Describe the migrations made by salmon and eels for purposes of reproduction.?

Answer 1

http://wfrc.usgs.gov/research/fish%20populations/STMaule3.htm

Salmon are reproductive migrants that start their lives in freshwater streams, move to the open ocean for their adult lives, then return to their home stream to lay eggs
http://www.nps.gov/akso/ParkWise/Students/ReferenceLibrary/general/MigrationBasics.htm

Anadromous fishes are the opposite of catadromous fishes in that hatching and a juvenile period occur in freshwater. This is followed by migration to and maturation in the ocean. Adult fish then migrate back up rivers— "anadromous" means "upward-running"—in order to reproduce in freshwater habitats. The length of the initial freshwater period and of the oceanic period vary greatly by species. Similarly, the length of the migration can vary tremendously. Some species travel hundreds of kilometers between their marine habitat and their breeding grounds, while others migrate only a short distance upstream from brackish water to reach freshwater spawning grounds.

There are approximately 100 known species of anadromous fishes. Several of these are well-known and of great commercial value, including many species of salmon along with striped bass, steelhead trout, sturgeon, smelt, shad, and herring. Salmon in particular have long been admired for their lengthy, arduous migrations up rivers to their original spawning grounds, as well as for the unusual homing ability that allows them to accomplish this. Their ability to navigate back to appropriate breeding areas is particularly impressive since migration often follows a lengthy period at sea, often as long as four or five years. Chemical cues are believed to guide them in this journey.

In some anadromous species, the majority of individuals die immediately after spawning, with only a few returning downstream and surviving to spawn again. In other species, multiple migrations and spawning bouts are common.
http://www.bookrags.com/Fish_migration

......................Eels.......................
Eel Migration: For centuries little was known about the European eels breeding habits. Elvers (young eels) swam upriver where they gradually developed into adults. They fed in the fresh water for several years before they became sexually mature, at which time they began swimming down river toward the sea. When they reached the sea, people were no longer able to track them. Years of patient research determined that once the eels left the rivers they migrated to their spawning, or breeding, grounds. Their migration carried them 3,700 miles from the coasts of Europe to the Sargasso Sea, a region of calm water in the North Atlantic northeast of the islands of the West Indies.

How the eels find their way to the spawning grounds is still unknown. Since birds appear to migrate by following the earths magnetic field, some scientists believe that migrating eels do the same. Alternatively, they may be sensitive to changes in the waters temperature, pressure, or scent, which they use to help them navigate. The eggs are laid in the warm (68 degrees) waters at depths of more than 1,000 feet; the Sargasso Sea is one of the few places in the world where this is possible.
http://ladywildlife.com/animal/fishmigration.html


Hope this helps!

Answer 2

Salmon travel hundreds of miles to return to the area of their birth to mate. Often times swimming against current or up a series of rapids. I don't know about eels.

Answer 3

http://encarta.msn.com/encyclopedia_761557464/Animal_Migration.html