Barnacle Habitat
Acorn Barnacles
Habitat Barnacles are found world wide
Of all the shellfish in Barnegat Bay, barnacles are among the most numerous and the most overlooked.
They gradually build up on almost any hard surface including rocks, pilings, driftwood, boats and even other animals.
All barnacles are marine, meaning they live in salt water.
Most inhabit shallow or tidal waters, with 75% of barnacle species living at water depths of less than 300 ft (100 m). However, they have been found at great depths of 2,000 feet.
Living in the intertidal zone, acorn barnacles are periodically above water, but are well adapted to prevent water loss.
Their calcite shells are impermeable, and they possess two movable plates (operculum) which they can slide across their apertures when not feeding.
These plates also protect against predation.
More details are available on the Barnacle Anatomy page.
Ecology
Barnacles have a multistage life cycle.
A recently fertilized eggs will live in the water column for several weeks.
The larval barnacles drift to some extent in the water column and when conditions are right, settle on a hard surface and undergo a transformation (metamorphosis).
A larval barnacle will settle on its head and cement itself to the substrate.
The legs and the rest of the body undergo a radical transformation similar to that of butterflies.
The result of this transformation is the adult barnacle. Barnacles will only settle and begin the transformation when conditions are right.
These include temperature, water conditions, suitable hard surface (substrate) and proximity to other barnacles.
