Measuring changes in locomotor activity of freshwater prawn larvae in response to exposure to water contaminants using the ViewPoint software and video tracking system


As the population grows, so does the drive for urbanization. Urbanization and the resulting anthropogenic activities have an impact on the quality of nearby water resources. Puerto Rico’s population density is one of the highest in the world. We seek to develop a protocol to measure how Puerto Rico´s high level of urban development has impacted the behavior and nervous system function of river fauna. We have started by recording movement trajectory and velocity of freshwater prawn larvae during five consecutive periods of 10-minutes light/dark cycles, using ViewPoint´s Zebrabox. Larvae of Macrobrachium rosenbergii, a species raised through aquaculture in Puerto Rico, were more active during dark cycles, whereas those of M. carcinus, the prawn species found most commonly in Puerto Rico´s rivers, were more active during the light cycles. Recordings were then made before and after exposure to two contaminants found in Puerto Rico´s urban rivers, chromium (Cr3+) and dibutyl phthalate (DBP), in levels allowed by the EPA for drinking water. Exposure of M. rosenbergii larvae to Cr3+ did not produce any significant changes in locomotion, whereas exposure of M. carcinus larvae to DBP did, affecting parameters such as total distance travelled at slow and fast speeds. This protocol will continue to be used to test effects of other river contaminants on locomotion at various developmental stages of prawns.