Hairy Sea-Mat

Electra pilosa

Electra pilosa is a colonial bryozoan that forms extensive mats or star-shaped patches on the surfaces of large algae, such as Laminaria and Fucus serratus. The colonies are typically found in the northeastern and northwestern Atlantic Ocean, the Mediterranean Sea, and as far south as Australia and New Zealand, where it is considered an introduced species. They inhabit intertidal zones and can be found at depths reaching up to 50 meters, thriving in sheltered rocky shores. The zooids of Electra pilosa are closely packed, cylindrical, and measure approximately 0.5 by 0.3 mm. Each zooid is protected by a mineralized exoskeleton featuring a transparent oval window and several spines, which give the colony its characteristic hairy appearance. These spines serve a protective function, particularly when the zooids are filter-feeding, sifting particles from the water, including flagellates, phytoplankton, and small algal debris. Reproduction occurs through asexual budding, with colonies being hermaphroditic, although individual zooids are either male or female. Breeding typically takes place in August and September, with fertilized embryos released into the water, where they develop into larvae before settling on suitable surfaces. Colonies can persist for several years in favorable conditions, although their lifespan may be shorter on ephemeral substrates. Encountering these colonies while diving can be intriguing, as they often cover large areas of the seafloor or algae, creating a textured environment. The conservation status of Electra pilosa is not evaluated, indicating its presence in various marine ecosystems.