Large blooms of Rhopilema nomadica, a highly venomous rhizostamatid scyphozoan species introduced to the Mediterranean through the Suez Canal, have become ubiquitous in the summer and winter months along the Israeli coasts since the mid-1980s. This species has since spread across the eastern Mediterranean and was sighted as far west as Tunisia and Sardinia. For the past 12 years, we have studied changes in the mitochondrial COI haplotypes diversity of R. nomadica to investigate small scale fluctuactions of genetic diversity and to reveal possible genetic structuring of the fast spreading invader in the Eastern Mediterranean. The 1091 COI sequences analysed, revealed a highly diverse population displaying 89 haplotypes, 46 of which appeared as singletons, low frequency haplotypes. All the specimens analysed throughout the period belong to a single unstructured population. Though lacking data from the source population in the Red Sea, the high within-population diversity and the high diversity of COI haplotypes support the hypothesis of multiple introductions events, or an open corridor with a continuous influx of propagules. Tajima’s D and Fu’s Fst negative values and the increased numbers of COI singletons from early to late sampling periods, have verified that the Israeli population is characterized by a rapid expanding population. Further research is needed for the evaluation of COI diversity and patterns in R. nomadica populations across the eastern Mediterranean Sea and Red Sea, as well as any correlation of the high variability between COI locus and phenotypic diversity.
Bibliographical noteFunding Information:
We gratefully thank Guy Paz for figures drawing, for D. Avraham for help in DNA extraction and to Mr. R. Gevili for the photograph in Fig . Rinkevich’s and Lubinevsky’s labs members are acknowledged for help in jellyfish collections. This study was supported by the Israeli Ministry of Energy, contract Nos.: 211-17-023 and 218-17-009. We thank also the two anonymous referees for their constructive suggestions that improved the presentation of the manuscript
© 2021, The Author(s), under exclusive licence to Springer Nature Switzerland AG.
- Haplotype diversity
- Invasive species
- Mediterranean Sea
- Mitochondrial cytochrome oxidase I (COI)
- Rhopilema nomadica
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics