Presenter(s): Ya Li—Environmental Science
Faculty Mentor(s): Marco Corrales-Ugalde, Kelly Sutherland
Session: Prerecorded Poster Presentation
Cnidarian jellyfish are ubiquitous predators of pelagic communities, however, very little is known about their phenology and how food availability affects their reproductive cycles . However, research shows that starved jellyfish tend to decrease somatic growth and allocate more resources to gonad development . Thus, a ratio of body size to gonad size might work as a proxy to the nutritional state of jellyfish . We hypothesize that when food is scarce, C . gregaria will have larger gonads relative to their body size . The jellyfish observed were collected both in a period of low primary productivity where food was scarce (winter) and a period of high primary productivity (summer) along two longitudinal transects in the North California Current System . ImageJ was used to analyze photos taken of the preserved specimens to obtain bell diameter and gonad area to then create a gonadal index (gonad area/bell area) . The data shows a slightly higher gonad area to bell area ratio in the winter C . gregaria than those from summer indicating an increased effort towards reproduction when resources are depleted . Due to the preservation method causing a loss in biomass of the collected specimens, it makes it difficult to relate morphological measurements on preserved specimens to the morphology of live organisms . In the future, we will make a correction factor to convert between the measurements of live and preserved organisms . Understanding the links between oceanographic conditions and population dynamics of gelatinous predators will allow us to better predict their effects on zooplankton community dynamics .