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Saturday, April 14, 2012

Gallery Of Trout And Salmon

Family Salmonidae

Family overview: The trout and salmon family includes great game fish like trout, salmon, chars and grayling, as well as food and baitfishes like whitefish and ciscoes. The trout and salmon family is large. It is native to cool and cold streams and lakes throughout Europe, northern Asia and North America, and reaches as far south as northwest Mexico and extreme northern Africa. One family member, the Arctic char, is the freshwater fish that occurs the farthest north. Because of their popularity for sport and commercial fishing, this family has been stocked in waters worldwide and is now found on nearly every continent. Many trout that anglers catch in Pennsylvania are the result of the stocking of hatchery-raised fish. However, where streams are cold and clean enough, with proper spawning habitat, Pennsylvania also has a wealth of reproducing populations of wild trout.

In Pennsylvania, the trout and salmon family includes three species of the genus Coregonus, all native and found in Lake Erie–the rare longjaw cisco, the cisco or lake herring, and the lake whitefish–silvery well-scaled fishes with deeply forked tails. The whitefish is currently an important commercial species. It has rebounded with reductions in the numbers of sea lampreys and rainbow smelt. Rainbow smelt were believed to prey on whitefish eggs and young. Other members of the trout family native to Pennsylvania, not introduced, are chars, of the genus Salvelinus, the brook trout and the lake trout.

The brown trout, native to Eurasia, is stocked in the state and has established itself in the wild here. The Atlantic salmon, also of the genus Salmo, is native to the North Atlantic Ocean and its tributaries. It is anadromous–the Atlantic salmon spends its adult life in salt water and returns to freshwater streams to spawn. A landlocked form of the Atlantic salmon, which lives its entire life in fresh water, was stocked in Harvey’s Lake, Luzerne County, and in Raystown Lake, Huntingdon County.
Anadromous Pacific salmon can use a large freshwater lake as adults. Pacific salmon were widely introduced throughout the Great Lakes, including Lake Erie, in the 1960s. Pennsylvania participated in the coho and chinook salmon plantings, but today the chinook is no longer stocked by the Fish & Boat Commission. Cohos are stocked only when available. Introduced pink salmon are self-sustaining and have spread through all the Great Lakes and are occasionally caught. The kokanee, a nonmigratory form of the sockeye salmon, was introduced into a few lakes in northeastern Pennsylvania, most notably Upper Woods Pond. The kokanee salmon did not reproduce sufficiently to sustain a continuing fishery, and stockings have been discontinued. These West Coast salmon are of the genus Oncorhynchus, as is the rainbow trout. The rainbow’s migratory form is the steelhead. It has replaced Pacific salmon, which die after spawning, in popularity with Lake Erie anglers.
Identification: In size, Pennsylvania’s trout and salmon range from wild fish that are less than six inches long at maturity to Lake Erie behemoths of nearly 30 pounds and three feet long. Trout and salmon have a fleshy lobe, called the adipose fin, between the dorsal fin and the tail. Their scales are small and cycloid, or smooth, and embedded in a slimy mucous that is most obvious in the salmons. Trout and salmon have an obvious lateral line, large mouth and teeth. In big specimens, the teeth are caninelike. The tail may be forked or squarish, depending on the species, and none of the fins has spines. Mature males look different from females because they develop a long, hooked lower jaw, called a “kype.” Mature males also deepen or gain in color at spawning time. Coloration in trout and salmon varies from dull to intense, according to the species, where the fish lives and the time of year. Trout and salmon that live in the sea or a large lake become silvery. Juvenile fish have a series of vertical, oval “parr marks” along each side from cheek to tail.
Life history: The trout and salmon family live either in fresh water all their lives, or migrate to the sea and return to fresh water to spawn. Salmon are especially noted for anadromous behavior. Through chemical cues and the sense of smell, they can home in on their birth streams when returning to spawn. Trout may also run to the ocean, or a large lake, when they have access. Trout and salmon spawn either in spring or fall, according to the species, over gravelly shoals, usually in small streams. The female digs a shallow dish nest in the gravel by lying on her side against the bottom and swimming forward energetically. Her body and fins flush out the stones. One or several males join her in the actual spawning. Afterward, the adults abandon the nest, called a redd. The eggs fall into the spaces between the gravel. They may be covered slightly with more gravel by the female before she leaves. Eggs hatch in four to 10 weeks, depending on water temperature. Silt, clogging the spaces between the stones, can reduce hatching success. Young trout stay in the gravel until the yolk sac is absorbed. Then they move out into the stream. The presence of reproducing populations of trout has been used as an indicator of high-quality, well-oxygenated, unpolluted water.

Trout and salmon are not school fish. Stream trout eat mostly adult and immature aquatic insects. They also eat terrestrial insects that fall onto the water, crayfish and other freshwater crustaceans. They also eat fish, especially as they grow larger. Trout feed most readily when water temperatures are in the 50s and 60s. They also feed in the winter and are popular with ice anglers.

In the early part of the 20th century and late 1800s, Pennsylvania streams were stocked extensively with trout, with varied success. Wild brook and brown trout are now widespread. Reproducing populations of rainbow trout are in a few scattered streams in the state. In the hatchery, trout strains were later developed that responded better to artificial culture. They were disease-resistant and spawned at times other than their natural times of the year. Manipulative fish culture also produced hybrids and genetic variations of trout as extras for anglers, including the splake (lake trout x brook trout), tiger trout (brown trout x brook trout), and the palomino trout (golden rainbow trout x rainbow trout).

Gallery of Pennsylvania Fishes Chapter 15

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