Jania Rubens


Type of fouling organism: Red Algae

Algae include several groups of relatively simple, eukaryotic, living aquatic organisms that capture light energy through photosynthesis to convert it to inorganic substances into organic matter. Algae vary from small, single-celled species to complex multicellular species, such as seaweeds. Seaweeds live in the sea or in brackish water occupying both the inter and sub-tidal. The algae can be distinguished by the different pigments into three basic colours: red, green and brown. Red algae are found in the intertidal to the subtidal at depths of up to 40m and in some cases up to 250m. There are over 6,500 described most of which are marine. Their red colour is attributed to the dominance of pigments phycoerythrin and phyocyanin. Components of their cell walls are in widespread commercial use and coralline algae which secrete calcium carbonate onto the surface of their cells have been used in bone replacement therapy.

Jania rubens is a red algae with calcareous jointed fronds, which branch dichotomously. It forms thick tufts, usually attaching to other algae.

Environment and Habitat

- Upper sublittoral and to a depth of 8 m.
- Epiphyte.


- Reproductive type: Alternation of generations.
- Reproductive frequency: Insufficient information.
- Age at maturity: Insufficient information.
- Development: Planktonic.
- Larval duration: Insufficient information (2 - 10 days in the related species Corallina officinalis).


- Epiphyte.


- Found on other biofouling organisms.
- Stock species particularly shellfish.
- Fishnets, cages, pontoons, shellfish trays, tanks, pipes.

Effects and Impacts

- Problematic for stock species as can compete for space and resources.
- Can obstruct the opening of bivalve shells and nets.
- Can reduce the value of shellfish.
- Increases the weight of equipment.
- Increases labour and production costs as a result of cleaning and removal of biofouling.

Control/ Strategies and Management

- Onshore Net washing
- Coatings (Copper sulphate, fouling release coatings e.g. silicon)
- Mechanical cleaning of infrastructure (Disk cleaners)
- Air drying nets
- Manual cleaning (scrubbing and/or brushing)
- Low power washing
- High power washing
- Jet washing
- Air drying
- Lowering trays below photic zone during major spatfalls
- Biological Control (Sea urchins and periwinkles)
- Coatings (Copper sulphate, fouling release coatings e.g. silicon)
- Manual Cleaning
- Mechanical Cleaning
- Hot water 55oC for 5 seconds (Stock mortalities of ca 5% with this method)
- Dipping (Freshwater or chemical solution)
- Lowering lines below photic zone during major spatfalls
- Biological control (Sea urchins and periwinkles)
- Coatings (Copper sulphate, spiky coatings, fouling release coatings e.g. silicon)

Principles of Management

C Combat Settlement
P Protect Equipment and Stock
R Remove Biofouling


- Range is from the Baltic Sea in the north to Portugal and the Azores in the south. Also found in the Mediterranean and Canary Islands.


Algaebase species detail Jania rubens (Linnaeus) J.V. Lamouroux,

Morton, O. & Picton, B.E., 2005. Jania Rubens [In] Encyclopedia of Marine Life of Britain and Ireland

Janet Moore (2001) An Introduction to the Invertebrates. Cambridge University Press

Hayward P, Nelson-Smith T & Shields C (1996) Seashore of Britain and Northern Europe. HarperCollins Pubs.

© Copyright