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.
This hydroid forms neat rounded aggregates of large polyps, which are more diffuse than Tubularia indivisa. The stems are tubular, with a yellowish coloured tegument and are branched at the base. The polyp colour is pale pink to red, and consists of a central circle of oral tentacles surrounded by paler but larger aboral tentacles. Average height is 40 - 60 mm (smaller than Tubularia indivisa) and the diameter of the polyp and tentacles is ca 10 mm. 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
- Intertidal, found on rocks and algae in shallow water down to ca 25 m.
- 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 and Mediterranean.
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