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AP® Environmental Science

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Dams and Fish Migration

APES-UGB5UN

One criticism of dams is that they prevent fish migration. For instance, salmon are born in freshwater, migrate to the ocean, then return to freshwater to reproduce. This return involves swimming up river. A dam can prevent them from reaching their destination.

Other than removing the dam, what can be done to help these fish?

A

Install a fish elevator to carry fish up and over the dam.

B

Construct a pool and weir fish ladder to help fish get up over the dam.

C

Use a fish siphon to allow fish to pass through a parallel waterway to get around the dam.

D

Construct a series of vertical slots that move fish up and over the dam.

E

All of these are used to help fish navigate past a dam.