Barnacles are crustaceans, related to crabs and lobsters, known for their ability to permanently attach themselves to various submerged surfaces. They begin their lives as free-swimming larvae before settling and cementing themselves to a substrate. Once attached, adult barnacles filter feed, extending feathery appendages to capture plankton. Their sessile lifestyle contributes to significant challenges across different marine environments.
Effects on Vessels and Infrastructure
Barnacles pose considerable challenges to vessels by increasing drag on ship hulls. This rough surface necessitates greater engine power to maintain speed, leading to increased fuel consumption. Heavy barnacle growth can increase a ship’s weight and drag by as much as 60 percent, leading to a fuel consumption increase of up to 40 percent. This translates into substantial economic burdens for the maritime industry, potentially adding between $200,000 and $1 million annually per ship in fuel expenses. The global shipping industry faces an estimated annual cost of up to $30 billion due to fouled hulls, encompassing increased fuel consumption and maintenance.
Beyond operational costs, barnacle infestations demand extensive maintenance. Regular cleaning and anti-fouling treatments are necessary to mitigate their growth, with a single dry-dock visit for barnacle removal often exceeding $100,000. Barnacles can also damage hull coatings and propellers, exposing underlying metal to seawater, accelerating corrosion and structural degradation, and incurring additional repair costs. This biofouling also extends to marine infrastructure like docks, buoys, and offshore platforms, complicating inspections and increasing structural load. Underwater pipes, such as those in cooling water systems, can experience reduced water flow efficiency and increased pumping loads due to barnacle accumulation.
Effects on Marine Organisms
Barnacles significantly impact other marine organisms through competition for resources. As sessile filter feeders, dense barnacle populations compete with other attached organisms, such as mussels, oysters, and corals, for space, food, and light on hard surfaces. This competition can alter local ecosystems by outcompeting native species, reducing biodiversity, and disrupting food web dynamics. Some barnacle species can rapidly grow and spread, effectively monopolizing available substrate. Barnacles also play a role in the spread of invasive species by hitchhiking on vessels, potentially disrupting new ecosystems.
Barnacles can also cause physical harm to marine animals. They commonly attach to the shells or skin of crabs, sea turtles, and whales. Excessive growth can increase drag, making it harder for motile animals to swim, forage, or escape predators. For crabs, heavy barnacle infestations can impede movement, interfere with feeding, and make them more vulnerable to predators. Certain parasitic barnacle species, like Sacculina, can burrow into a host crab’s body, altering its hormonal balance and reproductive capabilities. Barnacles can cause irritation, discomfort, and open wounds on their hosts, potentially leading to infections.