Maritime-Executive: Biofouling From Hormuz Shutdown Poses Major Invasive Species Risk

Published by maritime-executive

For months, industry analysts have noted that biofouling accumulation on vessels stuck in the Arabian Gulf would be a slow-down factor in restarting shipping operations through the Strait of Hormuz. Fouling pressure in the Gulf is intense, and hull cleaning services in the GCC nations’ ports have reportedly been in high demand. But all of that biofouling also poses a risk to regional ecosystems in overseas ports, according to a new research paper: once the 1,500 affected ships in the Gulf get under way and begin moving around, they will be carrying a forest of invasive species on their hulls wherever they go.

“If you had to design the worst-case scenario, I don’t know if you could have done it differently. It is a perfect storm,” environmental scientist and co-author Prof. Mario Tamburri told The Guardian. 

In a new paper in the journal Biological Invasions, Tamburri and his colleauges noted that the Hormuz standoff is the largest single forced shutdown for the global fleet in modern history: 1,500 merchant ships have been waiting at anchor and accumulating fouling for months. sd

“Given the unprecedented scale and duration of this mass lay-up of ships, conditions are primed for a large-scale, marine bioinvasion ‘super-spreader’ event as regular maritime trade in the region resumes,” Tamburri and his co-authors argued. “The combination of extensive biofouling growth and species accumulation, and the sheer number, size, and global reach of affected vessels, has created an immense international biosecurity threat.”

The vessels arrived with fouling from other regions, and will pick up new species that reside in the warm waters of the Gulf. The timing – spring and summer, when waters are warmest – is highly conducive to invasives’ growth and reproduction. The specific strains of barnacles, algaes, aquatic plants found in the Gulf are likely to have higher heat tolerance and overall hardiness from surviving in a hot, competitive environment, and might be especially invasive compared to similar examples of the same organisms elsewhere. 

Inevitably, the ships will carry these collections with them when they leave, spreading invasives around the world. IMO guidance recommends “immediate actions” to clean off the hull after a layup of more than 18-30 days. The researchers advised performing in-water cleaning before departure in order to scrape off the fouling, helping to reduce the risk of invasives and reduce the ship’s fuel consumption at the same time – but acknowledged that for most ships, this will not happen. 

In the Gulf, there is limited in-water cleaning capacity to service 1,500 ships, especially on shifting, uncertain timelines for the reopening of Hormuz. Most of the trapped vessels will take the first possible opportunity for departure, without waiting for optimal hull cleanliness. This will push the need for cleaning to the next port of call, or the one after that. “We therefore strongly encourage a coordinated global network of safe and effective [in-water cleaning] services,” the researchers concluded. 

Ideally, each ship would try to visually estimate the degree of fouling on the hull before leaving, and would calculate the change in fuel efficiency while under way. This information could then be used to prepare other ports to receive these ships in a prepared manner, with adequate resources for providing hull cleanings. In-water monitoring for new invasives (at high-risk ports of call) would help local authorities to respond if necessary to contain any outbreak of invasives. 

“Whether it becomes a global bioinvasion super-spreader event will now depend less on the biofouling communities already present on vessels than on the speed, coordination, and effectiveness of the responses that follow,” the team concluded. “Prevention is consistently recognized as the most effective and cost-efficient management strategy compared with post-introduction control.”