The productivity of the water column was evident in ISIIS imagery as a preponderance of diatoms visible throughout most images (Fig 3).
ISIIS imaged a total of 409 larvae, and the bongo tows collected a total of 359 larvae.
The bongo net sampled all depths equally as it was towed from depth to the surface, but ISIIS spent less time at depths >40 m than at depths near the surface (Fig.
The taxonomic diversity collected by each gear also was similar; both collected larval fishes representing the same 7 families (Table 1), although bongo samples were typically identifiable to lower levels (genus and species) than those in ISIIS samples.
ISIIS imaged a larger size range and larger mean size of fish larvae than the bongo sampler (Fig.
Results indicate that data collected with this prototype version of ISIIS are comparable to data collected with a bongo sampler.
Larval lengths were different for ISIIS and the bongo sampler.
Our results indicate that ISIIS could be a valuable addition to the survey sampling toolbox because it successfully has estimated larval fish concentration, and, in an environment of relatively low diversity, as in this study, resolved the taxonomic composition of the larval ichthyofauna.
Still, the results of this study indicate several specific functional aspects that need to be considered or addressed for ISIIS to be a highly effective sampling tool for survey and process-oriented studies.
We were able to use manual assessment of the images taken in the current study (by focusing only on fish larvae), but further analysis of these data or more extensive surveys with ISIIS will require automated computer analysis.
Although ISIIS can be a powerful tool for resolving fine to mesoscale patchiness in both vertical and horizontal distributions of plankton, it is limited by the fact that it is a nondestructive sampler (i.