An Insitu Plankton Camera

A camera has been developed for mounting on a plankton net cod end which makes it possible to take sequential insitu silhouette photographs of the organisms concentrated by the net. This camera, based on earlier laboratory and prototype field work, uses a specially-focused short-duration strobe light source to produce sharp shadow images on high resolution 35mm copy film. Time (minutes and seconds) is recorded on each frame to aid in analysis. This paper discusses the mechanical, electrical and optical details of this plankton recording method which is felt to be more convenient than previous plankton recording techniques. Illustrative photographs are also presented.