Some of the suplemental pontoons have openings in the middle. Soon after the pontoons arrived on the lake, WSDOT found that these functioned very effectively as cormorant traps. The small opening and tall walls meant that birds that landed inside the pontoons couldn't get up enough speed to take off and wound up stuck. This yellow ramp was the delightfully low-tech solution.
This Coast Guard boat patrolled up and down the lenght of the bridge the whole time we were there.