Type of fouling organism: Barnacle
Barnacles are a unique, and much modified group within the Phylum Crustacea. All barnacles are sessile marine animals, which remain fastened to hard substrates. When the barnacle is immersed under water, the upper shell plates open and the legs reach out casting a food collecting net. These basket like limbs are called cirri and filter food from the water and direct it towards the mouth. Barnacles have both male and female organs (hermaphroditic) and are all able to fertilise one another. As the adult stage is sessile, motile larval stages living in the plankton are the main method of dispersal. Barnacle larvae develop through a number of planktonic stages with the rate determined by feeding rate and temperature.
Balanus improvisus has a white or grey shell with a conical, smooth wall. The shell opening is diamond-shaped and toothed. The base is up to 15 mm in diameter, calcareous, flat, thin and permeated by pores with height being less than the base diameter.
Environment and Habitat
- Habitat - found from the mid shore to the sublittoral on rocks, algae and artificial surfaces in brackish water and estuarine areas.
- Reproductive type: Hermaphrodite.
- Found on other biofouling organisms.
Effects and Impacts
- Problematic for stock species as can compete for space and resources.
Control/ Strategies and Management
Principles of Management
C Combat Settlement
- Range includes western Norway and the Baltic down to south Atlantic coasts of Spain and Portugal and into the Mediterranean and Black Sea.
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