According to a report published on July 30, 2026, by The Maritime Executive, a new research paper warns that the prolonged shutdown of shipping through the Strait of Hormuz has created a major risk of invasive species spreading globally. The paper, published in the journal Biological Invasions, notes that approximately 1,500 merchant vessels have been anchored in the Arabian Gulf for months, accumulating significant biofouling on their hulls.

Read also: Iran Tightens Control Over Strait of Hormuz as Houthis Threaten Red Sea Shipping

Environmental scientist and co-author Professor Mario Tamburri described the situation as a worst-case scenario and a perfect storm, according to comments reported by The Guardian. The researchers argue that the combination of extensive biofouling growth, the number and size of affected ships, and their global routes has created an immense international biosecurity threat.

The vessels arrived with fouling from other regions and are now picking up new species from the warm Gulf waters. The timing—spring and summer, when waters are warmest—is highly conducive to the growth and reproduction of invasive organisms. The specific strains of barnacles, algae, and aquatic plants found in the Gulf are likely to have higher heat tolerance and hardiness, potentially making them more invasive than similar organisms elsewhere.

International Maritime Organization guidance recommends immediate hull cleaning after a layup of more than 18 to 30 days. The researchers advise performing in-water cleaning before departure to scrape off fouling, which would reduce both the risk of invasives and fuel consumption. However, they acknowledge that for most ships, this will not happen.

In the Gulf, there is limited in-water cleaning capacity to service 1,500 ships, especially given uncertain timelines for the reopening of the Strait of Hormuz. Most trapped vessels are expected to depart at the first opportunity without waiting for optimal hull cleanliness, pushing the need for cleaning to subsequent ports of call. The researchers strongly encourage a coordinated global network of safe and effective in-water cleaning services.

The paper suggests that each ship should visually estimate the degree of fouling before departure and calculate the change in fuel efficiency while underway. This information could help prepare other ports to receive these ships with adequate resources for hull cleanings. In-water monitoring for new invasives at high-risk ports would help local authorities respond to contain any outbreak.

The team concluded that whether the situation becomes a global bioinvasion super-spreader event will depend less on the biofouling communities already present on vessels than on the speed, coordination, and effectiveness of the responses that follow. They emphasized that prevention is consistently recognized as the most effective and cost-efficient management strategy compared with post-introduction control.

Source: IndexBox Market Intelligence Platform