Abstract

DIAZ D, Oscar  and  LINERO-ARANA, Ildefonso. Percentage of Infestation Level of Polydora cf. websteri Hartman, 1943 (Polychaeta: Spionidae) by Size Class of Crassostrea rhizhophorae (Guilding, 1828) on La Restinga Lagoon (Margarita Island, Venezuela).. Rev. Cient. (Maracaibo) [online]. 2009, vol.19, n.2, pp.113-118. ISSN 0798-2259.

The infestation of mollusks bivalves with commercial importance by spionid polychaetes belonging, mainly, to genera Polydora, Dipolydora and Carazziella, has been recorded in many occasions. A study about of infestation of mangrove oyster Crassostrea rhizophorae (Guilding, 1828) by spionid polychaete Polydora cf. websteri Hartman, 1943 was made in order to determine the level of infestation and the polychaete worm preference by one or the other shell. Monthly samplings (January-July) were made. Bivalves were manually separated of mangroves roots from La Restinga lagoon. Presence or not and attack intensity was recorded in both valves of each specimen in order to establish infestation levels according to galleries spionid abundance. Almost 65% of bivalves showed infestation by the polychaete. Highly significative differences in the abundance of galleries between valves (ts = 5.786, P < 0.001) were found. Not Pearson correlation between the bivalve size and galleries number, nor biomass and galleries number was observed.

Keywords : Crassostrea rhizophorae; polychaetes; Spionidae; infestation; Polydora.