Cascade -
While I have no personal knowledge of what you saw it is likely what you saw was some test netting by researchers studying the distribution and abundance of salmon fry using the estuary area of the Snohomish. A number of side channel habitats are being sampled (the fry being Identified and count) with either seines or fyke nets. Adult salmonids of any kind are rarely caught.

The tribal steelhead fishery has been closed for a month.

tight lines
S malma