They are now commonly used in conjunction with purse seiners, pump boats, and gillnet fishing. They are usually fished from beam trawlers, otter trawlers or seiners. In 1954, the power block was trialled by American purse seiners in the Pacific. In 1922, use of salmon purse seiners on and around the Columbia was made illegal. Boats deploying seine nets are known as seiners. Purse seiners are allowed one fishing session per day. Boats equipped with purse seines are called purse seiners. Inevitably the seiners still took the brunt of the losses. Purse seiners longer than 70 metres are called super seiners. In 1992, Sea Shepherd launched another campaign to stop tuna seiners from killing dolphins. Before FADs, pelagic purse seiners targeted free-swimming schools of tuna. During the summer, trollers and seiners both fish for all five species of Pacific salmon. Two main types of seine net are deployed from seiners&colon; "purse seines" and "Danish seines".