Overview
Early records indicate that shortnose suckers were once widespread and abundant in the upper Klamath Basin of Oregon and California. Currently, small populations occupy a few waterbodies in the upper Klamath Basin. Since 2001, the abundance of this species has decreased by nearly 85 percent. Long-term monitoring indicates that most adults in the Upper Klamath Lake hatched in 1991, and are well beyond the average expected life span of 12 years. The remaining populations appear to be somewhat more stable, but possess relatively low abundance and or high levels of hybridization with the Klamath large-scale sucker.
Although a number of factors have contributed to the decline of the shortnose sucker, habitat degradation is the primary cause. Construction of dams, the draining or dredging of lakes and wetlands and other alterations to natural hydrology are the primary sources of reduced population viability. Poor water quality and reduced and degraded habitat continue to threaten remaining shortnose sucker populations.
The shortnose sucker was federally listed as endangered in 1988 and critical habitat was designated in 2012. A recovery plan was published in 1993 and revised in 2013. The Sucker Assisted Rearing Program began in 2015 to augment sucker populations in Upper Klamath Lake with the first release of reared suckers occurring in 2018. With the planned construction of the new Klamath Falls National Fish Hatchery, annual production capacity will increase to approximately 60,000 juvenile suckers.
Scientific Name
Identification Numbers
Characteristics
Life Cycle
Adult shortnose suckers migrate from lake to river beginning in March through May in order to spawn. Mature spawners broadcast eggs and milt for fertilization over gravel or cobble bottoms. Once the larvae hatch, they quickly drift downstream to inhabit shoreline and wetlands areas around lakes. Shortnose suckers reach sexual maturity around four to six years. Each female can produce between approximately 20,000 to 70,000 eggs annually.
The longest lived shortnose sucker on record was 33 years, but the average life span is closer to 12 years.
Shortnose suckers reach sexual maturity around 4 to 6 years of age. Each female can produce between approximately 20,000 to 70,000 eggs annually. Adults migrate from the lakes into rivers beginning in March through May in order to spawn. They may also reproduce in springs from February to late April when water temperatures are a consistent 60 degrees Fahrenheit. Spawning adult fish broadcast eggs that are fertilized with milt over gravel or cobble bottoms. It takes approximately two weeks for shortnose sucker eggs to develop. Juvenile suckers normally hatch between April and June and begin to drift downstream. The juvenile shortnose suckers generally stay along the shore line of the water body, even if the shoreline is not vegetated.
Behavior
Shortnose suckers feed by suction as they siphon and filter food from lake bottoms.
Physical Characteristics
Shortnose suckers back and sides are a dark greenish brown and the belly is silvery to creamy white.
Large heads with oblique, terminal mouths that have thin, but fleshy, deeply-notched lower lips distinguish shortnose suckers apart from other suckers in the same range. Shortnose suckers can reach more than 20 inches in length, but adults usually average less, about 15.7 inches. The maximum reported length for this species is 25.2 inches.
Similar Species
The Lost River suckers occur in the same habitat and range as the shortnose suckers. They are listed as endangered under the Endangered Species Act and are being captive-reared at the Sucker Assisted Rearing Program facility along with shortnose suckers.
Habitat
The preferable habitat for the fish is a turbid, shallow, somewhat alkaline and well-oxygenated lake that is cool, but not cold, in the summer season. Adult shortnose sucker inhabit deeper water of lakes and reservoirs, and spawn tributary rivers of their home lake. Shoreline vegetation in both lake and river habitats is important for the rearing of larval and juvenile suckers.
A considerable inland body of standing water.
Food
The shortnose sucker diet consists of detritus or decomposing organic matter, zooplankton which are tiny floating aquatic animals, algae and aquatic insects.
Geography
Currently, remaining populations of shortnose sucker are found in the upper Klamath River and Lost River basins. In southern Oregon, this includes Upper Klamath Lake and Lake Ewauna. In northern California, they can be found in Gerber Reservoir and within the Klamath Basin National Wildlife Refuge Complex.
Timeline
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