Epiphytic diatoms of Macrocystis pyrifera (L.) C. Ag. from the Baja California peninsula, Mexico

Abstract

Blades of Macrocystis pyrifera and other kelp species used to feed young abalone (Haliotisspp.) in culture were observed in order to determine the species of epiphytic diatoms. For comparison rocksand sediments were also surveyed. The dominant taxon on M. pyrifera blades was Cocconeis cf. britannica.Other important species were Cocconeis speciosa, Gomphonemopsis pseudoexigua, and Climacosphenia moniligera, which was associated to a colonial Navicula sp. None of these species were observed on the other kelp species or on rocky substratum. Even though Cocconeis cf. britannica was very abundant itrepresents a new record for the Baja California Peninsula coasts. Other first records are C. speciosa, Pseudogomphonema kamtschaticum, Rhoicosphenia adolphi and Okedenia inflexa, albeit this one from sediments and rocky substratum. The absence of Cocconeis cf. britannica from other substrata and other kelp from the area suggests that it may have a preference for M. pyrifera as substrate. These observations should be considered when assessing the kelp's nutritional value for abalone feeding.