By Scott Shalaway
WHEN throngs of anglers gather along streams and swiftly flowing rivers in the spring, it means only one thing. It’s trout season.
Three species of trout fuel the quest on inland waters, though only one, the Brook Trout, is native to the eastern U.S.
The Brook Trout story begins in the fall. Shorter days and colder water temperatures trigger hormonal changes in the Brook Trout that inhabit cold, clear waterways. Males’ bellies and lower fins turn crimson. The blue-haloed red spots that dot the brookies’ sides sparkle. Bright white bands line the edges of the fins. And their lower jaws grow and turn upward.
The outward appearance of the females changes little. Internally, however, females transform into egg-making machines. Brook Trout spawn in the fall. Along the shores of Beaver ponds, small rivers and even the tiniest spring-fed mountain streams, females choose the spawning site. The gravel and stones that will hold the eggs must be rather large–1 to 10 inches in diameter. The water must be between 40 and 55 degrees. And most importantly, there must be an upwelling of ground water directly beneath the nest or at least a current to carry away silt and sediments.
When a female finds a site that meets her requirements, she builds the nest, or “redd,” as ichthyologists call it. She nestles herself tightly against the stream bed and violently swims in place, writhing her body back and forth creating a saucer in the gravel.
The female’s nest-building activity attracts males to the redd. When the female is ready to spawn, she drags her anal fin through the nest. In an act that lasts barely three or four seconds, the female opens her mouth widely and arches her back. Likewise, the male gapes, and a shiver-like action wracks his body. Simultaneously, the female releases her eggs, and the male discharges a dose of milt (sperm). The milky cloud settles into the redd. The spawn is complete.
The male leaves immediately. The female completes the redd by using her fins to shovel a load of clean gravel atop the fertilized eggs. The eggs are now hidden, safe and ready for a winter of dormancy. A few days later the female builds a new redd and repeats the ritual.
The eggs hatch in early March. The fry work their way up through the gravel. After resorbing the yolk sac, small fry eat plankton. Fingerlings switch to larger prey such as aquatic insects and other invertebrates. Under ideal conditions, Brook Trout can reach 3 to 4 pounds in three years.
The Brown Trout was first introduced to the United States in the late 1800s from locations in Europe. It has adapted well, perhaps because it tolerates a wider range of silt load and temperature, and often displaces Brook Trout. Like brookies, browns spawn in the fall when water temperature dip into the upper 40s.
Rainbow Trout, native to western North America and now stocked in most states where cool waters occur, spawn in the spring as water temperatures reach 50 degrees. Natural reproducing populations are uncommon. Anglers rely on state-run hatcheries to stock them.
Occasionally anglers will land Golden Rainbow or Palomino Trout. Not to be confused with the true Golden Trout found in California, Golden Rainbows were developed as a color mutation of the Rainbow Trout in a West Virginia hatchery in the early 1960s.
This year, the Pennsylvania Fish and Boat Commission will release 463,890 Brook Trout, 877,550 Brown Trout and 1,394,060 Rainbow Trout, including 7,485 trophy Golden Trout, into 745 streams. Another 684,100 trout will be stocked in lakes. –Pittsburgh Post Gazette