Behavioral study of Asian shore crabs (Hemigrapsus sanguineus) in different temperatures and salinities.

Abstract

The aim of this study is to investigate the effect of different salinities and temperatures on cannibalistic behavior of the Asian shore crab, Hemigrapsus sanguineus, an invasive species in the east coast of North America. Cannibalism is a common behavior in many crab species and is controlled by factors such as shelter and size difference. Hemigrapsus sanguineus is known to displace native crab species, but its own population has declined since 2001, raising questions about the factors affecting its survival. The experiment was conducted using crabs collected from Long Island Sound. Juvenile crabs (9-11 mm) and adult crabs (15-18 mm) were used in the study. The crabs were exposed to <10 different salinities and two different temperatures to observe their cannibalistic behavior. The study aimed to determine whether the Asian shore crab would survive under unfavorable conditions that could represent oligohaline estuarine conditions. The study also aimed to provide an idea of how the Asian shore crab would behave under potential future climate change conditions. Lastly, the study aimed to show how the Asian shore crab impacts their own population counts. Results of the study could contribute to a better understanding of the invasive species and its impact on native species in coastal and estuarine habitats. Results showed that predation and cannibalism were unlikely to occur among H. sanguineus, and that their population count was not affected by their own predatory behavior. The increase in deaths observed during the experiment was most likely due to lack of oxygen and buildup of waste. Additionally, the study suggested that the size and weight difference between adults and juveniles may have prevented predation from occurring.