Plankton abundance and community structure in reef manta ray (Mobula alfredi) feeding habitat in the Dampier Strait, Raja Ampat, West Papua, Indonesia.

Reef manta rays (Mobula alfredi) are pelagic filter feeders, primarily feeding on zooplankton. Plankton plays an important role in marine food webs and can be used as a bioindicator to evaluate water quality and primary productivity. This study aimed to determine the community structure and abundance of zooplankton and phytoplankton at a M. alfredi feeding habitat in the Dampier Strait region of Raja Ampat, West Papua, Indonesia. Plankton samples were collected and environmental conditions were recorded during two sampling sessions, in March and in July 2017, respectively, from five M. alfredi feeding sites using a 20 μm plankton tow net. Plankton richness was found to be higher in March (272 ind L-1±342) than in July (31 ind L-1±11), which may be due to seasonal variations in ocean current patterns in the Dampier Strait. Copepods (Phylum Arthropoda) were the dominant zooplankton found in samples in both sampling periods. Microplastics were also present in tows from both sampling periods, presenting a cause for concern regarding the large filter feeding species, including M. alfredi.