Especies de moluscos y grupos de invertebrados marinos intermareales más comunes de las Islas Galápagos, durante el tercer crucero insular del B/I Orion, marzo del 2001

Abstract

Con este aporte al mejor conocimiento de los invertebrados marinos intermareales en 10 islas se pretende ir completando la base de datos de bentos marino de Galápagos.

From of observations on the rocky substrate of the intertidal zone, realized at ten (10) islands of the Galápagos Archipelago: Pinta island (Ibbetson cape), Marchena I. (Montalvo cape), Genovesa I. (Darwin bay), San Salvador (James bay), Fernandina I. (Espinoza point), Santa Cruz I. (Academy and Tortuga bays), Isabela I. (General Villamil port), Floreana I. (Velasco Ibarra port), Española I. (Suarez point) and San Cristobal I. (Pitt point). Seven (7) phyla of invertebrates organisms were founded, which are the most common, abundance and frequents on the rocky substrate of the intertidal zone: Porifera, Coelenterate, Annelid, Mollusk, Arthropod, Brizoa and Echinodermata. A total of thitty seven specie of organisms were identified, of which twenty seven are Molluscks (19 gastropods, 6 Bivalve and 2 Poliplacophora); Seven (7) specie are Echinoderms (4 Echinoids, 1 Holothuroids, 1 ophiura and 1 Asteroid; Two (2) specie Arthropods (1 Cirripedia and 1 decapoda), 1 annelid specie (polichaeta), also organisms that belong to phyla: Porifera (sponge), Coelenterata (anemone) and Briozoa. The most common and frequent species of the Galapagos Islands intertidal zone is the crustacean Grapsus grapsus or zayapa crab. On second place, may be considered the gastropods mollusks Plicopurpura columellaris and Nodilittorina galapagensis, and on third place the echinoderms: Eucidaris thouarsii (erizo lapicero) and Lytechinus semituberculatus (erizo verde). The islands with the higher marine biodiversity of invertebrates in the intertidal zone area: San Salvador (James Bay) and Fernandina (Espinoza point), each one with sixteen (16) specie. The following islands are Isabela (General Villamil port) and Genovesa (Darwin bay). The lower biodiversity were observed on Marchena (Montalvo point) and Pinta (Ibettson cape). From the two islands, Marchena is considered like the more poor. There is the possibility that the worlf Island has the lower intertidal biodiversity among all the Galapagos Islands.