Hull Biofouling

The risk of a vessel becoming a host for marine invasive spread depends on the length of time it is kept in the water, so it is important to understand the fouling formation cycle and when marine invasive colonisation can take place. Small recreational watercraft hull fouling is a significant unregulated pathway for the introduction and spread of marine invasive species. They can travel long distances, and their relatively low speeds (compared to commercial ships) makes colonisation by marine invasives much more likely. Restrictions on antifouling compounds like tributyl tin (TBT) are likely to have increased the rate of invasion since their ban. Worldwide, recreational craft are known to have spread algae, mussels and bryzoans.

Stationary boats with high amounts of hull fouling would not pose a risk of marine invasive spread. The risk comes when the vessel moves. Boats with little overall fouling but highly fouled niche areas could pose a greater risk than heavily fouled boats if travel frequency is high.

The fouling formation cycle

In a few seconds....
As soon as you immerse a surface in sea water, organic particles naturally adhere to it. These are non-living particles.

In a few minutes....
The adhesion of the particles prepares the surface for the adhesion of bacteria. These are the first living organisms that colonize the hull.

In a few hours....
The bacteria create a kind of colony, a community, which grows rapidly.

In a few days...
Microalgae arrive and settle on the hull, feeding on the bacteria.

In about 2 months...

The arrival of larger algae (macroalgae) that become visible to the naked eye. This can be removed with a simple brushing, without forcing or needing a high pressure cleaner.

After more than 2 months...
The "superior" organisms make their appearance "encrusting species" that fix themselves by damaging the surface. For example shells, barnacles, calcareous algae... A high pressure cleaner is necessary to remove them.
 

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