trout mrs. garbiel: oceanography & environmental science

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TROUT Mrs. Garbiel: Oceanography & Environmental Science Slide 2 Salmon Family Scientific Family name is Salmonidae Includes three subfamilies: Salmon, Trout, and Char Whitefish Grayling Economically the most important family of cold water fishes in North America Sport Fisheries Commercial Fishing Hatcheries and Fish Farms Slide 3 Salmon Species Pacific Salmon Pink or HumpbackPink or Humpback Chinook or KingChinook or King Coho or SilverCoho or Silver Chum or DogChum or Dog Sockeye or RedSockeye or Red Atlantic Salmon Slide 4 Salmon Anadromous Spends its life in the ocean but returns to fresh water to spawnSpends its life in the ocean but returns to fresh water to spawn Pacific Salmon die shortly after spawningPacific Salmon die shortly after spawning Atlantic Salmon may live to spawn two or more times Slide 5 Landlocked Sockeye Salmon are called Kokanee Salmon. Kokanee were originally stocked into Lake Tahoe in 1950. Every fall, thousands of kokanee ascend Taylor Creek (Tahoe tributary) to spawn. Slide 6 Photo courtesy of Mike Sevon Slide 7 Trout Facts All salmonids are characterized by the presence of an adipose fin All salmonids require clean, cold water in which to live and have a low tolerance to habitat degradation. Primarily freshwater fish, however, many species develop seagoing races. Can you name the anadromous form of the rainbow trout? Steelhead Slide 8 True Trout Characteristics: Black spots on light background Stream obligate spawners Nevadas True Trout: Cutthroat Lahontan (Threatened species) Bonneville Yellowstone Rainbow* Brown Photo courtesy of Mike Sevon Slide 9 Char Characteristics: Light spots on dark background Prefer colder water than trout Spawn in the fall Can spawn in a lake environment Nevadas Chars: Lake Trout Brook Trout Bull Trout Slide 10 Slide 11 Cutthroat Trout Once the predominant native trout in lakes and streams across the Great Basin Competition with non-native trout and habitat degradation can be attributed to the decline in the species Recovery activities by NDOW and other agencies are ongoing to reestablish these fish in their historic range Official State Record Cutthroat Trout: 23 pounds 8 ounces (Pyramid Lake, 1977) Unofficial Record: 41 pounds (Pyramid Lake, 1925) Slide 12 Photo courtesy of John Rupp Slide 13 Rainbow Trout The most important trout in North America based on its contribution to sport fisheries Comprise over 90% of the hatchery production from Nevadas four hatcheries Rainbow are native to waters along the Pacific coast All rainbow trout existing in Nevada are introduced with the exception of the Redband Trout which can be found in 12-mile Creek in the Northwest corner of Nevada State Record: 16 pounds 4 ounces (Lake Mohave, 1971) Slide 14 Photo courtesy of Mike Sevon Slide 15 Brown Trout Imported from Europe in the late 1800s and stocked throughout the United States. They were first introduced into the Truckee River in 1895. Often described as the wariest and hardest to catch of all trout While they prefer colder water, brown trout can tolerate temperatures as warm as 75F and can be found in slower moving water that would be unsuitable to other trout State Record: 27 pounds 5 ounces (Cave Lake, 1984) Slide 16 Photo courtesy of Mike Sevon Slide 17 Brook Trout Native to the Eastern U.S. Stocked extensively throughout the U.S. approximately 100 years ago. Usually found inhabiting high mountain lakes and streams due to their preference for cold water (rarely found where temps exceed 65F.) Popular with anglers considered the easiest trout to catch and the best tasting State Record: 5 pounds 10 ounces (Bull Run Reservoir, 1980) Slide 18 Slide 19 Lake Trout (Mackinaw) Native range is the northern portion of North America from Alaska to Labrador and includes the Great Lakes Highly prized as a sport fish due to its large size (World Record 72 pounds 4 ounces) Generally only found in deep, cold lakes In Nevada, theyre found in Lake Tahoe where they have been reported at depths as deep as 1,400 feet State Record: 37 pounds 6 ounces (Lake Tahoe, 1974) Slide 20 Slide 21 Bull Trout Native to the Jarbidge River system north of Elko. The Jarbidge is a tributary to the Snake River in Idaho, however, the populations are separated by 150 miles of unsuitable trout habitat and several impassable dams. Federally listed as Threatened State Record: 4 pounds 6 ounces (Jarbidge River WF, 1985) World Record: 32 pounds 0 ounces (Lake Pend Oreille, Idaho) Slide 22 Life Cycle of Salmon and Trout Slide 23 Spawning Spawning occurs in the spring for Rainbow and Cutthroat All other Nevada salmonids are fall spawners Female seeks out a suitable location for her nest and begins digging her redd Video footage courtesy of Manu Esteve, University of Washington Slide 24 Factors Influencing Nest Location Water Temperature Depth Velocity Substrate Cover for maturing fish Size of Spawners (Larger fish may choose larger streams with bigger substrate) Trout and Char often spawn in the transition area between pools and riffles where water velocity is accelerating. Slide 25 Spawning Males will fight for spawning rights to the female. The most dominant male will spawn. The process of courtship and nest building will last for hours Only when the female is ready will spawning commence. Video footage courtesy of Manu Esteve, University of Washington Slide 26 When the female is ready, she will signify the male by arching her back and quivering over the redd (gravel nest) she has built with her tail. The male fertilizes them by covering them with a milky substance known as milt. The female immediately begins to bury the newly laid eggs. Video footage courtesy of Manu Esteve, University of Washington Slide 27 Egg Development Eggs are extremely vulnerable to predators, suffocation and fungus spores. Egg development depends entirely on water temperature Rainbow trout eggs will hatch in about three weeks at a water temperature of 54F. Females can lay between 200 to 8,000 eggs (depending on the size of the fish). Slide 28 Salmon are born in gravel beds in streams 10 to 700 miles (16 to 1200 km) from the sea. Laid in the fall, the eggs incubate over the winter, frequently under several feet (more than a metre) of snow and ice. Their pink eggs are always covered from direct sunlight. About a month after they have been deposited in the gravel, eyes begin to show. This normally happens in late November or early December. It is essential during this time that water flow and temperature are suitable. The period of greatest mortality in the salmon's life cycle is in the egg-to-fry stage. Slide 29 TROUT IN THE CLASSROOM When will they hatch? Slide 30 TROUT IN THE CLASSROOM Water Temperature 35 F 40 F 45 F 50 F 55 F Rainbow Trout Days to hatch- 80 48 31 24 DTUs- 640 624 558 552 Brown Trout Days to hatch 156 100 64 41- DTUs 468 800 832 738- Slide 31 Hatch between Feb. 12-14 th. Slide 32 TROUT IN THE CLASSROOM FACTORS EFFECTING EGG DEVELOPMENT LIGHT -Direct sunlight or UV light will effect the development of the eggs. 30 minutes of light will kill them -The optimal thing to do is minimize there light exposure. Slide 33 TROUT IN THE CLASSROOM TEMPERATURE -Fluctuation for developing eggs is a good thing within range. 2F to 3F is an optimal temperature variation. Slide 34 Cutthroat Trout Eggs Eyed eggs 22 days old @ 47 DegreesF Our eggs were fertilized on Jan. 13. 2009 Slide 35 Alevin (sac fry) Development Stay in gravel 1-6 wks after hatching The embryo produces an enzyme which dissolves the egg shell (a white foam on the surface at hatching time). Eggshells need to be removed to prevent fungus Change half the water and use the baster to remove shells. Slide 36 Alevin (sac fry) Development Newly hatched trout have a yolk sac that nourishes the young fish until it is mature enough to feed itself. Sac fry remain in the gravel until their yolk sack is absorbed. Slide 37 The vitelline vein, running through the centre of the sac, picks up oxygen from the water. Slide 38 Cutthroat Trout Alevin(sac fry) They will remain in the gravel and avoid light. Keep in darkness. Sac Fry 35 days old @ 47 degrees F Slide 39 Cutthroat Trout Sac Fry Sac Fry in late development 44days @ 47 Degrees F Slide 40 Cutthroat Trout Fry Fry 55 days @ 47 Degrees F Slide 41 Once it is buttoned-up, the fry will work their way through the gravel to the top of the stream bed. These swim-up fry dart to the surface and gulp air to fill their air bladders. From this point, they are free swimming fish and begin to feed. Fry Development Slide 42 2-5 Most hatchery trout are stocked into lakes at this size Develops finger markings At about 6 in length called Parr Fingerlings/Parr Slide 43 Smolt At this point, the juvenile salmon loses its vertical markings on its body and turns silvery in color. Now considered Smolt, they will school together in large groups. It's at this time that the young salmon will adjust their bodies to saltwater, allowing them to swim out into the Pacific Ocean to feed and grow into adult salmon. Slide 44 Slide 45 Juvenile Development To reach maturity a juvenile fish must: avoid predators, Find adequate food Survive summer heat and winter cold Release 5-7 days after button up Slide 46 Adult Only about 2% of fertilized eggs survive to become mature adults. Most salmonids reach sexual maturity at 3 to 5 years. Some precocious fish (usually males) mature at 2 years. Lahontan Cutthroat Trout Pyramid Lake

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