Fagatele Bay National MarineSanctuary Science Series 2003-1 Changes in the coral reef communities of Fagatele Bay National Marine Sanctuary and Tutuila Island (American Samoa), 1982-1995 Charles Birkeland, University of Guam Richard H. Randall, University of Guam Alison L. Green, American Samoa Department of Marine and Wildlife Resources Barry D. Smith, University of Guam Suzanne Wilkins, University of Guam U.S. Department of Commerce American Samoa Government National Oceanic and Atmospheric Administration Department of Commerce National Ocean Service Environment Division Office of National Marine Sanctuaries Pago Pago, American Samoa May, 2003 DISCLAIMER Report content does not necessarily reflect the views and policies of the National Marine Sanctuary Program or the National oceanic and Atmospheric Administration, nor does the mention of trade names or commercial products constitute endorsement or recommendation for use. REPORT AVAILABILITY Electronic copies of this report may be downloaded from the National Marine Sanctuaries Program web site at www. Sanctuaries.nos.noaa.gov. Hard copies may be available from the following address: Fagatele Bay National Marine Sanctuary PO Box 4318 Pago Pago, As 96799 SUGGESTED CITATION Suggested citation: Birkeland, C.1, Randall, R.1, Green, A.2, Smith, B.1, and Wilkins, S. 1. 2003. Changes in the coral reef communities of Fagatele Bay NMS and Tutuila Island (American Samoa), 1982-1995. Fagatele Bay National Marine Sanctuary Science Series. Pago Pago, AS. p. 237 1 University of Guam Marine Laboratory, UOG Station, Mangilao, Guam 96923 2 Department of Marine and Wildlife Resources, Pago Pago, AS 96799 TABLE OF CONTENTS Abstract vii Coral Communities (by R.H. Randall and C. Birkeland) 1 Introduction 1 Methods 2 Results 3 Discussion 3 Previous studies 3 Structural effects of Acanthaster planci on reef communities 4 Discussion and summary of Acanthaster planci effects 8 Tropical cyclones of 1990 and 1991 9 Structural effects of tropical Cyclones Ofa and Val on fringing reefs in Fagatele Bay 10 Discussion and summary of cyclone effects 16 Macrobenthic Invertebrate Communities (by Barry D. Smith) 111 Introduction 111 Methods 111 Results 112 Discussion 113 Algal Communities (by Suzanne Wilkins) 128 Introduction 128 Methods 128 Results and Discussion 129 Fish Communities (by Alison Green) 144 Introduction 144 Methods 144 Results 146 Discussion 156 Appendix A: Coralline Lethal Orange Disease 221 Acknowledgments 223 Literature Cited 224 Page i LIST OF TABLES Table 1. Coral communities at 6 transects in Fagatele Bay, based on 25 18-61 quantitative point-quarter transect surveys done in July 1995. Table 2. Coral communities at 10 locations around Tutuila, American 62-98 Samoa, based on 20 quantitative point-quarter surveys done in July 1995. Table 3. Abundance of hermatypic corals (colonies per m2) in Fagatele Bay 99 National Marine Sanctuary in April 1985, April 1988, and July 1995. Table 4. Percent cover of substrata by hermatypic corals in Fagatele Bay 100 National Marine Sanctuary in April 1985, April 1988, and July 1995. Table 5. Mean coral colony diameter (cm) in Fagatele Bay National Marine 101 Sanctuary in April 1985, April 1988 and July 1995. Table 6. Abundance (number per m2) of hermatypic coral colonies at 12 102-104 sites around Tutuila Island in April 1982, April 1985, April 1988, and July 1995 at two depths at each site. Table 7. Percent cover of substrata by hermatypic coral colonies at 12 sites 105-107 around Tutuila Island in April 1982, April1985, April 1988, and July 1995 at two depths at each site. Table 8. Mean diameter (cm) of hermatypic coral colonies at 12 sites 108-110 around Tutuila Island in April 1982, April 1985, April 1988, and July 1995 at two depths at each site. Table 9. Densities of macroinvertebrates occurring on the forereef slope at 115-116 Transects 1 and 2 (Figure 2) in Fagatele Bay. Data are means ± standard deviations of taxa observed in six 10-m2 quadrats, except where noted. Table 10. Densities of macroinvertebrates occurring on the forereef slope at 117-118 Transect 3 and 4 at Fagatele Bay. Data are means ± standard deviations of taxa observed in six 10-m2 quadrats. Table 11. Densities of macroinvertebrates occurring on the forereef slope at 119-120 Transects 5 and 6 in Fagatele Bay. Data are means ± standard deviations of taxa observed in six 10-m2 quadrats, except where noted. Page ii Table 12. Densities of macroinvertebrates occuring on the reef flat at 121-122 Transects 3 and 4 in Fagatele Bay. The reef at Transect 3 was 90 m in width and, therefore, consisted of 18 quadrats; the reef flat at Transect 4 was 145 m and consisted of 29 quadrats. Data are means + standard deviations of taxa observed in 10 m2 quadrats. Table 13. Densities of macroinvertebrates occurring on the forereef slope at 122 Sites 1 to 4 (Figure1) around Tutuila, American Samoa. Data are means ± standard deviations of taxa observed in six 10-m2 quadrats. Table 14. Densities of macroinvertebrates occurring on the forereef slope at 123-124 Sites 7 to 12 (Figure1) around Tutuila, American Samoa. Data are means ± standard deviations of taxa observed in six 10-m2 quadrats, except where noted. Table 15. Species list of non-scleractinian macroinvertebrates observed 125-127 adjacent to transects at 11 sites (see Figure 1) around Tutuila, American Samoa. Presence of a species is denoted by the symbol *. Table 16. Frequency and percent cover of the benthic flora in Fagatele Bay, 130-133 American Samoa. Plain numbers indicate percent cover, numbers in parenthesis indicate frequency of occurrence converted to percent (see Methods in text). Algal species occurring epiphytically on other algae or occurring in the vicinity of the transect are marked with and X. Table 17. Frequency and precent cover of the benthic flora in Fagatele Bay, 134-137 American Samoa (Transects 4, 5, 6). Plain numbers indicate percent cover, numbers in parenthesis indicate frquency of occurrence converted to percent (see Methods in text). Algal species occurring epiphytically on other algae or in the vicinity of the transect are marked with an X. Table 18. Frequency and percent cover of the benthic flora along 10 138-141 transects in 5 different bays of American Samoa. Plain numbers indicate percent cover, numbers in parenthesis indicate frequency of occurrence converted to percent (see Methods in text). Algal species occurring epiphytically on other algae or occurring in the vicinity of the transect are marked with an X. Table 19. Summary of mean percent cover and standard deviation of algae 142 at different depths in Fagatele Bay of the 1985 and 1995 survey. Table 20. Summary of mean percent cover and standard deviation of algae 142 at the Permanent Transects 1 - 6 at Fagatele Bay of the 1985 and 1995 survey. Page iii Table 21. Summary of overall percent algal and coralline algal cover in 5 143 days of American Samoa from the 1985 and 1995 survey. Table 22a. Fishes censused on the reef slope at Fagatele Bay in 1995, Sites 159-165 1 and 2. Numbers indicate the number of individuals of each species counted on the transect, and the letter P indicates the presence of a species in the vicinity of the transect lines. Table 22b. Fishes censused on the reef slope at Fagatele Bay in 1995, Sites 166-174 3 and 4. Numbers indicate the number of individuals of each species counted on the transect, and the letter P indicates the presence of a species in the vicinity of the transect lines. Table 22c. Fishes censused on the reef slope at Fagatele Bay in 1995, Sites 175-181 5 and 6. Numbers indicate the number of individuals of each species counted on the transect, and the letter P indicates the presence of a species in the vicinity of the transect lines. Table 23. Fishes censused on the reef flat at Fagatele Bay in 1995. 182-188 Numbers indicate the number of individuals of each species counted on the transect, and the letter P indicates the presence of a species in the vicinity of the transect line. Table 24a. Fishes censused on transects at various sites around Tutuila 189-197 Island in 1995: Masefau inside, Masefau outside, Aoa and Onenoa. Numbers indicate the number of individuals of each species counted on the transect, and the letter P indicates the presence of a species in the vicinity of the transect line. Table 24b. Fishes censused on transects at various sites around Tutuila 198-206 Island in 1995: Fagafue, Massacre Bay, Rainmaker and Fatu Rock. Numbers indicate the number of individuals of each species counted on the transect, and the letter P indicates the presence of a species in the vicinity of the transect line. Table 24c. Fishes censused on transects at various sites around Tutuila 207-213 Island in 1995:. Numbers indicate the number of individuals of each species counted on the transect, and the letter P indicates the presence of a species in the vicinity of the transect line. Table 25. Fishes censused along 100-m transects on the reef slopes at 214-220 Fatatele Bay, Sita Bay, and Cape Larsen in 1995. Numbers indicate the number of individuals of each species counted on the transect, and the letter P indicates the presence of a species in the vicinity of the transect line. Page iv Table 26. Total species richness and abundance of fishes recorded on the 221 reef slope transects in Fagatele Bay in each year of the survey. Where: Area = total area surveyed each year. Table 27. Summary of the number of transects surveyed on the reef flat and 221 reef slope at each depth in Fagatele Bay in each year. Table 28. The frequency of occurrence for the orange band disease and grey 223 sponge per quadrant for Transects 1-6.