Anadromous Fish of Glacier Bay

several colorful red sockeye salmon swim in a river
Sockeye salmon make a colorful appearance at Dry Bay. NPS Photo.
Anadromous fish are fish that spend part of their life cycle in the ocean and then return to freshwater to spawn. Fish such as salmon, trout, and char evolved an anadromous life cycle as a way to maximize growth and reproduction. Growth is maximized by feeding in productive oceans rather than comparatively nutrient poor streams. However, freshwater streams are optimal for reproduction because eggs and juveniles have fewer predators than in the ocean.

Five species of Pacific salmon (genus Oncorhynchus) frequent the fresh and salt waters of Glacier Bay National Park and Preserve: chinook, coho, sockeye, chum, and pink salmon. Several species of trout and char also spend time in the park: the coastal cutthroat trout, steelhead (coastal rainbow trout), and Dolly Varden char (genus Salvelinus). Eulachon (genus Thaleichthys), a type of smelt, are also found in park waters. For information on descriptions, abundance estimates, spawning run timing in freshwater or freshwater residency, and distribution among park and preserve streams for each of these anadromous species, visit the sections below. This online guide is intended to aid recreational anglers, wildlife viewers, and other interested persons in identifying some of the most numerous anadromous fish species within the park.
  • a group of sockeye in spawning colors (red and green) swim in murky water
    Sockeye Salmon

    Glacial outwash plains like many areas of Glacier Bay provide optimal spawning habitat for sockeye salmon.

  • underwater image of a coho salmon in spawning colors swimming in a clear shallow clear
    Coho Salmon

    Coho salmon are likely to be found in almost every stream in the park, from the smallest creeks to the Alsek River.

  • chinook salmon migrating in a river
    Chinook Salmon

    Thought chinook salmon frequent park marine waters, they are the least abundant salmon species in the park.

  • a group of pink salmon swim in clear water above a rocky river bed
    Pink Salmon

    Pink salmon are the most abundant of all Pacific salmon species in the park and preserve.

  • a fish jumping out from the ocean
    Chum Salmon

    Chum are the most widely distributed Pacific salmon, found near California, on the Arctic coast of North America, and as far as Korea.

  • underwater image of a small trout in a shallow, rocky river
    Coastal Rainbow Trout

    Coastal rainbow and steelhead trout are known from only 8 different stream systems in the park but undoubtedly occur within many more.

  • a cutthroat trout swims in clear water
    Coastal Cutthroat Trout

    Southeast Alaska spawning populations are typically small. Multiple cutthroat populations often overwinter together in lakes.

  • two dolly varden fish laying on grass
    Dolly Varden Char

    Char are thought to be a primary colonizing species in newly deglaciated streams because of their habit of moving among different streams.

  • a school of eulachon fish swim in murky water

    The name candle fish originated from the oil rendered from these fish by coastal Alaska native people as fuel for lamps.


Anadromous Fish Glossary

The lifestage of a salmonid between egg and fry. An alevin looks like a fish with a huge pot belly, which is the remaining egg sac. Alevin remain protected in the gravel riverbed, obtaining nutrition from the egg sac until they are large enough to fend for themselves in the stream.
Fish that live part or the majority of their lives in saltwater, but return to freshwater to spawn.
The act of salmon fry leaving the gravel nest.
A juvenile salmonid that has absorbed its egg sac and is rearing in the stream; the stage of development between an alevin and a parr.
The hooked jaw many male salmon develop during spawning.
Also known as fingerling. A large juvenile salmonid, one between a fry and a smolt. Displays vertical bands on its side called parrs.
A juvenile salmonid which has reared in-stream and is preparing to enter the ocean. Smolts exchange the spotted camouflage of the stream for the chrome of the ocean.
The material which comprises a stream bottom.
A fish that has completed spawning.

a drawing naming the different fins of a fish, including the dorsal, pectoral, pelvic, anal, and caudal fins.
a map depicting the streams that are recorded to contain anadromous fish in Glacier Bay and the streams that are lacking information
Glacier Bay streams with records of anadromous fish (blue) and those lacking information
(yellow). This view excludes known information for the outer coast of Glacier Bay and
the Dry Bay National Preserve.
Run timing and distribution information for this publication came from the Glacier Bay Anadromous Streams Database (ASD). This database of fish observations in freshwaters within Glacier Bay National Park and Preserve is continuously updated by park fisheries staff. Observations in the database include sightings by visitors, researchers, and park staff. These range from simple qualitative sightings (e.g., species presence) to repeated, quantitative observations (i.e., where, when, how many) made by fisheries researchers. Some of these observations were made more than a half century ago! Graphical information on run timing came from information in the ASD. The data represent a relative average of fish abundance observed each month across all records for that species. Anadromous Streams Database information was also used to construct the distribution map included in this document. Limited information exists for most streams and species of anadromous fish within Glacier Bay National Park and Preserve because of the size, remoteness, and dynamic nature of this habitat. Dolly Varden, salmon, and trout colonize new stream habitat as glaciers recede. The loss of glacial ice from watersheds often influences stream temperature. As streamside vegetation develops, sediment loads decrease resulting in clear water and more stable conditions favorable to fish. Change is constant even within stream habitats.

Last updated: February 9, 2018

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