Hemiuridae and Fellodistomidae trematode metacercariae parasitizing fish larvae from the reef lagoon of Puerto Morelos, Quintana Roo, Mexico

Parasitized fish larvae collected with a neuston net (0.40 x 0.40 m mouth) at two sampling stations in the coral reef lagoon of Puerto Morelos, Quintana Roo, Mexico, from September to November 2002 were analyzed. Fish larvae and the parasites were stained together with acetic carmine and cleared with methyl salicilate. Parasites were removed from the host and mounted in permanent slides with synthetic resin. Un encysted metacercariae of Hemiuridae and Fellodistomidae were found in the stomach of Sphyraena barracuda (Sphyraenidae) 816), Serranidae (2) and Ctenogobius sp. (Gobiidae) (3); in the intestine of Gerres cinereus sp. (Gerreidae) (2) and in the cloaca (12) and swim bladder (48) of Jenkinsia lamprotaenia (Clupeidae). Fish larvae are plankton feeders and as Acartia spinata and Paracalanus sp. are the most abundant copepods and the usual prey for predators, it is suggested that these microcrustaceans may be the first intermediate hosts and the usual infection via for fish larvae. Fish larvae would become the second or paratenic hosts and when adult fish feed on them, would become the final and definitive host.