Smith-Root Assesses Salmon Barotrauma During Pier Demolition

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Smith-Root Staff
Tuesday, November 29, 2016

On the weekends of October 15th and 29th 2016, Smith-Root partnered with Environmental Science Associates (ESA) to provide expertise in barotrauma assessment in 1,200 juvenile Chinook Salmon exposed to the demolition of the San Francisco-Oakland Bay Bridge Pier E4 and E5. Having conducted numerous barotrauma studies previously, Dr. Jackson Gross and Alecia Hunter of Smith-Root represented one of three necropsy specialist teams who oversaw fish health assessment of 600 fish on each of the two demolition days. The team was also visited by the History Channel camera crew on the final demolition day.

Although this study was not a requirement for any permit, CalTrans recognized the existing limitations in the available technical information regarding fish injury from underwater sound exposure. The purpose of the study was to assess the utility of a bubble curtain to prevent barotrauma in fish potentially exposed to sound energy emitted from explosive detonations. Juvenile salmon were selected as a surrogate for potentially exposed endangered fish species as well as for forage fish for endangered bird species. A study of this magnitude has never before been conducted in the field, and results from the fish health assessment will be integrated with future pier demolitions.