Fish assemblages and potential barriers in urban streams​

 

You may not realize that even in the city, streams are flowing all around you, hidden from sight in parks and wooded patches. Many small urban streams in Metro Vancouver provide important habitat to various species and life stages of fish, such as salmon, trout, and sculpin. However, when a stream flows under a road, it is sometimes temporarily funneled into a pipe called a culvert. If it not designed properly, culverts can block fish from swimming through. Corinna studied how fish communities in urban streams are impacted by culverts by using two different approaches. First, she examined individual culverts at a small scale (within watersheds), by determining whether there are upstream-downstream patterns in fish communities and species. Second, she examined culverts at a watershed scale to see how multiple culverts in a watershed can impact communities and species along the stream gradient. Her results revealed that culverts may drive changes in fish communities through species-specific impacts that are consistent both within small scales and across watersheds. For example, cutthroat trout were positively influenced by culverts, while prickly sculpin were negatively influenced by culverts within and across watersheds. Her study highlights persistence of fish in Metro Vancouver urban stream and brings to light the issue of disappearing urban stream connectivity.

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Current Position: Aquatic Science Technician, Fisheries and Oceans Canada, Newfoundland