Jellyfish are important components of aquatic ecosystems and may interfere with human priorities through damage to fisheries, tourism, and power production. Jellyfish populations are renowned for large, unexplained outbreaks (blooms) that may be affected by polyp density and environmental factors, including temperature, salinity, light, and food. In this study, 14 to 15 sites underneath marina floats were monitored by monthly photographs; temperature, salinity, and light intensities were recorded beneath the floats from December through March in 3 yr in order to quantify the amounts and times of strobilation of the moon jellyfish Aurelia labiata in relation to polyp density and environmental factors in Cornet Bay, Washington, USA. Strobilation occurred during February 2004 (Year 1), January and February 2005 (Year 2), and February to April 2006 (Year 3), when temperature, salinity, and light were increasing after the annual minima. Polyps averaged 58% cover and densities of 9.3 cm -2 with little variation among years. Polyp densities were not correlated with the amounts or start times of strobilation. By contrast, the amounts and times of strobilation and all physical factors tested (temperature, salinity/precipitation, light) differed significantly among years. Strobilation was greatest (~63% of polyps) and earliest in Year 2, when pre-strobilation temperature and daily light exposure were high and precipitation was low. The differences in amounts and times of strobilation were greater than predicted from previous laboratory experiments, thus suggesting additive effects of environmental factors. Warm temperatures, nutrient delivery from run-off, and high sunlight enhance plankton production, providing abundant food for the polyps and new jellyfish, and those environmental cues synchronize jellyfish and plankton production.KEY WORDS: Warming · Photoperiod · Jellyfish · Bloom · Climate · Reproduction · Density-dependent · Puget Sound 375: 139-149, 2009 some species have been correlated with high salinities (Goy et al. 1989, Purcell et al. 1999, Molinero et al. 2005. Laboratory experiments show significant effects of salinity on asexual reproduction (reviewed by Purcell 2007). High sunlight (insolation) is also related to abundant jellyfish in situ (Hernroth & Gröndahl 1985, Molinero et al. 2005, Purcell & Decker 2005, and greater light exposure accelerates jellyfish production in the laboratory (Loeb 1973, Purcell 2007, Liu et al. 2009). Given that climate models project global ocean warming and changes in precipitation and cloud cover for the foreseeable future (e.g. IPCC 2007), jellyfish populations would be expected to be affected. Resale or republication not permitted without written consent of the publisher OPEN PEN ACCESS CCESSMar Ecol Prog SerThe life cycle of most scyphomedusae and many hydromedusae includes a perennial clonal polyp stage that asexually buds more polyps and new jellyfish. For scyphozoans, the production of new jellyfish (ephyrae) is called strobilation. Population sizes of ma...

The rapid decrease of several stocks of Pacific herring, Clupea pallasi, in Puget Sound, Washington, has led to concerns about the effects of industrial and nonpoint source contamination on the embryo and larval stages of this and related forage fish species. To address these concerns, the state of Washington and several industries have funded efforts to develop embryo and larval bioassay protocols that can be used by commercial laboratories for routine effluent testing. This article presents the results of research to develop herring embryo and larval bioassay protocols. Factors evaluated during protocol development included temperature, salinity, dissolved oxygen (DO), light intensity, photoperiod, larval feeding regimes, use of brine and artificial sea salts, gonad sources, collection methods, and egg quality.