After butchering, salmon were cleaned. In the early days salmon were delivered by hand from the butchering tables to a hose-fed wooden trough filled with cold water, called the sliming tank. Here women scrubbed and scraped the fish to remove the scales and any remaining entrails.
This work was cold, and many workers developed arthritis in their hands if they worked at the sliming tank for too long.
Over time, the troughs were replaced with long wooden tables with overhead water pipes and faucets. This made washing a larger quantity of fish more efficient. Eventually, the wooden tables were replaced with stainless steel or aluminum ones.