aggregations of up to 100 ind m
-2 were observed. However, in May 2009, not a
single individual was observed in the entire reef area (4–12 m) between 2.30 and
3.20 m and surrounding rocky bottom. Instead there were a high number of spines
and hundreds of bare tests scattered over the reef, indicating a mass mortality event
in the sea urchin population. Observations made by the authors during further
monitoring suggested disease as the cause (Benitez-Villalobos et al. 2009).
The observed signs were similar to those described during the mass mortality event
of D. antillarum that occurred in the 1980s throughout the geographical range of
this species in the Western Atlantic.
Fodrie et al. (2007) studied the mechanisms that regulate the feedings position and
feeding mode selection of the sand dollar Dendraster excentricus in some Mexican
localities. Zamorano and Leyte-Morales (2009) worked on the association of the
echinoderms with reef formations on the central Mexican Pacific (Guerrero). TorresMartinez and Solis-Marin (2010) analyzed sediment utilization and feeding niche
breadth of the echinoid Meoma grandis in the central Mexican Pacific (Guerrero).
Ebert (2010) studied the demographic patterns of Strongylocentrotus purpuratus
along a latitudinal gradient and included one site on the Mexican Pacific territory.
Francisco and Herzka (2010) measured the role of physical and biological
factors regulating the mode of feeding of the sand dollar D. excentricus in a
shallow estuary in Baja California. The percentage of inclined sand dollars was
strongly and positively correlated with tidal level but no relationship was found
with current velocity, density and organic matter content of the water. The prone
position, indicative of deposit feeding, was largely limited to low tidal levels. Sand
dollars were only oriented parallel to the prevailing currents during the strongest
currents of spring tides ([20 cm s
-1 ). The regulation of the feeding mode of sand
dollars in shadow and hydrodynamically complex estuarine systems differs from
the feeding mode found in exposed coastal environments.
Sonnenholzner et al. (2010) evaluated the effect of three tagging methods on the
growth and survival of Strongylocentrotus purpuratus. The tags tetracycline and
two internal tags, Decimal Coded Wire Tags (CWT) and Passive Integrated
Transponder tags (PIT) were used alone or in combination to evaluate growth
rates, survival, tag retention and post-tagging stress. The results suggested that the
tags used did not affect growth or survival of the urchins. Post-tagging stress was
significantly affected by urchin size but not by tagging methods.
Palleiro-Nayar et al. (2011) analyzed spatial variation in Strongylocentrotus
franciscanus recruitment and assessed the impact of substrate availability and
adult sea urchin density on recruitment along the west coast of Baja California.
There were significant differences in recruit density among sites. Substrate
structure was the main factor that explained these differences. Adult densities did
not explain recruitment differences among sites. Temporal analysis showed that
both substrate structure and adult densities were important in explaining recruit
densities at both sites. The absence of a clear spatial pattern suggests other factors
may explain the differences observed in density and recruitment among sites.
34
F. A. Solís-Marín et al.
-2 were observed. However, in May 2009, not a
single individual was observed in the entire reef area (4–12 m) between 2.30 and
3.20 m and surrounding rocky bottom. Instead there were a high number of spines
and hundreds of bare tests scattered over the reef, indicating a mass mortality event
in the sea urchin population. Observations made by the authors during further
monitoring suggested disease as the cause (Benitez-Villalobos et al. 2009).
The observed signs were similar to those described during the mass mortality event
of D. antillarum that occurred in the 1980s throughout the geographical range of
this species in the Western Atlantic.
Fodrie et al. (2007) studied the mechanisms that regulate the feedings position and
feeding mode selection of the sand dollar Dendraster excentricus in some Mexican
localities. Zamorano and Leyte-Morales (2009) worked on the association of the
echinoderms with reef formations on the central Mexican Pacific (Guerrero). TorresMartinez and Solis-Marin (2010) analyzed sediment utilization and feeding niche
breadth of the echinoid Meoma grandis in the central Mexican Pacific (Guerrero).
Ebert (2010) studied the demographic patterns of Strongylocentrotus purpuratus
along a latitudinal gradient and included one site on the Mexican Pacific territory.
Francisco and Herzka (2010) measured the role of physical and biological
factors regulating the mode of feeding of the sand dollar D. excentricus in a
shallow estuary in Baja California. The percentage of inclined sand dollars was
strongly and positively correlated with tidal level but no relationship was found
with current velocity, density and organic matter content of the water. The prone
position, indicative of deposit feeding, was largely limited to low tidal levels. Sand
dollars were only oriented parallel to the prevailing currents during the strongest
currents of spring tides ([20 cm s
-1 ). The regulation of the feeding mode of sand
dollars in shadow and hydrodynamically complex estuarine systems differs from
the feeding mode found in exposed coastal environments.
Sonnenholzner et al. (2010) evaluated the effect of three tagging methods on the
growth and survival of Strongylocentrotus purpuratus. The tags tetracycline and
two internal tags, Decimal Coded Wire Tags (CWT) and Passive Integrated
Transponder tags (PIT) were used alone or in combination to evaluate growth
rates, survival, tag retention and post-tagging stress. The results suggested that the
tags used did not affect growth or survival of the urchins. Post-tagging stress was
significantly affected by urchin size but not by tagging methods.
Palleiro-Nayar et al. (2011) analyzed spatial variation in Strongylocentrotus
franciscanus recruitment and assessed the impact of substrate availability and
adult sea urchin density on recruitment along the west coast of Baja California.
There were significant differences in recruit density among sites. Substrate
structure was the main factor that explained these differences. Adult densities did
not explain recruitment differences among sites. Temporal analysis showed that
both substrate structure and adult densities were important in explaining recruit
densities at both sites. The absence of a clear spatial pattern suggests other factors
may explain the differences observed in density and recruitment among sites.
34
F. A. Solís-Marín et al.