In Situ Ichtyoplankton Imaging System (ISIIS)

The In Situ Ichthyoplankton Imaging System (ISIIS) was developed in collaboration between the University of Miami's Rosenstiel School of Atmospheric and Marine Science (RSMAS) and the subsea engineering company, Bellamare, LLC, located in San Diego CA. Funding was provided by the National Science Foundation, NOAA, and University of Miami (Maytag Chair of Ichthyology).

ISIIS is an underwater imaging system aimed at capturing in situ, real time images of marine zooplankton of relatively low abundance such as fish larvae and fragile gelatinous organisms. The first prototype, delivered in 2007, was attached to a relatively simple vehicle towed by an oceanographic vessel at a speed of five knots. The vehicle, and associated imaging system and sensors, was moved up and down through the water column by paying cable in and out via an oceanographic winch.

Subsequently, a new vehicle has been designed with the capacity of self undulation using motor actuated dive fins. The vehicle frame is divided into four compartmentalized enclosures with imaging and optical equipment seamlessly integrated into ISIIS' ventral housings and environmental sensors and electronics in the dorsal housings. The sensitive instrument equipment is isolated from the aluminum frame by using separating suspension and vibration absorbing materials. The dive fins are positioned ahead of the vehicle aligned with the tow point and away from the imaging pods. The vehicle is designed to undulate between the surface and a maximum depth of 200 meters.

The ISIIS system utilizes a high-resolution line-scanning camera with a Light Emitting Diode (LED) light source, modified by plano-convex optics, to create a collimated light field to back-light a parcel of water. The imaged parcel of water passes between the forward portions of two streamlined pods (UW housings), and thereby remains unaffected by turbulence. The resulting very high-resolution image is of plankton in their natural position and orientation. When a sufficient volume of water is imaged this way, quantification of density and fine scale distribution is possible. ISIIS is capable of imaging a maximum of 162 Liters of water per second (when flying at 5 knots) with a pixel resolution of 70 µm. Isiis is capable of imaging particles from 1 mm to 13 cm in size.

The imaging data and associated oceanographic data is ported to the surface via 0.322 in copper/fiber optic oceanographic wire and recorded onto a computer controlled raid array.


Cowen RK and Guigand CM. 2008. In situ Ichthyoplankton Imaging System (ISIIS): system design and preliminary results. Limnol. Oceanogr. Methods. 6:126-132 (PDF)

G Tsechpenakis, CM Guigand, and RK Cowen. 2008. Machine Vision assisted In Situ Ichthyoplankton Imaging System. Sea Technology, 49(12), pp. 15-20

G Tsechpenakis, CM Guigand, and RK Cowen. 2007. Image analysis techniques to accompany a new In Situ Ichthyoplankton Imaging System (ISIIS). IEEE OCEANS, Aberdeen , Scotland (PDF)

Sample physical data