Replete with massive rivers and thousands of cold-water tributaries, Alaska has a remarkable diversity of freshwater life. The opportunities to catch fish and enjoy the scenic beauty of its wetlands are endless. As conditions drastically change with the seasons, the biological communities of this northern state are nothing short of dynamic. These are largely shaped by the world-famous salmon run, which begins with the onset of melting ice in spring.
Alaska’s freshwater ecosystems can be divided into 3 regions. Each one has amazing scenery and a unique set of angling challenges. The dominant fish in these zones are largely determined by their access to major river systems and inland lakes. Coastal regions, which encompass archipelagos, teem with many anadromous species that annually migrate into freshwater systems to spawn. Thus, there are dozens of Alaskan fish that have evolved to withstand a wide range of salinities and temperatures.
The southcentral and southeast regions (i.e. those with rivers and tributaries extending into estuaries and coastal peninsulas) are arguably some of the best spots for salmon and trout fishing in the US. There’s enough fish to sustain the needs of hundreds to thousands of brown bears and birds of prey. The interior region, which includes more landlocked bodies of water, is a must-visit for anyone wishing to catch trophy-sized fish in crystal-clear lakes!
Alaska Freshwater Fish Species
1) King (Chinook) salmon (Oncorhynchus tshawytscha)
Among all salmon species of the Pacific Ocean, the king salmon is the largest. There’s no mystery as to why it’s Alaska’s official state fish; its hefty size, valuable meat, and extensive migration route make it one of the most favored and easily recognizable freshwater fish in all of North America. On average, adult chinooks can measure up to 36 inches (91 cm) long and weigh as much as 30 pounds (13.6 kg).
In Alaska, the king salmon is commonly found in the southeastern panhandle, all the way up to the Yukon River. Yearly king salmon runs, which typically occur from May to July, take place in countless cool water streams. These impressive fish, with their strong instinct to spawn, can cover a distance of 2,000 miles per day as they venture inland.
2) Sockeye (red) salmon (Oncorhynchus nerka)
Also referred to as blueback salmon or kokanee salmon, sockeyes are easily distinguished by their deep red coloration. This intensifies during the spawning season, after which the fish die (within just a few weeks) before they can return to the ocean. A single female can deposit as many as 5,000 eggs in cool lakes, streams, and estuaries!
Alaska has several landlocked populations of this high-protein species. They are quite abundant, numbering in the millions during remarkably good years, in the rivers that pour into Bristol Bay. Compared to sockeye habitats in the rest of the US, those in Alaska are fairly pristine. Population trends, however, are under threat of decline due to climate change and habitat degradation in some areas.
3) Lake trout (Salvelinus namaycush)
Able to live to the ripe age of 62 years, this freshwater species is the largest of all chars. In ecologically stable and oxygen-rich waters, it’s common to find 40-pounders (18 kg) that may measure north of 30 inches (76 cm). Lake trout are known for being slow-growing fish; they may take years to sexually mature. As a result, their native populations are highly susceptible to climate change, anthropogenic disturbances, and overfishing.
Lake trout favor conditions in Alaska’s mountain and glacial lakes. Their stable populations are found in Brooks Range, Alaska Range, Chugach Range, and Kenai Peninsula. They spend their entire lives in cool, deep waters, where their growth rate is significantly influenced by food availability and temperature.
4) Northern pike (Esox lucius)
A voracious predator with an appetite for small birds and mammals along the shoreline, the northern pike is a fantastic sport fish. In Alaska’s freshwater systems, it’s common to come across mature specimens weighing 20 pounds (9 kg) or more. The state record, which was caught in a tributary of the Yukon River, was a monstrous pike that weighed 38 pounds (17 kg)!
Distinguished by their greenish and heavily speckled flanks, northern pike favor sluggish and shallow bodies of cool water. They thrive in weedy areas where they can maximize their skills as ambush predators. The best places to search for their stable populations are in northern and western Alaska. Note that they are more likely to be present in remote bodies of freshwater.
5) Pink (humpback) salmon (Oncorhynchus gorbuscha)
Males of pink salmon develop hooked jaws and an enormous hump on their backs just prior to the spawning period. They aren’t called “pink” because of their external hues. O. gorbuscha are largely greenish-blue to silver all throughout their lives. It’s their internal flesh that is notably pink when fresh. The backs of adults become increasingly speckled with large black spots and they migrate inland.
In Alaska, pink salmon are one of the most abundant salmonids. Since the 1800s, these fish have been heavily harvested, filleted, and sold as a canned product. Unlike the wild pink salmon populations of the rest of the US, those in Alaska are stable due to proper management and rehabilitation efforts. Though this species rarely travels more than 40 miles (64 km) inland to spawn, it is found in some of the state’s largest river systems.
6) Arctic grayling (Thymallus arcticus)
Arguably one of the most eye-catching freshwater fish in Alaska, the arctic grayling has several striking features. Its sail-like dorsal fin is heavily dotted with blue, purple, and red spots that glow under bright light. The general coloration of this species tends to vary, with some stream populations being more vividly-colored than others. Larger specimens, which can measure up to 24 inches (61 cm), have more dramatic coloration.
Compared to other freshwater sport fish in Alaska, the arctic grayling has the most expansive range. They are found in all major wetland regions of the state, save for those close to the southeastern coast. Though manmade developments may impact the stability of local and isolated populations, graylings in Alaska are largely uncompromised by threats.
7) Rainbow trout (Oncorhynchus mykiss)
The rainbow trout is a frequent target of sport fishers because its strongest specimens put up a remarkable fight. This cold-water, anadromous fish may be present in landlocked or actively migrating populations. As they are iteroparous (i.e. able to spawn multiple times in a single lifetime), they regularly migrate between marine feeding grounds and their natal freshwater streams.
In Alaska, this iridescent fish has spring, summer, and fall runs. The state relies solely on wild populations to meet its fishing and commercial demands. Local stocks are most abundant in the southeastern parts of the state and in Bristol Bay, where they are landlocked residents. Despite the stable status of this species, hatchery-reared trout have occasionally been released in lakes and streams outside of their native distribution.
8) Silver (coho) salmon (Oncorhynchus kisutch)
In the North Pacific, thousands of tons of “silvers” are commercially harvested each year. This nutritionally valuable salmonid is a major target of Alaska’s net and troll fishery industries. As an anadromous species, it has life stages in marine and freshwater habitats. Like other types of pacific salmon, it gradually lightens in color as it migrates into cool streams to spawn.
O. kisutch fry occupy slow-moving and structurally diverse ponds, pools, and lakes that are connected by river and stream systems. Their range extends throughout the Yukon river, where populations may defend their territories from other closely related species. Juveniles may spend several years in freshwater before they exit into the sea as smolt.
9) Chum (dog) salmon (Oncorhynchus keta)
Chum salmon spend but a short period of their lives in freshwater. Juveniles migrate into saltwater shortly after hatching, when they measure just 1 – 2 inches (2.5 – 5 cm) long. On a diet of copepods, mollusks, and marine fishes, they gradually mature and lengthen over the course of 3 – 4 years. Once they are ready to spawn (usually at 4 years old for Alaskan populations), they migrate up to 2,000 miles (3,200 km) upstream. This species prefers to spawn in the natal streams where they were born.
As a food or sport fish, chum salmon are not as desirable as their close relatives. They are, however, a valuable winter food. Mature males are distinguished by their blotchy coloration, which becomes increasingly purple-red as they approach their spawning period. Adults may weigh anywhere from 9 – 33 pounds (4 – 15 kg) and measure as much as 40 inches (1 meter) long.
10) Arctic char (Salvelinus alpinus)
Arctic char populations favor cool salt and freshwater systems, where they may be fully landlocked or anadromous. Those in Alaska’s lakes tend to have a remarkably slow growth rate and rarely, if ever, migrate downriver. Dwarf and normal-sized populations, which tend to have different food and habitat preferences, can simultaneously occur within a single body of water.
It can take up to 9 years for arctic char to become sexually mature. In preparation for spawning, they tend to congregate close to the intersecting waterways between lakes and streams. They move back into arctic or subarctic lakes to spawn. Every 1 – 2 years or when fall conditions are desirable, eggs and smolt are released in “redds” or spawning nests.
11) Longnose sucker (Catostomus catostomus)
As suggested by its common name, the longnose sucker has an elongated snout with a mouth made for suction-feeding. Its teeth, which are only located in the pharynx and not in its jaws, aid in mashing a variety of bottom-dwelling invertebrates. In gravelly ponds, lakes, and streams, this species feeds on small crustaceans, fish eggs, algae, aquatic insects, and mollusks.
The oldest longnose suckers in Alaska usually measure around 23 inches (58 cm) long. In clear freshwater bodies, they deposit their eggs and smolt into crevices. The frequency with which they spawn is quite variable. While some mature specimens spawn every year, others spawn at multi-year intervals. After the spawning period, they may over-winter in downstream locations.
12) Humpback whitefish (Coregonus pidschian)
The humpback whitefish is an anadromous species that spends the majority of its early life stages in coastal and estuarine waters. Once it is sexually mature, it begins to migrate upstream to spawn. Some populations travel as far as 1,300 miles (2,100 km) into the Yukon River, where the largest females may release as many as 50,000 eggs within a single spawning period. After the fertilized eggs hatch, the whitefish fry migrate downstream.
Apart from the population in the Yukon River, distinct whitefish populations are found in the Kuskokwim and Susitna rivers. Subsequent generations consistently return to the same natal spawning sites, preventing their stocks from becoming mixed. The long-term survival of each population hinges on the conservation of their migration corridors.
13) Cutthroat trout (Oncorhynchus clarkii)
Named for its characteristic red bands along its lower jaw, the cutthroat trout comes in several distinct subspecies. The populations that occupy tributaries along the northern Californian and Alaskan coastline are designated as O. clarkii clarkii or “sea-run” cutthroat trout. These anadromous fish occupy a wide range of freshwater features, including deep, cool lakes and shallow headwater streams.
Though this species migrates downstream and into marine environments to feed, it tends to remain close to the coastline. It thrives best wherever there is ample cover and high-quality prey. At sea, coastal populations feed on insects, small fish, salmon eggs, and gastropods. Juveniles in lakes have a more passive mode of feeding, becoming increasingly carnivorous as they age. Compared to sea-run trout, landlocked cutthroats tend to reach larger sizes.
14) Alaska blackfish (Dallia pectoralis)
A slow-moving bottom dweller, the Alaska blackfish grows to an average length of just 4.3 inches (11 cm). Despite its relatively small size, it is easily distinguished by its large dorsal, anal, and pectoral fins. These are attached to a slender abdomen, which is contrasted by a flattened and broad head. This species is especially unique due to an esophageal adaptation that allows it to breathe air. This gives it a competitive edge in poorly oxygenated and stagnant waterbodies.
The Alaska blackfish favors lowland waters with heavily vegetated shorelines. Its spread was once restricted to ponds, rivers, and lakes in western Alaska. It became fairly widespread after it was introduced into the Cook Inlet Basin.
15) Ninespine stickleback (Pungitius pungitius)
Interchangeably referred to as the ninespine or tenspine stickleback, this freshwater fish bears 7 – 12 spines on its dorsal fin. Its elongated body tapers into a markedly narrow caudal peduncle, where its fan-shaped tail fin is attached. Scaleless, its skin color is olive-green to light brown. In contrast, its ventral region is yellowish-white but may also have dark and irregular blotches.
This stickleback has fully freshwater and anadromous forms, though populations that migrate to the coast rarely venture far into the sea. They favor the calm and quiet waters of ponds, streams, and estuaries, where they are an important food for piscivorous birds and larger fish.
16) Burbot (Lota lota)
Throughout its native range, burbot are often mistakenly referred to as lingcod. While they are, indeed, a type of freshwater cod, they are taxonomically and morphologically different from lingcod (which belong to the Hexagrammidae family). In terms of appearance, burbot are far from pretty. They continue to be popular with anglers, however, because of the desirable quality of their meat.
Alaska’s burbot populations occupy large lakes and glacial rivers. They are especially abundant in the Tanana River system, where they voraciously feed on small invertebrates, aquatic insects, and fish (including conspecifics). Late to mature, they can live for more than 20 years. Healthy specimens can persist in very cool water temperatures, which they require to successfully spawn.
17) Lake chub (Couesius plumbeus)
In Alaskan waters, lake chub is the sole representative of the large minnow family (Cyprinidae). A small fish that grows to just 2 – 4 inches (5 – 10 cm), it is found in the Yukon River and associated drainage systems. Apart from its miniature size, this species is characterized by spineless fins, a forked caudal fin, an overbite, and a dark band on each of its flanks.
During its spring-to-summer spawning period, lake chub populations congregate in shallow rivers and streams with gravel-rich substrates. They release their eggs into the gaps between sediment particles, after which they abandon them entirely. Successfully fertilized eggs, specifically those that don’t get eaten, hatch in just 10 days. Juveniles feed on phytoplankton before developing a more opportunistic diet.
18) Pacific lamprey (Entosphenus tridentatus)
Also referred to as the three-tooth lamprey, E. tridentatus is a jawless fish with a distinctly primitive morphology. One of the most complex parts of its body is its densely-toothed and funnel-like mouth. This is sturdy enough to latch onto the skin of larger fish and whales, which they parasitize. Vampires of the sea, both juveniles and adults subsist on the blood and fluids that they suck from their victims.
Pacific lampreys have a southern distribution in Alaska. They are found close to coastlines and archipelagos, where they can easily migrate into marine waters to feed. They don’t feed during their upriver migration into suitable spawning sites. They make their nests in the cool headwaters of streams, where females collectively release hundreds of thousands of eggs in a single spawning period.
19) Slimy sculpin (Cottus cognatus)
Often misidentified as juvenile burbots due to their morphological similarities, the slimy sculpin is another freshwater fish with a somewhat unappealing face. Its brown and mottled skin is free of scales and allows it to effectively remain camouflaged under logs and above fine substrates. It is far from streamlined and graceful in water as it lacks a swim bladder and has large pectoral fins. Instead, it may appear to “hop” on the substrate as it rapidly darts from one spot to another.
The slimy sculpin is the most widely distributed Cottus species in Alaska. This nocturnal fish prefers cool waters with temperatures ranging from 9 – 14˚C (48 – 57˚F). As it can survive in slightly acidic waters, researchers have recently begun to recognize this species as a bioindicator of freshwater acidification. Despite its tolerance for a wide pH range, however, its reproductive rates are higher in neutral pH conditions.
20) Rainbow smelt (Osmerus mordax)
The rainbow smelt is an important forage fish for many larger predators in and around freshwater systems. Trout, piscivorous birds, bears, and river otters can feast on this nutritionally rich fish. Those that survive feed on smaller organisms like copepods and juvenile fish. Despite this species’ slender and streamlined body, it is unfortunately a weak swimmer that may struggle to swim against mild countercurrents.
This anadromous fish prefers to spawn in lowland rivers and streams. Those that are unable to swim into fully freshwater systems may spawn in estuaries instead. Currents naturally carry their hatched young out to sea, where they remain until they are mature enough to venture inland and spawn. In Alaska, rainbow smelt are found along northern and western coastlines.
21) Trout-perch (Percopsis omiscomaycus)
Often used as bait fish due to its small size, the trout-perch is also referred to as the sand minnow or grounder. On average, its thick body grows to just 3.5 inches (9 cm) long. It serves as a valuable food item for larger Alaskan fish, such as northern pike and lake trout. It subsists on a diet that is limited by its small gape. Zooplankton, tiny crustaceans, and aquatic insects are its preferred prey types.
In Alaska, this trout-perch is largely restricted to the slow-moving sections of the Yukon and Porcupine rivers, though its presence in the latter is relatively new. During the day, its populations keep to deeper and cooler waters. At night, they may venture toward the shallows, where they may spawn and feed.
22) River lamprey (Lampetra ayresii)
River lamprey are distributed throughout the eastern pacific, where their northernmost reaches extend toward Juneau, Alaska. Like its close cousin, the Pacific lamprey, it is an anadromous species that starts and ends its life in freshwater. Once juveniles metamorphose into adults, they spend up to four years feeding and bulking up at sea.
Adult river lampreys measure, on average, between 9 – 12 inches (23 – 30 cm) long. They feed by parasitizing larger fish, such as salmon and trout. Their natural predators include sea lions and sharks. Those that survive life at sea over-winter in freshwater streams and rivers, where they may eventually make their nests and spawn.
23) Arctic cisco (Coregonus autumnalis)
The distribution of Alaska’s Arctic cisco population is restricted to the Beaufort Sea region, which is above the state’s northern coastline. This anadromous fish doesn’t actually spawn in Alaska! It simply makes its way through the Colville River (just west of the Canadian border) before swimming into Canada’s Mackenzie River to spawn.
Once their fertilized eggs hatch, the cisco juveniles are pushed by easterly winds back into the Colville River, where they can begin to swim downstream towards the Beaufort Sea. Because the westward migration of juveniles is largely facilitated by wind-driven currents, they are threatened by climate change. Adults that make it into Alaska thrive on a diet of krill, shrimp, and crabs.
24) Sheefish (Stenodus nelma)
A member of the Salmonidae family, the sheefish or ‘inconnu’ is a freshwater whitefish with commercial value. It is fairly widespread in the Yukon River, Kuskokwim River, and their tributaries. In these areas, sheefish heavily feed on freshwater shrimp and smelt. As adults migrate upriver, they may also feed on out-migrating juveniles of their own kind.
Sheefish spawn in shallow waters, usually during the cool months of September to October. Due to the high-energy requirements of egg production (a single female can produce 400,000 eggs), they may not spawn each year. Not all sheefish migrate back and forth between coastal and riverine waters; some are permanent residents of interior rivers.
