Barnacles are commonly observed adhering to the shells of marine creatures, including lobsters. This association highlights a fascinating aspect of marine biology, revealing specific adaptations and interactions within the ocean environment.
An Unlikely Partnership: Commensalism
The relationship between barnacles and lobsters is commensalism, a symbiotic interaction where one organism benefits while the other is neither significantly helped nor harmed. Barnacles, as sessile crustaceans, gain several advantages by attaching to a mobile host like a lobster. This attachment provides constant access to new feeding grounds as the lobster moves through the water.
The lobster’s movement refreshes the water around the barnacle, ensuring a steady supply of oxygen and food particles. Being elevated on the lobster’s shell protects the barnacle from certain benthic predators. This mobility prevents the barnacle from being buried by sediment, a common challenge for bottom-dwelling organisms.
Barnacle’s Strategy: Attachment and Feeding
Barnacles begin as free-swimming larvae, undergoing several developmental stages before settling. The nauplius larva hatches from the egg and develops into a cyprid larva, which then seeks a suitable substrate for attachment. These cyprid larvae possess specialized sensory organs that help them detect chemical cues and surface textures for a favorable settling site, such as a lobster’s carapace.
Once a suitable location is identified, the cyprid larva attaches itself headfirst to the lobster’s shell using a powerful, fast-curing adhesive, often described as a natural superglue. This cement-like substance is secreted from glands at the base of their antennae, forming a permanent bond. After attachment, the larva undergoes metamorphosis, developing into the familiar adult barnacle form enclosed within calcareous plates.
Adult barnacles are filter feeders, extending feathery appendages called cirri through an opening in their protective plates. These cirri rhythmically sweep through the water, capturing plankton and other suspended organic matter.
What It Means for the Lobster
For the lobster, the presence of barnacles is a minor inconvenience. Lobsters periodically shed their exoskeletons through molting, which removes attached barnacles, along with other epibionts and accumulated debris. This natural cycle prevents an excessive build-up of barnacles on the lobster’s shell, limiting their long-term impact.
While a heavy infestation could create slight drag, increasing the energy expenditure for movement, or cause minor irritation, these effects are rarely severe enough to compromise the lobster’s survival or mobility. The lobster’s robust shell and regular molting cycle effectively manage the barnacle population, maintaining the commensal nature of the relationship. Barnacles do not pose a substantial threat to the health or foraging abilities of their lobster hosts.