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ANNUAL REPORT 2017 Smith TB, Ennis RS, Kadison E, Brandtneris VW, Canals M, Mukherjee S, Nemeth RS, Henderson LM The United States Virgin Islands TERRITORIAL CORAL REEF MONITORING PROGRAM A collaboration between: The Center for Marine and Environmental Studies, University of the Virgin Islands The Division of Coastal Zone Management, USVI Department of Planning and Natural Resources The Coral Reef Conservation Program, National Oceanic and Atmospheric Administration Special Thanks To: Brandt ME, Byrne I, Ewen K, Gutting A, Heidmann S, Hollister K, Jerris K, Jobsis P, Potts C, Prosterman S, Taylor M, Tonge R, Townsend J, and the 2018 NSF RAPID Sponge Cruise INDEX i © 2017 Cite As: Smith TB, Ennis RS, Kadison E, Brandtneris VW, Canals M, Mukherjee S, Nemeth RS, Henderson LM (2017) The United States Virgin Islands Territorial Coral Reef Monitoring Program. 2017 Annual Report. University of the Virgin Islands, United States Virgin Islands 297pp INDEX ii INDEX OF TABLES XIII MISSION 14 OUR VISION 14 OBJECTIVES 14 EXECUTIVE SUMMARY 15 CORAL REEFS OF THE VIRGIN ISLANDS: MANGEMENT ACTIONS NEEDED 15 CORAL REEFS OF THE VIRGIN ISLANDS: POSITIVE SIGNS 18 THE IMPACT OF HURRICANE IRMA AND HURRICANE MARIA ON CORAL HABITATS OF THE US VIRGIN ISLANDS 21 UPDATE: INVASION OF THE INDO-PACIFIC RED LIONFISH 27 IMPROVED SIGNS FOR THE THREATENED NASSAU GROUPER 32 EMERGENCE OF THE INVASIVE RED ALGAE RAMICRUSTA SPP. 36 INTRODUCTION 41 OBJECTIVES FOR MONITORING CORAL REEFS 44 METHODS 48 BENTHIC ASSESSMENTS 48 FISH CENSUS 54 TERRITORIAL CORAL REEF MONITORING SUMMARY 56 BENTHIC COMMUNITIES AND CORAL REEF HEALTH 57 CORAL COVER 57 EPILITHIC ALGAL COMMUNITY COVER 61 MACROALGAL COVER 63 INDEX iii FILAMENTOUS CYANOBACTERIA 65 GORGONIAN AND ANTIPATHARIAN COVER 67 SPONGE COVER 69 FISH COMMUNITIES 71 FISH ABUNDANCE 74 FISH BIOMASS 76 BLACK SPINY SEA URCHIN DIADEMA ANTILLARUM 79 SITE SUMMARIES 81 RATIONALE 81 SITE SUMMMARY ELEMENTS 81 ST. CROIX 85 BUCK ISLAND, ST. CROIX 87 CANE BAY 93 CANE BAY DEEP 99 CASTLE 105 EAGLE RAY 111 GREAT POND 117 JACKS BAY 123 KINGS CORNER 131 LANG BANK EAST END MARINE PARK 137 LANG BANK RED HIND FISH SPAWNING AGGREGATION 143 MUTTON SNAPPER 149 SALT RIVER WEST 155 SALT RIVER DEEP 161 SPRAT HOLE 167 ST. JOHN 173 CORAL BAY 175 INDEX iv FISH BAY 181 MERI SHOAL 187 ST. THOMAS 193 BLACK POINT 195 BOTANY BAY 202 BREWERS BAY 208 BUCK ISLAND, ST. THOMAS 214 COCULUS ROCK 220 COLLEGE SHOAL 226 FLAT CAY 232 GINSBURGS FRINGE 238 GRAMMANIK TIGER 244 HIND BANK 250 LITTLE SAINT JAMES 256 MAGENS BAY 262 SAVANA ISLAND 269 SEAHORSE COTTAGE SHOAL 275 SOUTH CAPELLA 281 SOUTH WATER 287 LITERATURE CITED 293 INDEX v Index of Figures Figure 1. Partially bleached and recovering colony of Siderastrea siderea at Flat Cay, St. Thomas (Nov. 12, 2005). ................................................................................................................................................................................................................. 16 Figure 3. The damaged research infrastructure and coral reefs of the US Virgin Islands following Hurricanes Irma and Maria in September 2017. .................................................................................................................................................... 22 Figure 5. Modeled surface (top) and seafloor (bottom) orbital velocities over Hurricane Irma (left) and Hurricane Maria (right). ........................................................................................................................................................................... 23 Figure 6. Coral reef habitats potentially damaged by storms (>2 m s-1 seafloor velocity). ......................................... 24 Figure 7. Proportions of coral reef habitat potentially damaged by storms (seafloor velocity > 2 m s-1) by depth category and island group (NUSVI = northern USVI – St. John and St. Thomas; STX = St. Croix). ............... 25 Figure 8. Indo-Pacific red lionfish (Pterois volitans) on Seahorse Cottage Shoal, 2017; depth 22m. ..................... 28 Figure 9. The abundance (±SEM) of red lionfish on TCRMP transects from 2011 to 2018. ........................................ 31 Figure 10. Nassau grouper on the Grammanik Bank, St. Thomas during spawning season. ...................................... 32 Figure 11. Nassau grouper observed across all northern USVI sites on belt transects, conducted annually from 2003-2017. ....................................................................................................................................................................................................... 33 Figure 12. Maximum number of Nassau grouper observed on a single point count during the spawning season (January- April) on the Grammanik Bank from 2002 through 2018. .................................................................................... 35 Figure 13. Representative photos of Ramicrusta spp. overgrowing Orbicella faveolata (A), Orbicella annularis (B), Orbicella annularis (C), and Millepora alcicornis (D) at the TCRMP location Savana. ........................................ 37 Figure 14. Abundance of Ramicrusta sp. presence in non-overlapping video clips at TCRMP locations in 2016. .............................................................................................................................................................................................................................. 38 Figure 15. Benthic cover (±SEM) of Ramicrusta sp., coral, epilithic algae community, and fleshy macroalgae at Savana from 2003-2016. ........................................................................................................................................................................... 39 Figure 16. Locations of Territorial Coral Reef Monitoring Sites in the US Virgin Islands. Boundaries indicate federal and territorial marine protected areas. .............................................................................................................................. 46 Figure 17. A screen grab of benthic video used for the determination of percent cover of coral reef organisms and non-living substrate. ........................................................................................................................................................................... 50 Figure 18. Coral cover (±SE) across TCRMP monitoring sites over time. ............................................................................ 60 Figure 19. Epilithic Algal Community cover (±SE) across TCRMP monitoring sites over time. ................................ 62 Figure 20. Macroalgae cover (±SE) across TCRMP monitoring sites over time. .............................................................. 64 Figure 21. Filamentous cyanobacteria cover (±SE) across TCRMP monitoring sites over time. .............................. 66 INDEX vi Figure 22. Gorgonian and Antipatharian cover (±SE) across TCRMP monitoring sites over time. ......................... 68 Figure 23. Sponge cover (±SE) across TCRMP monitoring sites over time. ........................................................................ 70 Figure 24. Fish abundance (±SE) across TCRMP monitoring sites over time. St. Croix sites are to the left and northern USVI to the right on the x-axis. ............................................................................................................................................ 75 Figure 25. Mean fish biomass (±SE) across TCRMP monitoring sites over time. St. Croix sites are to the left and northern USVI to the right on the x-axis. ............................................................................................................................................ 77 Figure 26. Mean abundance (±???) of fish counted on surveys conducted at eight sites before and after the 2017 hurricanes. Abundance was lower at most sites both directly after the storms and several months later. Pre-storm data for St. James is from 2016. Numbers above bars indicate sample size. ................................................ 78 Figure 27. Mean biomass (±???) of fish on surveys conducted at eight sites before and after the 2017 hurricanes. Biomass appeared to drop after the storms but increased to pre-storm levels by April 2018. Pre- storm data for St. James is from 2016. Numbers above bars indicate sample size. ......................................................... 78 Figure 28. Abundance of the black spiny sea urchin (Diadema antillarum) at TCRMP monitoring sites. Note the log scale. .................................................................................................................................................................................................... 80 Figure 29. The Buck Island, St. Croix. (top) Position in the Buck Island Reef National Monument. (right)A representative photo. .................................................................................................................................................................................. 87 Figure 30. Buck Island, St. Croix benthic temperatures (14 m depth). Data provided by the National Park Service (site BUIS_SFR). ............................................................................................................................................................................. 88 Figure 31. Buck Island, St. Croix. (left) Relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. .................................................... 89 Figure 32. Buck Island, St. Croix benthic cover and coral health through time (mean ± SE). .................................... 90 Figure 33. The Buck Island, St. Croix fish community by absolute and relative biomass. ............................................ 92 Figure 34. Cane Bay. (top) Location. (right) A representative photo of the reef. ........................................................... 93 Figure 35. Cane Bay benthic temperatures (8 m depth) ............................................................................................................ 94 Figure 36. Cane Bay. (left) Relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. ..................................................................................... 95 Figure 37. Cane Bay benthic cover and coral health through time (mean ± SE). ............................................................ 96 Figure 38. The Cane Bay fish community by absolute and relative biomass. .................................................................... 98 Figure 39. Cane Bay Deep. (top) Location. (right) A representative photo of the reef during the 2005 bleaching event. Bleached colonies are 0.5 – 3 m wide. .............................................................................................................. 99 Figure 40. Cane Bay Deep temperature (39 m depth). ............................................................................................................. 100 Figure 41. Cane Bay Deep. (left) Relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. ................................................................ 101 INDEX vii Figure 42. Cane Bay Deep benthic cover and coral health through time (mean ± SE). ............................................. 102 Figure 43. The Cane Bay Deep fish community by absolute and relative biomass. ..................................................... 104 Figure 44. Castle. (top) Location. (right) A representative photo of the reef. ............................................................... 105 Figure 45. Castle benthic temperatures (9 m depth). ............................................................................................................... 106 Figure 46. Castle. (left) Relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. .................................................................................. 107 Figure 47. Castle benthic cover and coral health through time (mean ± SE). ................................................................ 108 Figure 48. The Castle fish community by absolute and relative biomass. ........................................................................ 110 Figure 49. Eagle Ray. (top) Location. (right) A representative photo of the reef. ....................................................... 111 Figure 50. Eagle Ray benthic temperature at 9 m depth ........................................................................................................ 112 Figure 51. Eagle Ray. (left) Relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. .................................................................................. 113 Figure 52. Eagle Ray benthic cover and coral health through time (mean ± SE). ....................................................... 114 Figure 53. The Eagle Ray fish community by absolute and relative biomass. ................................................................ 116 Figure 54. Great Pond. (top) Location. (right) A representative photo of the reef. .................................................... 117 Figure 55. Great Pond benthic temperature (5 m depth). ...................................................................................................... 118 Figure 56. Great Pond (left) Relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. .................................................................................. 119 Figure 57. Great Pond benthic cover and coral health through time (mean ± SE). ..................................................... 120 Figure 58. The Great Pond fish community by absolute and relative biomass. ............................................................. 122 Figure 59. Jacks Bay. (top) Location. (right) A representative photo of the reef. ........................................................ 124 Figure 60. Jacks Bay benthic temperature at 12 m depth ....................................................................................................... 125 Figure 61. Jacks Bay (left) relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. .................................................................................. 126 Figure 62. Jacks Bay benthic cover and coral health through time (mean ± SE). ........................................................ 127 Figure 63. The Jacks Bay fish community by absolute and relative biomass. ................................................................ 129 Figure 64. Kings Corner. (top) Location. (right) A representative photo of the reef with a school of lane snapper (Lutjanus synagris). ................................................................................................................................................................ 131 Figure 65. Kings Corner benthic temperature (17 m depth) ................................................................................................. 132 Figure 66. Kings Corner (left) Relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. ................................................................ 133 Figure 67. Kings Corner benthic cover and coral health through time (mean ± SE). ................................................. 134 Figure 68. The Kings Corner fish community by absolute and relative biomass. ......................................................... 136 INDEX viii Figure 69. Lang Bank EEMP. (top) Location. (right) A representative photo of the reef. ........................................ 137 Figure 70. Lang Bank EEMP benthic temperature (28 m depth) ........................................................................................ 138 Figure 71. Lang Bank East End Marine Park (left) relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. ...................... 139 Figure 72. Lang Bank EEMP benthic cover and coral health through time (mean ± SE). ........................................ 140 Figure 73. The Lang Bank EEMP fish community by absolute and relative biomass. ................................................ 142 Figure 74. Lang Bank Red Hind FSA. (top) Location. (right) A representative photo of the reef ......................... 143 Figure 75. Lang Bank Hind current speed (left) and benthic temperature (right; 33 m depth) ........................... 144 Figure 76. Lang Bank Red Hind FSA (left) Relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. ................................................. 145 Figure 77. Lang Bank Red HindFSA benthic cover and coral health through time (mean ± SE). .......................... 146 Figure 78. The Lang Bank Red Hind FSA fish community by absolute and relative biomass. ................................. 148 Figure 79. Mutton Snapper. (top) Location. (right) A representative photo of the reef taken in 2014. ............ 149 Figure 80. Mutton Snapper benthic temperature record at 23 m (left) and 39 m depth (right). ......................... 150 Figure 81. Mutton Snapper (left) Relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. ................................................................ 151 Figure 82. Mutton Snapper benthic cover and coral health through time (mean ± SE). .......................................... 152 Figure 83. The Mutton Snapper fish community by absolute and relative biomass. .................................................. 154 Figure 84. Salt River. (top) Location. (right) A representative photo of the reef with TCRMP researcher recording coral health data (Oct. 1, 2015). .................................................................................................................................... 155 Figure 85. Salt River West surface-benthic temperature record 5m depths. Data provided by the NOAA ICON monitoring network. ................................................................................................................................................................................ 156 Figure 86. Salt River West (left) Relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. ................................................................ 157 Figure 87. Salt River West benthic cover and coral health through time (mean ± SE). ............................................. 158 Figure 88. The Salt River West fish community by absolute and relative biomass. ..................................................... 160 Figure 89. Salt River Deep. (top) Location. (right) A representative photo of the reef with TCRMP team (Oct. 1, 2015). ......................................................................................................................................................................................................... 161 Figure 90. Salt River Deep benthic temperature at 30 m depth (left) and 40 m depth (right). ............................. 162 Figure 91. Salt River Deep (left) Relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. ................................................................ 163 Figure 92. Salt River Deep benthic cover and coral health through time (mean ± SE). ............................................ 164 Figure 93. The Salt River Deep fish community by absolute and relative biomass. .................................................... 166 INDEX ix Figure 94. Sprat Hole. (top) Location. (right) A representative photo of the reef. ..................................................... 167 Figure 95. Sprat Hole benthic temperature (7 m depth). ........................................................................................................ 168 Figure 96. Sprat Hole (left) Relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. .................................................................................. 169 Figure 97. Sprat Hole benthic cover and coral health through time (mean ± SE). ...................................................... 170 Figure 98. The Sprat Hole fish community by absolute and relative biomass. .............................................................. 172 Figure 99. Coral Bay. (top) Location. (right) A representative photo of the reef. ....................................................... 175 Figure 100. Coral Bay benthic temperature (9 m depth) ........................................................................................................ 176 Figure 101. Coral Bay (left) Relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. .................................................................................. 177 Figure 102. Coral Bay benthic cover and coral health through time (mean ± SE). ..................................................... 178 Figure 103. The Coral Bay fish community by absolute and relative biomass. ............................................................. 180 Figure 104. Fish Bay. (top) Location. (right) A representative photo of the reef. ....................................................... 181 Figure 105. Fish Bay benthic temperature record (6 m depth). ........................................................................................... 182 Figure 106. Fish Bay (left) Relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. .................................................................................. 183 Figure 107. Fish Bay benthic cover and coral health through time (mean ± SE). ........................................................ 184 Figure 108. The Fish Bay fish community by absolute and relative biomass. ................................................................ 186 Figure 109. Meri Shoal. (top) Location. (right) A representative photo of the reef during the 2005 coral bleaching event (Oct. 6, 2005). The brain coral in the foreground is 1.8 m wide. ...................................................... 187 Figure 110. Meri Shoal benthic temperature record (30 m depth). ................................................................................... 188 Figure 111. Meri Shoal (left) Relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. ................................................................ 189 Figure 112. Meri Shoal benthic cover and coral health through time (mean ± SE). ................................................... 190 Figure 113. The Meri Shoal fish community by absolute and relative biomass. ........................................................... 192 Figure 114. Black Point. (top) Location. (right) A representative photo of the reef. ................................................. 195 Figure 115. Black point current speed and benthic temperature record (8 m depth). .............................................. 196 Figure 116. Black Point chlorophyll (left) and turbidity (right) record (16 m depth). .............................................. 197 Figure 117. Black Point. (left) Relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. ................................................................ 198 Figure 118. Black Point benthic cover and coral health through time (mean ± SE). .................................................. 199 Figure 119. The Black Point fish community by absolute and relative biomass. .......................................................... 201 Figure 120. Botany Bay. (top) Location. (right) A representative photo of the reef. ................................................. 202 INDEX x Figure 121. Botany Bay benthic temperature record (11 m depth). .................................................................................. 203 Figure 122. A large colony of pillar coral (Dendrogyra cylindricus) dislodge, toppled, and diseased after the 2009 swell event (Botany Bay, June 25, 2009). ............................................................................................................................. 203 Figure 123. Botany Bay. (left) Relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. ................................................................ 204 Figure 124. Botany Bay benthic cover and coral health through time (mean ± SE). .................................................. 205 Figure 125. The Botany Bay fish community by absolute and relative biomass. .......................................................... 207 Figure 126. Brewers Bay. (top) Location. (right) A representative photo of the reef. ............................................... 208 Figure 127. Brewers Bay. (left) Relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. ................................................................ 210 Figure 128. Brewers Bay benthic cover and coral health through time (mean ± SE) ................................................ 211 Figure 129. The Brewers Bay fish community by absolute and relative biomass. ....................................................... 213 Figure 130. Buck Island, St. Thomas. (top) Location. (right) A representative photo of the reef. ....................... 214 Figure 131. Buck Island, St. Thomas benthic temperature record (12 m depth). ........................................................ 215 Figure 132. Buck Island, St. Thomas. (left) Relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. ................................................. 216 Figure 133. Buck Island, St. Thomas benthic cover and coral health through time (mean ± SE). ........................ 217 Figure 134. The Buck Island, St. Thomas fish community by absolute and relative biomass. ................................ 219 Figure 135. Coculus Rock. (top) Location. (right) A representative photo of the reef showing the aggregation of redfin parrotfish. ................................................................................................................................................................................... 220 Figure 136. Coculus Rock benthic temperature record (7 m depth). ................................................................................. 221 Figure 137. Coculus Rock. (left) Relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. ................................................................ 222 Figure 138. Coculus Rock benthic cover and coral health through time (mean ± SE). .............................................. 223 Figure 139. The Coculus Rock fish community by absolute and relative biomass. ...................................................... 225 Figure 140. College Shoal. (top) Location. (right) A representative photo of the reef. ............................................. 226 Figure 141. College Shoal benthic temperature record (29 m depth). .............................................................................. 227 Figure 142. College Shoal (left) Relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. ................................................................ 228 Figure 143. College Shoal benthic cover and coral health through time (mean ±SE). ............................................... 229 Figure 144. The College Shoal fish community by absolute and relative biomass. ...................................................... 231 Figure 145. Flat Cay. (top) Location. (right) A representative photo of the reef. ........................................................ 232 Figure 146. Flat Cay benthic current speed (left) and temperature record (right) (14 m depth). ....................... 233 INDEX xi Figure 147. Flat Cay (left) Relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. .................................................................................. 234 Figure 148. Flat Cay benthic cover and coral health through time (mean ± SE). ........................................................ 235 Figure 149. The Flat Cay fish community by absolute and relative biomass. ................................................................ 237 Figure 150. Ginsburgs Fringe. (top) Location. (right) A representative photo of the reef showing whorled lettuce coral colonies up to 7m in width and research diver filming permanent transect in background (Nov. 13, 2015). ....................................................................................................................................................................................................... 238 Figure 151. Ginsburgs Fringe current speed (50 m depth) and benthic temperature (63 m depth). BT = bleaching threshold ; DHW = degree heating weeks . ................................................................................................................ 239 Figure 152. Ginsburgs Fringe. (left) Relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. ................................................................ 240 Figure 153. Ginsburgs Fringe benthic cover through time (mean ± SE). ......................................................................... 241 Figure 154. The Ginsburgs Fringe fish community by absolute and relative biomass. ............................................... 243 Figure 155. Grammanik Tiger (top) Location. (right) A representative photo of the reef. .................................... 244 Figure 156. Grammanik Tiger benthic currents speed and temperature record (38 m depth). ............................ 245 Figure 157. Grammanik Tiger FSA. (left) Relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. ................................................. 246 Figure 158. Grammanik Tiger benthic cover and coral health through time (mean ± SE). .................................... 247 Figure 159. The Grammanik Tiger fish community by absolute and relative biomass. ............................................ 249 Figure 160. Hind Bank (top) Location. (right) A representative photo of the reef. ................................................. 250 Figure 161. (top) Hind Bank benthic current speed (40m depth). (bottom) Benthic temperature record at 40 m depth. ......................................................................................................................................................................................................... 251 Figure 162. Hind Bank. (left) Relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. ................................................................ 252 Figure 163. Hind Bank benthic cover and coral health through time (mean ± SE). ................................................... 253 Figure 164. The Hind Bank East fish community by absolute and relative biomass. ................................................. 255 Figure 165. Little St. James. (top) Location. (right) A representative photo of the reef with derelict fish trap ........................................................................................................................................................................................................................... 256 Figure 166. Little St. James benthic temperature record (19 m depth). ........................................................................... 257 Figure 167. Little St. James. (left) Relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. ................................................................ 258 Figure 168. Little St. James benthic cover and coral health through time (mean ± SE). ........................................... 259 Figure 169. The Little St. James fish community by absolute and relative biomass. ................................................... 261 INDEX xii Figure 170. Magens Bay. (top) Location. (right) A representative photo of the reef. ............................................... 262 Figure 171. Magens Bay current speed and benthic temperature record (9 m depth). ............................................ 263 Figure 172. Magens Bay chlorophyll (left) and turbidity (right) record (16 m depth). ............................................ 264 Figure 173. Magens Bay. (left) Relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. ................................................................ 265 Figure 174. Magens Bay benthic cover and coral health through time (mean ± SE). ................................................ 266 Figure 175. The Magens Bay fish community by absolute and relative biomass. ........................................................ 268 Figure 176. Savana. (top) Location. (right) A representative photo of the reef showing large colonies of Orbicella faveolata (Nov. 17, 2015). .................................................................................................................................................. 269 Figure 177. Savana benthic temperature record (10 m depth). .......................................................................................... 270 Figure 178. Savana Island. (left) Relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. ................................................................ 271 Figure 179. Savana Island benthic cover and coral health through time (mean ± SE). ............................................ 272 Figure 180. The Savana Island fish community by absolute and relative biomass. ................................................... 274 Figure 181. Seahorse Cottage Shoal. (top) Location. (right) A representative photo of the reef. ........................ 275 Figure 182. Seahorse benthic temperature record (21 m depth). ....................................................................................... 276 Figure 183. Seahorse Cottage Shoal. (left) Relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. ................................................. 277 Figure 184. Seahorse Cottage Shoal benthic cover and coral health through time (mean ± SE). ......................... 278 Figure 185. The Seahorse Cottage Shoal fish community by absolute and relative biomass. ................................. 280 Figure 186. South Capella. (top) Location. (right) The reef with a derelict Antillean fish trap in Transect #1. ........................................................................................................................................................................................................................... 281 Figure 187. South Capella benthic temperature record (24 m depth). ............................................................................. 282 Figure 188. South Capella. (left) Relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. ................................................................ 283 Figure 189. South Capella benthic cover and coral health through time (mean ± SE). ............................................. 284 Figure 190. The South Capella fish community by absolute and relative biomass. ..................................................... 286 Figure 191.South Water. (top) Location. (right) A representative photo of the reef. ................................................ 287 Figure 192. South Water benthic temperature record (24 m depth) ................................................................................. 288 Figure 193. South Water. (left) Relative composition of the sessile epibenthic animal community. (right) Relative composition of the algal community and unconsolidated sediment. ................................................................ 289 Figure 194. South Water benthic cover and coral health through time (mean ± SE). ............................................... 290 Figure 195. The South Water fish community by absolute and relative biomass. ....................................................... 292 INDEX xiii Index of Tables Table 1. TCRMP site reef complex type, location coordinates (decimal degrees; WGS 1984), and depths. FSA = Fish Spawning Aggregation. EEMP = East End Marine Park. .................................................................................................. 51 Table 2. TCRMP site sampling data (benthic/health) and type of sampling. Pre and post-storms sample dates refer to surveys completed prior to the passage of Hurricanes Irma (9/6/17) and Maria (9/19/17). Incomplete surveys indicated by “-“ while completed surveys indicated by “X”. ........................................................................................ 52 Table 3. The 2017/18 species richness for belt transects and roving diver surveys (RDS). Sites are divided into nearshore, offshore, and mesophotic sites as described in the text. ....................................................................................... 73 MISSION 14 Mission OUR VISION To provide critical information on the status and threats to all Virgin Islands coral reef ecosystems, increasing management effectiveness and improving basic and applied coral reef research OBJECTIVES • Monitor the status and trajectories of coral reefs across a majority of habitats and threats, including land-based sources of pollution & thermal stress • Link changes in coral reef health with specific stressors, indicating specific management interventions most effective for preserving reefs • Integrate assessments of understudied mesophotic coral reef ecosystems and threatened species in the USVI • Provide data, outputs, and advice to stakeholders and create a nexus of information for reef research EXECUTIVE SUMMARY 15 Executive Summary Coral reefs in the Caribbean are facing a dramatic decline and are at a crossroads. Management decisions made today will affect the goods and services that reefs provide for decades to come. The government of the United States Virgin Islands (USVI), in coordination with the NOAA Coral Reef Conservation Program and the University of the Virgin Islands, implemented the Territorial Coral Reef Monitoring Program (TCRMP). The TCRMP has established baseline conditions and temporal trends of coral reefs and fish populations and has identified threats that will influence the future reef health and development. A major focus of the TCRMP is to provide information that can lead to more effective management strategies that balance the immediate needs of the Virgin Island’s population with preservation and sustainability of coral reefs and the renewable goods and services they provide. The intent of this report is to distill monitoring data into actionable information that can guide management decisions and inform the public and policy-makers about areas that need further effort. This executive summary presents information on threats to USVI reefs that require management intervention/action as well as positive signs that can inform our understanding of sustainability. CORAL REEFS OF THE VIRGIN ISLANDS: MANGEMENT ACTIONS NEEDED The TCRMP data has identified threats to USVI coral reef ecosystems that need increased management attention if reef corals are to persist in a condition that is equal to or better than current conditions. Coral Reef Bleaching. High thermal stress caused by climate change is currently the greatest threat to USVI coral reef ecosystems. The 2005 coral bleaching event caused the EXECUTIVE SUMMARY 16 largest loss of coral in the documented history of the USVI, with a 50% decline in coral cover in shallow waters less than 25m/85’ deep (Smith et al. 2013b; Smith et al. 2016a). This event surpassed all known modern impacts from physical damage (storms and anchoring), ecosystem changes (fishing and disease), and pollution (terrestrial sediments and toxins). These events are predicted to increase with a warming planet, troubling news for the USVI. While local management actions cannot remove impacts to reefs from global warming, reefs that are otherwise less stressed by land-based sources of pollution, fishing, and/or physical damage are known to recover more quickly from bleaching. Hence, local management actions that promote seascape-wide coral reef health offer the best strategy for sustainable reefs. We can also identify areas that are naturally more resistant to thermal stress and offer these areas further protection, since they offer insurance against the worst possible future outcomes for USVI reefs. Figure 1. Partially bleached and recovering colony of Siderastrea siderea at Flat Cay, St. Thomas (Nov. 12, 2005). EXECUTIVE SUMMARY 17 Overfishing. There are clear indications that reefs of the USVI are suffering the effects of overexploitation of reef resources, although there are also positive signs. The entire district of St. Croix has an extremely low abundance of commercially important grouper species, including the threatened Nassau grouper (Kadison et al. 2017). In St. John and St. Thomas, many common species have completely or nearly disappeared from nearshore waters in the last 30 years. For example, a study conducted by Rogers et al. (1982) on the southwest coast of St. Thomas during the airport runway expansion (1979- 1981) found a variety of species that are no longer encountered or are rare, including the black, Nassau, tiger, and yellowfin groupers, as well as the federally protected parrotfish species blue, midnight, and rainbow. A study by Randall (1963) also found high relative abundances of groupers and threatened parrotfish on the south coast of St. John. Rebuilding these fish stocks will require comprehensive life-history information for target species, a willingness to find strategies to rebuild stocks, and partnerships between commercial and recreational fishers, community stakeholders and managers. Land-Based Source of Pollution. The steep hillsides of the USVI are natural conduits for run-off during heavy rain events and in many instances there is little interception of materials before they reach the sea and impact coral reefs. When tropical soils are naturally disturbed or altered through human activity, they can erode and release fine- grained silt and clay particles. In the USVI, these fine-grained particles are quickly transported to coral reefs where they can block sunlight, directly smother corals, or increase the growth of organisms that compete with corals for space. There is evidence from the TCRMP that terrestrial sediments are having large negative impacts on nearshore coral reefs by increasing mortality of ecologically important corals (Henderson et al. in press). EXECUTIVE SUMMARY 18 CORAL REEFS OF THE VIRGIN ISLANDS: POSITIVE SIGNS Despite the incredible declines in reef health witnessed since the inception of the TCRMP in 2001, there are many positive signs for the USVI that should be highlighted. These successes offer lessons that can be applied to troubled reefs and may indicate refuge areas where we might “double-down” on current management strategies. Reef Refuges. The USVI is blessed, perhaps uniquely for the Caribbean, with extensive areas of deep bank and slope reefs that may be buffered from the direct impacts of local pressures (Smith et al. 2019a,b). The mesophotic (pronounced: me-zo-photik; meaning; “middle-light”) reefs of the USVI are the best developed in the Caribbean from what is currently known. Mesophotic Coral Ecosystem (MCE) bank reefs with high populations of star corals (Orbicella spp.), which have recently been listed as threatened on the United States Endangered Species List (NOAA 2014), form extensive tracts on the south shelf of St. John and St. Thomas, from the British Virgin Islands to Vieques, Puerto Rico. Well- formed, but patchier mesophotic boulder coral reefs also form on the Lang Bank, St. Croix and the northern Puerto Rican Shelf. The lower MCE consists mostly of lettuce corals (primarily Agaricia undata) and form a semi-continuous ring on steep slopes and walls at depths between 50-70m. These reef are isolated from some local impacts, but may be susceptible to global climate change (see below). In federal waters some of these areas are wholly or partly protected from fishing of ecologically important species that help maintain reef health. These include the Red Hind Marine Conservation District (est. 1999), the Grammanik Bank Seasonally Closed Area (est. 2005), and the Lang Bank Red Hind Seasonally Closed Area (est. 1993). However, extensively developed mesophotic reef in unprotected territorial waters also exist near the island of French Cap and Sail Rock, St. Thomas District. It is important that these areas are identified, their threats assessed, and they are incorporated into the territorial and federal management planning process. EXECUTIVE SUMMARY 19 Rebounding Fisheries Species. There are positive signs of recovery for certain fish species in some areas. At the Grammanik Bank grouper spawning aggregation site there have been increasing numbers of Nassau grouper present for annual spawning (Kadison et al. 2010; Jackson et al. 2014) and a red hind aggregation in the Red Hind Marine Conservation District (MCD) has dramatically rebounded (Nemeth 2005). Red hind caught in the fishery on the south side of St. Thomas are more numerous and larger (D. Olsen, pers. comm.). In 2015 there was a recruitment pulse of juvenile Nassau grouper to shallow nearshore environments of St. Thomas and St. John in 2015. In Brewers Bay, St. Thomas over 70 juvenile Nassau grouper were recorded (R. Nemeth, unpub. data), increasing evidence that the reproductive population is contributing to the recovery of the species. It is also the impression of the authors that stocks of grouper and snapper are increasing in the MCD, although TCRMP measurements are confounded to some degree by the rotating array of aggregating fishes. Other territorial and federal closed areas in St. Croix, St. John, and St. Thomas are more recently established and may not show effects for several years. Although uncommon, Nassau grouper have been seen around St. Croix since 2011, a positive sign. For species that are completely protected from fishing (Nassau grouper and blue, midnight, and rainbow parrotfish), educational campaigns for recreational and commercial fisherman are critical, as awareness of regulations appears to be lacking (Authors, unpub. obs.). Land-based source of pollution. While development of steep island slopes has continued despite current regulations intended to prevent sediments from entering nearshore waters, research has identified key targets for restoration and some effective habitat restoration best-management practices. Results from TCRMP research suggest that there are certain levels of silt-laden terrestrial run-off that are damaging to corals, providing a target for reductions of sediment in the marine environment (Henderson et al. 2019). Unpaved road segments have been implicated as the worst culprits in the production of sediment-laden run-off (Ramos-Scharrón and MacDonald 2007b) and this provides a EXECUTIVE SUMMARY 20 clear target for where management can be most effectively applied. Restoration of watersheds has shown that implementation of best-management practices and control structures can be effective in reducing sedimentation. For example, the American Recovery and Reinvestment Act project “USVI Coastal Habitat Restoration Through Watershed Stabilization” showed promising results (Virgin Islands Resource Conservation and Development Council; P.I. M. Taylor). This report presents results of the 17th year of monitoring on reefs surrounding St. Croix, St. John, and St. Thomas (years 2001-2018). This year of monitoring was impacted by the passage of Hurricane Irma and Hurricane Maria in September 2017, before the initiation of monitoring. Due to heavy damage to the territory and to the UVI marine science facilities, in particular, monitoring scheduled for October – December 2017 was not completed until the spring of 2018. Monitoring sites were distributed across the insular platform in depths from 5 to 63 m (16 – 220’) in an effort to capture the diversity of reef types present in the Virgin Islands. Long-term data is presented from 33 sites. While not exhaustive, the TCRMP is generally representative of the geographic areas and variety of reef types in the USVI. Digital video and diver surveys were used to quantify benthic cover and coral health at 14 permanent sites surrounding the island of St. Croix and 19 permanent sites on the Puerto Rican Shelf surrounding the island of St. John and St. Thomas. In addition, at 32 of these sites sea urchin density and fish community structure were evaluated. All data is now available at the TCRMP website and updated annually after quality control: https://sites.google.com/site/usvitcrmp/home