In Situ Ichthyoplankton Imaging System (ISIIS)



The ISIIS (aka Deep Focus Plankton Imager) 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. Continued development involves Oregon State University. Funding was provided by the National Science Foundation, NOAA, and the UNH Large Pelagics Center.

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 was 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's ventral housings and environmental sensors and electronics in the dorsal housings. 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 m.

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 backlight 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. DPI is capable of imaging a maximum of 162 L of water per second (when flying at 5 knots) with a pixel resolution of 70 µm, imaging particles from 1 mm to 13 cm in size. The imaging data and associated oceanographic data are ported to the surface via 0.322 in copper/fiber optic oceanographic wire and recorded onto a computer controlled raid array.

Deep Focus Plankton Imager (aka In Situ Ichthyoplankton Imaging System)

System & image analysis description

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

Tsechpenakis G, Guigand CM, Cowen RK. 2008. Machine Vision assisted In Situ Ichthyoplankton Imaging System. Sea Technology 49: 15-20

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

Publications utilizing DPI/ISIIS data

Timmerman AHV, McManus MA, Cheriton OM, Cowen RK, Greer AT, Kudela RM, Ruttenberg KC, Sevadjian JV. 2014. Hidden thin layers of toxic diatoms in a coastal bay.  Deep-Sea Res. II. Top Stud Oceanogr 101: 129-140

Greer AT, Cowen RK, Guigand CM, Hare JA, Tang D. 2014. The role of internal waves in larval fish interactions with potential predators and prey. Prog Oceanogr 127: 47-61

Luo JY, Grassian B, Tang D, Irisson J-O, Greer AT, Guigand CM, McClatchie S, Cowen RK. 2014. Environmental drivers of the fine-scale distribution of a gelatinous zooplankton community across a meso-scale front. Mar Ecol Progr Ser 510: 129-149.  doi: 10.3354/meps10908

Sevadjian JC, McManus MA, Ryan JP, Greer AT, Cowen RK, Woodson CB. 2014. Across-shore variability in plankton layering and abundance on the northern Monterey Bay inner shelf. Cont Shelf Sci 72: 138-151

Cowen RK, A Greer, C Guigand, JA Hare, DE Richardson, H Walsh. 2013. Evaluation of the In Situ Ichthyoplankton Imaging System (ISIIS): comparison with the traditional (bongo net) sample sampling. US Fish Bull 111: 1-12

Greer AT, Cowen RK, Guigand CM, McManus MA, Sevadjian J, Timmerman AHV. 2013. Interrelationships between phytoplankton thin layers and fine-scale spatial distributions of two trophic levels of zooplankton. J Plank Res 35: 939-956

McClatchie S, Cowen RK, Nieto KM, Greer A, Luo JY, Guigand C, Demer DA, Griffith DA, Rudnick DL. 2012. Resolution of fine biological structure including small narcomedusae across a front in the Southern California Bight. J Geophys Res 117: C04020



To enable synchronous sampling of larval fishes and their zooplankton prey, we coupled two existing sampling systems (Biological Environmental

Sampling System Inc.) to form a new, coupled MOCNESS. This involved joining a system with large mouth and large mesh nets (a MOCNESS 4 m2) with a smaller mouth and smaller mesh net system (MOCNESS 1 m2) to form a double, synchronous opening/closing net system within a single frame. For more detailed description, see Guigand et al. (2005).



Equipment description

Guigand CM, Cowen RK, Llopiz JK, Richardson DE. 2005. A coupled asymmetrical multiple opening closing net with environmental sampling system. Mar Tech Soc J 39: 22-24


Otolith microstructure analysis

Most fishes have otoliths, paired “ear stones” that are used in hearing and balance. These structures grow with the fish by daily deposition of material, in an “onion” type arrangement. By examining the cross-sectional deposition of increments we can obtain information on age and growth on a daily basis for individual fishes. Analysis of this otolith microstructure has enabled us to examine many processes occurring during early life such as environmental influences on larval growth and survivorship, mechanisms of larval transport, dynamics of dispersal and population connectivity, determinants of recruitment magnitude, and traits that influence survival in one stage and carry-over to influence survival in the next stage. Thus, otolith microstructure is a valuable tool that allows us to shine a light into the “black box” of larval life and identify ecological and oceanographic processes that are important to population replenishment and fisheries recruitment.

Lab publications on methodology

Sponaugle S. 2010. Otolith microstructure reveals ecological and oceanographic processes important to fisheries management. Environ Biol Fish 89: 221-238

Sponaugle S. 2009. Daily otolith increments in the early stages of tropical fishes. Pp. 93-132 In: B. Green, B. Mapstone, G. Carlos, and G. Begg, eds. Gathering information from otoliths of tropical fishes. Methods and Technologies in Fish Biology and Fisheries. Springer