Growth patterns of Mytilopsis leucophaeata, an invasive biofouling bivalve in Europe

Abstract

For the first time, growth of Mytilopsis leucophaeata, an important European fouling species, was investigated. By means of growth cages, individual shell growth of three cohorts, with, respectively, initial shell lengths of ≤5 mm, 10 mm and 15 mm, was monitored in the harbour of Antwerp, Belgium, during 2003 – 2004. M. leucophaeata followed an oscillatory growth pattern with a single summer growing period per year (May to August). Growth decreased during wintertime, but never ceased completely. M. leucophaeata has an average growth rate of <3 – 6 mm year⁻¹. Temperature was found to be the main environmental factor affecting growth. The von Bertalanffy growth function was used to model growth of individuals ≤5 mm, resulting in L_∞ = 16.7 mm and K = 0.56. Based on a combination of growth of all three cohorts, the hypothetical growth of an average individual mussel could be modelled over a 5-year period, resulting in a maximum length >19 mm with a growth rate of 0.41. Its longevity (more than 5 years) and the positive effect of higher water temperatures on growth, combined with its high resistance to chlorination, provides M. leucophaeata with a high potential for severe and long-lasting biofouling

Keywords:

• Mytilopsis leucophaeata
• growth
• Westerschelde
• temperature

Acknowledgements

The first author was financially supported by a BOF-project (contract 011D13503) of Ghent University and especially appreciates the logistic and financial support of BASF, Antwerp N.V. and ONDEO Nalco (contract d.d. 21/10/2001). This research is part of the UGent project GOA 01G00705. Dr Gheskiere provided constructive comments on the manuscript. We would also like to thank Endis-Risk for the picture of the Schelde river ( Figure 1) and the chemical measuring network MWTL (The Netherlands) for the use of their chlorophyll a data.