Meeting Abstract

P2.4  Saturday, Jan. 5  Seasonal variation in abundance and reproductive activity in the calcareous sponge, Leucetta losangelensis (deLaubenfels). SHOWS, A.; JENSEN, D.A*; SHUSTER, S.M.; Northern Arizona University dj274@nau.edu

Leucetta losangelensis is a calcareous sponge known to inhabit intertidal zones in the northern Gulf of California. Like most sponges, the basic biology of this species is poorly known. To document seasonal variation in sponge availability and reproductive activity, we recorded monthly abundances and body volumes for sponges growing on and under boulders within a 21 m2 area located within the mid-intertidal zone near Puerto Peñasco, Sonora, Mèxico. To document reproduction, we collected a 1 cm3 core sample from the center of 1-3 sponges in each census, and examined this material microscopically for the presence of oocytes and larvae. We found a significant negative relationship between sea surface temperature and total sponge volume. Oocytes and/or larvae appeared in all core samples indicating year-round reproduction in this species. However, we found no significant correlation between sea surface temperature and the number of reproducing sponges. This sponge is known to provide habitat for a number of infaunal invertebrate species. Our results suggest that the relative abundance of L. losangelensis in the northern Gulf of California decreases with increasing temperature, possibly making its availability to dependent species sensitive to climate change.