"Super-spreading event of biological invasion": Closure of the Strait of Hormuz creates extreme global threat to marine biodiversity

The closure of the Strait of Hormuz in February 2026, following the war between Iran and the US, left over 1,500 ships stranded in the Persian Gulf. A new study warns of 'biofouling' – the accumulation of organisms on ship hulls, which, when navigation resumes, could invade foreign oceans and endanger marine biodiversity.

The closure of the Strait of Hormuz in February 2026, with the outbreak of war between Iran and the US, created an extreme global threat to marine biodiversity. Over 1,500 commercial ships have been stranded in the Persian Gulf since the closure. An international team of marine biologists published a new study finding that while the ships sit motionless, their submerged hulls become covered in marine organisms – from microbes to algae, sea snails, and invertebrates. This phenomenon, known as 'biofouling', could cause the spread of invasive species across the oceans when shipping resumes. The lead researcher, Professor Mario Tamburri from the University of Maryland, calls it "the perfect storm" and "a super-spreading event of biological invasion." The ships have been stranded for months, unlike normal docking of one to three days, allowing marine communities to establish. Invasive species could outcompete local species, spread diseases, and cause billions of dollars in damage annually. Hotspots like India and Singapore are at high risk. The study calls for cleaning the ships before leaving the Gulf and increasing monitoring at ports. The International Maritime Organization (IMO) is developing a mandatory procedure to reduce spread.

"Super-spreading event of biological invasion": Closure of the Strait of Hormuz creates extreme global threat to marine biodiversity