Melissa Romero

Temperature effects on growth rate and diel vertical migration of Kelletia kelletii larvae.

Kelletia kelletii, a ubiquitous gastropod in southern CA kelp forests, recently expanded its range into the colder waters of central California past its historical northern range limit at Point Conception. The shift to colder water can affect larval life-history traits such as planktonic larval duration (PLD), growth rate, and behavior. I investigated whether K. kelletii larval growth was affected by temperature, explored whether they undergo diel vertical migration (DVM), and examined whether a change in DVM occurred as a function of age or temperature or both.  In laboratory culturing experiments, I found that larval developed slower in colder water, that they undergo daily vertical migration, with upward migration during nighttime and downward migration during the day, that temperature had a profound impact on their DVM behavior, with more larvae at he surface in colder water, even during the day, and, last, that their DVM behavior changed as a function of age, with more demersal behavior as they progressed toward metamorphosis. K. kelletii larvae developing in colder water might have longer PLD and they spend more time in dispersive surface currents. Thus, they might have the potential to disperse further than larvae developing in warmer water. Follow-up experiments by other students in the Zacherl will explore the cues that control DVM behavior and will validate my findings in the field. We will eventually work with modelers to identify the dispersal consequences of K. kelletii larval behavior.

In separate culturing experiments, I was able to define the planktonic larval duration as between 5-9 weeks, and I tentatively identified a metamorphosis cue, the vermetid gastropod Petaloconchus sp.  Currently, I am an NSF-funded CREST scholar pursuing my Master’s degree at CSU Los Angeles with Dr. Patrick Krug.