At over 150,000 acres, Naknek Lake is the largest lake in Katmai National Park and Preserve. With a length of 40 miles and a width of 3 to 8 miles, Naknek Lake acts as not only a tourist destination but also a landing spot for floatplanes.
This large lake is found at the core of the Naknek River system, where it connects to several smaller lake systems via thin streams and tributaries. It drains into Kvichak Bay through the Naknek River, a long, 35-mile trip undergone by many anadromous species.
Situated between it and Brooks Lake is a short, thin river that houses Brooks Falls. Tourists often gather on the shores of Naknek Lake at Brooks Camp during salmon season in the hopes of watching brown and grizzly bears snatch trophy-sized fish out of the air. Local flora and fauna thrive in the aftermath of a successful run, with salmon carcasses providing abundant nutrients for predators and even salmon fry.
Naknek Lake may be most famous as salmon spawning grounds, but it is also the permanent home of other species such as trophy-sized rainbow trout. This article will explore several noteworthy fish species in Naknek Lake, from its famed king salmon to its less-celebrated Arctic char.
Fish Species in Naknek Lake
1) King salmon (Oncorhynchus tshawytscha)
Also known as the Chinook salmon, king salmon are probably the most famous fish in Naknek, and it’s easy to see why. As the largest salmon species, adults are typically 3 feet long and 30 pounds, but regularly surpass 50 pounds, with one individual reaching a record 126 pounds. As with other salmons, size is directly correlated with age. King salmon sizes have noticeably decreased in recent years for an unknown reason, but they still reach massive sizes.
King salmon are an anadromous species— that is, one that hatches in freshwater streams and then lives out its life in saltwater. The king salmon’s coloration and appearance change based on their current environment. In saltwater, king salmon have blue-green backs, silver sides, and white bellies. Upon entering freshwater, spawning fish turn brown, red, or purple. Males become especially bright and develop hooked upper jaws, known as kypes, to fight one another for dominance.
Spawning king salmon can be found throughout the Naknek River and Lake from mid-June to July, and hatchlings typically spend 1 to 2 years growing in the lake before migrating to sea. After 1 to 8 years, hatchlings return to the specific area they were born in through an unknown mechanism.
Females dig out nests known as redds by dislodging stones and rocks from the riverbed with their tails. Males fight extensively, with the winner spawning with females. After laying, females loosely cover their eggs and then continue to spawn upstream. After spawning several times, both male and female salmon die. After dying, salmon become an important source of food and provide their newly hatched offspring with ample nitrogen and phosphorus.
2) Rainbow trout (Oncorhynchus mykiss)
Rainbow trout are a beautiful and abundant species that are full-time inhabitants of Naknek Lake. While some rainbow trout — known as steelheads — are anadromous, most found in Naknek are adfluvial, meaning they inhabit Naknek Lake and migrate into the river to spawn.
Rainbow trout are named for their bright coloration and iridescent sheen. They have olive-green bodies with dark spots and white underbellies. On their sides, they have a wide band of red, pink, or purple, which is often broken or blotched.
This species is closely related to brown trout and is biologically capable of interbreeding with them. Wild specimens rarely interbreed due to differences in spawning times and genetics.
They are opportunistic feeders, which are primarily insectivorous. Many adults prefer terrestrial insects such as grasshoppers that fall into the stream. Rainbow trout may opportunistically feed on small fish, crustaceans, and fish eggs.
Alaskan rainbow trout are long-lived and mature slowly compared to those found elsewhere. Typically, Alaskan trout mature at 4 to 5 years of age and have been observed spawning up to age 11. Once mature, females lay clutches depending on their size, typically laying 2000 to 3000 eggs per kilogram of weight. In the case of fluvial rainbow trout, which typically weigh from 0.5 to 2.5 kg (1.1 to 5.5 lbs), this is often as much as 7500 eggs. After hatching, rainbow trout larvae spend several weeks in their redds, slowly consuming their egg yolk before leaving.
3) Sockeye salmon (Oncorhynchus nerka)
King salmon may be the largest salmon in Naknek Lake, but sockeyes are the most prevalent. At an adult size of 4 to 15 pounds, sockeye salmon are easy to distinguish from monstrous king salmon.
Sockeyes change their shape and coloration throughout their lives, beginning as a clear, pigment-less fry. These young salmon gradually develop green bodies with black spots for camouflage, and change again upon entering saltwater. Adults have dark blue backs, silvery sides, and white bellies.
For the last stage of their lives (spawning), sockeye develop vibrant crimson bodies with green and black heads. Males are especially bright, and develop a slightly humped back and hooked jaws. These jaws are used by males to fiercely fight one another for dominance. Males may be attacked by other males as well as displeased females. Dominant males often breed with several females, and smaller males may not get to breed at all.
Historically, sockeyes spent 2 years growing in freshwater before leaving for sea. Due to warmer waters associated with climate change, the plankton they eat at this early stage of life are especially prolific. Now sockeye typically spend only 1 year in their birth lake. Competition with hatchery fry, in addition to this artificially accelerated adolescence, means that Alaskan sockeyes are getting smaller on average.
4) Arctic char (Salvelinus alpinus)
Referred to as the most variable vertebrate on earth by some ichthyologists, the Arctic char is a unique species with a massive variety in appearance. These different variants, known as morphs, are distinct in size, shape, color, and even behavior. Some morphs are anadromous in nature and others remain in lakes their entire lives. In Alaska, there are two major morphs, but dramatic changes in appearance can occur even within an individual specimen.
The two Alaskan morphs are easy to differentiate— dwarf char average 3 inches in length and normal char average 16 inches. This larger morph is known to cannibalize on dwarf char, but these cannibalistic specimens may become highly concentrated with parasites as a result. Outside of eating one another, Arctic char are opportunistic carnivores with diets varying based on location.
Generally speaking, Arctic char can be distinguished from other species by their trout-like bodies that feature light spots rather than dark ones. Alaskan Arctic char are typically dark greenish-brown with pink or reddish spots and light undersides. Spawning males develop bright orange or red undersides.
Unlike many other fish, Arctic char rely heavily on scent and pheromones to hunt, detect predators, and communicate. When spawning, males use pheromones to attract females to their territory. Once within his territory, the female selects a spot to form a redd.
Unlike most salmonids, Arctic char do not die after spawning. Instead, they continually spawn every 2 to 3 years upon reaching adulthood. They are long-lived, with one wild specimen being at least 40 years old.
5) Silver salmon (Oncorhynchus kisutch)
Also known as coho salmon, silver salmon are named for the silvery sides and metallic blue backs of ocean-dwelling specimens. When seen in Naknek Lake, these salmon are instead a deep crimson, with males developing a hooked beak and large teeth.
The life cycle of a silver salmon is very unpredictable compared to most other species. While silver salmon enter Naknek Lake in late July and typically remain until September, the species is known for its erratic nesting timelines.
Silver salmon remain in the waters they were born in for 1 to 2 years, migrating to and from brackish water. After entering the ocean, they continue before returning to spawn. Many males remain in the ocean for around 18 months to achieve a large size.
Others, known as jacks, spend only 6 months in the ocean and return to spawn when they are two years old. Rather than compete with other males, jacks almost exclusively spawn by sneaking past others. While it is presumed to be low, the breeding success of silver salmon jacks is currently unknown.
Jacking is known to be heritable in king salmon, but it is currently unknown why certain silver salmon reenter spawning waters at such a young age.
6) Lake trout (Salvelinus namaycush)
The lake trout is the largest member of the char family, with Alaska’s record-holder weighing 47 pounds and the world record specimen weighing 102 pounds. This species is very slow-growing and long-lived, usually living 30 years but occasionally surpassing 50. Due to their younger age, most caught specimens are in the 8 to 10-pound range, but those who only eat plankton may remain even smaller than 2 pounds.
Aside from its large size, lake trout can be distinguished from similar species by its deeply forked tail. Its coloration differs depending on its age and sex. Young specimens have 7 to 12 vertical parr marks, which fade with age. Adult fish have grey or greenish bodies with light undersides and cream or yellow splotches throughout their bodies. Adult males develop a lateral stripe and long, hooked upper jaws.
This species thrives in cold waters and, as its name would suggest, lives its entire life in a lake. It may surface in cooler months to feed on mammals, birds, and insects, but spends much of the year feasting on fish and zooplankton in lake depths. Eggs are spawned randomly on lake bottoms in September or October and are slow to hatch due to the weather. Eggs may overwinter for as many as 7 months before hatching.
Introduced lake trout have been known to do well in rivers as long as water conditions are appropriate. On the other hand, lake trout can rapidly fall victim to invasive lampreys, with some Great Lakes populations being nearly extinct.
7) Pink salmon (Oncorhynchus gorbuscha)
The pink salmon is the smallest species of Pacific salmon found in North America, typically reaching only 3.5 to 5 pounds. It is named for its pink flesh rather than its wild coloration, which is steely blue on its back, silver on its sides, and white on its stomach.
Upon entering breeding waters, pink salmon develop a dark back, green sides, and brownish-green blotches. Spawning males are brighter than females, and develop a pronounced hump on their backs upon entering freshwater. Due to this abnormally large hump, pink salmon are often called “humpies”.
Unlike other salmon species, pink salmon have a strict two-year life cycle. In many areas of Alaska, there exist two independent populations of even-year and odd-year breeding salmon that do not interact with each other.
In Naknek Lake, pink salmon spawn only in the summers of even-numbered years. As with many other salmonids, eggs are spawned into redds and end in the death of both parents. Unusually, however, females guard their redds for as long as possible before they die. After hatching, fry immediately leave for the ocean to live the bulk of their brief lives.
8) Northern pike (Esox lucius)
Northern pike are large, elongated fish that can be easily recognized by their single, soft-rayed dorsal fin far back on the body. Their duck-like snout has many rows of sharp teeth in their jaws, tongue, and roof of their mouth.
As its many teeth would suggest, northern pike are aggressive feeders and grow rapidly, with the Alaska state record holder being 38 pounds. Northern pike vary in color from light green to dark gray to match whatever waters they are in. Lake-bound pike, such as those in Naknek, are usually a light green.
Northern pike are native throughout most of Alaska, but introduced populations in southeast Alaska have ravaged native ecosystems. In these waters, northern pike feast on salmon fry until the salmon population is depleted. Then, after turning to aquatic insects and even one another, invasive northern pike become stunted and eventually die off.
Luckily, the pikes found in Naknek Lake are native. While they are still voracious predators that eat whatever can fit in their mouths, the northern pike population is kept in check by other equally aggressive species.
Northern pike are not anadromous as many native species are, but instead migrate to and from Naknek River to Naknek Lake in the winter and summer to hibernate and spawn respectively.
9) Chum salmon (Oncorhynchus keta)
Unlike most anadromous species, chum salmon immediately leave freshwater after absorbing their full egg yolk sacs around 33 days after hatching. They do not fully enter the ocean for several months. Instead, young chum spend this time close to the seashore, feasting primarily on terrestrial insects and crustaceans. Once they are large enough, chum salmon join the ocean depths.
There they spend 3 to 6 years, feasting on a variety of aquatic animals. While much of their diet overlaps with other salmon, adult chum salmon have a unique niche of eating primarily gelatinous zooplankton.
While in their adult stage, chum salmon swim vast distances and are consequently the most widely distributed species of Pacific salmon. Depending on their spawning grounds, they may swim as far as 7,700 miles to return to the waters they were born in. During these long trips, chum salmon rely on their fat reserves for energy and stop eating entirely.
In the sea, chum salmon are a metallic blue along their back with small speckles above their lateral line, but upon entering freshwater, chum salmon undergo dramatic physical changes. Spawning adults develop bold red and black stripes, with males having a calico pattern. Male chum salmon develop sharp, prominent canine teeth that have earned them the title of “dog salmon”.
