Tracking Coral Reef Health
RHI
symbol
s h r ou s
The Reef Health Index (RHI) integrates four indicators to measure coral reef health (coral cover, fleshy
macroalgae, herbivorous fish and commercial fish). The RHI “pie” symbol on the map is displayed at the site,
subregional and national levels.* (For more information visit www.caribnode.org)
Ma Fle
cro
y
sh l
ver
Co
m
Co m F
No
Data
Very
Good
ID Sub-
region
26 Saint
Lucia
South
27 Saint
Lucia
West
Saint Lucia
The Reef Health Index for Saint Lucia is based
on data shared by Steve Newman and Stacey
Williams of FORCE 1 , who surveyed 8 fore
reefs (10-15 m) in 2011 and Robert Steneck
of University of Maine, who surveyed 9 fore
reefs (6-11 m) in 2014. Saint Lucia is divided
into subregions based on biogeographical
features to facilitate the reporting of Reef
Health Index data. Data were not available for
two subregions. 2 The combination of data into
the RHI pie symbol allows the visualization and
mapping of reef health data. Subregions for the
6 ECMMAN countries are numbered 1 to 41
from Grenada north to St. Kitts and Nevis.
Indicator
28
Saint
Lucia
East/
North
East
Subregion Description #
Sites
Southwest - Laborie, few patch reefs, mangroves, seagrass.
Southeast - wide shelf south tip, mosaic of coral reefs,
seagrasses, mangroves. Pointe Sable - patch reefs Saltibus
Pointe to Maria Islands, protected by Pointe Sable EPA
(PSEPA), sea turtle nesting, recreational area. Maria Islands
- exposed reef flats, wildlife reserve. Few or no reef health
surveys. 0
Western - leeward narrow shelf, steep slope. Shallow - isolated
patch reefs, small corals, elkhorn rare. Coastline - boulders
from land covered with small corals, numerous fish in crevices.
Slope - higher abundance/diversity of corals, sponges, seafans,
fish in 15-30 m. Soufriere - largest reef complex, most people
concentrated here, Soufriere MMA protects 17 km 2 , Canaries
Anse la Raye MMA protects 9 km 2 . 17
Eastern - windward, high wave exposure, leatherback turtle
nesting on Grand Anse Beach. Unique NE corner - near Anse
Lavoutte/Esperance Harbor, wider shelf, numerous healthy
endangered elkhorn coral. Reef flat - high energy areas along
coast with hardbottom, small corals, gorgonians, West Indian
urchins. No reef health surveys. 0
Description of Saint Lucia’s Reef Health
Corals Corals build the reef’s 3D structure, provide habitat, and protect coastlines
• Coral cover higher than other Caribbean reefs, but lower than historic
• Previous surveys report loss of ~47% coral cover in SMMA **
• Vigie Beach Reef most impacted (silt, trash, dead corals, damage)
• New healthy reefs of endangered elkhorn corals found on NE coast
Fleshy
macroalgae Fleshy macroalgae, when too abundant, outcompete corals
• Less macroalgae (3-56%) than other Caribbean reefs
• High silt covering many reefs prevents coral growth or settlement
• Macroalgae overgrowth at Turtle Reef, Coral Garden
• Cyanobacteria high near populated areas (Coral Garden, Malgretoute)
Herbivorous fish clean algae off reefs, large parrotfish remove more algae
• Herbivorous fish biomass was fair (range 918-4017 g/100 m 2 )
• Few large parrotfish, less grazing allows seaweed to grow
Herbivorous • Herbivorous fish at CAMMA > SMMA; low at Malgretoute, Blue Hole
Fish
• Parrotfish are harvested and caught in traps
Groupers & snappers are key predators that keep food chain in balance
• Fish biomass was low (155-1695 g/100 m 2 ), groupers absent
• Fish were small in size meaning fewer mature females to produce eggs
Commercial • More fish in protected areas, SMMA > CAMMA > Vigie Beach
Fish
• Reefs with more complex structure had more fish
Diadema
Coral
Recruits
3
Diadema urchins clean algae off reefs and open space for coral recruits
• Urchins were abundant (~0.2/m 2 ) on several reef types
• Eleven of 17 sites had urchins present
• Many reefs with more urchins had less macroalgae
• If nutrients and sediments reduced, urchins could increase
Coral recruits are “baby” corals. Recruits prefer macroalgal free areas
• Recruits present, but mostly of smaller sized corals
• High siltation and sediments have reduced space for coral recruits
• Lack of crustose coralline algae means less available substrate
• Reducing sediments and increasing herbivory will improve substrate
Threatened
Score
Healthy
Patricia Kramer Frances Grenda
Andy Bruckner Ken Marks
Clare Morrall Ken Marks
Emma Doyle Ken marks
Clare Morrall Patricia Kramer
Clare Morrall Andy Bruckner