Eagle Lake trout, ''Oncorhynchus mykiss aquilarum'', is a subspecies of

rainbow trout The rainbow trout (''Oncorhynchus mykiss'') is a species of trout native to cold-water tributaries of the Pacific Ocean in Asia and North America. The steelhead (sometimes called "steelhead trout") is an anadromous (sea-run) form of the coasta ...

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

Eagle Lake Eagle Lake may refer to: Cities, towns, townships etc. Canada * Eagle Lake, Haliburton County, Ontario * Eagle Lake, Parry Sound District, Ontario * Eagle Lake 27, Ontario (Indian reserve) * Eagle Lake, Kenora District, Ontario United States * ...

, in

Lassen County, California Lassen County () is a county in the northeastern portion of the U.S. state of California. As of the 2020 census, the population was 32,730. The county seat and only incorporated city is Susanville. Lassen County comprises the Susanville, Calif ...

. It is a type of

trout Trout are species of freshwater fish belonging to the genera '' Oncorhynchus'', ''Salmo'' and ''Salvelinus'', all of the subfamily Salmoninae of the family Salmonidae. The word ''trout'' is also used as part of the name of some non-salmoni ...

known for its ability to withstand high

alkalinity Alkalinity (from ar, القلوي, al-qaly, lit=ashes of the saltwort) is the capacity of water to resist acidification. It should not be confused with basicity, which is an absolute measurement on the pH scale. Alkalinity is the strength of ...

.http://stevenojai.tripod.com/elrain.htm Eagle Lake Rainbow Its unique adaptations to the harsh environment of Eagle Lake make the fish a specialist with a very narrow environmental specificity. The Eagle Lake Trout is a State Species of Special Concern, but not considered endangered according to the Federal Endangered Species Act.

Range

The ''Eagle Lake trout'' name comes from its former exclusive-endemic Eagle Lake territory. Eagle lake is approximately 24,000 acres, making it one of the largest natural lakes in

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

. The streams and rivers that reach the lake only connect with the lake in the late spring after the snowmelt. The lake is highly basic, with an alkalinity of pH 8-9, making it uninhabitable for many aquatic species. The Eagle Lake trout have adapted to this high pH. While formerly only in Eagle Lake, the Department of Fish and Wildlife (formerly the Department of Fish and Game) has transplanted the Eagle Lake trout into dozens of other lakes in California.

Characteristics

The Eagle Lake trout has a pink horizontal band, white rimmed fins, and irregular spots across its body which become less prolific towards the belly. Large square-shaped tales, large eyes, and a large body give the fish a predatory advantage in the lake. On average the fish is about 18 inches long and 2 pounds, but they have been found to get as big as 28 inches and 10 pounds. Eagle Lake rainbow trout are

invertivore Feeding is the process by which organisms, typically animals, obtain food. Terminology often uses either the suffixes -vore, -vory, or -vorous from Latin ''vorare'', meaning "to devour", or -phage, -phagy, or -phagous from Greek φαγ ...

s and

piscivore A piscivore () is a carnivorous animal that eats primarily fish. The name ''piscivore'' is derived . Piscivore is equivalent to the Greek-derived word ichthyophage, both of which mean "fish eater". Fish were the diet of early tetrapod evoluti ...

s. As young, they mainly eat

leech Leeches are segmented parasitic or predatory worms that comprise the subclass Hirudinea within the phylum Annelida. They are closely related to the oligochaetes, which include the earthworm, and like them have soft, muscular segmented bodie ...

es,

amphipods Amphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. Amphipods range in size from and are mostly detritivores or scavengers. There are more than 9,900 amphipod species so far descri ...

, and

zooplankton Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...

. As they mature, the trout consume

tui chub The tui chub (''Siphateles bicolor'') is a cyprinid fish native to western North America. Widespread in many areas, it is an important food source for other fish, including the cutthroat trout. Range The tui chub's range includes the Lahonta ...

fish.

FMIB 38978 Salmo aquilarum Type Eagle Lake trout

Eagle Lake rainbow trout naturally spawn in Pine Creek which runs into Eagle Lake. The young trout spend the first one to two years of their life in the upper regions of the stream before swimming down into Eagle Lake. The natural environment of this

tributary A tributary, or affluent, is a stream or river that flows into a larger stream or main stem (or parent) river or a lake. A tributary does not flow directly into a sea or ocean. Tributaries and the main stem river drain the surrounding drainage ...

is shaded and gravelly. This natural spawning process is now almost wholly eradicated.

Human Uses

The Eagle Lake rainbow trout play a significant role in the economy of the region around Eagle Lake. The fish attracts anglers who support the local economy. The Lake allows for the use of

trolling In slang, a troll is a person who posts or makes inflammatory, insincere, digressive, extraneous, or off-topic messages online (such as in social media, a newsgroup, a forum, a chat room, a online video game), or in real life, with the i ...

float tube A float tube, also known as a belly boat or kick boat, is a small, lightweight inflatable fishing craft which anglers use to fish from. They were originally doughnut-shaped boats with an underwater seat in the "hole." Modern designs include a V- ...

pontoon boat A pleasure boat with two lengthwise pontoons A pontoon boat is a flattish boat that relies on floats to remain buoyant. These pontoons (also called ''tubes'') contain much reserve buoyancy and allow designers to create large deck plans fitted w ...

s, and bait and

fly fishing Fly fishing is an angling method that uses a light-weight lure—called an artificial fly—to catch fish. The fly is cast using a fly rod, reel, and specialized weighted line. The light weight requires casting techniques significantly diffe ...

. The trout are also meaningful and culturally important to the native Paiute people.

Environmental Threats

The Eagle Lake Trout face competition with the invasive

brook trout The brook trout (''Salvelinus fontinalis'') is a species of freshwater fish in the char genus ''Salvelinus'' of the salmon family Salmonidae. It is native to Eastern North America in the United States and Canada, but has been introduced elsewhere ...

, which first came to Eagle Lake in the 1940s. These invasive trout have taken over and damaged the habitat of important spawning locations.

Logging Logging is the process of cutting, processing, and moving trees to a location for transport. It may include skidding, on-site processing, and loading of trees or logs onto trucks or skeleton cars. Logging is the beginning of a supply chain ...

agriculture Agriculture or farming is the practice of cultivating plants and livestock. Agriculture was the key development in the rise of sedentary human civilization, whereby farming of domesticated species created food surpluses that enabled people to ...

, anthropogenic water usage,

railways Rail transport (also known as train transport) is a means of transport that transfers passengers and goods on wheeled vehicles running on rails, which are incorporated in tracks. In contrast to road transport, where the vehicles run on a pre ...

, and

road A road is a linear way for the conveyance of traffic that mostly has an improved surface for use by vehicles (motorized and non-motorized) and pedestrians. Unlike streets, the main function of roads is transportation. There are many types of ...

s also all contribute to the

habitat degradation Habitat destruction (also termed habitat loss and habitat reduction) is the process by which a natural habitat becomes incapable of supporting its native species. The organisms that previously inhabited the site are displaced or dead, thereby ...

that poses a threat by blocking off the natural

hydrology Hydrology () is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water resources, and environmental watershed sustainability. A practitioner of hydrology is calle ...

of Eagle Lake and its tributaries. Further barriers have made Pine Creek, the location of Eagle Lake trout spawning, inaccessible. Furthermore,

climate change In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...

leading to

drought A drought is defined as drier than normal conditions.Douville, H., K. Raghavan, J. Renwick, R.P. Allan, P.A. Arias, M. Barlow, R. Cerezo-Mota, A. Cherchi, T.Y. Gan, J. Gergis, D. Jiang, A. Khan, W. Pokam Mba, D. Rosenfeld, J. Tierney, an ...

and rising temperatures pose threats to the Eagle Lake ecosystem and the health of the Rainbow trout. View of Eagle Lake Facing South

History of Conservation

The Eagle Lake Trout spawn in Pine Creek, the creek which runs into Eagle Lake from the Western shore. In the 1930s and 1940s, the Eagle Lake Trout population faced a massive decline due to low water levels, habitat degradation, and overfishing. By the 1950s, in an effort to replenish the trout population, a

weir A weir or low head dam is a barrier across the width of a river that alters the flow characteristics of water and usually results in a change in the height of the river level. Weirs are also used to control the flow of water for outlets of l ...

was installed in Pine Creek which captured the trout on their spawning migration. The Eagle Trout were bred in California state

hatcheries A hatchery is a facility where eggs are hatched under artificial conditions, especially those of fish, poultry or even turtles. It may be used for ex-situ conservation purposes, i.e. to breed rare or endangered species under controlled condi ...

and eventually released back into Eagle Lake. In 2012, the weir was modified and now allows the Eagle Lake trout partial entry to Pine Creek for natural reproduction. Currently, the Crystal Lake Hatchery program releases around 200,000 fish to Eagle Lake every year. Still, modern day conservation focuses on developing a self-perpetuating population. Efforts include creating livestock-free areas, removing invasive species, and taking out

culvert A culvert is a structure that channels water past an obstacle or to a subterranean waterway. Typically embedded so as to be surrounded by soil, a culvert may be made from a pipe, reinforced concrete or other material. In the United Kingdom ...

s that reroute Pine Creek. Young, naturally spawned Eagle Lake rainbow trout have recently been discovered in Pine Creek, marking a massive success for the Eagle Lake trout

conservationists The conservation movement, also known as nature conservation, is a political, environmental, and social movement that seeks to manage and protect natural resources, including animal, fungus, and plant species as well as their habitat for the f ...

. Still, the species is not yet fully

sustainable Specific definitions of sustainability are difficult to agree on and have varied in the literature and over time. The concept of sustainability can be used to guide decisions at the global, national, and individual levels (e.g. sustainable livin ...

and conservationists continue to work to ensure the future of the Eagle Lake Rainbow Trout.

References

{{Taxonbar, from=Q5325155 Oncorhynchus Trout, Eagle Lake Trout, Eagle Lake Trout, Eagle Lake Natural history of Lassen County, California Fauna without expected TNC conservation status