Which organism can be described as a fouling, filter-feeding organism?

• A. Barnacle
• B. Blue mussel
• C. Oyster
• D. Periwinkle snail

Answer: (A)

Fouling organisms attach to submerged surfaces and create maintenance challenges on boats, piers, and pilings. Barnacles fit this role perfectly: they cement themselves permanently to a surface and feed by extending feathery cirri to filter plankton from the water. This combination of fixed attachment and filter feeding makes barnacles the best example of a fouling, filter-feeding organism.

Blue mussels and oysters also filter feed, but they aren’t the signature hull-fouling creatures in the same way barnacles are; they tend to attach to rocks or other substrates rather than form the quintessential hull fouling layer. Periwinkle snails are grazing herbivores that scrape algae off surfaces, not filter feeders.