A recent study suggests that the standstill of ships in the Gulf region due to the closure of the Strait of Hormuz may lead to a significant environmental threat known as a “super-spreader” event. The paper, released in the Biological Invasions journal on July 22, highlights the potential risk of various organisms like algae, barnacles, and tunicates growing on immobile vessels in the Persian Gulf and the Gulf of Oman. Lead author Mario Tamburri, from the University of Maryland Center for Environmental Science, emphasized that this situation could result in the widespread movement of species, posing a substantial international biosecurity hazard once the ships start moving again.
Approximately 1,500 ships are currently stranded in the Persian Gulf, with additional vessels stuck in the Gulf of Oman because of the closure of the strait amid ongoing U.S.-Iran tensions. The accumulation of organisms on the ships’ hulls, known as biofouling, could facilitate the spread of invasive species to ports worldwide if not adequately addressed, as stated in the paper.
Tamburri and his colleagues describe the current situation as a “worst-case scenario.” Ships in the region have been stationary for an extended period, far exceeding the usual duration, which could compromise the effectiveness of hull coatings designed to prevent biofouling. The sheer number and size of the vessels, their close proximity, and the timing of the closure increase the risk of a potential “super-spreader” event, particularly as organisms in the region are entering their growing and reproductive phases.
The movement of species through biofouling has received less attention compared to other vectors like ballast water. The study mentions the example of tunicates, which can compete with native species when introduced to new environments. Efforts to regulate biofouling are still evolving, with updated guidelines released by the International Marine Organization in 2023.
Marine invasions, akin to a network, can result in the spread of organisms to new hubs through ships reaching different ports. The multitude of ships stalled in the Gulf region may harbor a diverse array of organisms, heightening the risk of invasions in other areas. The ecological implications of the current situation underscore how geopolitical events can have far-reaching consequences on global marine ecosystems. The long-term effects of potential species spread remain uncertain, signaling a significant shift in the risk of marine invasions on a global scale.
