A cluster of hair cells (arrow) make up a neuromast located in the lateral line of a coho salmon (year 0). The hair or sensory cells are stimulated by vibrations in the water and, subsequently, transmit this information to the brain.

Non-point source pollutants such as pesticides and dissolved metals are frequently detected in stormwater runoff in urban and urbanizing watersheds. We are using the zebrafish experimental model to investigate the sublethal effects of common stormwater contaminants on the sensory biology of exposed fish. This study is specifically focused on the impacts of dissolved copper on the fish mechanosensory system. The mechanosensory system, or lateral line, detects the movement of water and mediates several important behaviors, including rheotaxis (orientation to flow), schooling, and predator avoidance. Preliminary evidence in zebrafish suggests that dissolved copper triggers the degeneration of sensory neurons and is therefore toxic to the lateral line system. Results in zebrafish are currently being used to design laboratory and field studies to evaluate the sublethal effects of metals and other stormwater pollutants on the mechanosensory systems of juvenile salmon and other at-risk fish species in the Pacific Northwest.

Investigators
Tiffany Linbo, Carla Stehr, John Incardona and Nat Scholz

Relevant Publications/Presentations
Linbo, T.L., Stehr, C.M., Incardona, J.P. and Scholz, N.L. (2004) Dissolved copper causes cell death in the mechanosensory system of developing fish larvae. Proceedings of the Society of Environmental Toxicology and Chemistry's 4th World Congress, Portland, OR. Poster presentation.

Kao, T. and Scholz, N.L. (2003) Effects of copper on mechanosensory structures in developing fish embryos and larvae. Proceedings of the Georgia Basin/Puget Sound Research Conference 2003, Vancouver, BC, Canada. Poster presentation.

Related Links
ZFIN (zebrafish biology)

A.) Epifluorescence imaging highlights the lateral line system of a zebrafish larvae at 4 days post-fertilization (dpf). The neuromasts are labeled with a vital dye, DASPEI. B.) A schematic diagram of the lateral line system illustrates the stereotypic positions of individual neuromasts (dots) at 4 dpf (adapted from Whitfield et al., 1996, Development 123:241).

A.) A scanning electron micrograph of a zebrafish neuromast reveals long cilia that project from a cluster of sensory neurons. B.) The cilia are greatly reduced following an exposure to dissolved copper (50 �g/L, 5 hrs).