WHITE STURGEON
DID YOU KNOW? White sturgeon are the largest freshwater fish
in North America and can weigh over 1,500 pounds, be 20 feet in length,
and live for over 100 years.
SCIENTIFIC NAME: Acipenser transmontanus, acipenser
is an old world name meaning sturgeon and transmontanus meaning
beyond the mountains.
COMMON NAMES: Pacific sturgeon, Oregon sturgeon, Columbia sturgeon,
and Sacramento sturgeon.
DESCRIPTION: Like the green sturgeon the white sturgeon is a
primitive, bottom dwelling fish. It is characterized by its large body
size, large head and mouth, and long cylindrical body. It has four barbels
located in front of its large, wide and toothless mouth, located on the
bottom (ventral) side of its head. It has no scales, but "scutes"
along its body for protection. Scutes are actually large modified scales,
that serve as a type of armor or protection. White sturgeon have 11-14
scutes in front of their single dorsal fin, no scutes behind the dorsal,
38-48 scutes on the side, and 9-12 bottom (ventral) scutes. Dorsal color
is dark to light gray, pale olive, or gray-brown. The white sturgeon's
ventral or bottom surface is white. The scutes are lighter than the body
in color, and the fins are dusky to opaque gray.
LIFECYCLE: The white sturgeon is a slow growing, late maturing
anadromous fish. White sturgeon spawn in large rivers in the spring and
summer months and remain in fresh water while young. Older juveniles and
adults are commonly found in rivers, estuaries, and marine environments.
Anadromous white sturgeon most commonly move into large rivers in the
early spring, and spawn May through June. Spawning usually takes place
in swift current with a rocky bottom, near rapids. White sturgeon can spawn
multiple times during their life, and apparently spawn every 4-11 years
as they grow and mature. Females can produce from 100,000 to several million
eggs each. Older white sturgeon produce more eggs and wait longer times
between spawns. Adults apparently broadcast spawn in the water column and
the fertilized eggs sink and attach to the bottom to hatch. Research shows
that eggs can hatch in 4 days to 2 weeks, depending on water temperature,
and it has been estimated that white sturgeon reach maturity in 15-25 years.
RANGE: In North America, white sturgeon are found from Ensenada,
Mexico to Cook Inlet, Alaska. Found in most estuaries along the Pacific
coast, white sturgeon prefer estuaries of large rivers. However, it is
rare to find white sturgeon in Puget Sound or Hood Canal, Washington.
HABITAT AND ECOLOGY: White sturgeon rely on streams, rivers,
and estuarine habitat as well as marine waters during their lifecycle.
White sturgeon prefer to spawn in rivers with swift currents and large
cobble; no nest is built. Research indicates that water flow is one of
the key determinants of larval survival.
Young white sturgeon primarily feed on algae and aquatic insects while
remaining in rivers and estuarine environments. White sturgeon primarily
feed on fish, shellfish, crayfish, and on various aquatic invertebrates,
clams, amphipods, and shrimp.
The building of dams has negatively impacted white sturgeon by creating
landlocked populations and destroying spawning grounds by altering water
flow. White sturgeon do not normally use fish ladders, so bypass mitigation
measures tend to be unsuccessful.
Because of its long life span white sturgeon tend to concentrate pollutants
in their flesh. Bioaccumulation of PCBs and other contaminants inhibit
sturgeon growth and decrease egg and larval survival. As a result, industrial
pollutants as well as chemicals washing off farm, forest, urban, and residential
lands all negatively impact white sturgeon.
ECONOMIC VALUE: A significant economic and cultural resource
throughout the Northwest, white sturgeon recently became a popular target
fishery with major commercial landings in the Columbia River. In fact,
Columbia River sturgeon production, with its valuable roe for caviar, is
second only to the former Soviet Union's production. The Columbia River
is also the site of an intense sport fishery, as is the San Joaquin Delta
in California and the Willapa Bay in Washington. The white sturgeon is
also an important fish for Native American fishermen on the Columbia and
Klamath rivers.
Revised 12/16/96
