Hannah Blair Blog 14 June 2018

Hello again from the night shift. We completed our third night of zooplankton towing last night, and while retrieving the net were accompanied by an energetic school of bandwing flyingfish. Turns out they had good reason for their leaping and gliding above the surface of the water: a pod of rough-toothed dolphins emerged from the dark ocean around us, eagerly chasing after flying fish snacks. A couple of the flyingfish stranded themselves on deck, allowing us a closer look.

Part of processing each zooplankton tow is measuring the density of individual animals. These measurements are used as inputs for acoustic scattering models for these animals, helping clarify the biology we see on the echosounders. Our on-ship method involves adding different fluids of known density to a beaker, until the fluid density matches that of the animal, demonstrated by the animal’s neutral buoyancy.