A dramatic northward range expansion of a Red Sea soft coral in the Mediterranean Sea

Abstract

Historically isolated from tropical influences, the Mediterranean Sea underwent drastic changes, including the Lessepsian migration facilitated by the opening of the Suez Canal, connecting the Red Sea to the Mediterranean Sea. Here, we report on the discovery of a thriving and lush population of an Indo-Pacific soft coral in the transforming Mediterranean Sea. This species was identified as Dendronephthya hemprichi (Klunzinger, 1877) through morphological and genetic assessments. The unexpected appearance of a dense population of this tropical coral off the Israeli Mediterranean coast signifies a northward range expansion of approximately 350 km from the northern Red Sea. Considering the potential for this soft coral to alter benthic community structure and create new marine animal forests, the population's sudden and massive colonization of artificial structures raises intriguing questions about its possible long-term ecological implications in the Mediterranean ecosystem. This study emphasizes the urgency of continuous monitoring and research to understand the ecological consequences of this unprecedented abrupt tropical incursion of hundreds of colonies and its potential implications for the region's biodiversity. Moreover, the findings contribute to the broader discourse on the tropicalization of temperate and subtropical regions, highlighting the need to adapt conservation strategies that embrace and understand novel configurations of ecosystems in the face of ongoing local and global changes.