Squawfish Northern

Ptychocheilus oregonensis

The northern squawfish is a large-growing member of the Cyprinidae family of minnows that is often caught in northwestern North America trout and salmon waters. Yet it is not actively sought and is viewed as a threat to more popular species. Related fish include the Colorado squawfish (P. lucius), the Sacramento squawfish (P. grandis), and the Umpqua squawfish (P. umpquae), which have limited distribution in their respective river systems. The Colorado squawfish, which is endangered, is North America's largest native minnow and can grow to 6 feet.

Identification. The northern squawfish's mouth is terminal and large, extending back past the front edge of the eye. The head is somewhat conical and flattened between the eyes, and the body is slender and barely compressed. All fins are clear, with no spots or coloration, and there are 9 to 10 rays in the dorsal fin and 8 rays in the anal fin. The caudal fin is deeply forked. Its coloring is usually dark green or greenish brown above and lighter and often silvery on the sides, and it has a whitish belly. The spawning male takes on a yellowish or yellow-orange color and develops tubercles on the head, the back, and some fins.

Size/Age. This species can live 10 years and can grow to 25 inches, although it has been reported to attain lengths between 3 and 4 feet. Common sizes are in the 7- to 10-inch range.

Food. The diet of northern squawfish is terrestrial insects, aquatic insect larvae, plankton, crustaceans, small fish, and fish eggs. Large individuals especially prey on small fish and are considered serious predators of juvenile salmonids. In the Columbia River, fisheries managers undertake efforts to control squawfish numbers to minimize this problem.


squawfish, Columbia River dace, Columbia squawfish; French: sauvagesse du nord.

Distribution. Northern squawfish occur in North America in the Pacific drainages from the Nass River in British Columbia to the Columbia River in Nevada, in the Harney River basin in Oregon, and in the Peace River system (Arctic basin) in British Columbia and Alberta.

Habitat. Northern squawfish inhabit lakes, ponds, and runs of small to large rivers.

Squawfish, Northern 193


Oncorhynchus mykiss

Steelhead Distribution North America


steelhead trout, steelie, sea-run rainbow.

Distribution. The original steelhead range in North America extended from Alaska's Kenai Peninsula to the Baja Peninsula in Mexico, and far inland in coastal rivers. Northern California, Oregon, Washington, southern Alaska, and especially British Columbia have had significant steelhead populations. Overfishing, pollution, dams, other habitat alterations, and additional factors have adversely affected many native runs of steel-head, as they have impacted Pacific salmon stocks. Some coastal runs are depressed, if not threatened. Steelhead are also native to the eastern Pacific and portions of Asia and have been widely introduced throughout the Great Lakes in North America, where they are primarily supported through hatchery production, as well as to other waters in North America and on other continents.

The term "steelhead" refers to the anadromous form of rainbow trout, and the fish known as steelhead bears the same scientific name as rainbow trout. Most scientific evaluations of rainbow trout list the steelhead as a form of rainbow trout. There are no major physical differences between a steelhead and a rainbow trout, although the nature of their differing lifestyles results in subtle differences in shape and general appearance and a greater difference in color. Technically, the steelhead is a rainbow trout that migrates to sea as a juvenile and returns to freshwater as an adult to spawn, a process known as anadromy. Pacific salmon do this too, although steelhead (and rainbow trout) are positively separated from the various Pacific salmon species by having 8 to 12 rays in the anal fin. Steelhead may exist both in coastal environments and in large inland lake-river systems. The appearance and behavior of both forms of steel-head are largely the same.

Identification. Steelhead are generally more slender and streamlined than rainbow trout. Coloration on the back is basically a blue green, shading to olive with black, regularly spaced spots. The black spots also cover both lobes of the tail. The black coloration fades over the lateral line to a silver-white coloration that blends more toward white on the stomach. Steelhead fresh from the ocean or an inland lake are much more silvery than the resident rainbow is. On steelhead, the typical colors and spots of the trout appear to be coming from beneath a dominant silvery sheen, which gradually fades when the fish are in rivers.

Steelhead have white leading edges on their anal, pectoral, and pelvic fins. A spawning fish develops a distinct pink to red striplike coloration that blends along the sides, both above and below the lateral line. On steelhead, coloration gradually fades following spawning to the more characteristic silvery color that the fish display during their ocean and lake journey.

Size/Age. Steelhead grow much larger on average than rainbow trout do and are capable of exceeding 40 pounds. The all-tackle world record is for a 42-pound, 2-ounce Alaskan fish caught in 1970. Steelhead are typically caught from 5 to 12 pounds, and fish exceeding 15 pounds are not uncommon in some waters. Most fish returning to rivers are 5 to 6 years old, and they can live for 8 years.

Life history/Behavior. Each spring, 6-inch-long steelhead smolts leave their natal streams to begin an ocean journey that few survive. Over a period of 1 to 3 years, steelhead move hundreds of miles or more from their parent stream. Most populations of steelhead reappear in rivers in the fall; called fall-run steelhead, they enter freshwater systems as adults from August into the winter. Some river systems have spring-run steelhead, which end their ocean journeys in mid-April, May, and June; bright, shiny springrun fish may be mixed with well-marked resident rainbows that have spent the entire winter waiting for the spring spawning period. Still other populations return to their home stream in July and are known as summer steelhead. Spring and summer runs are much less common.

Spawning takes place in the winter and the spring. Unlike salmon, steelhead commonly spawn more than once, and fish exceeding 28 inches are almost always repeat spawn-ers. The ragged and spent spawners move slowly downstream to the sea, and their spawning rainbow colors of spring return to a bright silvery hue.

Steelhead of the Great Lakes and inland systems have a similar life history, although their appearance in or near tributaries varies, depending on their origins. Most migrate into tributaries from late fall through early spring, spawning in the late winter or the early spring. Summer-run fish, called Skamania steelhead, appear near shore and in tributaries in the summer months.

Food and feeding habits. Steelhead in the ocean consume squid, crustaceans, and small fish. In large lakes, they primarily consume pelagic baitfish such as alewives and smelt. When making spawning runs in rivers and streams, they do not feed.


Stickleback Plate Lake Washington

Ninespine Stickleback

Pungitius pungitius

Sticklebacks are small, slim members of the Gasterosteidae family that are rarely more than 3 inches long and are confined to the Northern Hemisphere, occurring most abundantly in North America. They are primarily freshwater fish, but some also occur in brackish or shallow inshore waters of seas. The family contains seven genera, nine species, and several subspecies; they are of minimal forage value for predatory fish and are little used as bait, but they have a distinctive appearance and unusual courtship and spawning behaviors.

The stickleback gets its name from the short, stout spines in its first dorsal fin, the number of spines generally identifying the species. Each family member has from 3 to 26 well-developed isolated dorsal spines, preceding a normal dorsal fin having 6 to 14 rays. Almost every species also has a spine at the leading edge of the anal fin and each pelvic fin. The body lacks scales, but in most species it is armored along the sides with bony plates.

Several species of sticklebacks are kept in aquariums. They swim with short spurts of speed, then pause. This makes them interesting to watch, as does their spawning ritual, which people are unlikely to observe in the wild. At spawning time, the males adopt courtship colors, with the bellies bright red in some and velvety black in others. Each male builds a nest among the stems of aquatic plants; the nest is hollow inside but completely covered on the top, the bottom, and the sides, with stems held together with a secretion of sticky threads. Once the nest has been built, the male searches for a female and drives her toward the nest, nipping at her fins and chasing after her if she turns the wrong way.

As soon as the female has laid her eggs, she leaves the nest, sometimes squirming out through the bottom. The male enters the nest immediately and fertilizes the eggs.

Often he may go out again and get one or two other females to lay eggs in the nest. Some males build several nests at the same time. The eggs hatch in a week or less. While the eggs are incubating, the males of most species aerate them by fanning currents of water through the nests (the male of one species builds a nest with two holes in the top and sucks water from one of the holes to cause circulation over the eggs). After the eggs hatch, the male tends the fry for several days, generally trying to keep them near the nest.

One of the common species in North America is the brook stickleback (Culaea inconstans), found in streams from southern Ohio westward to Montana and northward, and throughout southern Canada from Nova Scotia to eastern British Columbia. It is generally less than 3V2 inches long. The five or six spines on its back are completely separate from one another, rather than joined by a membrane, and the caudal peduncle is especially slender. Like most sticklebacks, it is quarrelsome and guards its territory, particularly its nest, from intruders.

The threespine stickleback (Gasterosteus aculeatus) occurs in northern Eurasia and North America, living in both brackish water and freshwater. A number of subspecies are recognized. The ninespine stickleback (Pungitius pungitius), found in northern Europe, China, Japan, and northern North America, is dark brown, and the male becomes a rich black during the courtship and spawning periods. The fifteenspine stickleback (Spinachia spinachia) is a European saltwater species restricted to northwestern Europe. The fourspine stickleback (Apeltes quadracus) is found only along the eastern coast of North America, from North Carolina to the Gulf of St. Lawrence. The blackspotted or twospine stickleback (G. wheatlandi) is another western Atlantic species.

Sticklebacks 197


Noturus flavus

Distribution. The stonecat has a widespread distribution. It exists in the Great Lakes, the St. Lawrence River, drainages of Hudson Bay, and the Mississippi River basin. It can be found from the Hudson River drainage of New York, west to the Red River drainage of Hudson Bay. It is found in drainages of the Mississippi River basin from Quebec to Alberta, southerly to northern Alabama and Mississippi, and westerly to northeastern Oklahoma.

Habitat. Generally, the stonecat inhabits riffles of medium to large rivers in places with many large rocks. It also occurs in lakes where currents or wave action produces streamlike conditions. In the main channels of large rivers, it has been found in swift water over sand substrate.

The stonecat is a widely distributed and relatively common member of the madtoms. It is the largest madtom in body size, is the species with the longest life span, and has a lower relative fecundity than other madtoms. It may be used for bait, especially in bass fishing.

Identification. Stonecats are olive, yellowish, or slate colored on the upper half of their bodies and are the only madtoms that exceed 7 inches in total length. The stonecat has backward extensions from the sides of the toothpatch on the roof of its mouth. In most cases, the stonecat has a patch on its nape, a white spot at the rear of the dorsal fin base, and another white spot on the upper edge of the caudal fin. There are either no or a few weak teeth on the rear of the pectoral spine.

Size/Age. Of 261 specimens collected from Missouri and Illinois streams, the largest specimens were a 7-inch male and a 6.4-inch female. Growth is fastest in the first year of life. Individuals up to 5.3 inches are at least 3 years of age. Individuals greater than 6.5 inches are 4 years and older. The largest and oldest stonecat ever collected was 12.25 inches in total length and 9 years old.

Spawning behavior. Females mature at 3 to 4 years of age and a mean standard length of 4.7 inches. Clutches are guarded by males under large flat rocks in pools or crests of riffles. Rocks used as spawning cover averaged 200 square inches and were found in water averaging 34 inches deep.

Food. Mayfly larvae are important food for all sizes of stonecat. Excluding those specimens greater than 4.7 inches in standard length, all stonecats consume stonefly, caddisfly, and midge larvae. Stonecats less than 3.1 inches in standard length consume blackfly larvae, whereas larger stonecats consume more crayfish. Like most typical madtoms, stonecats consume a variety of organisms that are only infrequent prey, including fish eggs, worms, amphi-pods, and chilopods.

Stoneroller, Central

Montana Squawfish

The central stoneroller is a member of the Cyprinidae family of minnows. It is a hardy species that provides important forage for gamefish and is commonly used as bait.

Identification. The central stoneroller has a thick and barely compressed torpedo-shaped body that is dull gray with a brassy tint and a pale golden stripe along the upper sides. It has an unusual appearance due to its subterminal mouth and a hard cartilaginous ridge on the lower jaw. The mouth formation and the lower ridge enable the central stoneroller to scrape algae and other minute organisms off rocks. There are dark brown to black blotches on the back and the sides of large specimens, the caudal fin is moderately forked, and the lateral line is nearly straight. A breeding male exhibits large tubercles on the top of the head and the upper scales almost to the base of the tail, and there are small tubercles on the pectoral rays and the first dorsal ray; it also has an orange cast, with orange and black anal and dorsal fins.

Size. This species grows to 8V2 inches but is usually 4 to 6 inches long.

Spawning behavior. The male central stoneroller primarily builds pit nests by carrying pebbles in its mouth or disturbing the upstream gravel to float pebbles downstream. Nests are communal and are constructed in gravel areas at the top of riffles. They are relatively shallow and are built in quiet areas, those with moderate current, or where there is overhanging protection. Spawning occurs in the spring, and males defend their territories and aggressively challenge other males.


stoneroller, minnow, hornyhead, knottyhead.

Distribution. The central stoneroller ranges widely in the eastern and central United States and southern Canada in the Atlantic, Great Lakes, Hudson Bay, and Mississippi River basins, from New York to North Dakota and south to Georgia and Texas and northern Mexico. It is least common in the Great Plains.

Habitat. Central stonerollers prefer clean riffles, runs, and pools with current in streams, creeks, and small to medium rivers.

Stoneroller, Central 199


Green Sturgeon

Acipenser medirostris

Green Sturgeon

Acipenser medirostris

The mouth and barbels of a shovelnose sturgeon.

Sturgeon are large, slow-maturing, long-lived, and primitive fish found in large inland and coastal rivers, as well as in some lakes. They are contemporary species of ancient lineages; fossil remains of sturgeon and related paddlefish have been dated to early in the Triassic period of the Mesozoic era (230 to 265 million years ago), making them contemporaries of dinosaurs and causing them to be referred to as "living fossils."

Best known for the black caviar made from their eggs, sturgeon and paddlefish are members of the order Acipenseriformes, but at some distant point they separated from a common ancestor. As a result, sturgeon are members of the family Acipenseridae, and paddlefish are members of Polyodontidae. Both are considered bony fish; however, they have a mostly cartilaginous skeleton. Their closest living relatives are gar and bowfin.

Like paddlefish, sturgeon are distinctive in appearance. Each species possesses a heterocercal tail (the upper lobe is larger than the lower), a spiral valve intestine, a spiracle (aperture for breathing), an upper jaw that is not fused with the cranium, and a cartilaginous backbone as an adult. The sturgeon have five rows of bony scutes (scalelike plates), a bottom-oriented, extendible, hoselike mouth with fleshy lips; four barbels; an extended snout; and a teardrop-shaped body.

Species. In North America, there are nine recognized species. White sturgeon (Acipenser transmontanus) and green sturgeon (A. medirostris) occur on the West Coast of North America. White sturgeon occur in lower and upper waters, sometimes hundreds of miles inland. Green sturgeon are usually found in the lower areas of estuaries. Atlantic sturgeon (A. oxyrinchus oxyrinchus) and shortnose sturgeon (A. brevirostrum) live on the East Coast. The lake sturgeon (A. fulvescens) occurs in the Great Lakes and the upper Mississippi river system. Shovelnose sturgeon (Scaphirhynchus platorhynchus) and pallid sturgeon (S. albus)

are found in the Mississippi River system. The Alabama sturgeon (S. suttkusi) is endemic to the Mobile River drainage in Alabama. The gulf sturgeon (A. oxyrinchus desotoi), a subspecies of the Atlantic sturgeon, occurs frequently in all Gulf drainages from Tampa Bay, Florida, west to Mermantau River, Louisiana.

Life history. Members of the genus Scaphirhynchus, as well as the lake sturgeon, are potamodromous. They live in rivers or lakes, respectively, and migrate upstream into smaller tributaries or rivers to spawn. Their migratory patterns are similar to those of paddlefish.

Adult sturgeon of the genus Acipenser, with the lone exception of lake sturgeon, are anadromous. They typically winter in the ocean, migrating into coastal rivers as the water warms above 54°F. Sturgeon also use peak river discharge in the spring as a cue for migratory behavior. Most sturgeon stage in brackish water for a few days before migrating upstream or out to the ocean. They then migrate hundreds of miles upstream to reach gravel bars and spawn in high-velocity currents. Several males spawn with each female, and the eggs adhere to the gravel. The eggs hatch, and the fry are carried downstream to areas with slower water velocity. Adults then move downstream to summer habitats, where they remain until the fall.

Early growth is rapid, and juveniles may reach their adult size in as few as 3 years. Sturgeon often do not mature until 6 years of age, and in some areas they do not mature until age 10 or 12. Sturgeon spawn intermittently, every 2 to 6 years, depending on the species.

Most sturgeon are opportunistic feeders. Juveniles primarily eat aquatic invertebrates, whereas subadults may also consume mollusks, fish, and crayfish. Some species, such as white sturgeon, are good predators and willingly prey on other fish. Migrating adults of Acipenser, except white and lake sturgeon, typically do not feed while in freshwater.

Sturgeon are most often found on or near the bottom. They are typically concentrated in deep pools that occur in river bends. During migration (spring and fall), juveniles and adults inhabit deep pools that occur in brackish water along the freshwater-saltwater interface of coastal rivers.

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  • jesse
    What is the difference betweena hornyhead and a cyprinidae?
    8 years ago

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