Benthic diatoms associated to abalone (Haliotis spp.) on a rocky substratum from Isla Magdalena, Baja California Sur, Mexico

A preliminary taxonomic analysis was carried out on epilithic diatom assemblages collected in an abalone fishing site at Isla Magdalena, Baja California Sur. To date 97 taxa have been determined, including fifteen new records for the Baja California peninsula and a form of Cymbellonitzschia not recorded for marine habitats. The most conspicuous diatoms were highly silicified centric taxa, but many small pennate forms were also abundant. The association structure differs from that of other assemblages hitherto studied for the peninsula, although this is the first study on benthic diatoms from rocky sustrata for the region. These observations confirm the need for resorting to a rocky source of diatoms when inoculating the rearing tanks for post-larvae and small juveniles of abalone (Haliotis spp.).