Life history and population dynamics of Moerisia sp., a non-native hydrozoan, in the upper San Francisco Estuary (U.S.A.)

TitleLife history and population dynamics of Moerisia sp., a non-native hydrozoan, in the upper San Francisco Estuary (U.S.A.)
Publication TypeJournal Article
Year of Publication2011
AuthorsWintzer, A. P., Meek M. H., & Moyle P. B.
JournalEstuarine, Coastal and Shelf Science
Volume94
Issue1
Pagination48 - 55
Date Published07/2011
ISSN0272-7714
Keywordsasexual reproduction, hydrozoa, life history, Moerisia, population dynamics, sexual reproduction
AbstractSome populations of gelatinous zooplankton appear to be increasing and causing ecological disruptions during large bloom events. The goal of this study was to investigate the life history and population dynamics of the small, invasive Moerisia sp. and its potential ecological impacts in the upper San Francisco Estuary, California. Medusae and polyps were collected from 8 and 2 sites, respectively, during 2007 and 2008. Polyps emerged from a resting stage during June. Asexual reproduction of medusae buds was positively correlated with temperature and negatively related to salinity. The production of polyp buds was positively correlated with dissolved oxygen and water transparency levels. Sexual reproduction, defined by the presence of eggs, was related to the size of medusae. Cessation of reproduction of both polyps and medusae occurred in October, when temperatures dropped below 17 °C. This life history is similar to other hydrozoans and allows Moerisia sp. to reach large numbers seasonally in the San Francisco Estuary, possibly contributing to the recent declines of pelagic fish and zooplankton.
URLhttp://www.sciencedirect.com/science/article/pii/S0272771411001740
DOI10.1016/j.ecss.2011.05.017