Type of fouling organism: Hydroid
Hydroids are simple in structure, all are aquatic and most are marine. The life cycle includes both sessile polyps and freely floating medusae, with hydroids formed as the sessile asexual polyp stage with a reduced pelagic free floating sexual medusae or jellyfish stage. In many hydroids, the medusa stage is reduced and remains attached to the hydroid. Some species may even have a swimming polyp stage in the life cycle.
Tubularia indivisa is a large hydroid reaching 100 - 150 mm in height. It has a stem holding a solitary, conical polyp that is brightly coloured with shades of pink and red and flask shaped. The stems stand erect and are fused together with other stems into dense tufts at the base . The polyp looks like a flower and consists of a central cluster of about 40 oral tentacles surrounded on the outside by 20 - 30 paler but larger tentacles. Polyps are often present only in the spring. Tubularia indivisa and Tubularia larynx can be difficult to distinguish and the two often occur together. In Tubularia larynx, the stems branch, while in Tubularia indivisa they are unbranched, though separate individuals settle on the stems of others forming irregular clumps.
Environment and Habitat
- Attaches to hard substrata from the inter tidal to the shallow shore, particularly abundant in areas with strong tidal currents.
- Reproduction type: Budding separate sexes vegetative.
- Neat, bushy colonies.
- 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
- Widespread throughout the north east Atlantic but not in the Mediterranean.
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