Taxonomic structure, spatial distribution, and temporal variations of Appendicularian communities in coastal waters of Bushehr- Persian Gulf

Appendicularians are the most important group among zooplankton communities, widely distributed in all the oceans and they are considered as one of the most important sources of productivity and food supplies for secondary consumers. So this study aimed to identify, introduce and assess the temporal and spatial variations of the Appendicularians in the Persian Gulf, restricted to coastal waters of northern part of Bushehr. Appendicularians were collected during seven sampling programs, from Frake river-estuary, three sites of large creek-estuary of the Shif, one site in the sea, and one site in the Lashkari creek-estuary, at middle and last day of each season, midsummer of 2016 to spring of 2017. During all surveys, depth of the sampling location, Secchi depth, water temperature, pH, and salinity were measured. Finally, 4 species were identified, Oikopleura dioica, Oikopleura longicauda Appendicularia sicula and Fritillaria sp. The highest total density was observed in the sea station at March, with dominance of O. dioica and a relative abundance of 80%, relative abundance of O. longicauda, A. sicula and Fritillaria sp. were calculated 18.9%, 1.06% and 0.04% respectively, so Fritillaria sp were introduced as rare species. Two species of O. dioica and O. longicauda demonstrated completely different spatial and temporal distribution pattern, and based on dbRDA (distance based Redundancy Analysis), transparency explains effectively the distribution pattern of O. longicauda, and also depth and salinity are the most important factors which explain the distribution pattern of O. dioica and temperature was correlated factor with abundances of A. sicula, in our study area.