1.1.3
Agelas Reef – 50 m
This is a live hermatypic reef found at depths between 45 – 70 meters (148 – 230’) on
e southwestern insular slope of Isla Desecheo. It is established across a gently
sloping terrace separated from the SW Wall reef by a sand strip of approximately 40
meters (Figure 11). The reef extends offshore approximately 200 meters and ends at a
second drop-off wall at 70 meters. Agel
pears to be a crustose algal formation
mostly colonized by encrusting brown algae, large erect and branching sponges and
ttuce corals (Agaricia spp). Sessile-benthic biota grows over a vast deposit of rhodolite
tructures loosely anchored to the bottom. The reef has very low topographic relief as it
s over an essentially flat platform and massive corals do not contribute significantly to
ostly
ariegata was the main taxonomic component of the algal assemblage with a mean
the
d third in terms of substrate cover and were present in
lmost all transects surveyed. The basket sponge (Xestospongia muta) was present,
th
as Reef ap
le
s
lie
its rugosity.
Table 35 shows the percent substrate cover by sessile-benthic categories at Agelas
Reef. Benthic algae dominated substrate cover by sessile biota with a combined mean
of 57.6% (range: 54.2 – 66.4%). The benthic algal assemblage was comprised by
encrusting and fleshy brown macroalgae, and a mixed stand of short filamentous (m
microscopic) algae, forming an “algal turf”. The encrusting fan leaf alga, Lobophora
v
cover of 37.1 % (range (33.2 – 47 %). The leafy flat-blade alga, Stypopodium zonale,
the pink bush alga (Wrangelia sp.), and the large leaf watercress alga (Halimeda
discoidea) were also present at depths between 47 – 53 meters in Agelas Reef. Loose
oval shaped structures of calcite (biogenic) origin, or rhodoliths were covered by what
appears to be an assemblage of at least two or more species of (live) encrusting red
crustose algae.
Sponges (Class Demospongiae) were the most important invertebrate component of
sessile-benthic community at Agela’s reef with an assemblage of nine species within
transects and a combined substrate cover of 28 % (range: 20.6 – 39.2 %) (Table 36).
The Brown tube sponge (Agelas conifera) was the most prominent species within
transects with a mean of 5.9 % substrate cover. Agelas clathrodes and Aplysina
cauliformis ranked second an
a
116
Agelas Reef – 50 m
This is a live hermatypic reef found at depths between 45 – 70 meters (148 – 230’) on
e southwestern insular slope of Isla Desecheo. It is established across a gently
sloping terrace separated from the SW Wall reef by a sand strip of approximately 40
meters (Figure 11). The reef extends offshore approximately 200 meters and ends at a
second drop-off wall at 70 meters. Agel
pears to be a crustose algal formation
mostly colonized by encrusting brown algae, large erect and branching sponges and
ttuce corals (Agaricia spp). Sessile-benthic biota grows over a vast deposit of rhodolite
tructures loosely anchored to the bottom. The reef has very low topographic relief as it
s over an essentially flat platform and massive corals do not contribute significantly to
ostly
ariegata was the main taxonomic component of the algal assemblage with a mean
the
d third in terms of substrate cover and were present in
lmost all transects surveyed. The basket sponge (Xestospongia muta) was present,
th
as Reef ap
le
s
lie
its rugosity.
Table 35 shows the percent substrate cover by sessile-benthic categories at Agelas
Reef. Benthic algae dominated substrate cover by sessile biota with a combined mean
of 57.6% (range: 54.2 – 66.4%). The benthic algal assemblage was comprised by
encrusting and fleshy brown macroalgae, and a mixed stand of short filamentous (m
microscopic) algae, forming an “algal turf”. The encrusting fan leaf alga, Lobophora
v
cover of 37.1 % (range (33.2 – 47 %). The leafy flat-blade alga, Stypopodium zonale,
the pink bush alga (Wrangelia sp.), and the large leaf watercress alga (Halimeda
discoidea) were also present at depths between 47 – 53 meters in Agelas Reef. Loose
oval shaped structures of calcite (biogenic) origin, or rhodoliths were covered by what
appears to be an assemblage of at least two or more species of (live) encrusting red
crustose algae.
Sponges (Class Demospongiae) were the most important invertebrate component of
sessile-benthic community at Agela’s reef with an assemblage of nine species within
transects and a combined substrate cover of 28 % (range: 20.6 – 39.2 %) (Table 36).
The Brown tube sponge (Agelas conifera) was the most prominent species within
transects with a mean of 5.9 % substrate cover. Agelas clathrodes and Aplysina
cauliformis ranked second an
a
116