• How do dams affect rivers and streams?

    Dams can block American shad and other migratory fish from reaching their upstream spawning grounds. Dams can also affect the natural flow of rivers and streams.

  • What is fish passage?

    Fish passage is the ability of fish to migrate up rivers, streams and other waterways, often to access spawning or rearing ground. Barriers to fish passage (which include road culverts, dams, dikes and other obstructions) can reduce the distribution and habitat available to American shad and other migratory fish and, in some cases, eliminate fish populations altogether.

  • Are American shad endangered?

    American shad are not listed as an endangered species. However, populations along the East Coast are very low.

  • Where do shad spawn?

    Shad are anadromous, which means they migrate from the ocean to spawn in freshwater rivers and streams.

  • Where do shad live?

    Shad spend most of their lives in the ocean. They migrate to freshwater rivers and streams to spawn. After hatching, young shad slowly migrate downstream, eventually leaving the Chesapeake Bay for the ocean.

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  • Anadromous fish

    Fish that spend their adult lives in salt water but must migrate to freshwater tributaries to spawn. For example, Atlantic sturgeon and American shad are both anadromous fish.

  • Fish passage

    Features of a dam that enable fish to move around, through or over a dam without harm. Generally an upstream fish ladder or a downstream bypass system.

  • Food chain/web

    A food chain is formed as one organism eats another. A food web is a system of interlocking and interdependent food chains, in which each organism supplies energy to another life form.

  • Sediment

    Loose particles of sand, silt and clay that settle on the bottom of rivers, lakes, estuaries and oceans. Suspended sediment pushed into the water by erosion is one of the biggest impairments to water quality in the Chesapeake Bay.

  • Spawn

    To release eggs and/or sperm into the water.

  • Year class

    All of the fish of any species that hatched during one annual spawning period.

  • Zooplankton

    Planktonic animals that float in the water and range in size from single-celled protozoa to comb jellies. Zooplankton feed on detritus, phytoplankton and other zooplankton. They are eaten by fish, shellfish and whales.

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