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Acorn Barnacle Facts

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Acorn barnacles (Balanus balanoides) are seashore organisms that are prevalent in intertidal regions. If you take a walk on a shore locale, you may just spot some acorn barnacles over rocks and other types of flat planes -- think the undersides of boats. Acorn barnacles are crustaceans, and are therefore associated with aquatic creatures such as shrimp, lobsters and crabs.

Appearance of the Acorn Barnacle

As far as diameter goes, acorn barnacles are capable of growing to a maximum of just over half an inch. The hermaphroditic organisms are generally gray or white in color, and consist of six shell slabs, all of which are of differing sizes and are attached to smaller shell portions. Acorn barnacles also feature gaps that are shaped similarly to diamonds.

Geographic Location

Acorn barnacles are prevalent in many spots all over the planet, from the northeastern region of the Atlantic Ocean to coastal sections of the Pacific. The organisms live in both tropical and temperate waters. Rugged shores are the natural habitat for acorn barnacles.

Basic Diet of the Acorn Barnacle

When underwater, acorn barnacles consume zooplankton. The filter feeding crustaceans also eat a lot of detritus. In the cold winter months, acorn barnacles abstain from eating, depending entirely on previously saved sustenance supplies. They also occasionally consume waste matter from fish. Acorn barnacles utilize their "cirri" for feeding purposes. "Cirri" have a feathery, soft texture and are appendages similar to feet. Cirri are also used for breathing.

Activity of the Acorn Barnacle

Acorn barnacles are largely inactive beings. The bulk of the organisms' activity typically consists of mating and vying for precious "real estate" in shore settings, whether over a large rock or on a boulder or wharf.

Reproduction in the Acorn Barnacle

Acorn barnacles are hermaphroditic animals, meaning they feature reproductive organs from both genders. Despite this, individual acorn barnacles operate in terms of gender. One acorn barnacle is female with both types of organs, while the same applies to a male. During mating, an acorn barnacle proceeds either as male or female. The mating season takes place during the fall months.

Life Expectancy

Acorn barnacles in generally stay alive in the range of 5 to 10 years, although it always depends on the specific specimen.