The Effect of Turbidity on Functional Responses of European Shore Crab

Abstract

Understanding the mechanisms of the natural environment that affect the interaction between consumers and resources is the key to understanding the stability and function of ecosystems. Although the effects of many environmental factors on predator-prey interactions have been well studied, turbidity in aquatic ecosystems is not one of them. Turbidity is ubiquitous and can be important because it is related to water pollution and can significantly reduce visibility of both predator and prey. In this study, the effect of turbidity on the interaction between the shore crab Carcinus maenas and the gammarid amphibians Echinogammarus marinus is studied. The functional response of the predator (crab) under different turbidity levels (consumption rate under different prey (shrimp) densities) was quantified, and it was found that turbidity increased the search speed and handling time. In zero turbidity, that is, completely clear water, the performance of the predator (crab) is not as good as the performance under low turbidity conditions. This may be caused by many reasons, such as the crab is get used to low turbidity conditions because they live at the bottom of intertidal and they will stir up sand at the bottom when they are moving. However, in order to better understand how the interaction between consumers and resources responds to turbidity, more research is needed.