Carbaryl, Carbofuran, and Methomyl - National Marine Fisheries ...

Bay, California. Historically, chum salmon were distributed throughout the coastal
regions of western Canada and the U.S. Presently, major spawning populations are found
only as far south as Tillamook Bay on the northern Oregon coast. We discuss the
distribution, life history diversity, status, and critical habitat of the two species of
threatened chum salmon separately.
Chum salmon are semelparous, spawn primarily in freshwater, and exhibit obligatory
anadromy (there are no recorded landlocked or naturalized freshwater populations).
Chum salmon spend two to five years in feeding areas in the northeast Pacific Ocean,
which is a greater proportion of their life history than other Pacific salmonids. Chum
salmon distribute throughout the North Pacific Ocean and Bering Sea. North American
chum salmon (as opposed to chum salmon originating in Asia) rarely occur west of 175°
E longitude.
North American chum salmon migrate north along the coast in a narrow coastal band that
broadens in southeastern Alaska. However, some data suggest that Puget Sound chum,
including Hood Canal summer run chum, may not make extended migrations into
northern British Columbian and Alaskan waters. Instead, they may travel directly
offshore into the north Pacific Ocean.
Chum salmon, like pink salmon, usually spawn in the lower reaches of rivers, with redds
usually dug in the mainstem or in side channels of rivers from just above tidal influence
to nearly 100 km from the sea. Juveniles outmigrate to seawater almost immediately
after emerging from the gravel that covers their redds (Salo 1991). The immature salmon
distribute themselves widely over the North Pacific Ocean. The maturing adults return to
the home streams at various ages, usually at two through five years, and at some cases up
to seven years (Bigler 1985). This ocean-type migratory behavior contrasts with the
stream-type behavior of some other species in the genus Oncorhynchus (e.g., coastal
cutthroat trout, steelhead, coho salmon, and most types of Chinook and sockeye salmon),
which usually migrate to sea at a larger size, after months or years of freshwater rearing.
This means that survival and growth in juvenile chum salmon depend less on freshwater
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