Northwest Fisheries Science Center

Ecotoxicology Research Areas


Dr. Nat Scholz
Program Manager
Staff Directory

Sea Unseen

Carla Stehr, a research fisheries biologist, enjoyed a long career in the Ecotoxicology Program before retiring in 2011. Carla specialized in scanning electron microscopy (SEM), a technology that uses electrons to provide information about the surface structure of tiny objects. Using this technique, images can be magnified up to 300,000 times. The result is pictures with a three-dimensional appearance that is both artistic and scientifically informative. Carla used SEM to study fish development, identify marine algae that produce harmful toxins, and assess how contaminants affect the fine structure of fish sensory organs (e.g., the nose).

In 2009, Carla's images were the focus of an exhibit at the Seattle Aquarium, entitled "Sea Unseen". This slideshow contains photos from the event, as well as examples of SEM micrographs, including highly-magnified images of fish scales, olfactory cells, diatoms, dinoflagellates, larval marine worms, and octopus suckers.

  • Sea Unseen slideshow
    View a sample of Carla’s SEM images.