USVI Public Records

Document text

SITE  SUMMARIES       157   St.  John     ST.  JOHN         158     SITE  SUMMARIES       159   CORAL  BAY   Descrip(on.    The  Coral  Bay  site  is  atop  a   patch  reef  complex  at  the  southeast   mouth  of  Coral  Harbor.    The  reef  is  a  low   carbonate  build  up  with  high  coral   diversity.    Coral  Bay  appears  to  be  a  true   reef  with  a  well-­‐developed  carbonate   framework  over  bedrock.    Coral  Bay   monitoring  was  initiated  in  2011.   Outstanding  Feature.    Coral  Bay  supports   a  high  diversity  of  coral  and  an  apparent   high  rate  of  coral  recruitment.   Threats.    Coral  Bay  is  subject  to  land-­‐ based  sources  of  pollution,  primarily  as   sediment  influx  from  the  large  and  steep  Coral  Bay  watershed.    Recent  restoration  activities   in  the  watershed  are  expected  to  decrease  the  sediment  influx.  Coral  Bay  may  also  be   threatened  by  maritime  activities  within  Coral  Harbor.    Proximity  to  land  makes  this  site  in   territorial  waters  potentially  vulnerable  to  fishing.     Figure  85.    Coral  Bay.  (top)  Location.     (right)  A  representative  photo  of  the   reef.     CORAL  BAY         160   Figure  86.    Coral  Bay  benthic  temperature  (9  m  depth)     Physical  Characteris.cs.       Current.    Currents  have  not  been  measured  by  the  TCRMP,  however,  Dr.  Sarah  Gray   (University  of  San  Diego)  has  measured  2-­‐D  near  bottom  measurements  for  some  years   between  2009-­‐2011.    Oscillatory  currents  are  expected  to  be  light  and  only  weak   unidirectional  currents  have  been  experienced.       Temperature.    Coral  Bay  may  have  restricted  water  circulation  and  had  very  high   temperatures  during  the  2010  bleaching  event.   Other.    This  site  and  the  wider  Coral  Bay  area  have  been  under  investigation  for  land-­‐based   sources  of  pollution  impacts  since  2009.    Projects  have  been  involved  terrestrial  sediment   measurement/modeling,  marine  sediment  flux,  coral  demographic  plots,  and  biological   monitoring.      The  area  has  also  been  involved  in  water  quality  monitoring.       J F M A M J J A S O N D 24 25 26 27 28 29 30 31 2010 2011 Temperature ( oC) Month SITE  SUMMARIES       161     Benthic  Community.  Coral  Bay  has  a  very  diverse  coral  community,  with  no  clear  dominance   of  cover.    In  contrast  to  most  sites,  the  mustard  hill  coral  Porites  astreoides  has  the  greatest   cover  among  coral  species.    Sponges  and  gorgonians  are  also  very  common  at  this  site.    The   algal  community  is  dominated  by  epilithic  algae  and  a  high  abundance  of  crustose  coralline   algae,  with  very  low  abundance  of  macroalgae.    This  is  surprising  at  this  turbid  reef  site  that   likely  receives  high  inputs  of  particulate  and  dissolved  nutrient  sources,  and  indicates  that   grazing  is  quite  high.    Although  fish  communities  will  not  be  assessed  until  2012,  there  is   not  a  high  abundance  of  herbivorous  fish  and  only  the  occasional  occurrence  of  Diadema   antillarum.    However,  there  is  a  great  abundance  of  the  rock  boring  urchin  Echinometra  spp.   that  appears  to  be  the  dominant  grazer.    This  genus  is  not  monitored  in  TCRMP  protocols,   but  perhaps  should  be  included  in  future  years.   Coral  Health.    It  is  not  known  how  corals  were  affected  by  bleaching  in  2005.    There  was  a   low  prevalence  of  low  extent  bleaching  in  2011.    Diseases  were  not  recorded  in  2011.    Old   partial  mortality  prevalence  was  low  in  2011,  but  this  may  partly  be  explained  by  the  high   abundance  of  small  coral  colonies  that  are  less  prone  old  partial  mortality.    Recent   mortality  had  low  prevalence  in  2011.     Figure  87.    Coral  Bay  (left)  Relative  composition  of  the  sessile  epibenthic  animal  community.    (right)   Relative  composition  of  the  algal  community  and  unconsolidated  sediment.   CORAL  BAY         162   Figure  88.    Coral  Bay  benthic  cover  and  coral  health  through  time  (mean  ±SE).       Benthic Community Cover 0% 20% 40% 60% 80% 100% Coral Cyanobacteria Epilithic Algae Macroalgae Bleaching Prevalence/Extent 0% 20% 40% 60% 80% 100% Prevalence Extent Disease Prevalence 0% 5% 10% 15% 20% 25% 30% All disease Black Band Lesion Dark Spots Intercostal White Disease Yellow Band Unknown Partial Mortality 2001 2002 2003 2004 2005 2005 BL 2006 2007 2008 2009 2010 2011 2012 2013 Prevalence 0% 20% 40% 60% 80% 100% Old Recent SITE  SUMMARIES       163     Fish  Community.  The  Coral  Bay  site  is  relatively  low  in  fish  diversity,  biomass  and   abundance.  Although  epilithic  algae  is  prolific,  large  grazers  are  nearly  absent.  Three  spot   damselfish  dominate  the  group  in  both  abundance  and  biomass.  In  2012  planktivores  in  the   high  turbidity  habitat  were  limited  to  a  few  juvenile  yellowtail  snapper  and  pomocentrids.   Although  benthic  invertivores  were  more  prolific  and  diverse,  only  a  few  individuals   comprised  each  species  group.  Likewise  piscivores  had  a  very  low  biomass  and  were   limited  to  a  few  individuals,  most  notably  the  schoolmaster  snapper.         CORAL  BAY         164               Herbivores threespot damsel striped parrotfish redband parrotfish stoplight parrotfish princess parrotfish blue tang doctorfish dusky damsel queen parrotfish Beaugregory cocoa damsel Fish Biomass (g) 0 2000 4000 6000 8000 10000 Invertivores mutton snapper tomtate French grunt blackbar soldierfish yellowhead wrasse lane snapper shy hamlet squirrelfish butter hamlet yellowbelly hamlet indigo hamlet harlequin bass striped grunt Fish Biomass (g) 0 200 400 600 800 1000 1200 1400 1600 1800 Planktivores yellowtail snapper bicolor damsel blue chromis Fish Biomass (g) 0 200 400 600 800 1000 Piscivores schoolmaster sand diver graysby black hamlet bar jack Fish Biomass (g) 0 100 200 300 400 SITE  SUMMARIES       165   FISH  BAY   Descrip(on.    Fish  Bay  is  a   nearshore  Fringing  Reef  in   territorial  waters.    The   monitoring  site  is  a  sharp  edge  of   a  shallow  water  coral  community   dropping  to  sand  at  7  m  depth.     The  site  has  been  monitored   since  2001.   Outstanding  Feature.    Fish  Bay   inner  transects  (1  –  3)  are   heavily  sediment  impacted,  while   outer  transects  (4-­‐6)  support   large  boulder  star  corals   (Orbicella  faveolata).   Threats.    Fish  Bay  is  subjected  to   land-­‐based  sources  of  pollution     and  tends  to  have  turbid   water  and  overgrowth  by   macroalgae  on  inner   transects.    This  site  may   also  be  vulnerable  to   fishing  impacts.     Figure  89.    Coral  Bay.  (top)   Location.    (right)  A   representative  photo  of  the   reef.       FISH  BAY         166   Figure  90.    Fish  Bay  benthic  temperature  record  (6m  depth).     Physical  Characteris.cs.       Current.    Fish  Bay  currents  have  not  been  measured  directly  by  the  TCRMP.    Unidirectional   currents  are  mild  to  slack.    Because  of  the  southeast  exposure,  wave  driven  oscillatory   currents  can  be  quite  intense,  particularly  on  the  outer  transects.   Temperature.    Fish  Bay  has  relatively  high  mean  temperatures  and  was  very  far  over  the   local  bleaching  threshold  in  2010.       J F M A M J J A S O N D 24 25 26 27 28 29 30 31 2006 2009 2007 2010 2008 2011 Temperature ( oC) Month SITE  SUMMARIES       167     Benthic  Community.  The  coral  community  of  Fish  Bay  is  dominated  by  the  boulder  star  coral   Orbicella  spp..    In  particular,  large  (>2m  wide)  colonies  of  O.  faveolata  are  common  on  the   seaward  transects  (4-­‐6).    The  inner  transects  (1-­‐3)  are  mostly  depauperate  of  coral  (<  4%   cover  as  of  2011).    The  site  lost  37.1%  of  its  cover  due  to  the  2005  coral  bleaching  event,   but  had  regained  136.1%  of  cover  by  2011.    Gorgonians  are  also  very  common  on  the  wave-­‐ washed  outer  transects.    The  algal  community  is  dominated  by  equal  parts  epilithic  algae   and  the  macroalgae  Dictyota  spp.    The  site  also  has  a  high  abundance  of  Halimeda  opuntia,   which  can  be  very  abundant  on  inner  transects  closest  to  land-­‐based  sources  of  pollution.   Coral  Health.    Fish  Bay  corals  were  very  severely  affected  in  the  2005  with  100%  of  corals   showing  almost  100%  bleaching.    Bleaching  is  also  normally  high  at  this  site  even  in  years   without  thermal  stress,  a  likely  consequence  of  sediment  and  macroalgal  interactions.     Diseases,  particularly  dark  spots  disease  and  white  disease  can  have  very  high  prevalence   at  Fish  Bay.    Old  partial  mortality  did  increase  after  the  2005  coral  bleaching  event,  with  a   decline  in  2010  and  resurgence  in  2011.    Recent  partial  mortality  can  also  be  relatively  high   compared  with  other  sites,  largely  as  the  results  of  bites  from  site-­‐attached  damselfish   (Stegastes  spp.).     Figure  91.    Fish  Bay  (left)  Relative  composition  of  the  sessile  epibenthic  animal  community.    (right)   Relative  composition  of  the  algal  community  and  unconsolidated  sediment.   FISH  BAY         168   Figure  92.    Fish  Bay  benthic  cover  and  coral  health  through  time  (mean  ±SE).       Benthic Community Cover 0% 20% 40% 60% 80% 100% Coral Cyanobacteria Epilithic Algae Macroalgae Bleaching Prevalence/Extent 0% 20% 40% 60% 80% 100% Prevalence Extent Disease Prevalence 0% 5% 10% 15% 20% 25% 30% All disease Black Band Lesion Dark Spots Intercostal White Disease Yellow Band Unknown Partial Mortality 2001 2002 2003 2004 2005 2005 BL 2006 2007 2008 2009 2010 2011 2012 2013 Prevalence 0% 20% 40% 60% 80% 100% Old Recent SITE  SUMMARIES       169   Fish  Community.  The  Fish  Bay  fish  community  is  typical  of  a  nearshore  reef  habitat  that   receives  moderate  to  heavy  sedimentation.  The  site  is  dominated  by  herbivores  that  include   all  of  the  common  Caribbean  parrotfishes,  large  schools  of  mixed  acanthurids  and   herbivorous  pomocentrids.  Planktivores  in  the  turbid  water  are  limited  to  juvenile   yellowtail  snapper  and  a  few  small  pomocentrids.  Benthic  invertivores  and  piscivores  are   more  diverse  and  abundant  but  are  dominated  by  wrasses  and  jacks  respectively.  Large   serranids  and  lutjanids  are  absent  from  Fish  Bay  although  occasion  juvenile  lemon  sharks   are  seen  in  the  murky  water,  where  adult  females  are  known  to  pup.           FISH  BAY         170     Herbivores stoplight parrotfish redband parrotfish doctorfish blue tang striped parrotfish yellowtail damsel princess parrotfish ocean surgeonfish redfin parrotfish dusky damsel threespot damsel redtail parrotfish greenblotch parrotfish queen parrotfish Beaugregory cocoa damsel Fish Biomass (g) 0 2000 4000 6000 8000 10000 Invertivores Spanish hogfish yellowhead wrasse slippery dick French grunt spotted goatfish clown wrasse saucereye porgy yellowfin mojarra puddingwife tomtate Fish Biomass (g) 0 200 400 600 800 1000 1200 Planktivores yellowtail snapper bicolor damsel blue chromis Fish Biomass (g) 0 100 200 300 400 500 600 Piscivores bar jack schoolmaster trumpetfish blue runner redspotted hawkfish black hamlet Fish Biomass (g) 0 1000 2000 3000 4000 5000 SITE  SUMMARIES       171   MERI  SHOAL   Descrip(on.    Meri  Shoal  is  an  offshore   mesophotic  coral  bank  30  m  depth.    The   reef  is  located  four  miles  south  of  St.   John  and  is  on  the  southernmost  of  two   impressive  midshelf  coral  banks.    The   reef  is  dominated  by  interlocking   colonies  of  boulder  star  corals  (Orbicella   spp.).    The  reef  top  is  very  flat  coral   plain.  The  site  is  named  for  Dr.  Meri   Whitaker,  former  director  of  the  VI   EPSCoR  Program  who  passed  away  in   2009.    Meri  Shoal  has  been  monitored   since  2005.   Outstanding  Feature.    Meri  Shoal  has  the   highest  star  coral  abundance  of  any  site  in  the  TCRMP  and  is  bathed  in  clear,  clean  water.   Threats.    Meri  Shoal  is  vulnerable  to  fishing  impacts,  as  it  is  outside  any  marine  protected   area.    The  high  density  of  corals  may  make  this  sight  vulnerable  to  disease  impacts.     Figure  93.    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   1.8m  wide.       MERI  SHOAL         172     Figure  94.    Meri  Shoal  benthic  temperature  record  (30m  depth).     Physical  Characteris.cs.       Current.  Currents  have  not  been  measured  directly  at  the  Meri  Shoal  site,  although  the   Caribbean  Regional  Association  buoy  VI  1  is  located  within  700  m  and  its  downward   focused  ADCP  has  been  recording  data  since  April  2011.       Temperature.    Black  Point  has  low  circulation  and  relatively  high  mean  temperatures  with   very  low  day  to  day  variability.       J F M A M J J A S O N D 24 25 26 27 28 29 30 31 2006 2009 2007 2010 2008 2011 Temperature ( oC) Month SITE  SUMMARIES       173     Benthic  Community.  The  Meri  Shoal  site  is  exceptional  for  its  domination  by  boulder  star   corals  (Orbicella  spp.).    Cover  of  this  and  other  coral  species  was  exceptionally  high  when   the  site  was  first  monitored  during  the  2005  coral  bleaching  event,  but  declined  by  36.0%   after  bleaching  and  had  not  recovered  any  cover  as  of  2011  (-­‐9.6%).    Surprisingly,  given  the   high  coral  cover,  the  algal  community  is  dominated  by  Lobophora  variegata  and  not  epilithic   algae  and  there  has  been  a  trend  of  increasing  macroalgal  cover  since  2008.   Coral  Health.    Coral  bleaching  was  relatively  high  for  a  mesophotic  site  during  the  coral   bleaching  event  in  2005.    Bleaching  was  again  at  high  prevalence,  but  low  extent  in  the   thermal  stress  of  2010.    However,  low-­‐extent  bleaching  at  moderate  prevalence  is  a   persistent  feature  of  Meri  Shoal.    Disease,  particularly  white  disease  and  lesions  that  are   likely  the  remnants  of  white  disease,  are  highly  prevalent,  particularly  in  years  following   high  thermal  anomalies,  such  as  2006  and  2011.    Old  partial  mortality  climbed  steeply  from   the  2005  coral  bleaching  event  onwards  and  reached  very  high  levels  by  2006.    Recent   partial  mortality  has  also  been  consistently  high  as  the  result  of  white  disease  and  disease   lesions.     Figure  95.    Meri  Shoal  (left)  Relative  composition  of  the  sessile  epibenthic  animal  community.    (right)   Relative  composition  of  the  algal  community  and  unconsolidated  sediment.   MERI  SHOAL         174   Figure  96.    Meri  Shoal  benthic  cover  and  coral  health  through  time  (mean  ±SE).       Benthic Community Cover 0% 20% 40% 60% 80% 100% Coral Cyanobacteria Epilithic Algae Macroalgae Bleaching Prevalence/Extent 0% 20% 40% 60% 80% 100% Prevalence Extent Disease Prevalence 0% 5% 10% 15% 20% 25% 30% All disease Black Band Lesion Dark Spots Intercostal White Disease Yellow Band Unknown Partial Mortality 2001 2002 2003 2004 2005 2005 BL 2006 2007 2008 2009 2010 2011 2012 2013 Prevalence 0% 20% 40% 60% 80% 100% Old Recent SITE  SUMMARIES       175   Fish  Community.    Meri  Shoal  is  a  beautiful  site  in  deep  water  and  holds  a  dynamic  fish   community  of  high  biomass.  Important  planktivores  include  the  very  prolific  creole  wrasse,   feeding  on  tiny  jellyfish,  invertivore  larvae  and  phytoplankton,  and  the  black  durgeon,   primarily  a  zooplankton  feeder.  Herbivores  observed  on  the  site  include  large  stoplight   parrotfish,  all  of  the  common  smaller  parrotfish,  and  all  three  acanthurids.  Queen   triggerfish  and  red  hind  are  both  common.  In  2012  a  tiger  grouper  was  observed  on  a  belt   transect  and  another  on  a  roving  dive.  A  Nassau  grouper  was  also  observed  on  a  roving   dive.  These  are  exciting  encounters  as  the  site  is  not  near  a  spawning  aggregation  area  and   is  not  protected  from  traps  or  any  type  of  fishing.    Jacks,  mackerels  and  barracuda  are  also   regularly  observed  in  the  water  column  at  Meri  Shoal.             MERI  SHOAL         176     Herbivores stoplight parrotfish princess parrotfish redband parrotfish striped parrotfish queen parrotfish doctorfish blue tang ocean surgeonfish threespot damsel orangespotted filefish dusky damsel Beaugregory Fish Biomass (g) 0 5000 10000 15000 20000 25000 30000 Invertivores queen trigger red hind saucereye porgy Spanish hogfish blackbar soldierfish French grunt spotted goatfish bluestriped grunt yellowhead wrasse yellowtail hamlet longsnout butterflyfish fairy basselet Fish Biomass (g) 0 2000 4000 6000 8000 10000 12000 Planktivores creole wrasse black durgon creolefish bicolor damsel blue chromis yellowtail snapper brown chromis Fish Biomass (g) 0 2000 4000 6000 8000 10000 12000 14000 16000 18000 Piscivores tiger grouper cero graysby great barracuda schoolmaster trumpetfish bar jack red lionfish redspotted hawkfish Fish Biomass (g) 0 500 1000 1500 2000 2500 3000