DRENNAN, R.W.; MCCLARY, JR., M.: Predation does not control the distribution of barnacles in the tidal Hackensack River.

There are sites in the tidal Hackensack River of New Jersey where the barnacle, Balanus improvisus, lives and where they once lived. Previous investigation showed that when five out of ten rocks from the site where the barnacles live were transplanted to the site where they once lived, there was a significant decrease in the percentage of living barnacles on transplanted rocks (from 70% to 14%). To determine if this decrease was due to turbidity, three out of six rocks, from the living site, were covered with burlap to exclude sediments. The remaining three rocks were not covered with burlap to allow passage of sediments. To exclude predators, all crates were covered with steel mesh. After seven days, living barnacles covered with burlap significantly decreased from 88% to 70% (P<0.001), and from 85% to 46% (P<0.001) without burlap covering. The results of this study suggests that turbidity is a factor in the distribution of living barnacles in the tidal Hackensack River. Future studies will determine the location in the river that sediments begin to kill Balanus improvisus, as well as the mechanism, be it physical by smothering, or chemical by contamination.