FRESHWATER AND MARINE DIATOMS FROM THE WESTERN PACIFIC ISLANDS OF YAP AND GUAM, WITH NOTES ON SOME DIATOMS IN DAMSELFISH TERRITORIES

Abstract

First records of diatoms from Yap, Federated States of Micronesia, are presented, including freshwater samples from an initial assessment of collections made in streams and estuaries and marine samples from nearby coral reefs during a brief survey of the Wa'ab group of islands. Thirty-eight species were documented from Yap; of these 13 had been reported from Guam. In addition we report 25 new records for Guam. The Guam records include especially some large chain-forming Coscinodiscophyceae and Mediophyceae, for which we have new observations on living cells and their habitats: the marine Chrysanthemodiscus floriatus, Stictocyclus stictodiscus, Biddulphiopsis membanacea, Lampriscus shadboltianum var. crenulata, L. orbiculatum, and Biddulphia biddulphiana; and the freshwater Terpsinoë musica. Diatoms have recently been shown to be significant components in the diets of some farmer fish and in Guam C. floriatus and B. membranacea, among others, commonly form blooms or dense mixed communities of epiphytes on the seaweed turfs in territories of these damselfish, including Plectroglyphidodon lacrymatus and Stegastes nigricans.