Grazing rates of Elysia tomentosa on native and introduced Caulerpa taxifolia
- 146 Downloads
The marine alga Caulerpa taxifolia Vahl (C. Agardh), recognized globally as one of the most prolific non-native species introductions, has been introduced to several temperate locations from where it has since rapidly expanded. C. taxifolia is protected by a toxin (terpenoid) in its tissues that limits grazing by native herbivores. Sacoglossan molluscs of the genus Elysia are among the few organisms that graze C. taxifolia; however, little is known about their feeding ecology. In the current study, we quantified the grazing rates of Elysia tomentosa on native C. taxifolia (Moreton Bay, Queensland) and introduced C. taxifolia (Botany Bay and Lake Conjola, New South Wales). Grazing rates were similar at Moreton Bay sites and Botany Bay; however, they were significantly lower in Lake Conjola. At the maximum observed grazing rate, slugs ate their body weight in C. taxifolia (dry weight) every 18–24 h. Differences in grazing rates between locations may be explained by differences in C. taxifolia morphology rather than native or introduced origin.
KeywordsElysia tomentosa Caulerpa taxifolia Introduced species Grazing
We thank Kimberley Townsend and the staff of Moreton Bay Research Station for assistance with lab trials and Romain Mari for assistance with field collections. We acknowledge funding provided by the Moreton Bay Research Station Community Research Scholarship and the Tangalooma Research Foundation. In addition, we thank the two anonymous reviewers whose thoughtful comments greatly improved the earlier drafts of this manuscript.
- Boudouresque, C. F., A. Meinesz, M. A. Ribera & E. Ballesteros, 1995. Spread of the green alga Caulerpa taxifolia (Caulerpales, Chlorophyta) in the Mediterranean: possible consequences of a major ecological event. Sciencia Marina 59(Suppl. 1): 21–29.Google Scholar
- Cheshire, A., G. Westphalen, V. Boxall, R. March, J. Gilliland, G. Collings, S. Seddon & M. Loo, 2002. Caulerpa taxifolia in West Lakes and in the Port River, South Australia: distribution, eradication options, and consequences. SARDI Aquatic Sciences, Adelaide: 75 pp.Google Scholar
- Creese, R. G., A. R. Davis & T. M. Glasby, 2004. Eradicating and preventing the spread of the invasive alga C. taxifolia in NSW. NSW Fisheries Final Report Series No. 64.Google Scholar
- Lemee, R., C. F. Boudouresque, J. Gobert, P. Malestroit, X. Mari, A. Meinesz, V. Menager & S. Ruitton, 1996. Feeding behaviour of Paracentrotus lividus in the presence of Caulerpa taxifolia introduced in the Mediterranean Sea. Oceanologica Acta 19: 245–253.Google Scholar
- Meinesz, A. & B. Hesse, 1991. Introduction of the tropical alga C. taxifolia and its invasion of the northwestern Mediterranean. Oceanologica Acta 14: 415–426.Google Scholar
- Thibaut, T., A. Meinesz, P. Amade, S. Charrier, K. De Angelis, S. Ierardi, L. Mangialajo, J. Melnick & V. Vidal, 2001. Elysia subornata (Mollusca) a potential control agent of the alga Caulerpa taxifolia (Chlorophyta) in the Mediterranean Sea. Journal of the Marine Biological Association of the United Kingdom 81: 497–504.CrossRefGoogle Scholar
- Williams, S. I. & D. I. Walker, 1999. Mesoherbivore-macroalgal interactions: feeding ecology of sacoglossan sea slugs (Mollusca, Opisthobranchia) and their effects on their food algae. Oceanography and Marine Biology 37: 87–128.Google Scholar
- Zuljevic, A., T. Thibaut, H. Elloukal & A. Meinesz, 2001. Sea slug disperses the invasive Caulerpa taxifolia. Journal of the Marine Biological Association of the United Kingdom 81: 343–344.Google Scholar