The Abundance and Distribution of Small Zooplankton near Cross Seamount

Abstract

Seamounts are isolated shallow regions of the oceans formed by volcanoes. Seamounts have been found to support unusually large numbers of fish. It is possible that fish on seamounts are feed on small animals called zooplankton that drift over seamounts with the currents. In most of the surface ocean, fish hunt using their eyes, and to avoid being eaten some species of zooplankton swim down during the daytime until it is too dark to be seen, then return to the surface to feed at night. The shallow summit of a seamount could prevent zooplankton from descending far enough to avoid fish, giving fish an unusually rich food supply. In this study, I examine the distribution and abundance of zooplankton over, near and far from Cross Seamount. I captured small zooplankton with nets to examine under a microscope. I hypothesized that the small zooplankton would be unaffected by the seamount because their daytime depths are not shallow enough for them to reach the seamount summit, while larger migrating organisms would be less abundant.