Interim profile, incomplete information
Taxonomic name: Zoobotryon verticillatum (Della Chiaje, 1822)
Common names: spaghetti bryozoan
Organism type: bryozoan
Zoobotryon verticillatum is a stoloniferous fouling organism found in many temperate and warm waters around the world, it is commonly found on boat hulls, which may explain its current worldwide distribution. This bryozoan has been recorded as an invasive alien species in many places all over the world, causing ecological and economical damages.
Zoobotryon verticillatum is a stoloniferous fouling organism that grows in the form of irregularly-branched translucent colonies which can attain lengths exceeding one meter (Hayes et al., 2005; Hill, 2001).
Zoobotryon verticillatum is found in temperate and warm waters, fouling on any hard subtidal surface. Optimal growth at temperatures above 22 °C (Bullivant, 1967 in Winston, 1995; Elkhorn Slough Research, 2002; Fox, 2001; Hill, 2001).
Zoobotryon verticillatum can have ecological and economical impacts due to its capacity to expand in an aggressive way (Gossett et al., 2004): it has been reported to cause the collapse of eelgrass cover when proliferating in summer (Williams, 2007). It can also (i) affect navigation when fouling on submerged structures; (ii) cause clogs in industrial seawater pipes (Fox, 2001) and; (iii) affect fishing by fouling on fishing gear (Elkhorn Slough Research, 2002).
Because of it’s impressive suspension-feeding, Zoobotryon verticillatum is considered to play a key role in maintaining good water quality in the Indian River Lagoon (Bullivant, 1968; Hill, 2001; Robinson 2001; Winston, 1995).
In the Galveston Bay Invasive Species Risk Assessment (Gossett et al., 2004), Zoobotryon verticillatum accumulated the greatest number of points of ‘‘risk criteria”, however, it received the lowest score on the scale of control feasibility.
Z. verticillatum produces secondary metabolites that prevent its predation, limit settlement of organisms and protect it from viral or bacterial infection. Only a few nudibranch species, namely Okenia zoobotryon, are known to directly feed upon Z. verticillatum (Hill, 2001; Robinson, 2001; Winston, 1995).
Zoobotryon verticillatum has a worldwide distribution, probably due to its primary vector of translocation: hull fouling (Fox, 2001). Recorded as an invasive alien species in many places all over the world, such as the United States (Gossett et al., 2004), Australia (Hayes et al., 2005) and Seychelles (Ikin and Dogley, 2005).
Preventative measures: In the Galveston Bay Invasive Species Risk Assessment (Gossett et al., 2004), Zoobotryon verticillatum accumulated the greatest number of points of ‘‘risk criteria”, however, it received the lowest score on the scale of control feasibility.
In a study (Hayes et al 2005) designed to identify and rank introduced marine species found within Australian waters (potential domestic target species) and those that are not found within Australian waters (potential international target species), Z. verticillatum was ranked as a 'Low priority species'- these species have a low impact potential and a low invasion potential relative to the other domestic non-native species identified here.
Zoobotryon verticillatum is a suspension feeder - between 25,000 and 344,000 L of water day-1 m-2. Each individual zooid in a colony has 8 ciliated tentacles that are extended to filter phytoplankton (Bullivant, 1968; Hill, 2001).
Asexual reproduction, via fragmentation is thought to be an important reproductive strategy for Zoobotryon verticillatum. Sexual reproduction may occur very infrequently, environmental temperature beeing the major influence on larval production. (Robinson, 2001)
Principal sources: Bullivant, 1968. The rate of feeding of the bryozoans, Zoobotryon verticillatum. nzj Mar. Freshwat. Res. 2: 111-134.
Elkhorn Slough Research., 2002. Least Wanted Aquatic Invaders, Spaghetti Bryozoan (Zoobotryon verticillatum).
Fox, R., 2001. Invertebrate Anatomy Online. Zoobotryon verticillatum, Ctenostome Bryozoan.
Gossett, L., Lester, J., Gonzalez, L., 2004. Galveston Bay Invasive Species Risk Assessment, Final Report. Prepared for Galveston Bay Estuary Program, Texas Commission on Environmental Quality, Webster, Texas. 57 pp.
Hayes, K., Sliwa, C., Migus, S., McEnnulty, F., Dunstan, P., 2005. National priority pests: Part II ranking of Australian marine pests. CSIRO Marine Research. 106 pp.
Hill, K., 2001. Zoobotryon verticillatum. Smithsonian Marine Station at Fort Pierce.
Ikin, R., Dogley, D., 2005. Invasive Alien Species Review for UNDP-GEF PDF-B Project, Mainstreaming Biodiversity in Seychelles Final Report. 81 pp.
Robinson, N.M., 2001. Interactions between the nudibranch Okenia zoobotryon and its bryozoan prey Zoobotryon verticillatum. Thesis Master of Sciences, Department of Biology, University of Central Florida, Orlando, Florida. 67 pp.
Williams, S.L., 2007. Introduced species in seagrass ecosystems: status and concerns. Journal of Experimental Marine Biology and Ecology 350, 89–110.
Winston, J.E., 1995. Ectoproct diversity of the Indian River Coastal Lagoon. Bulletin of Marine Science 57 (1), 84–93.
Compiled by: Jaen Nieto Amat, Departamento de Oceanografia e Pescas, Universidade dos Açores Portugal
Last Modified: Thursday, 17 September 2009