Sophie Abdulla

Marine biologists warn that roughly 1,500 ships stranded in the Persian Gulf and hundreds more in the Gulf of Oman since February could become major carriers of invasive marine species when shipping through the Strait of Hormuz resumes. Months of inactivity, warming seasonal waters and the Gulf’s scarcity of hard underwater surfaces may have allowed microbes, algae, barnacles, mussels and other organisms to build up on ship hulls. These species could spread to vulnerable ports worldwide, displace native organisms, damage fisheries and aquaculture, clog power-plant cooling systems, carry pathogens and increase ships’ fuel consumption. Researchers say cleaning the heavily fouled fleet before departure may be impractical, making coordinated international monitoring, containment and cleaning at destination ports essential to limiting a potentially global biological invasion.

Around 1,500 ships stranded in the Persian Gulf and hundreds more in the Gulf of Oman may have accumulated extensive marine biofouling after months of inactivity. Scientists warn that when the vessels resume global voyages, attached microbes, algae, invertebrates, larvae and potentially pathogens could spread invasive species on an unprecedented scale. The risks are heightened by the Gulf's warm seasonal waters and the timing of the Strait of Hormuz closure. Invasive organisms could damage ecosystems, fisheries, aquaculture and infrastructure, while biofouling could increase ships' fuel consumption by up to 25%. Cleaning vessels before departure would be difficult because of the scale, limited capacity and risk of releasing organisms and toxic paint debris. Researchers therefore call for international cooperation and for destination ports to inspect and clean arriving ships, saying the eventual impact will depend heavily on the international response.