Effects of behavioral responses on vertical distributions of snail larvae (Ilyanassa obsoleta and trivittata)
Effects of behavioral responses on vertical distributions of snail larvae (Ilyanassa obsoleta and trivittata)
Abstract:
Hydrodynamic signals influence the behavior of many zooplankton, including dispersing larvae. These behavioral responses often include changes in vertical swimming speed and direction and may increase the likelihood of benthic larvae settling in habitat favorable for survival of adults. The study presented here examines the effects of different swimming behaviors on vertical distribution of larvae in different oceanic environments.
The hydrodynamic signals most relevant to larval behavior are acceleration, shear and vorticity that are generated by turbulence and waves. We have conducted laboratory experiments to quantify behavioral responses to these cues for larvae of cogeneric snail species with different adult habitats: Ilyanassa obsoleta (sheltered inlets) and Ilyanassa trivittata (continental shelf). Results of the laboratory studies show that the different snail species have distinct responses to shear and acceleration (see related abstract by Fuchs and Gerbi). We used a numerical model to simulate vertical distributions of particles that have behavioral responses similar to those of late-stage larvae for these species. Behavioral parameterizations were derived from the experiments, and we used hydrodynamic signals taken from turbulence and wave motions in a numerical circulation model that included onshore and offshore locations. We find that the particles representing each snail species have different vertical distributions that are likely to affect their regional transport and could affect their settlement success. The details of the vertical distributions vary with location and hydrodynamic conditions.
The hydrodynamic signals most relevant to larval behavior are acceleration, shear and vorticity that are generated by turbulence and waves. We have conducted laboratory experiments to quantify behavioral responses to these cues for larvae of cogeneric snail species with different adult habitats: Ilyanassa obsoleta (sheltered inlets) and Ilyanassa trivittata (continental shelf). Results of the laboratory studies show that the different snail species have distinct responses to shear and acceleration (see related abstract by Fuchs and Gerbi). We used a numerical model to simulate vertical distributions of particles that have behavioral responses similar to those of late-stage larvae for these species. Behavioral parameterizations were derived from the experiments, and we used hydrodynamic signals taken from turbulence and wave motions in a numerical circulation model that included onshore and offshore locations. We find that the particles representing each snail species have different vertical distributions that are likely to affect their regional transport and could affect their settlement success. The details of the vertical distributions vary with location and hydrodynamic conditions.