Caso et al. (1996) performed qualitative and quantitative analyses of the
echinoderm fauna from the littoral of Mazatlan Bay, Sinaloa and identified 25
species. The results showed that P. unifascialis, Ophiocoma alexandri and
Echinometra vanbrunti were conspicuous because of their density and abundance.
Cluster analysis showed the existence of three groups: the first included species
with a limited distribution and low abundance, the second and the third had species
widely distributed on sandy substrates in the bay. The highest diversity and
specific richness index values corresponded to the species located in protected
areas of the Bay, whereas the lowest diversity and specific richness index values
corresponded to the species found in the exposed areas.
Reyes-Bonilla and Calderon-Aguilera (1999) analyzed the abundance, spatial
distribution and consumption rate of Eucidaris thouarsii and Acanthaster planci at
Cabo Pulmo, Gulf of California. The results showed that the action of corallivore
organisms in terms of their population density and consumption rates was not a
key factor determining scleractinian abundance in the reef of Cabo Pulmo.
Holguin-Quiñones et al. (2000) analyzed the spatial and temporal variation of
Asteroidea, Echinoidea and Holothuroidea from shallow water at Loreto Bay, Gulf
of California. The greatest mean abundance by transect and mean densities in order
of importance for Echinoidea were E. vanbrunti, Centrostephanus coronatus,
Tripneustes depressus, E. thouarsii and Diadema mexicanum; and for Asteroidea,
P. unifascialis, Mithrodia bradleyi and A. planci. Asteroidea was the dominant
class with 12 species, followed by Echinoidea.
Reyes-Bonilla et al. (2005) examined and compared the community structure of
asteroids in four regions of the Gulf of California, characterized by the presence
of rocky reefs. They found Loreto Bay had the highest richness and abundance of
asteroids. However, there were no statistically significant interregional differences
among ecological indices and no groups of locations singled out in terms of
species composition. Phataria unifascialis was the dominant species followed by
Pharia pyramidatus. There were statistically significant positive associations
between three pairs of species, indicating competition between these asteroids in
the Gulf of California is not particularly relevant.
Cintra-Buenrostro et al. (2005) determined the correlation between species
richness of shallow water (depth \ 200 m) asteroids and key oceanographic
factors in nine sections of one degree latitude (from 23 to 31°N) of the Gulf of
California. They reported continental shelf area (at 100 and 200 m depth), mean
temperature and range at three depth levels (0, 60 and 120 m), thermocline depth,
surface nutrient concentrations (nitrates, phosphates and silicates), surface
photosynthetic pigment concentration, and productivity. Sea star species were
assigned to different feeding guilds: predators of small mobile invertebrates,
predators of colonial organisms, generalist carnivores, detritivores, and planktivores. The results showed that total species richness and guild species richness had
strong latitudinal attenuation patterns and were higher in the southernmost Gulf.
Nutrients and surface pigments always presented negative relationships with
species richness, indicating that productive environments set limits to the diversity
of sea stars in the study area.
2 The Echinoderms of Mexico
29
echinoderm fauna from the littoral of Mazatlan Bay, Sinaloa and identified 25
species. The results showed that P. unifascialis, Ophiocoma alexandri and
Echinometra vanbrunti were conspicuous because of their density and abundance.
Cluster analysis showed the existence of three groups: the first included species
with a limited distribution and low abundance, the second and the third had species
widely distributed on sandy substrates in the bay. The highest diversity and
specific richness index values corresponded to the species located in protected
areas of the Bay, whereas the lowest diversity and specific richness index values
corresponded to the species found in the exposed areas.
Reyes-Bonilla and Calderon-Aguilera (1999) analyzed the abundance, spatial
distribution and consumption rate of Eucidaris thouarsii and Acanthaster planci at
Cabo Pulmo, Gulf of California. The results showed that the action of corallivore
organisms in terms of their population density and consumption rates was not a
key factor determining scleractinian abundance in the reef of Cabo Pulmo.
Holguin-Quiñones et al. (2000) analyzed the spatial and temporal variation of
Asteroidea, Echinoidea and Holothuroidea from shallow water at Loreto Bay, Gulf
of California. The greatest mean abundance by transect and mean densities in order
of importance for Echinoidea were E. vanbrunti, Centrostephanus coronatus,
Tripneustes depressus, E. thouarsii and Diadema mexicanum; and for Asteroidea,
P. unifascialis, Mithrodia bradleyi and A. planci. Asteroidea was the dominant
class with 12 species, followed by Echinoidea.
Reyes-Bonilla et al. (2005) examined and compared the community structure of
asteroids in four regions of the Gulf of California, characterized by the presence
of rocky reefs. They found Loreto Bay had the highest richness and abundance of
asteroids. However, there were no statistically significant interregional differences
among ecological indices and no groups of locations singled out in terms of
species composition. Phataria unifascialis was the dominant species followed by
Pharia pyramidatus. There were statistically significant positive associations
between three pairs of species, indicating competition between these asteroids in
the Gulf of California is not particularly relevant.
Cintra-Buenrostro et al. (2005) determined the correlation between species
richness of shallow water (depth \ 200 m) asteroids and key oceanographic
factors in nine sections of one degree latitude (from 23 to 31°N) of the Gulf of
California. They reported continental shelf area (at 100 and 200 m depth), mean
temperature and range at three depth levels (0, 60 and 120 m), thermocline depth,
surface nutrient concentrations (nitrates, phosphates and silicates), surface
photosynthetic pigment concentration, and productivity. Sea star species were
assigned to different feeding guilds: predators of small mobile invertebrates,
predators of colonial organisms, generalist carnivores, detritivores, and planktivores. The results showed that total species richness and guild species richness had
strong latitudinal attenuation patterns and were higher in the southernmost Gulf.
Nutrients and surface pigments always presented negative relationships with
species richness, indicating that productive environments set limits to the diversity
of sea stars in the study area.
2 The Echinoderms of Mexico
29