Meeting Abstract
Competitive interactions and foraging speed were observed in four estuarine grass shrimp, Palaemon species. Three species of shrimp were native to New Jersey waters (P. pugio, P. vulgaris, P. intermedius), while the fourth species was an invasive species originating in Japan (P. macrodactylus). Since invasive species can have an economic and ecological impact on native species, they are important organisms to study. It was hypothesized that the invasive would be more aggressive and faster at finding food than the native species due to their larger average body size. Two shrimp were placed in a maze to run separate, but identical courses to reach a common food source. Two different food sources, mussels and clams were used as bait for this experiment and, for each shrimp, the time to locate and reach the food source was measured. For each food source, a Kruskal-Wallis H test was used to determine whether there were significant differences, between the four species. When mussels were used as bait, the times to reach the food source were not significantly different between groups, χ2(3) = 7.072, p = 0.070. When clams were used as bait, the times to reach the food source the differences between groups was not significantly different, χ2(3) = 2.506, p = .474. After reaching the food source, the shrimp were allowed to remain in the area of the bait and their interactions were observed and recorded. P. macrodactylus were more aggressive toward their competitors, suggesting that this invasive species may have a favorable advantage controlling food sources.
