Can Dredging Disturb Fish Runs?

The Army Corps of Engineers received a permit to do maintenance dredging in Grays Harbor during August 2009 through February 2010. An annual occurrence, this has never really raised any red flags with regard to the possible disturbance of fish runs as most of the dredging was usually done prior to the 12 weeks that comprise the majority of fall salmon runs.

The Corps received stimulus dollars for both dredging activities including pier modifications for the Port of Grays Harbor and for that reason this year's dredging was scheduled further into fall rather than the the usual late summer time frame. The dredging will occur just downstream from the Hoquiam airport and material dredged will consist primarily of sediment of coarse sands and gravels which will be disposed of at either Point Chehalis or the South Jetty "open-water: disposal sites adjacent to Westport, Washington. The Corps mentioned that there will be minimal sediment "plumes" and "water fouling" will be minimal or non-existent.

An area fish biologist along Washington's outer coast points out with concern, the figures referencing this year's fish run timing for the wild stocks which begins to peak around September 1. With dredging scheduled for October 12 by the corps it would have been difficult to choose a worse date to potentially impact all three stocks of wild fish. Biologists held that they would monitor this year's dredge during and after the project to denote any possible effects with the hopes of course of discovering that the dredging won't in fact harm the fish runs, but the fact remains that it certainly can't be terribly beneficial.

The Corps agreed to do the furthest downstream portion of the dredging first to help minimize impacts upstream. A similar incident in Oregon earlier this year the Corps worked on a dredging project along the Marshfield Channel and Coos River Inlet also during salmon runs. When concerned citizens of the local area asked the question, "does dredging harm the salmon," district fish biologist Mike Gray, with the Oregon Department of Fish and Wildlife said, "the fish are going to avoid areas of disturbance." Mr. Gray also said "we don’t have any reason to believe that there is any direct impact to the fish.” Project Manager John Craig with the Army Corps of Engineers noted that there were no toxins in the dredged material and they work closely with all federal, state and local agencies to make sure the dredging is not detrimental. “To my knowledge," he said, " we’ve never caught one."

An interesting comparison. Two very viable and sensitive fish habitats undergoing near identical processes and mirroring the same concerns from area citizens and local scientists. So the jury is out and perhaps by spring there will be a clearer picture as to the effects that dredging projects all along the west coast may or may not have on our precious wild fish runs. However, one has to remember the cyclical effect of things in nature and otherwise and also how damage done today may not show up for years to come.