1.2.3 Agelas Reef 50 m
A total of 40 fish species, including 33 present within belt-transects were identified fr
a depth of 50 meters at Agelas Reef (Table 42). The study mean abundance of fishes
within belt-transects was 82.0 Ind/30 m (range: 60 – 104 Ind/30 m ). This represents a
decline of 468 % from the mean abundance at a depth of 40 m on the SW Wall Reef.
A decline of fish species richness was also observed between Agelas Reef (14.2
spp/transect) and the SW Wall Reef (24.6 and 24.1 spp/transect) at 40 and 30 m depth
Differences of fish abundance and species richness from belt-transect surveys between
Agelas Reef at 50 m, and the SW Wall Reef at depths of 30 and 40 m were s
significant (ANOVA; p < 0.001).
An assemblage of five (5) species accounted for 78.8 % % of the total fish abundance
within belt-transects at Agelas Reef (Table 42). The bicolor damselfish (Stegastes
partitus) was the numerically dominant species with a study mean abundance o
om
s.
tatistically
f 27.2
d/30 m
2
, representing 33.2 % of the total fish abundance within belt-transects. The
hine
he
Ind/30
, low-relief bathymetry of Agelas Reef, without large coral outcrops and
verhangs, but with many small protective microhabitats created by branching sponges
2
2
In
blue chromis (Chromis cyanea), peppermint goby (Coryphopterus lipernes), suns
chromis (Chromis insolata), and cherubfish (Centropyge argi) comprised the rest of t
numerically dominant assemblage at a depth of 50 meters. The numerically dominant
fish assemblage is composed by a combination of shallow and moderately deep coral
reef species (Randall, 1983; Human, 1989). Both the sunshine chromis and cherubfish
are rare at depths over 25 m (Randall, 1983). The cherubfish, also known in the
aquarium trade market as the ”pigmy angel” presented a mean abundance of 6.8
m
2
, which represents an increment of more than 750% (statistically significant; ANOVA,
p < 0.001) over its abundance at depths of 30 and 40 meters on the SW Wall Reef.
The uniform
o
(Agelas spp.) and plate corals (Agaricia spp.) appear to favor a resident ichthyofauna
dominated by small territorial species. The bicolor damselfish exhibited a variance to
mean abundance ratio of 0.6, which is indicative of a highly uniform spatial distribution
over the reef. The cherubfish presented a variance to mean ratio of 1.2, which is close
to a random distribution. The peppermint goby and the blue and sunshine chromis
displayed aggregated distributions, as suggested by the high variance to mean
143
A total of 40 fish species, including 33 present within belt-transects were identified fr
a depth of 50 meters at Agelas Reef (Table 42). The study mean abundance of fishes
within belt-transects was 82.0 Ind/30 m (range: 60 – 104 Ind/30 m ). This represents a
decline of 468 % from the mean abundance at a depth of 40 m on the SW Wall Reef.
A decline of fish species richness was also observed between Agelas Reef (14.2
spp/transect) and the SW Wall Reef (24.6 and 24.1 spp/transect) at 40 and 30 m depth
Differences of fish abundance and species richness from belt-transect surveys between
Agelas Reef at 50 m, and the SW Wall Reef at depths of 30 and 40 m were s
significant (ANOVA; p < 0.001).
An assemblage of five (5) species accounted for 78.8 % % of the total fish abundance
within belt-transects at Agelas Reef (Table 42). The bicolor damselfish (Stegastes
partitus) was the numerically dominant species with a study mean abundance o
om
s.
tatistically
f 27.2
d/30 m
2
, representing 33.2 % of the total fish abundance within belt-transects. The
hine
he
Ind/30
, low-relief bathymetry of Agelas Reef, without large coral outcrops and
verhangs, but with many small protective microhabitats created by branching sponges
2
2
In
blue chromis (Chromis cyanea), peppermint goby (Coryphopterus lipernes), suns
chromis (Chromis insolata), and cherubfish (Centropyge argi) comprised the rest of t
numerically dominant assemblage at a depth of 50 meters. The numerically dominant
fish assemblage is composed by a combination of shallow and moderately deep coral
reef species (Randall, 1983; Human, 1989). Both the sunshine chromis and cherubfish
are rare at depths over 25 m (Randall, 1983). The cherubfish, also known in the
aquarium trade market as the ”pigmy angel” presented a mean abundance of 6.8
m
2
, which represents an increment of more than 750% (statistically significant; ANOVA,
p < 0.001) over its abundance at depths of 30 and 40 meters on the SW Wall Reef.
The uniform
o
(Agelas spp.) and plate corals (Agaricia spp.) appear to favor a resident ichthyofauna
dominated by small territorial species. The bicolor damselfish exhibited a variance to
mean abundance ratio of 0.6, which is indicative of a highly uniform spatial distribution
over the reef. The cherubfish presented a variance to mean ratio of 1.2, which is close
to a random distribution. The peppermint goby and the blue and sunshine chromis
displayed aggregated distributions, as suggested by the high variance to mean
143