Organims

Bugula neritina (Brown or common bryozoan)

Bryozoa

Type of fouling organism: Erect Bryozoan

Bryozoa are sessile colonies of microscopic animals where each animal inhabits a separate box of the cuticle within the colony which is called a zooid. The zooid body has a fixed trunk and a lophophore for food collection. zooids are hermaphroditic. Gametes are passed out through the pores and fertilised eggs are brooded. After hatching motile larvae are released and while most are generally of short duration (minutes to hours), some can survive for up to a year in the plankton before settling. Bryozoa are common intertidal and subtidal animals, most are marine but there are some freshwater species.

Bugula neritina form flexible bushy colonies, which are branched and reach 10 cm in height. The colonies can be dark red-purple or purple-brown, though occasionally they are a dull, dark red. A single zooecium of is 0.2 - 0.3 mm wide and 0.6 - 1.1 mm long. Its front is a flexible membrane, and it bears no spines, although the upper, outer corner of the zooecium is pointed.

Environment and Habitat

- Habitat - intertidal to subtidal.
- Feeding - bacteria, phytoplankton, detritus, and dissolved organic material.
- High intolerance of substratum loss.
- Needs salinities above 14 ppt to grow.

Reproduction

- Reproductive type: Hermaphrodite, budding.
- Reproductive frequency: Annual protracted.
- Age at maturity: 6 - 8 weeks.
- Development: Lecithotrophic, viviparous (no care).
- Larval duration: 2 - 10 hours.
- Life span: 1 year.

Communities

- Colonial.

Equipment

- 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.
- 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

Nets
- Onshore Net washing
- Coatings (Copper sulphate, fouling release coatings e.g. silicon)
- Mechanical cleaning of infrastructure (Disk cleaners)
- Air drying nets
Trays
- 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)
Shellfish
- 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

Distribution

- Found from the Mediterranean north to south west England, where it is occasionally found in warm dock habitats.


References


Guide to exotic species of San Francisco Bay Bugula neritina (Linnaeus 1758) species_pages/b_neritina.html

Gordon, D.P. and S.F. Mawatari. 1992. Atlas of marine-fouling Bryozoa of New Zealand ports and harbours. New Zealand Oceanographic Institute, Pub. 107: 1
52.

Zabin, C.J. 1999. HBS/invertguide/species/bugula_neritina.htm

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 www.crabproject.com