August 1, 2014.
Jellyfish are generally characterized by their jelly-like bodies and internal lining (two tissue layers). They found both in the phylum Ctenophora and the phylum Cnidaria. Ctenophores differ from cnidarians primarily due to the rows of “combs”, or cilia, which are used for transportation. Additionally, ctenophores possess sticky cells while cindarians possess stinging cells. Jellyfish depend on zooplankton (small floating aquatic animals) as a food source; as a result, they are potential competitors and predators to plankton-eating fish and may negatively impact fish populations.
As recently as 1950, jellyfish have entered the San Francisco Bay from the Mediterranean Sea (probably in water carried by ships as ballast), becoming an invasive species in this delicate ecosystem. Among the varieties of jellyfish found, the most common include: P. brachei (native), B. virginica (invasive), M. marginata (invasive), and M. lysoni (invasive). Little is known about the jellyfish community in the San Francisco Estuary, and information on their abundance and distribution will help scientists better understand their role in local food webs. In order to obtain this information, samples were regularly taken from 9 different stations in the delta over the course of 2 years (2010-2011). Jellyfish were isolated from these samples, identified based on their characteristic morphological features, measured by diameter and height, and counted. The data from this study was analyzed in order to determine niches of the jellyfish and their potential impacts on the delta smelt.
Biology | Environmental Education | Environmental Sciences | Marine Biology
Romberg Tiburon Center for Environmental Studies (RTC)
This material is based upon work supported by the S.D. Bechtel, Jr. Foundation and by the National Science Foundation under Grant No. 0952013. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the S.D. Bechtel, Jr. Foundation or the National Science Foundation. This project has also been made possible with support of the National Marine Sanctuary Foundation. The STAR program is administered by the Cal Poly Center for Excellence in Science and Mathematics Education (CESaME) on behalf of the California State University (CSU).