Ackerman, J. D., 1995.  Zebra Mussel Life History, Environmental Studies Programme, University of Northern British Columbia

Proceedings of The Fifth International Zebra Mussel and Other Aquatic Nuisance Organisms Conference, Toronto, Canada, February 1995

Zebra Mussel Life History

Abstract:
The success of introduced zebra mussels (Dreissena polymorpha (Pallas) and Dreissena bugensis Andrusova) can be related in large part to a life history that is unlike that of the indigenous freshwater fauna and yet is conserved with marine bivalves. Following external fertilization and embryological development, there is a brief trochophore stage. With the development of a velum and the secretion of a D-shaped larval shell, the larva becomes a D-shaped veliger, which is the first recognizable planktonic larva. Later, the secretion of a second larval shell leads to the last obligate free- swimming veliger stage known as the veliconcha. The last larval stage known as the pediveliger, however, can both swim using its velum or crawl using its fully-functional foot. Pediveligers actively select substrates on which they "settle" by secreting byssal threads and undergo metamorphosis to become plantigrade mussels. The secretion of the adult shell and concomitant changes in growth axis leads to the heteromyarian or mussel-like shape, which is convergent with marine mussels. Like a number of other bivalves, zebra mussels produce byssal threads as adults, but these attachments maybe broken enabling their translocation to new areas. The recognition and examination of these life history traits will lead to a better understanding of zebra mussel biology.