PARENT SESSION
Contributed Oral Session 74: Biodiversity: Aquatic Systems
Wednesday, August 10, 8:00 AM - 11:30 AM, Meeting Room 513 C, Level 5, Palais des congrès de Montréal

Gastropod communities associated to the green calcareous alga Halimeda opuntia.

Soto-Santiago, Francisco^*,1, Colón-Rivera, Ricardo¹, Medina-Hernández, Javier¹, García-Ríos, Cedar¹, ¹ University of Puerto Rico at, Humacao, Puerto Rico

ABSTRACT- We described and compared gastropods associated to a common calcareous alga (Halimeda opuntia) on coral reefs in Puerto Rico. A total of 15 samples (702 g) of algae collected on Cayo Enrique, La Parguera and 21 (2102 g) on Cayo Icacos, Fajardo were examinated. We found 514 gastropods, 96% of which were identified on 55 different taxa. We found no correlation between sample size and snail frequency. Gastropod density (number of individuals in 100 g of algae) was of 48.2 on La Parguera and 8.4 on Cayo Icacos. We identified 40 different species on La Parguera and 32 on Cayo Icacos. Simpson diversity index value (D_S) was higher for the community of La Parguera (D_S =0.91) than the one of Cayo Icacos (D_S = 0.84). The species that presented a frequency of 3 or more individuals, only 2 were found associated to the algae samples of Cayo Icacos and 13 to La Parguera. The structure and composition of the gastropod community associated with Halimeda opuntia on La Parguera was different to the one found on Cayo Icacos.We believe that the differences between both reef environments could explain the contrast in the communities.

Key words: Halimeda opuntia, gastropods