Albert, 
57

and Barrera and Tunnell that clearly demonstrated the incompleteness of the knowledge of 

the biodiversity of the Flower Garden Banks. Combined, Fredericq et al. and Lehman and 

Albert produced a list of 72 species of algae and Barrera and Tunnell added 100 new species 

to the catalog of molluscs found at the FGB. Thomas (1996) stated, “Coral reefs are 

undergoing unprecedented changes throughout the world. A major problem in 

understanding this change is the almost total lack of information on biodiversity from reef 

systems.” Further he stated, “Long-term protection of coral reefs will be realized only with 

the understanding of where and how biodiversity levels are established and maintained.” 

Thomas advocated concentrated comprehensive efforts to catalog the biodiversity of 

important reef systems. Wells (1995) noted that not only should the basic knowledge of reef 

biodiversity be expanded, but also knowledge of adjacent habitats. 

 Generally, of the flora and fauna of the Flower Garden Banks, only the stony corals 

have been completely identified. Relatively little work has been undertaken to fully describe 

the crustaceans, sponges, and echinoderms. Almost all-taxonomic investigation has been 

restricted to the shallow habitats of the coral cap. The authors suggest that efforts to more 

fully describe the flora and fauna of the FGB are warranted. This would likely be outside the 

limits of a monitoring project, but it could prove insightful in assessing long-term change. 

To be fully comprehensive and instructive, this effort should include seasonal investigations 

of the planktonic communities as well. 
59

5.0 RECOMMENDATIONS 

Dokken et al. (1999) concluded their report with the following recommendations: 

1) Eliminate growth spikes as a method for measuring accretionary growth. Use 

sclerochronology measurements to measure accretionary growth exclusively. 

2) Continue and expand water chemistry analysis using SPMD technology. Record 

data no less than quarterly. 

3) Expand water chemistry analysis to include nutrients (nitrogen and phosphorous) 

on a schedule no less than quarterly. 

4) The protocol and technology applied to the measurement of light characteristics 

should be enhanced to allow diurnal collections, particularly during the late 

summer months before and after the annual spawning event. 

5) Use random photographic transects outside the boundaries of the 100 m2 study 

sites to test the representativeness of the designated study sites. 

6) Continue analysis of sea urchin abundance on a quarterly basis. 

7) Add qualitative and quantitative analysis of macroalgae. 

8) Add fish census (stationary visual and/or roving diver census). 

9) Add seasonal photographic transects to assess temporal occurrences, such as 

disease and bleaching. 

10) Continue and expand monitoring and studies of the biogenic zones below the 

coral cap. Trophic structure analysis should be undertaken to describe biological 

energy linkages between the biogenic zones. 

11) Measure seasonal and annual current patterns around and above the FGB. 

12) Develop and apply dynamic ecosystem models to research and management 

decision making. 

In 2001, Dokken et al. made the following recommendations: 

1) The monitoring program be continued. 

2) The monitoring program be expanded to include algal studies, nutrient flows in 

the trophic structure, nutrient concentrations in the water column, and pore water 

toxicity, and detailed studies of disease. If necessary, the budget should be 

adjusted to accommodate these studies. 

3) The in situ water quality monitoring instrumentation be upgraded and the suite of 

parameters of water quality measured be expanded to include dissolved oxygen, 

salinity, pH, and turbidity, nitrites, nitrates, ammonium, and phosphates. If 

necessary, the budget should be adjusted to accommodate these upgrades. 

4) Sample no less than four times per year those flora/faunal components and water 

quality parameters that can undergo short term fluctuations (i.e. algal biomass, 

bleaching, herbivore populations, and contaminant concentrations). 

5) Expand monitoring program to include Stetson Bank to both monitor the health 

and sustainability of the Stetson Bank ecosystem and as a more terrestrially 

influenced habitat against which to compare and contrast the FGB. 

The Minerals Management Service and FGBNMS have made substantial progress in 

implementing most of these recommendations. The 2002 and 2003 monitoring program, as 

specified within the RFP will include: 
60

1) Expanded algal studies, nutrient flows, and nutrient concentrations will be 

conducted. 

2) The in situ water quality monitoring instrumentation has been upgraded. 

3) More rigorous measurements of potential contaminants will be conducted in 

the laboratory. 

4) Population densities of the herbivore, Diadema antillarum, will be monitored. 

5) Deep water stations below the coral cap will be monitored. 

6) Fish census will be conducted. 

These actions will not only expand our knowledge and understanding of the FGB ecosystem, 

but will also improve the foundation from which management decisions are made. 
61

6.0 CONCLUSION 

The results of the 1998 through 2001 monitoring efforts were consistent with those of 

Gittings et al. (1992), CSA (1996), and Dokken et al. (1999; 2001) in that variability was 

common. Growth rates, coral cover, algal cover, and bare rock exposure varied annually. 

Negative conditions such as bleaching and increased algal cover did occur, but were not 

permanent and did not significantly impact the stony corals. Disease, although present, was 

not a significant factor in the gain or loss of coral cover. Abundance of the herbivore, 

Diadema antillarum, was low, but there was no indication that the habitat was degraded by 

this condition. 

Investigations of the algal community and micromolluscan fauna added substantially 

to the species list of the FGB. This advance underscored the need for additional 

investigations into the community diversity of the FGB. Other investigations described the 

trophic structure and nutrient flows of the FGB with comparison to Stetson Bank. Whereas 

preliminary indications were that the FBG are autogenous, Stetson Bank, closer to the Texas 

coast is allochthonous. 

Water conditions, temperature and transmissivity, followed historical patterns staying 

within the limits required for coral growth and health. Preliminary measurements of salinity, 

pH, and turbidity indicated that water conditions are dynamic with both short and long-term 

changes and patterns occurring. Although contaminants such as PAH were recorded from 

the water column, the concentrations were very low (i.e. 0 to ~1,200 part per trillion) and had 

no measurable impact on the habitat. Investigations of benthic pore water quality indicated 

no contamination. 

Within the boundaries of the study area there were no indications that commercial or 

recreational activity in the area had significant negative impact on the health of the coral 

community. The coral habitat was judged to be in balance relative to the health and growth 

of the stony corals. 
63

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69

8.0 APPENDIX 1 - OUTSIDE RANDOM TRANSECTS 

8.1 East Bank – Community Composition, Structure and Trends 

The Montastraea annularis complex in transects outside the study area increased to a 

peak in 2000 but slightly less cover was recorded in 2001 (Table 8.1.0.1). However, the 

same general pattern of increase in M. annularis complex, a peak in algal cover in 1999, and 

declining cover of reef rock was also evident outside the study area. Shannon diversity and 

evenness of the coral community were lowest in 2000 and dominance was highest, reflecting 

the greater coverage of the M. annularis complex recorded (Table 8.1.0.2). Diversity 

increased and dominance decreased in 2001 with the decreased coverage of the M. annularis

complex recorded, but neither returned to pre-2000 levels. Bray-Curtis cluster analysis of 

community similarity indicates that overall similarity among the years is 66% with 2 clusters, 

generally reflecting the increased cover of the M. annularis complex during 2000-2001 

(Figure 8.1.0.1). Using Mann-Whitney U, the non-parametric equivalent of a t-test, no 

significant differences were found between major reef components inside the study area 

versus outside the study area (Table 8.1.0.3). The community described outside of the study 

area is generally the same as that described inside the study area although it appears to be 

slightly more variable with regards to some of the less common species such as Colpophyllia 

natans. 

8.2 West Bank – Community Composition, Structure and Trends 

The outside transects at the WFGB exhibit an identical pattern for the M. annularis

complex as was seen in the outside transects at the EFGB, with increasing cover of the M. 

annularis complex to a peak in 2000, then a slight decrease in the 2001 data (Table 8.2.0.1). 

The data collected outside the study area at the WFGB is in general agreement with that 

collected inside the study area with similar patterns of slightly increased M. annularis

complex, a peak of algal cover in 1999. The declines in coral species diversity and evenness 

and the increase in dominance reflect an increase in the M. annularis complex cover recorded 

in 2000 and 2001 (Table 8.2.0.2). Although the M. annularis complex cover was slightly 

less in 2001, cover of several other species was either less or the species was absent in 2001 

data collections. It is likely that, like the area outside of the study area on the EFGB, the area 

outside the study area on the WFGB is slightly more variable with regard to the nondominant species. Like the EFGB, there were no significant differences between percent 

cover of major reef components inside the study area vs outside the study area (Table 

8.2.0.3). Bray-Curtis cluster analysis of community similarity indicates that communities 

recorded for each year were about 80% similar (Figure 8.2.0.1). However, the same clusters 

of 1998-99 and 2000-01, as were delineated at the EFGB were also delineated at the WFGB, 

again reflecting the increased dominance of the M. annularis complex in 2000-02. 
70

Table 8.1.0.1. 

Mean cover (%) with standard deviation in parenthesis from outside random transects, East 

Flower Garden Bank. 

19981 19991 2000 2001 

Agaricia agaricites 0.6 0.3 0.2 (0.2) 0.6 (0.6) 

Agaricia fragilis 0.0 0.0 0.0 0.0 

Colpophyllia natans 2.3 3.3 0.7 (1.1) 8.2 (7.4) 

Diploria strigosa 9.7 8.7 5.4 (0.4) 4.0 (3.6) 

Montastraea annularis complex* 29.0 33.6 56.8 (3.3) 52.9 (14.3) 

Montastraea cavernosa 3.8 2.3 1.6 (2.3) 6.2 (8.3) 

Scolymia sp. 0.1 0.0 0.0 0.02 (0.04) 

Stephanocoenia michilini 0.6 0.4 0.0 1.1 (1.5) 

Mussa angulosa 0.1 <0.1 0.3 (0.5) 0.4 (0.7) 

Madracis sp. 0.3 2.4 0.0 0.0 

Porites astreoides 4.7 4.1 2.6 (1.3) 3.1 (2.8) 

Porites porites 0.1 <0.1 0.01 (0.02) 0.02 (0.04) 

Siderastrea sp. 0.4 1.0 0.02 (0.05) 0.02 (0.04) 

Millepora sp. 1.7 1.3 0.4 (0.3) 0.5 (0.4) 

Total Coral 53.1 58.2 67.9 (3.4) 73.0 (17.3) 

Filamentous algae * * 11.2 (3.0) 8.3 (7.4) 

Crustose coralline algae * * 1.6 (0.9) 2.2 (1.2) 

Dictyota sp. * * 0.2 (0.2) 0.2 (0.1) 

Total Algae 2.2 22.4 13.1 (3.4) 10.7 (8.4) 

Total Sponge 1.4 0.0 0.3 (0.2) 0.4 (0.5) 

Serpulidae * * 0.06 (0.07) 0.2 (0.1) 

Other * * 0.3 (0.6) 1.6 (2.8) 

Reef rock 46.7 17.4 2.1 (0.9) 1.7 (2.2) 

19981 19991 2000 2001 

Sand 0.0 1.0 0.0 0.07 (0.1) 

Artifacts * * 0.6 (1.1) 0.3 (0.4) 

Unidentifiable * * 15.7 (4.2) 11.9 (2.8) 

Number of transects N/A N/A 4 3 

1

 The original data were not available so new means and standard deviations could not be calculated. These 

data are presented as they appeared in the 1998-99 report; categories with a ‘*’ were not used during these years *

Montastraea annularis complex is comprised of M. annularis, faveolata, and franksi. 
71

Table 8.1.0.2. 

Shannon diversity (H’, base 10), evenness (J’) and Berger-Parker dominance (d), outside 

study area at the East Flower Garden Bank. 

1998 1999 2000 2001 

Diversity 0.65 0.63 0.30 0.50 

Eveness 0.58 0.58 0.30 0.46 

Dominance 0.54 0.58 0.83 0.69 

Table 8.1.0.3. 

Results of non-parametric Mann-Whitney U comparing inside transects to outside transects 

for major reef components, East Flower Garden Bank. 

Component N U Z Significance 

 

Montastraea annularis complex* 8 5.00 -0.866 0.486 

 

Colpophyllia natans 8 8.00 0.000 1.000 

Diploria strigosa 8 8.00 0.000 1.000 

Madracis sp. 8 5.50 -0.730 0.486 

Montastraea cavernosa 8 7.00 -0.289 0.886 

Porites astreoides 8 7.50 -0.145 0.886 

 

Siderastrea sp. 8 7.00 -0.292 0.886 

 

Total algae 8 5.00 -0.866 0.486 

Reef rock 8 7.00 -0.289 0.886 

 *Montastraea annularis complex is comprised of M. annularis, faveolata, and franksi. 
72

Figure 8.1.0.1. Bray-Curtis community similarity dendrogram for outside random transects 

from 1998-2001 for the East Flower Garden Bank. 

0% Similarity 50 100
73

Table 8.2.0.1. 

 Mean cover (%) with standard deviation in parenthesis from outside random transects, West 

Flower Garden Bank. 

1998 1999 2000 2001 

Agaricia agaricites 0.4 0.3 0.3 (0.2) 0.4 (0.4) 

Agaricia fragilis 0.0 0.0 0.008 (0.02) 0.0 

Colpophyllia natans 2.0 2.0 1.3 (1.2) 2.6 (3.4) 

Diploria strigosa 8.6 10.1 6.1 (2.0) 4.2 (1.4) 

Montastraea annularis complex* 27.1 31.2 40.1 (4.9) 35.6 (7.3) 

Montastraea cavernosa 2.9 3.7 3.2 (1.8) 1.1 (2.1) 

Scolymia sp. <0.1 0.1 0.0. 0.0 

Stephanocoenia mechelinii 0.5 0.5 1.3 (1.8) 1.1 (1.2) 

Mussa angulosa 0.1 <0.1 0.0 0.5 (0.8) 

Madracis sp. 0.3 1.3 0.0 0.0 

Porites astreoides 2.5 4.4 2.1 (1.8) 2.4 (1.0) 

Porites porites <0.1 <0.1 0.0 0.0 

Siderastrea sp. 1.2 1.1 0.5 (1.0) 0.0 

Millepora sp. 1.4 1.1 1.4 (1.6) 0.2 (0.2) 

Total Coral 47.0 55.7 56.8 (7.1) 48.0 (5.7) 

Filamentous algae * * 21.2 (5.3) 25.5 (3.4) 

Crustose coralline algae * * 3.5 (0.9) 2.7 (1.5) 

Dictyota sp. * * 0 0.007 (0.01) 

Total Algae 2.7 21.7 24.7 (5.8) 28.2 (4.7) 

Total Sponge 1.0 0.0 0.9 (1.3) 0.8 (0.5) 

Serpulidae * * 0.04 (0.03) 0.02 (0.02) 

Other * * 0.03 (0.07) 0.07 (0.1) 

Reef rock 49.0 18.6 4.1 (1.6) 4.2 (1.8) 

Sand 0.1 2.0 0.0 0.07 (0.1) 

Artifacts * * 0.4 (0.5) 0.4 (0.8) 

Unidentifiable * * 13.1 (2.0) 16.8 (3.2) 

Number of transects * * 4 4 

*

Montastraea annularis complex is comprised of M. annularis, faveolata, and franksi. 1

 The original data were not available so new means and standard deviations could not be calculated. These 

data are presented as they appeared in the 1998-99 report; categories with a ‘*’ were not used during these 

years. 
74

Table 8.2.0.2. 

Shannon diversity (H’, base 10), evenness (J’) and Berger-Parker dominance (d), outside 

West Flower Garden Bank. 

1998 1999 2000 2001 

Diversity 0.63 0.64 0.48 0.45 

Evenness 0.56 0.58 0.48 0.47 

Dominance 0.57 0.56 0.71 0.74 

Table 8.2.0.3. 

Results of non-parametric Mann-Whitney U comparing inside transects to outside transects 

for major reef components, West Flower Garden Bank. 

Component N U Z Significance 

 

Montastraea annularis complex* 8 6.00 -0.577 0.686 

 

Colpophyllia natans 8 7.00 -0.290 0.886 

Diploria strigosa 8 4.00 -1.155 0.343 

Madracis sp. 8 7.00 -0.290 0.886 

Montastraea cavernosa 8 7.00 -0.289 0.886 

Porites astreoides 8 7.00 -0.292 0.886 

 

Siderastrea sp. 8 3.00 -1.443 0.200 

 

Total algae 8 6.00 -0.577 0.686 

*

Montastraea annularis complex is comprised of M. annularis, faveolata, and franksi. 
75

Figure 8.2.0.1. Bray-Curtis community similarity dendrogram for outside random transects 

from 1998-2001 for the West Flower Garden Bank. 

0% Similarity 50 100
77

9.0 APPENDIX 2

Dates of monitoring and other servicing cruise with summary of data collection intervals and 

quality description for East and West Flower Garden Banks and HI389 Platform reference sensor. 

Letters describing data gaps refer to notation in Figures 3.7.2.1 – 3.7.2.4. 

Cruise start date EFG data interval WFG data interval HI389 data interval 

 9-Sep-97 to 8-Nov-97 

(D. data logger overflow) 

8 Sep 97 10-Sep-97 to 3-Mar-98 

(good data) 

9-Nov-97 to 2 Mar 98 

(good data) 

9-Sep-97 to 3-Mar-98 

(good data) 

2 Mar 98 3-Mar-98 to 26-Aug-98 

(A. sensor broken on 

deployment) 

3-Mar-98 to 24-Aug-98 

(good data) 

4-Mar-98 to 26-Aug-98 

(good data) 

24 Aug 98 24-Aug-98 to 11-Oct-98 

(good data) 

24-Aug-98 to 14-Oct-98 

(good data) 

26-Aug-98 to 13-Oct-98 

(good data) 

14 Oct 98 14-Oct-98 to 23-Mar-99 

(B. sensor broken on 

deployment) 

14-Oct-98 to 23-Mar-99 

(good data) 

13-Oct-98 to 22-Mar-99 

(acceptable data, 

E. transient error 25-Nov to 30 

Dec-99) 

23 Mar 99 22-Mar-99 to 5-Apr-99 

(data logger overflow) 

5-Apr-99 to 27-July-99 

(good data) 

23-Mar-99 to 26-Jul-99 

(good data) 

23-Mar-99 to 26-Jul-99 

(acceptable data, 

F. transient error 12-Mar to 

26-Apr-99) 

26-Jul-99 27-Jul-99 to 13-Sep-99 

(good data) 

27-Jul-99 to 13-Sep-99 

(good data) 

26-Jul-99 to 13-Sep-99 

(good data) 

2- Sep 99 14-Sep-99 to 26-Oct-99 

(C. data logger overflow) 

14-Sep-99 to 26-Oct-99 

(data logger overflow) 

14-Sep-99 to 26-Oct-99 

(G. data logger overflow) 

25 Oct 99 26-Oct-99 to 16-Feb-00 

(good data) 

26-Oct-99 to 16-Feb-00 

(good data) 

26-Oct-99 to 16-Feb-00 

(good data) 

15 Feb 00 16-Feb-00 to 22-Jun-00 

(battery failure; no data) 

16-Feb-00 to 22-Jun-00 

(housing flooded; no data) 

16-Feb-00 to 22-Jun-00 

(data intermittent) 

22 Jun 00 22-Jun-00 to 11-Sep-00 

(readings low—acceptable 

data) 

22-Jun-00 to 11-Sep-00 

(good data) 

22-Jun-00 to 11-Sep-00 

(sensor failure) 

11 Sep 00 11-Sep-00 to 12-Dec-00 

(sensor failure; no data) 

11-Sep-00 to 12-Dec-00 

(good data) 

11-Sep-00 to 12-Dec-00 

(sensor failure) 

12 Dec 00 12-Dec-00 to 28-Apr-01 

(readings low—acceptable 

data) 

12-Dec-00 to 28-Apr-01 

(good data) 

12-Dec-00 to 28-Apr-01 

(good data) 

28 Apr 01 28-Apr-01 to 18-Aug-01 

(acceptable data) 

28-Apr-01 to 18-Aug-01 

(good data) 

28-Apr-01 to 18-Aug-01 

(intermittent data) 

18 Aug 01 18-Aug-01 to 17-Sep-01 

(acceptable data) 

18-Aug-01 to 17-Sep-01 

(acceptable data) 

18-Aug-01 to 17-Sep-01 

(intermittent data) 

 28 Sep 01 28-Sep-01 to 08-Feb-02 

(YSI sonde installed; good 

data) 

28-Sep-01 to 08-Feb-02 

(YSI sonde installed; good 

data) 

28-Sep-01 to 08-Feb-02 

(sensor failure) 
79

10.0 APPENDIX 3 

Encrusting growth stations of Diploria strigosa exhibiting net gain (+), loss (−), and no 

change (=) in percent cover of coral tissue at the East and West Flower Garden Banks, 

1998-2001. 

East Flower Garden Bank 1998 

Station Area of Coral Tissue (cm2) Difference from 1997 (cm2) Change in % Cover 

Tissue Gain (+) 

1 190.40 32.80 12.52 

3 138.93 15.63 5.97 

5 208.31 9.61 3.67 

6 231.10 14.70 5.61 

13 191.93 83.35 31.81 

15 149.16 39.71 15.16 

20 195.32 41.29 15.76 

33 225.99 57.34 21.88 

39 102.70 22.90 8.74 

41 219.66 13.20 5.04 

49 184.95 50.01 19.09 

52 137.58 11.45 4.37 

56 198.10 34.21 13.06 

59 138.81 16.19 6.18 

62 138.81 7.03 2.68 

63 78.40 8.12 3.10 

68 169.36 14.64 5.59 

75 186.40 6.17 2.35 

79 221.10 22.80 8.70 

82 124.66 5.96 2.27 

100 103.70 18.45 7.04 

 

Tissue Loss (-) 

2 0.00 -63.40 0.68 

4 1.65 -143.74 0.15 

7 117.33 -61.48 2.13 

11 10.77 -147.68 1.94 

12 0.00 -188.69 1.63 

27 100.94 -33.55 1.63 

28 115.36 -9.06 -0.16 

31 35.38 -99.21 2.21 

32 105.70 -40.15 1.10 

35 79.15 -130.34 1.83 

46 0.00 -114.59 -0.44 

53 121.79 -22.95 0.68 

54 154.17 54.60 0.15 

55 159.58 -5.13 2.13 

 
80

East Flower Garden Bank 1998, continued 

Station Area of Coral Tissue (cm2) Difference from 1997 (cm2) Change in % Cover 

No Change (=) 

10 210.45 1.78 -24.20 

16 148.30 0.40 -54.86 

25 141.19 5.57 -23.46 

26 172.11 5.09 -56.36 

42 128.70 4.28 -72.02 

64 78.40 4.28 -12.80 

70 177.54 -0.43 -3.46 

83 99.55 5.80 -37.86 

84 102.99 2.87 -15.32 

85 124.47 4.80 -49.75 

8 139.04 -1.16 -43.73 
81

West Flower Garden Bank 1998 

Station Area of Coral Tissue (cm2) Difference from 1997 (cm2) Change in % Cover 

Tissue Gain (+) 

2 166.5 62.1 23.70 

4 156.6 55.69 21.25 

5 209.43 36.07 13.77 

7 123.67 23.3 8.89 

10 153.58 27.06 10.33 

30 155.49 63.69 24.31 

31 128.79 15.88 6.06 

36 192.76 41.04 15.66 

42 157.9 13.11 5.00 

44 192.24 48.76 18.61 

50 188.2 34.94 13.34 

56 150.9 52.61 20.08 

58 158.99 19.13 7.30 

73 192.4 22.97 8.77 

100 188.71 67.76 25.86 

318 154.8 33.96 12.96 

45a 191.24 47.19 18.01 

67b 111.71 34.97 13.35 

 

Tissue Loss (-) 

3 99.65 -49.54 -18.91 

6 73.56 -106.84 -40.78 

9 139.63 -68.81 -26.26 

11 179.28 -95.31 -36.38 

34 133.83 -52.55 -20.06 

35 116.87 -16.75 -6.39 

37 66.47 -106.04 -40.47 

38 180.91 -16.91 -6.45 

43 104.34 -38.43 -14.67 

53 100.28 -20.94 -7.99 

54 75.49 -10.25 -3.91 

59 129.39 -37.57 -14.34 

60 70.17 -50.27 -19.19 

101 120.41 -5.41 -2.06 

 

No Change (=) 

39 101.17 -0.63 -0.24 

41 127.52 -2.96 -1.13 

52 147.31 -3.65 -1.39 

57 147.63 1.75 0.67 

70 209.99 -0.75 -0.29 

45b 228 2.21 0.84 
82

East Flower Garden Bank 1999 

Station Area of Coral Tissue (cm2) Difference from 1998 (cm2) Change in % Cover 

Tissue Gain (+) 

3 138.93 16.48 6.29 

5 208.31 43.99 16.79 

6 231.10 54.98 20.98 

7 117.33 19.91 7.60 

10 228.00 17.55 6.70 

11 40.70 29.93 11.42 

15 165.68 16.52 6.30 

16 178.32 30.02 11.46 

21 24.75 10.80 4.12 

31 155.10 119.72 45.69 

32 120.74 15.03 5.74 

35 199.73 120.58 46.02 

37 188.10 48.07 18.35 

39 142.37 39.67 15.14 

42 154.32 25.62 9.78 

49 199.12 14.17 5.41 

52 163.22 25.64 9.79 

54 176.31 22.14 8.45 

56 227.40 29.30 11.18 

62 158.42 14.62 5.58 

64 112.54 25.12 9.59 

68 187.55 18.19 6.94 

75 212.61 26.21 10.00 

79 245.47 24.36 9.30 

83 140.17 40.62 15.50 

84 189.78 86.79 33.12 

100 129.31 25.61 9.77 

 

Tissue Loss (-) 

2 0.00 -39.74 -15.17 

4 1.65 -65.49 -25.00 

13 8.95 -182.98 -69.84 

25 6.93 -134.26 -51.24 

26 0.47 -171.50 -65.46 

29 87.48 -37.70 -14.39 

47 1.63 -175.18 -66.86 

58 94.56 -7.24 -2.76 

59 122.71 -16.10 -6.14 

82 80.92 -43.74 -16.69 

85 108.19 -16.28 -6.21 
83

East Flower Garden Bank 1999, continued 

Station Area of Coral Tissue (cm2) Difference from 1997 (cm2) Change in % Cover 

No Change (=) 

1 197.53 7.13 2.72 

8 107.78 -3.44 -1.31 

27 107.30 6.36 2.43 

28 119.83 4.47 1.71 

33 229.45 3.46 1.32 

36 107.75 6.63 2.53 

41 228.60 8.94 3.41 

53 118.60 -3.19 -1.22 

55 166.13 6.55 2.50 

63 77.98 -0.42 -0.16 

70 169.71 -4.75 2.72 
84

West Flower Garden Bank 1999 

Station Area of Coral Tissue (cm2) Difference from 1998 (cm2) Change in % Cover 

Tissue Gain (+) 

1 160.64 94.79 36.18 

8 128.09 13.12 5.01 

11 211.43 32.15 12.27 

12 140.94 24.20 9.24 

13 190.53 66.97 25.56 

25 205.28 111.31 42.48 

33 206.70 36.39 13.89 

34 155.03 21.20 8.09 

37 182.35 115.88 44.23 

39 119.21 18.04 6.89 

41 151.21 23.69 9.04 

43 169.49 65.14 24.86 

44 203.72 11.48 4.38 

53 127.58 27.30 10.42 

59 207.42 78.03 29.78 

60 89.24 19.06 7.27 

70 225.18 15.18 5.79 

 

Tissue Loss (-) 

2 75.94 -90.58 -34.57 

3 54.28 -45.38 -17.32 

4 103.34 -53.29 -20.34 

5 156.19 -53.24 -20.32 

9 0.00 -139.63 -53.29 

15 148.86 -16.07 -6.13 

19 109.78 -19.48 -7.43 

23 68.09 -129.58 -49.46 

24 6.99 -132.50 -50.57 

26 1.16 -163.47 -62.39 

29 89.26 -38.65 -14.75 

31 36.85 -91.94 -35.09 

32 117.37 -55.95 -21.35 

35 101.80 -15.07 -5.75 

36 117.71 -75.05 -28.65 

38 156.26 -24.65 -9.41 

40 36.50 -141.34 -53.94 

45 138.68 -44.31 -16.91 

55 123.54 -65.93 -25.16 

56 139.08 -11.81 -4.51 

57 121.91 -25.73 -9.82 

58 92.14 -70.19 -26.79 

 
85

West Flower Garden Bank 1999, continued

Station Area of Coral Tissue (cm2) Difference from 1997 (cm2) Change in % Cover 

No Change (=) 

6 73.57 0.00 0.00 

10 149.54 -4.04 -1.54 

14 176.12 3.44 1.31 

21 24.54 -1.74 -0.66 

22 180.76 5.83 2.23 

28 121.14 7.75 2.96 

30 164.14 8.64 3.30 

42 151.07 -6.83 -2.61 
86

East Flower Garden Bank 2000 

Station Area of Coral Tissue (cm2) Difference from 1999 (cm2) Change in % Cover 

Tissue Gain (+) 

15 133.65 30.25 11.55 

28 110.64 36.17 13.80 

35 107.02 16.11 6.15 

37 171.69 40.06 15.29 

79 215.45 15.68 5.99 

 

Tissue Loss (-) 

21 23.91 -23.91 -9.12 

64 91.15 -77.50 -29.58 

83 128.33 -8.25 -3.15 

 

No Change (=) 

12 124.22 -2.52 -0.96 

31 8.93 -2.86 -1.09 

32 113.12 -3.03 -1.16 

46 0.00 0.00 0.00 

49 184.14 3.58 1.37 
87

West Flower Garden Bank 2000 

Station Area of Coral Tissue (cm2) Difference from 1999 (cm2) Change in % Cover 

Tissue Gain (+) 

29 131.41 10.10 3.86 

32 173.91 13.15 5.02 

47 221.96 27.23 10.39 

50 206.72 22.99 8.78 

51 140.04 15.90 6.07 

68 163.92 27.97 10.68 

U4 201.71 6.25 2.38 

U5 190.39 9.28 3.54 

U7 208.85 10.97 4.19 

 

Tissue Loss (-) 

02 169.43 -8.97 -3.43 

04 167.91 -11.76 -4.49 

05 149.81 -49.51 -18.90 

31 135.99 -6.09 -2.32 

42 154.96 -11.02 -4.21 

56 121.32 -7.52 -2.87 

61 4.87 -6.49 -2.48 

70 206.39 -11.81 -4.51 

U2 136.06 -16.81 -6.42 

U6 144.36 -6.21 -2.37 

 

No Change (=) 

10 0.00 -3.37 -1.29 

11 174.62 2.68 1.02 

33 196.77 0.92 0.35 

41 202.19 0.50 0.19 

53 111.72 3.99 1.52 

XXX 182.72 0.79 0.30 
88

East Flower Garden Bank 2001 

Station Area of Coral Tissue (cm2) Difference from 2000 (cm2) Change in % Cover 

Tissue Gain (+) 

12 121.70 24.06 9.18 

24(168) 175.22 38.19 14.58 

56(187) 227.39 14.50 5.54 

60 65.78 11.53 4.40 

83(173) 120.08 31.14 11.88 

92 147.11 17.04 6.50 

 Tissue Loss (-) 

01(110) 37.00 -9.31 -3.55 

08 236.46 -40.45 -15.44 

13 214.95 -10.55 -4.03 

15(119) 163.90 -27.65 -10.55 

20(179) 210.81 -8.69 -3.32 

37 211.74 -22.63 -8.64 

43 198.59 -8.20 -3.13 

54(192) 137.97 -31.13 -11.88 

65(189) 182.07 -15.44 -5.89 

79 231.14 -33.47 -12.77 

82 130.06 -16.79 -6.41 

 No Change (=) 

02 0.00 2.41 0.92 

03(2) 229.70 5.18 1.98 

05 190.54 2.42 0.93 

21 0.00 0.00 0.00 

22 0.00 0.00 0.00 

28(193) 146.81 -4.06 -1.55 

32 110.09 1.85 0.71 

33(118) 161.27 -1.00 -0.38 

39 69.28 -4.38 -1.67 

53(176) 126.33 -4.30 -1.64 

57 262.01 0.00 0.00 

64 13.65 -0.03 -0.01 

Station numbers followed by parentheses represent stations that have been retagged 
89

West Flower Garden Bank 2001

Station Area of Coral Tissue Difference from 2000 Change in % Cover 

Tissue Gain (+) 

02(104) 185.21 15.78 6.02

04 190.47 22.56 8.61

05 235.57 85.76 32.73

13 169.95 6.17 2.35

18 207.21 33.65 12.84

24(108) 136.65 29.13 11.12

25 94.43 19.55 7.46

26(121) 217.96 40.08 15.30

33(134) 229.04 32.27 12.32

41/41 DIG 181.51 41.29 15.76

47(102) 231.42 9.46 3.61

51(131) 155.96 15.91 6.07

68 190.01 26.08 9.96

XXX 

(147) 228.09 45.37 17.32

 

 Tissue Loss (-) 

17(109) 107.92 -8.43 -3.22

19(103) 95.17 -26.39 -10.07

29(117) 115.23 -16.18 -6.18

50(101) 186.89 -19.83 -7.57

 

 No Change (=) 

20 0.00 0.00 0.00

23 111.95 -1.15 -0.44

35(125) 117.41 -3.02 -1.15

56 84.39 2.84 1.08

61 3.15 -1.72 -0.66

70(113) 207.48 1.10 0.42

Station numbers followed by parentheses represent stations that have been retagged 
The Department of the Interior Mission

As the Nation's principal conservation agency, the Department of the Interior has responsibility 

for most of our nationally owned public lands and natural resources. This includes fostering 

sound use of our land and water resources; protecting our fish, wildlife, and biological diversity; 

preserving the environmental and cultural values of our national parks and historical places; 

and providing for the enjoyment of life through outdoor recreation. The Department assesses 

our energy and mineral resources and works to ensure that their development is in the best 

interests of all our people by encouraging stewardship and citizen participation in their care. 

The Department also has a major responsibility for American Indian reservation communities 

and for people who live in island territories under U.S. administration. 

The Minerals Management Service Mission 

As a bureau of the Department of the Interior, the Minerals Management Service's (MMS) 

primary responsibilities are to manage the mineral resources located on the Nation's Outer 

Continental Shelf (OCS), collect revenue from the Federal OCS and onshore Federal and Indian 

lands, and distribute those revenues. 

Moreover, in working to meet its responsibilities, the Offshore Minerals Management Program 

administers the OCS competitive leasing program and oversees the safe and environmentally 

sound exploration and production of our Nation's offshore natural gas, oil and other mineral 

resources. The MMS Minerals Revenue Management meets its responsibilities by ensuring the 

efficient, timely and accurate collection and disbursement of revenue from mineral leasing and 

production due to Indian tribes and allottees, States and the U.S. Treasury. 

The MMS strives to fulfill its responsibilities through the general guiding principles of: (1) being 

responsive to the public's concerns and interests by maintaining a dialogue with all potentially 

affected parties and (2) carrying out its programs with an emphasis on working to enhance the 

quality of life for all Americans by lending MMS assistance and expertise to economic 

development and environmental protection.