Mesozooplankton communities related to water masses in the Persian Gulf and the Gulf of Oman

The spatial and temporal variations of mesozooplankton in relation to environmental parameters were investigated in the Persian Gulf and the Gulf of Oman. For this purpose, the physicochemical parameters were measured using a CTD probe and mesozooplankton were sampled vertically using a closing net aboard the RV Persian Gulf Explorer during two expeditions. Results showed a relationship between mesozooplankton assemblages and water mass distributions. Four mesozooplankton cluster station groups divided the sampled stations into masses, which was also confirmed by the PERMANOVA test. Overall, ninety taxa were identified that were dominated by copepods and characterized by small cyclopoids. Based on the results the mesozooplankton communities of the Persian Gulf and the Gulf of Oman are mostly shaped by the combined effect of temperature, salinity, and dissolved oxygen that significantly influences mesozooplankton occurrence during summer and spring. •The effects of water masses on the mesozooplankton communities in the Persian Gulf and the Gulf of Oman were investigated.•Environmental parameters revealed four main water masses in the study area: (1) Western Persian Gulf Waters (WPGW), (2) Middle Persian Gulf Water (MPGW), (3) Eastern Persian Gulf Water (EPGW), and (4) the Gulf of Oman Waters (GOW).•Overall, ninety taxa were identified that were dominated by copepods at all stations and characterized by small cyclopoids.