This proposal requests support for the design, construction and testing of a towed video instrument for surveying and identifying macrozooplankton and micronekton in the water column. Called the Large Area Plankton Imaging System (LAPIS), the device would fill a scale gap between existing optical instruments designed for small particles and zooplankton, such as the Video Plankton Recorder, and acoustic systems that have a greater range but currently lack the resolution to identify different taxa of organisms. We intend to build a device that would illuminate and image objects ranging from 0.5 to 100 cm in size, within a field of view ranging from 2 to 4 m2. Towed at 1-2 knots, LAPIS would survey volumes of water approaching those filtered by Midwater trawls. Power, operational data and video signals would be transmitted between the surface and LAPIS via standard electro-optical cable.
The instrument would use an array of high efficiency LEDs to create a field of intense red light, imaged by a high resolution (4 Mpixel) digital camera operating at 8 frames s-1. Red light is invisible to most marine organisms, and together with a hydrodynamically quiet profile, will render the instrument inconspicuous to target organisms. We will take advantage of several technologies that are either existent or in development by other groups at WHOI, including the control and data telemetry electronics built for the SeaSoar, and the video processing and Telemetry being developed for the next generation Video Plankton Recorder. Existing winches, wire and slip rings are WHOI will be available for evaluation and use of LAPIS. We believe this device will fill an important niche in optical survey instruments, allowing rapid and extensive quantification of larger organisms, including gelatinous plankton, larger crustaceans and midwater fishes. Although proposed now as a towed instrument, the basic configuration could be adapted for use on ROVs, packaged with acoustics instruments, or on profiling or fixed moorings. Expected applications in the near future include survey of salp swarms, of gelatinous predators in the Gulf of Maine, and future midwater exploration and quantification in connection with the Census of Marine Life.
