Species composition of Discomedusae jellyfish (Scyphozoa) in the coastal waters of Eastern Surabaya, East Java

The Indo-Pacific is recognized as a hotspot for marine diversity. The taxonomy of certain taxa, such as Discomedusae jellyfish, has been neglected, despite its importance in the fishery industry. This study documents the first records of Discomedusae for the Java Sea using an integrative approach and provide notes about its distribution in the area. We used up to 53 morphological and meristic characters and amplified one mitochondrial marker (COI). The comparison and assessment of these data resulted in the recognition of seven species of Discomedusae, from which five has been recorded for the Indo-Pacific area. Two other species require a taxonomic revision to confirm the species assignation. The distribution of jellyfish in the coast of Java Sea might be correlated with the jellyfish life history and species-specific ranges of tolerance, and not solely determined by the environmental parameters. These findings provide the foundations for extending the taxonomic research in the area; the description of the biodiversity will increase the understanding of the population dynamics and its implications in the fisheries.