Valdez and Villalobos (1978) studied the spatial distribution, and the correlation with the substrate and the degree of aggregation of D. antillarum on the coral
reef at Cahuita National Park, Costa Rica in 1977. They reported densities between
3.83 and 8.8 ind m
-2 and a higher degree of aggregation during morning hours that
could be a protection mechanism. In the afternoon, D. antillarum started to disperse to the reef substrate to feed. Cortés (1981) reported D. antillarum densities in
this same location in 1980 between 4 and 33 ind m
-2 . In June 1983, a high
mortality of this sea urchin was observed in Cahuita decreasing the densities to
0.25–2 ind m
-2 (Murillo and Cortés 1984). By 1992, the densities were low (0.01
ind m
-2 ) and D. antillarum had almost disappeared from this reef (Cortés 1994).
These low densities remained from 1999 until 2003 (Fonseca 2003; Alvarado et al.
2004; Bolaños et al. 2005). Bolaños et al. (2005) indicated a low density of
D. antillarum (0.03 ind m
-2 ) on the reef lagoon of Cahuita National Park,
in October 2003. In this same area, they reported the presence of 15 echinoderms
species (one asteroid, seven ophiuroids, five echinoids and two holothurians) that
were more diverse at sites with coral substrate and algae than seagrass or sand
sites.
Between January and November, 1984, Morales and Murillo (1996) performed
the first study on the distribution, abundance and composition of the zooplankton
present at the coral reef of Cahuita National Park. As part of the merozooplankton,
they described the echinopluteus larvae of the sea urchins D. antillarum and
L. variegatus. In general, the larvae were scarce, with a single peak in abundance in
November (36 ind m
-2 ). This peak probably corresponded to spawning during the
new moon as observed in Panama (Lessios 1981). The low numbers of D. antillarum
larvae are presumed to be related to the high adult mortality in 1983 (Morales and
Murillo 1996).
At the CARICOMP monitoring site in Cahuita (Meager Shoal), between 1999 and
2008, the density of D. antillarum oscillated between 2 and 7 ind m
-2 , while densities of E. viridis decreased significantly from 20 to 0.6 ind m
-2 from 2000 to 2008
(Fonseca et al. 2006; Cortés et al. 2010). At this same site, densities of E. tribuloides
were always low (\1 ind m
-2 ; Cortés et al. 2010). Thus there has been a recovery of
urchin grazers at Cahuita, and probably with a replacement of the main grazers.
For the Gandoca–Manzanillo Wildlife Refuge, Costa Rica, to the south of
Cahuita National Park, Myhre and Acevedo-Gutiérrez (2007) reported a slight
increase on D. antillarum from 2000 to 2004. In 2000, Fonseca (2003) reported a
mean density of 0.10 ± 0.22 ind m
-2 , that increased to 0.2 ± 0.2 in adult urchins
(40–70 mm test diameter) m
-2 in 2004 (Myhre and Acevedo-Gutiérrez 2007). An
increased abundance of live coral within the refuge seems to be associated with
this small recovery in density of urchins, because in zones with high densities of
D. antillarum, the cover of non-calcareous macroalgae was low, presumably as a
result of herbivory (Myhre and Acevedo-Gutiérrez 2007).
At Corn Island, Nicaragua, Ryan et al. (1998), reported D. antillarun densities
being below 4 ind m
-2 in some shallow (\ 5 m) nearshore reefs but not at the
CARICOMP sites. On those sites the mean density of E. viridis was 29.2 ± 25.2
ind m
-2 .
3 Central America Echinoderms: Diversity, Ecology and Future Perspectives
81
reef at Cahuita National Park, Costa Rica in 1977. They reported densities between
3.83 and 8.8 ind m
-2 and a higher degree of aggregation during morning hours that
could be a protection mechanism. In the afternoon, D. antillarum started to disperse to the reef substrate to feed. Cortés (1981) reported D. antillarum densities in
this same location in 1980 between 4 and 33 ind m
-2 . In June 1983, a high
mortality of this sea urchin was observed in Cahuita decreasing the densities to
0.25–2 ind m
-2 (Murillo and Cortés 1984). By 1992, the densities were low (0.01
ind m
-2 ) and D. antillarum had almost disappeared from this reef (Cortés 1994).
These low densities remained from 1999 until 2003 (Fonseca 2003; Alvarado et al.
2004; Bolaños et al. 2005). Bolaños et al. (2005) indicated a low density of
D. antillarum (0.03 ind m
-2 ) on the reef lagoon of Cahuita National Park,
in October 2003. In this same area, they reported the presence of 15 echinoderms
species (one asteroid, seven ophiuroids, five echinoids and two holothurians) that
were more diverse at sites with coral substrate and algae than seagrass or sand
sites.
Between January and November, 1984, Morales and Murillo (1996) performed
the first study on the distribution, abundance and composition of the zooplankton
present at the coral reef of Cahuita National Park. As part of the merozooplankton,
they described the echinopluteus larvae of the sea urchins D. antillarum and
L. variegatus. In general, the larvae were scarce, with a single peak in abundance in
November (36 ind m
-2 ). This peak probably corresponded to spawning during the
new moon as observed in Panama (Lessios 1981). The low numbers of D. antillarum
larvae are presumed to be related to the high adult mortality in 1983 (Morales and
Murillo 1996).
At the CARICOMP monitoring site in Cahuita (Meager Shoal), between 1999 and
2008, the density of D. antillarum oscillated between 2 and 7 ind m
-2 , while densities of E. viridis decreased significantly from 20 to 0.6 ind m
-2 from 2000 to 2008
(Fonseca et al. 2006; Cortés et al. 2010). At this same site, densities of E. tribuloides
were always low (\1 ind m
-2 ; Cortés et al. 2010). Thus there has been a recovery of
urchin grazers at Cahuita, and probably with a replacement of the main grazers.
For the Gandoca–Manzanillo Wildlife Refuge, Costa Rica, to the south of
Cahuita National Park, Myhre and Acevedo-Gutiérrez (2007) reported a slight
increase on D. antillarum from 2000 to 2004. In 2000, Fonseca (2003) reported a
mean density of 0.10 ± 0.22 ind m
-2 , that increased to 0.2 ± 0.2 in adult urchins
(40–70 mm test diameter) m
-2 in 2004 (Myhre and Acevedo-Gutiérrez 2007). An
increased abundance of live coral within the refuge seems to be associated with
this small recovery in density of urchins, because in zones with high densities of
D. antillarum, the cover of non-calcareous macroalgae was low, presumably as a
result of herbivory (Myhre and Acevedo-Gutiérrez 2007).
At Corn Island, Nicaragua, Ryan et al. (1998), reported D. antillarun densities
being below 4 ind m
-2 in some shallow (\ 5 m) nearshore reefs but not at the
CARICOMP sites. On those sites the mean density of E. viridis was 29.2 ± 25.2
ind m
-2 .
3 Central America Echinoderms: Diversity, Ecology and Future Perspectives
81