9.5. Fishways Fishways provide fish that migrate upstream with a means to pass natural or man made obstructions. They are required by law where the Federal Minister of Fisheries and Oceans determines it to be necessary (see Laws and Regulations). Fishways usually consist of a series of steps with baffles that slow the water to a speed such that fish can pass upstream. Fishways may be used to open up new areas suitable for spawning and rearing that have been previously inaccessible, or they may assist fish in reaching traditional spawning areas. The placement of the entrance to the fishway is important. Some fish may be reluctant to climb it, or may not be able to find it. The entrance should be located where fish tend to gather, at the base of a dam or waterfall. Each species has its own preferred migration flow that dictates their route. Fishway flows must intercept these differing routes and provide suitable attraction. The two most common types of fishways are the vertical slot fishway and the pool-and-weir type. The vertical slot fishway consists of a flume with partitions and may be single or double slot, creating a series of stepped pools and drops. Water flows from pool to pool through narrow slots that extend the full height of the partitions. This type of fishway is self adjusting to changes in stream flow level and volume. The pool-and-weir type, or "fish ladder" (illustrated below), consists of a series of vertical partitions, each slightly lower than the one above it, installed at intervals down the length of the flume. Water flows over the top of the partitions, creating pools. This fishway is most effective on streams with a fairly stable flow.