Manual removal of sargassum offers reduced up front expense when compared to a barrier but also carries hidden costs because the process is so much less effective than a barrier. Moreover, when the infestation is heavy, keeping the beach free of sargassum is impractical and too costly, resulting in heavy, toxic accumulations.
The stench of rotting sargassum can be mitigated by spraying it with products that neutralize the smell. This product is environmentally safe and allows sargassum to dry out in place so that it can be more easily disposed of once weight and volume have been reduced. The HMB Sargassum Project does expect to use spray prior to removal if/when any sargassum:
- jumps the barrier and ends up on the beach
- collects in excessive quantities along the southern headlands
Spraying alone, however, is not an effective way to mitigate sargassum infestations. It does not stop sargassum from rotting, prevent metal corrosion, protect the reef, prevent beach erosion or mitigate other environmental impacts. Nor does it improve the beach going experience. And, in 2021 at least, supplies were somewhat limited.
Beach removal is the most common solution to a sargassum infestation but raking and dumping is generally not effective:
Beach removal causes erosion because it removes sand
Beach removal is a Sisyphean task: once the beach is clean, the next tide of seaweed is never far behind.
Beach removal fails to protect the reef or to ensure clean water for swimming and snorkeling.
Beach removal does not prevent unpleasant beach experiences for visitors who must put up with the stench, impediments to walking on the sand and unpleasant swimming experiences.
Beach removal is expensive. The average building on Half Moon Bay spends $$$/week on shoveling and disposal.
Careless dumping of decomposing sargassum seaweed can cause:
Direct and indirect damage to mangroves
toxic fumes from hydrogen sulfide cause flu-like symptoms in people
damage to expensive equipment
(such as air conditioning units, plumbing, and electric systems)
As you can see, the benefits of a barrier are significantly greater than Manual Beach Removal: