Surface of zebrafish skin

Fish — a closer look

Cells are the building blocks of life. Fishery scientists use the SEM to get a closer look at the structure, function, and health of individual cells, which ultimately helps improve understanding of the aquatic organisms themselves.

A group of scientists in the NWFSC’s Ecotoxicology Program investigate the impacts of chemical contamination, such as pesticides and heavy metals, on fish health. Using the SEM, these scientists discovered that low levels of contaminants may not kill fish outright, but they may cause sublethal changes in the health of individual cells that are not apparent to the naked eye. SEM images have revealed damaged sensory cells that are part of the lateral line and the nose, which can affect a fish’s ability to school, avoid predators, hunt for food, or find their way back to their natal river to spawn.

  • Surface of zebrafish skin

    Surface of zebrafish skin

    Thumbprint-like microridges are present on the surface of individual skin cells of this newly hatched zebrafish. Openings for three goblet cells that produce mucus can also be seen between skin cells.

  • Chinook salmon olfactory rosette

    Chinook salmon olfactory rosette

    Folds or lamellae of olfactory tissue form a rosette, which is located inside the nose of a one year old chinook salmon.

  • Neuromasts on a 4 day old zebrafish

    Neuromasts on a 4 day old zebrafish

    Neuromasts are small sensory organs that detect water movement; they are located on the head and lateral line of fish. Fish with damaged neuromasts are less likely to be able to swim in schools, avoid predators or find food.