List of Fish Species in the Innoko River 2023 [Updated]

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List of Common Innoko River Fish Species [Updated]

Sunset over the Yukon River, Alaska
Innoko River empties into the Yukon River (pictured) near the city of Holy Cross. Alaska Region U.S. Fish & Wildlife Service / No copyright

The Innoko River is located in west-central Alaska and is a 500-mile-long tributary of the Yukon River. The river is the fifth largest river in Alaska and originates in the Kuskokwim Mountains, emptying into the Yukon River near the city of Holy Cross.

Despite the river covering a large amount of land, there are only about 100 people living alongside the Innoko River. All of the inhabitants near the river are citizens of the village of Shageluk, and there are an estimated 104 people that reside in the village in the year 2022. This low population near the river has not always been the case, however.

In the early 1900s, the Gold Rush came to Alaska, and miners from all over moved to cities near the Innoko River in hopes to find gold. Very soon after the Gold Rush, almost all of the inhabitants abandoned the cities that lined the Innoko River, which left only the villages of Holikachuk and Shageluk. In 1963, residents of Holikachuk decided to all move down to the Yukon River due to flooding.

Today, only Shageluk remains along the Innoko River, and despite moving the village 15 miles west of the river, they still battle extreme floods. Most recently, in the spring of 2022, Shageluk experienced one of its most extreme floods as a result of an ice jam and the melting of ice and snow.

Although the Innoko River proves to be a difficult place to live for humans, this river is home to many different animals. Much of the Innoko River runs through the Innoko National Wildlife Refuge, which was made primarily for protecting land that is crucial for the survival of many different waterfowl species. While the Innoko River may not be the most popular fishing location, there are still plenty of species that love to call the river home. Below are the most common fish species found in the Innoko River.

List of Fish Species in the Innoko River

1) Northern pike (Esox lucius)

Northern pike underwater
Northern pike love areas with lots of vegetation. Павлик Лисицын / CC BY 4.0

Native to North America and Eurasia

Northern pike are by far the most popular sport fish in western Alaska, and they can be found in areas with lots of vegetation. This species is characterized by its torpedo-shaped body that is dark green or brown in color and covered in light spots. Northern pike grow to about 15 – 25 inches long and can easily weigh 20 pounds in Alaska, although the largest fish caught on record in the Innoko River weighed in at 38 pounds. They also have pointed mouths that contain many sharp teeth that are pointed backward to ensure a tight grip on prey.

Due to the structure of their body, northern pike prove to be vicious predators and will wait motionless until the right moment comes to lunge and eat other fish, frogs, crayfish, small mammals, and birds. In the Innoko River, there is a three-fish daily possession limit for northern pike, and only one pike can exceed 30 inches in length.

2) Chinook salmon (Oncorhynchus tshawytscha)

Person holding Chinook salmon
Adult Chinook salmon do not actually feed in the Innoko River, but their fry and smolt do. Lee Cain / CC BY 4.0

Native to northwestern North America and Japan

Chinook salmon are often found in the waters of Alaska, and they commonly use the lower Innoko River as spawning grounds before they head back to the Yukon River. This species can be identified by its blue-green back, silver sides, and white belly. There are black speckles spotted along the back, dorsal fin, and tail fin, and they also have relatively small eyes as well as blackish gums.

During spawning season, both male and female chinook salmon turn a reddish color on their sides, but the sexes can be distinguished by the hooked nose and rigid back that the males possess. Chinook salmon are the largest of the salmon family, and they can easily reach over five feet long and weigh over 100 pounds! While in the Innoko River, adult Chinook salmon do not actually feed, but the fry and smolt salmon will eat plankton, terrestrial and aquatic insects, amphipods, and crustaceans.

3) Chum salmon (Oncorhynchus keta)

Chum salmon in net
During spawning season, male chum salmon develop a striking calico pattern on their bodies. Gabe Schp / No copyright

Native to the North Pacific and Beringian Arctic

Chum salmon, also known as dog salmon, can be found in the lower Innoko River during spawning season and in the Pacific Ocean during the rest of the year. In the ocean, chum salmon are a metallic greenish-blue along the back and they have black specks along the body. During spawning season, however, both males and females develop red and black stripes along the sides of their bodies, and the males develop many unique features including canine-like fangs and a bold calico pattern made with jagged lines.

Chum salmon are the second largest Pacific salmon species, and these fish generally average 24 – 28 inches in length and weigh around 10 – 13 pounds. In the Innoko River, young chum salmon will eat insects and marine invertebrates, and adults in the ocean will feed on copepods, fishes, mollusks, squid, and tunicates. For the year 2022, the federal waters of the Innoko and Yukon Rivers are closed to the taking of Chinook and chum salmon due to predicted poor salmon runs.

4) Coho salmon (Oncorhynchus kisutch)

Coho salmon
Juvenile coho salmon usually live in freshwater for about a year and feed on aquatic insects & plankton. Lee Cain / CC BY 4.0

Native to the North Pacific

Coho salmon, like other Pacific salmon species, use the lower river and river drainage areas of the Innoko River as spawning grounds. Also like other Pacific salmon species, coho salmon have different appearances depending on if they are in freshwater or in the sea. When in the sea, this species has a metallic blue back and bright silver sides with black spots on the back and upper caudal fin.

During spawning season, males and females develop black backs and heads and deep red sides. Males will also develop a hooked jaw in freshwater. In Alaska, coho salmon typically grow to about 24 – 30 inches long and will weigh around 6 – 12 pounds. After hatching, juvenile coho salmon will typically live in freshwater for one year, and they will feed on aquatic insects and plankton. As adults, coho salmon will primarily feed on other fishes and squid in the ocean.

5) Pink salmon (Oncorhynchus gorbuscha)

Man holding pink salmon
When adult pink salmon reach freshwater to spawn, the males develop black, humped backs with bright white bellies. Nick Newberry / CC BY 4.0

Native to the North Pacific and northern Asia

Pink salmon are the most abundant species of Pacific salmon, and they also use the lower Innoko River and drainage areas as spawning grounds. When pink salmon are residing in the sea, they will be a bright greenish-blue on the back and have silvery sides. When adults reach freshwater to spawn, they will develop large, dark spots along their backs and tails, and females will turn an olive green color with bars or patches along the body that can be lavender or dark gold. Males, on the other hand, will develop black backs and bright white bellies, and they will also grow a large hump on their backs and a hooked jaw.

Pink salmon are the smallest Pacific salmon species, ranging from 20 – 25 inches in length and 3.5 – 5 pounds in weight. This species is also very interesting in terms of spawning because they have a two-year life cycle that results in two genetically distinct populations of pink salmon. Because their lifespan is so short, young pink salmon migrate immediately to the ocean where they grow and eat plankton, other smaller fishes, squid, and marine crustaceans that give their flesh its iconic pink color.

6) Sockeye salmon (Oncorhynchus nerka)

Sockeye salmon underwater
The bodies of sockeye salmon become a bright red color when the fish reach freshwater to spawn. Kalvin Chan / CC BY 4.0

Native to the North Pacific

Sockeye salmon is another species of Pacific salmon that can be seen using the Innoko River as spawning grounds. While in the sea, this species is characterized by metallic green-blue backs, iridescent silver sides, a white belly, and fine speckling across the top of the body. When sockeye salmon reach freshwaters for spawning, their heads turn olive green and their bodies turn a bright red. Males will also develop a humped back and hooked jaw much like that of a male pink salmon.

Sockeye salmon are on the smaller side, and they average about 18-  31 inches in length and weigh around 4 – 15 pounds. After hatching, juveniles will spend one to three years in freshwater and will feed on zooplankton and small crustaceans. As adults, sockeye salmon will eat plankton, insects, small crustaceans, and occasionally squid and small fishes. The current daily possession limit for salmon species in the Yukon River drainage areas is 10 fish, with the exception of Chinook and chum salmon.

7) Burbot (Lota lota)

Burbot in hand
You can catch a maximum of 15 burbot a day in the Innoko River. Andrew Bazdyrev / CC BY 4.0

Native to northern North America, Europe, and Asia

Burbot are the only freshwater cod species in North America, and they enjoy the cold, clear waters that the Innoko River has to offer. These fish come in a variety of colors from gray to brown to olive, and they have dark mottling covering their whole body. Burbot also have very long dorsal and anal fins that almost seem to attach to the caudal fin, and their microscopic scales make them appear to be scaleless.

Burbot are relatively long-lived fish, so it takes about six or seven years for them to grow around 16 inches long and 3 – 5 pounds in weight. As juveniles, burbot mainly feed on zooplankton and insects, and adults will primarily eat other fishes. In Innoko River, there is a 15-fish daily possession limit for burbot.

8) Arctic grayling (Thymallus arcticus)

Caught burbot
Arctic graylings have varying colored sides and can be found in the Innoko River. Rob Foster / CC BY 4.0

Native to Russia and northern North America

Arctic grayling are the only grayling species found in North America, and they can be found in the Innoko River and river drainage areas. These fish typically have black backs and can have varying colored sides including black, silver, gold, or blue. The dorsal fins of these fish have red fringes and large iridescent red, aqua, or purple spots. These fish also have a gold band right above their light bellies that match their gold irises.

As adults, Arctic graylings grow to about 10 – 12 inches in length, and they weigh around five pounds. These fish feed on aquatic insects during the summer months and will also feed on fish eggs, smaller fishes, and the occasional shrew or mole. Currently, there is a possession limit of five fish for Arctic grayling.

9) Arctic char (Salvelinus alpinus)

Arctic char
Males develop a red or orange belly during spawning season. Anders Gravbrøt Finstad / CC BY 4.0

Native to the northern polar region

Arctic char can be found in the cool waters throughout Alaska including the Innoko River, and they are characterized by their whitish bellies and brown to green bodies covered in a few large pink and red spots. During spawning season, males will develop an orange or pink tinge on their bellies and lower fins.

These fish are highly variable in size, but the largest they tend to grow is 38 inches long and 15 pounds in weight. Arctic char will feed on a variety of food items including zooplankton, insects, and other fishes, including smaller fish of their own species.

10) Dolly Varden trout (Salvelinus malma)

Dolly Varden trout underwater
Although Dolly Varden trout look very similar to Arctic char, they can be told apart by the number of spots they have on their bodies, with the Dolly Varden having more than Arctic char. Валерия Ковалева / CC BY 4.0

Native to northern North America, Russia, Japan, and Korea

Dolly Varden trout are widely distributed in Alaska and are commonly found in the Innoko River. There are two forms of Dolly Varden trout: the northern and southern form, which differ in the number of chromosomes and the number of vertebrae. In the Innoko River, the northern form is present, which has 66 – 70 vertebrae and 78 chromosomes.

Dolly Varden trout look very similar to Arctic char, but there are a few differences that distinguish the two. One of the easiest ways to tell the difference is that Dolly Varden have a great number of much smaller spots across the body compared to Arctic char. Dolly Varden also have a thicker caudal peduncle and a slightly forked tail.

During spawning season, male Dolly Varden trout will most likely develop a hooked jaw, while male Arctic char do not develop this feature. Northern Dolly Varden tend to be larger than the southern form, and they typically grow to about 16 – 24 inches in length and weigh over 20 pounds. Dolly Varden trout are carnivorous and will feed on insects, crustaceans, various fish species, and salmon eggs. In the Innoko River, there is currently a daily possession limit of 10 Arctic char and Dolly Varden combined.

11) Broad whitefish (Coregonus nasus)

Broad whitefish
Broad whitefish are usually around 15 inches in length and have developed a downturned mouth as an adaptation to being bottom feeders. Brent Guinn / CC BY-NC 4.0

Native to northern North America and Eurasia

Broad whitefish are somewhat tolerant of brackish waters, but they are often found in clear river systems like the Innoko River. These fish are silver in color with a white belly, and they get their name due to their broad build from back to belly. This species also has a blunt head and a deeply forked caudal fin like other whitefish species.

These fish average around 15 inches in length and weigh anywhere from 4.5 – 11 pounds. Broad whitefish have evolved to have a downturned mouth, which has helped them adapt to being bottom feeders that primarily search for mollusks and aquatic insects.

12) Humpback whitefish (Coregonus pidschian)

Humpback whitefish
The humpback whitefish can be found in the Innoko River where the water is slower. Андрей Беспалов / CC BY-NC 4.0

Native to the Arctic Basin

Humpback whitefish can be found in the Innoko River where the water runs a bit slower. These fish get their name from their large humped back that protrudes right behind their heads. Humpback whitefish usually have a dark brown or dark blue back that fades to silver sides and a white belly.

They are medium-sized fish that vary in size, but adults can reach around 20 inches in length, although they do tend to be smaller. Like broad whitefish, humpback whitefish also have a terminal, or inferior, mouth that allows them to feed on benthic invertebrates, crustaceans, and insect larvae off the bottom of the river.

13) Least cisco (Coregonus sardinella)

Caught least cisco
The least cisco isn’t particularly popular with anglers as humpback whitefish are considered to be a better food fish. Alexey V. Ivanov / CC BY-NC 4.0

Native to the Arctic Basin

Least cisco are a type of salmonid that inhabits cool water like that of the Innoko River. This species is characterized by its brown or dark green back and silver sides and belly. These fish also sport some black dots on their heads, backs, and dorsal and adipose fins. This species is similar in size to the humpback whitefish, but the humpbacks are generally considered to be better food fish, so anglers prefer to catch humpback whitefish over least cisco.

Least cisco stand out from other Alaskan cisco species with their protruding lower jaw. They use this superior mouth to feed on items such as zooplankton, insects, and small fishes that are in front or above them.

14) Bering cisco (Coregonus laurettae)

Bering cisco illustration
Most of the time, the Bering cisco can be found along the coast, but migrates to the Yukon River and sometimes Innoko River for spawning. H. L. Todd, Public domain, via Wikimedia Commons

Native to Alaska

Bering cisco are an anadromous fish that spends much of its time in the coastal waters of the Bering Sea, but will migrate to the Yukon River and sometimes the Innoko River for spawning. Bering cisco have very similar coloration and patterning to that of least cisco; however, Bering cisco have pale, colorless pelvic and pectoral fins, unlike the darker fins of the least cisco.

These fish grow up to 18 inches in length, and they are a schooling species that will work together to find small fishes, amphipods, and other invertebrates to eat.

15) Sheefish (Stenodus leucichthys)

Sheefish illustration
Sheefish, members of the whitefish family, have large, downturned mouths that are filled with small teeth. University of Washington, Public domain, via Wikimedia Commons

Native to northwestern North America and northern Asia

Sheefish, also known as the inconnu whitefish, like to inhabit freshwater habitats including the drainage areas of the Innoko River. This species has a white or silvery body covered in large scales. These fish are the largest of the whitefish subfamily, and they can grow to be three feet long and easily weigh 30 pounds in certain waters.

Sheefish have a large mouth with an overbite, and these mouths are filled with many small teeth that help the fish catch other fishes such as smelt and herring. Currently, there is a possession limit of 10 sheefish a day in the Innoko and Yukon Rivers.

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