What is a Fish Ladder?

Question

What is a Fish Ladder?

Answer 1

A fish ladder is a man made, usually concrete, way around a dam, designed to give the spawning fish a way to get to their spawning grounds.

Answer 2

Info provided is pretty good so far, so let me take this time to say that fish ladders are better than nothing but are a very expensive solution or price to pay for our mucking up the system.  Overall, fewer fish are able to make the journey they need to make and mortality is higher.  It depends too on other decisions, such as water level and flow, the presence of invasive aquatic species, and fishing quotas.  

If you've never seen one in action it is rather impressive.

Answer 3

Fishways, most commonly called fish ladders but also known as fish passes, are structures on or around artificial barriers (such as dams and weirs) to facilitate diadromous fishes' natural migration. Most fishways enable fish to pass around the barriers by swimming and leaping up a series of relatively low steps (hence the term ladder) into the waters on the other side. The velocity of water falling over the steps has to be great enough to attract the fish to the ladder, but it cannot be so great that it washes fish back downstream or exhausts them to the point of inability to continue their journey upriver.

Fish ladders are known to be very effective. Written reports of rough fishways date to 17th-century France, where bundles of branches were used to create steps in steep channels to bypass obstructions. In 1852–1854, the Ballisodare Fish Pass was built in County Sligo, Ireland, to draw salmon into a river that had not supported a fishery. In 1880, the first fish ladder was built in Rhode Island on the Pawtuxet Falls Dam. The ladder was removed in 1924, when the City of Providence replaced the wood dam with a concrete one.

As the Industrial Age advanced, dams and other river obstructions became larger and more common, leading to the need for more-efficient fishways.

There are five main types of fishways:

Rock-ramp fishway

Pool and weir

Vertical-slot fish passage

Denil fishway

Fish elevator

See also Eel Ladder and Fish migration.

Answer 4

Many fish swim upstream to spawn.  When man dams the stream, they can no longer get to their spawning grounds.  So they (men, not fish) build a series of steps around the dam and release water over them.  The fish can then swim up the ladder and spawn as usual.

Answer 5

Usually seen in areas where  fish are known to migrate through an area that has been damned up.  It enables the fish to get through and continue on their journey.

I saw on of these, where they had a part of the fish ladder cut open and a plexiglass panel inserted so that people could watch the salmon migrate when I was in Scotland. It was fascinating to see the fish sort of swim through something that looked almost like a murky platform elevator shaft.  They had to build a d**n in the area, actually so they could use the water as it was part of a distillery, but they knew that they couldn't interfer with the natural order of the lives of the Salmon, so they had to build the fish ladder to keep the ecology running smoothly.

Answer 6

It is wat a fish uses to fall down on>

Answer 7

Fishways, most commonly called fish ladders but also known as fish passes, are structures on or around artificial barriers (such as dams and weirs) to facilitate diadromous fishes' natural migration. Most fishways enable fish to pass around the barriers by swimming and leaping up a series of relatively low steps (hence the term ladder) into the waters on the other side. The velocity of water falling over the steps has to be great enough to attract the fish to the ladder, but it cannot be so great that it washes fish back downstream or exhausts them to the point of inability to continue their journey upriver.

Answer 8

it is awy for fish to get across a dam or other blockage, it allows them to swim up through a series of steps to get to the other side. Other sytems include fish lifts, DENIL, pool and wier, steep pass.