DOCSLIB.ORG

Lahontan Cutthroat Trout Program Lahontan National Fish Hatchery Complex US Fish and Wildlife Service

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Lahontan Cutthroat Trout Program Lahontan National Fish Hatchery Complex US Fish and Wildlife Service Lahontan Cutthroat Trout Program Lahontan National Fish Hatchery Complex US Fish and Wildlife Service Tahoe Working Group Meeting February 16, 2010 Presentation Outline ¾ Lahontan cutthroat trout –Background ¾ LCT reintroduction in Fallen Leaf Lake using adaptive management strategies ¾ Lake Tahoe Assessment Lahontan cutthroat trout –A Tahoe Legacy ¾ The only trout native to the basin ¾ Provided extensive recreational and commercial fisheries ¾ Extirpated from the basin in the 1930’s Pilot Peak LCT ¾ Represents the original Tahoe Basin strain based on genetic comparisons with museum specimens ¾ Exhibits ancestral life history characteristics Conservation and Recovery Efforts ¾ Recovery Plan in 1995 ¾ Short‐term Action Plans for Walker and Truckee Basins 2003 ¾ Formation of Tahoe Basin Recovery Implementation Team 2007 ¾ Recovery Implementation Plan 2010 Fallen Leaf Lake Research 2002‐2005 (FWS,UCD,UNR,UW) ¾ Stunted lake trout indicate resource limited system ¾ High shore angler catch rate of LCT ¾ Significant lake trout predation on stocked LCT ¾ Full compliment of native zooplankton species Fallen Leaf Lake Research 2007 (FWS,UNR) ¾ Refined lake trout abundance estimate: 8,799 lake trout (Schnabel) 95% CI = 4,990 –16,530 ¾ Identification of refugia from predation for LCT z Thermocline segregation z LCT refuge in woody debris ¾ Diet of lake trout dependent on size and time of year Adaptive management at Fallen Leaf Lake ¾ The challenges z Lake trout z Mysid shrimp z Over fishing ¾ The strategy z Improve stocking methods z Research lake trout removal methods z Monitor ecosystem effects of management actions Adaptive Management Implementation 2008 and 2009 ¾ Remote Site Incubation ¾ Adaptive Stocking Methods ¾ Hydroacoustic Detection of Lake Trout ¾ Lake trout abundance estimation: 15,675 lake trout (Peterson) 95% CI = 9,564 –27,086 GLEN ALPINE CREEK Remote Site Incubation Remote Site Incubation Results 2008 and 2009 ¾ 4 incubators for both years z 3,500 per incubator 2008 z 7,500 per incubator 2009 Down stream monitoring ¾ Fry released z 2008 – 7,000 z 2009 – 20,000 Juvenile Stocking Strategy ¾ Implemented in 2008 • Stocked over 60,000 4‐6 “ fish ¾ Thermocline • June‐October ¾ Dispersion • Released at 11 Sites ¾ Refugia Adult Stocking Strategy ¾ Implemented in 2009 • Stocked over 30,000 10” fish ¾ Thermocline • June‐October ¾ Dispersion • Released at 5 different sites over 5 days ¾ Refugia 2009 Adaptive Management Objectives ¾ Enhance the recreational fishery at Fallen Leaf Lake by stocking LCT ¾ Refine Lake trout netting methods to reduce incidental catch of fishes native to the Tahoe basin ¾ Test the feasibility of systematic removal of lake trout Percentage of Anglers Interviewed Reporting Fishing Success 90.0% 80.0% success 70.0% Catchable LCT stocked before creel 60.0% survey fishing 50.0% Year without 40.0% stocking catchable LCT 30.0% reporting 20.0% 10.0% Anglers 0.0% % 2002 2003 2004 2005 2006 2007 2008 2009 Year Primary Angler Catch Stocking vs. Non‐stocking Years 2008 Creel 2009 Creel KOK RBT BT MWF KOK RBT Lake trout Lake Trout LCT 61% 97% n = 73 Number of fish caught per angler shore fishing 4 Catchable LCT 3.5 stocked 3 No catchables Caught stocked 2.5 Fish of 2 1.5 number 1 Average 0.5 0 2002 2003 2004 2005 2006 2007 2008 2009 Creel Census Year 2009 LCT Initial Survival Predation vs. Angler Catch Rate 3 1.400 Number of LCT per lake trout Number of LCT caught per angler 1.200 2.5 1.000 2 0.800 1.5 0.600 0.400 1 0.200 0.5 0.000 0 0.200 7/26/2009 7/31/2009 8/5/2009 8/10/2009 8/15/2009 8/20/2009 8/25/2009 8/30/2009 9/4/2009 Date LCT Diet Locating lake trout with hydroacoustics to increase netting efficiency Lake Trout Specific Gill Nets Native non‐game fishes 3% 95% Lake Trout (2% other non‐native trout) Lake trout donations to South Lake Tahoe food bank Summary for Adaptive Management Actions ¾ Improved remote site incubation ¾ Successful stocking program z Larger fish z Stocked during thermocline z Not tagged ¾ Improved recreational fishery ¾ Lake trout specific netting methods z 4” mesh z During fall spawning ¾ Donation of lake trout filets to local food bank Lake Tahoe Strategies ¾ Use the methods and tools refined at Fallen Leaf Lake to guide initial strategies in Lake Tahoe for assessment and reintroduction ¾ Select 2‐5 Lake Tahoe streams/tributaries and areas within Tahoe for LCT recovery/reintroduction ¾ Provide LCT production at levels to support harvest and recreational fishing in Lake Tahoe Questions/Comments.
Load more

Recommended publications
  • Bonneville Cutthroat Trout (Oncorhynchus Clarki Utah) Bonneville Cutthroat Trout Is One of Three Cutthroat Trout Subspecies Native to Utah
    FISH Bonneville Cutthroat Trout (Oncorhynchus clarki utah) Bonneville cutthroat trout is one of three cutthroat trout subspecies native to Utah. Bonneville cutthroat trout historically occurred in the Pleistocene Lake Bonneville basin, which included portions of Idaho, Nevada, Utah, and Wyoming (Kershner 1995). The desiccation of Lake Bonneville into the smaller Great Salt Lake and fragmentation of other stream and lake habitats may have led to three slightly differentiated groups of Bonneville cutthroat trout. These groups are found in the Bonneville basin proper, the Bear River drainage, and the Snake Valley (Behnke 1992). There are five known populations of pure strain Bonneville cutthroat trout on the Fishlake National Forest inhabiting approximately 38 miles of stream habitat. There are several recently reintroduced populations, and several small potential remnant populations. Habitat for the Bonneville cutthroat trout is widely distributed and variable. It ranges from high elevation (3,500 m mean sea level) streams with coniferous and deciduous riparian trees to low elevation (1,000 m mean sea level) streams in sage-steppe grasslands containing herbaceous riparian zones. As such, Bonneville cutthroat trout have adapted to a broad spectrum of habitat conditions throughout their range (Kershner 1995). Sexual maturity is typically reached during the second year for males and the third year for females (May et al. 1978). Both the age at maturity and the annual timing of spawning vary geographically with elevation, temperature, and life history strategy. Lake resident trout may begin spawning at two years of age and usually continue throughout their lives, while adfluvial individuals may not spawn for several years.
    [Show full text]
  • The Native Trouts of the Genus Salmo of Western North America
    CItiEt'SW XHPYTD: RSOTLAITYWUAS 4 Monograph of ha, TEMPI, AZ The Native Trouts of the Genus Salmo Of Western North America Robert J. Behnke "9! August 1979 z 141, ' 4,W \ " • ,1■\t 1,es. • . • • This_report was funded by USDA, Forest Service Fish and Wildlife Service , Bureau of Land Management FORE WARD This monograph was prepared by Dr. Robert J. Behnke under contract funded by the U.S. Fish and Wildlife Service, the Bureau of Land Management, and the U.S. Forest Service. Region 2 of the Forest Service was assigned the lead in coordinating this effort for the Forest Service. Each agency assumed the responsibility for reproducing and distributing the monograph according to their needs. Appreciation is extended to the Bureau of Land Management, Denver Service Center, for assistance in publication. Mr. Richard Moore, Region 2, served as Forest Service Coordinator. Inquiries about this publication should be directed to the Regional Forester, 11177 West 8th Avenue, P.O. Box 25127, Lakewood, Colorado 80225. Rocky Mountain Region September, 1980 Inquiries about this publication should be directed to the Regional Forester, 11177 West 8th Avenue, P.O. Box 25127, Lakewood, Colorado 80225. it TABLE OF CONTENTS Page Preface ..................................................................................................................................................................... Introduction ..................................................................................................................................................................
    [Show full text]
  • History of Lahontan Cutthroat Trout in Spring Creek, Utah
    Spring Creek Population History of the Pyramid Lake Rediscovery (Again) Unfortunately, given its small size, the trout Lahontan Cutthroat population at Spring Creek has a very low In October 2009, a team from Weber State probability of survival. It lacks the numbers The Lahontan cutthroat trout, Oncorhynchus University in conjunction with personnel and space necessary to maintain sufficient clarkii henshawi, is native to the Lahontan Basin from the DWR identified several specimens genetic diversity. It is believed that for a on the border between California and Nevada. believed to be of a pure or hybrid strain of mountain stream cutthroat population to For thousands of years it thrived and played the Pyramid Lake Lahontan cutthroat trout survive it must have a minimum of 3.3 km an important economic and cultural role in Spring Creek in Uintah, Utah. Using of habitat and an abundance in the area of among the Native American tribes of the electrofishers and dip nets, a 600 m stretch 0.3 fish per meter.3 Based on our region. The largest strain of this fish of the stream was sampled. A maximum observations, the Spring Creek population originated in Pyramid Lake, in western of 16 different individuals was collected in A Unique Environment has a maximum abundance of 0.1 fish/m Nevada and has reached recorded weights of two sampling trips. The fish appeared to Spring Creek’s unique vegetation and only 200 m of habitat. However, against up to 41 pounds, making it the largest “The Fish that Won’t Die” be restricted to a 200 m stretch.
    [Show full text]
  • Lake Trout Management Plan
    LAKE TROUT MANAGEMENT PLAN DEPARTMENT OF INLAND FISHERIES AND WILDLIFE DIVISION OF FISHERIES AND HATCHERIES PREPARED BY PAUL JOHNSON REGIONAL FISHERIES BIOLOGIST REGION E MARCH 2001 LAKE TROUT LIFE HISTORY Description The lake trout (Salvelinus namaycush) lacks the distinctive coloration of its close relative, the eastern brook trout. Lake trout are usually either dark green or grayish brown in color, with white or pale yellow bean-shaped spots. In clear waters lake trout are often so silvery that the white spots are difficult to see. In stained waters they are very dark, almost black. Generally, a narrow border of white is present along the anterior margins of the pectoral, pelvic, and anal fins. This is most pronounced during spawning; however, at no time is this border as accentuated as it is on the fins of the brook trout. Lake trout fins are not orange or orange-red, like those of the brook trout. Distribution Lake trout are distributed throughout Canada. In the United States their natural range was restricted to northern New England, the Great Lakes, New York, Pennsylvania, Michigan, Minnesota, Montana, Idaho, and Alaska. In Maine they were originally found in about 100 lakes throughout the State. However, lake trout have been successfully reared in hatcheries. Consequently, their range has been extended considerably in the United States. In Maine they have been introduced into waters from Aroostook County in the north, to York County in the south. Throughout their native range lake trout are known by a wide variety of common names. In Maine they are called togue, whereas in other parts of the country and Canada they are referred to as mackinaw, salmon trout, lakers, grey trout, namaycush, Great Falls char, or mountain trout.
    [Show full text]
  • Lake Superior Food Web MENT of C
    ATMOSPH ND ER A I C C I A N D A M E I C N O I S L T A R N A T O I I O T N A N U E .S C .D R E E PA M RT OM Lake Superior Food Web MENT OF C Sea Lamprey Walleye Burbot Lake Trout Chinook Salmon Brook Trout Rainbow Trout Lake Whitefish Bloater Yellow Perch Lake herring Rainbow Smelt Deepwater Sculpin Kiyi Ruffe Lake Sturgeon Mayfly nymphs Opossum Shrimp Raptorial waterflea Mollusks Amphipods Invasive waterflea Chironomids Zebra/Quagga mussels Native waterflea Calanoids Cyclopoids Diatoms Green algae Blue-green algae Flagellates Rotifers Foodweb based on “Impact of exotic invertebrate invaders on food web structure and function in the Great Lakes: NOAA, Great Lakes Environmental Research Laboratory, 4840 S. State Road, Ann Arbor, MI A network analysis approach” by Mason, Krause, and Ulanowicz, 2002 - Modifications for Lake Superior, 2009. 734-741-2235 - www.glerl.noaa.gov Lake Superior Food Web Sea Lamprey Macroinvertebrates Sea lamprey (Petromyzon marinus). An aggressive, non-native parasite that Chironomids/Oligochaetes. Larval insects and worms that live on the lake fastens onto its prey and rasps out a hole with its rough tongue. bottom. Feed on detritus. Species present are a good indicator of water quality. Piscivores (Fish Eaters) Amphipods (Diporeia). The most common species of amphipod found in fish diets that began declining in the late 1990’s. Chinook salmon (Oncorhynchus tshawytscha). Pacific salmon species stocked as a trophy fish and to control alewife. Opossum shrimp (Mysis relicta). An omnivore that feeds on algae and small cladocerans.
    [Show full text]
  • Additional Information for Lake Ontario Anglers
    Additional Information for Anglers 2020 Lake Ontario Stocking Decision Q: How will this stocking reduction impact fishing in 2020? A: The reductions being implemented in 2020 will have little impact on fishing in the near term as the fish that anglers will catch next year have already been stocked in the system. In addition, about 50% of the adult Chinook salmon in Lake Ontario are naturally reproduced or “wild” fish. Q: How will this impact fishing in the future? A: If alewife abundance continues to decline, the size of Chinook may decline, but angler success (i.e. catch rate) may remain high as Chinook salmon become more vulnerable to angling. Q: Are other fish species slated for reductions? A: Not at this time. Q: What are the actual numbers of fish being stocked? A: Even with these reductions, lake-wide salmon and trout stocking in Lake Ontario in 2020 will exceed 3.6 million fish, including approximately 1.1 million Chinook salmon, 755,000 rainbow trout/steelhead, 556,000 brown trout, 601,000 lake trout, 325,000 coho salmon and 200,000 yearling Atlantic salmon. Q: Why isn’t the stocking of other species of trout and salmon being reduced? A: While other trout and salmon species eat alewife, Chinook salmon consume the largest amount in the shortest timespan. Reducing Chinook salmon numbers provides the greatest reduction of alewife consumption in the short-term. Further reducing lake trout stocking is intended to provide more long-term relief, since they grow slower and live longer than Chinook salmon. Lake Ontario’s diversity of trout and salmon supports a world-class fishery, and managers want to maintain that diversity to the extent possible.
    [Show full text]
  • Coyote Lake Lahontan Cutthroat Trout
    Oregon Native Fish Status Report – Volume II Coyote Lake Lahontan Cutthroat Trout Existing Populations Lahontan cutthroat trout populations in the Coyote Lakes basin are remnant of a larger population inhabiting pluvial Lake Lahontan during the Pleistocene era. Hydrologic access routes of founding cutthroat trout from Lake Lahontan basin into the Coyote Lakes basin have yet to be described (Coffin and Cowan 1995). The Coyote Lake Lahontan Cutthroat Trout SMU is comprised of five populations (Table 1). All populations express a resident life history strategy; however large individuals in the Willow and Whitehorse Complex populations suggest a migratory component may exist. Table 1. Populations, existence status, and life history of the Coyote Lake Lahontan Cutthroat Trout SMU. Exist Population Description Life History Yes Willow Willow Creek and tributaries. Resident / Migratory Yes Whitehorse Complex Whitehorse and Little Whitehorse Creeks, and Resident / Migratory tributaries. Yes Doolittle Doolittle Creek above barrier. Resident Yes Cottonwood Cottonwood Creek above barrier. Resident Yes Antelope Antelope Creek. Resident Lahontan cutthroat trout from Willow and Whitehorse creeks were transplanted into Cottonwood Creek in 1971 and 1980, and into Antelope Creek in 1972 (Hanson et al. 1993). Whether Lahontan cutthroat trout were present in these creeks prior to stocking activities is disputed (Behnke 1992, Hanson et al. 1993, Coffin and Cowan 1995, K. Jones, ODFW Research Biologist, Corvallis, OR personal communication). For the purpose of this review these populations are considered native. Lahontan cutthroat trout were also transplanted into Fifteenmile Creek above a natural barrier (Hanson et al. 1993), but they did not establish a self- sustaining population (ODFW Aquatic Inventory Project, unpublished data).
    [Show full text]
  • Market-Sized Cutthroat Trout Technical Report Western Regional Aquaculture Center
    Feeds for Production of Market-sized Cutthroat Trout Technical Report WESTERN REGIONAL AQUACULTURE CENTER Gary Fornshell, University of Idaho Christopher Myrick, Colorado State University Madison Powell, University of Idaho Wendy Sealey, United States Fish and Wildlife Service United States Department of Agriculture National Institute of Food and Agriculture 1 PROJECT PARTICIPANTS Christopher Myrick, Colorado State University Cheyenne Owens, Colorado State University Biswamitra Patro, University of Idaho Madison Powell, University of Idaho Pat Blaufuss, University of Idaho Tracy Kennedy, University of Idaho Wendy Sealey, United States Fish and Wildlife Service Brian Ham, United States Fish and Wildlife Service Gary Fornshell, University of Idaho Jeremy Liley, Liley Fisheries, Inc. David Brock, Rangen, Inc. Jackie Zimmerman, Skretting USA Rick Barrows, Aquatic Feed Technologies, LLC Photo credits: Cover: Gary Fornshell Above: iStock.com/KaraGrubis 2 Table of Contents Introduction: Why Consider Cutthroat Trout? 1 Snake River Cutthroat Trout—A Culturable Cutthroat 2 Is Raising Fish for the Recreational Market Worthwhile? 3 Overcoming Challenges to Raising Cutthroat Trout 3 Fish Nutrition 101—A Primer on Feed Formulation 3 Feed Pellet Texture Matters 5 Cutthroat Trout Growth—Does It Match Rainbow Trout? 5 Thermal Growth Coefficient 5 Comparing Rainbow and Cutthroat Trout Performance 6 Suggested Readings 10 Acknowledgments 11 Figures 1. Snake River cutthroat trout. 1 2. Map showing the distribution of extant cutthroat trout 2 subspecies in the western United States. 3. Juvenile Snake River cutthroat trout ready for stocking. 3 4. Classic bell-shaped growth-temperature curve. 6 5. Sigmoid growth curve. Based on Fish Hatchery Management, Second Edition, Gary Wedemeyer, editor 7 6.
    [Show full text]
  • 1 EAGLE LAKE RAINBOW TROUT Oncorhynchus Mykiss Aquilarum
    EAGLE LAKE RAINBOW TROUT Oncorhynchus mykiss aquilarum (Snyder) Status: High Concern. The Eagle Lake rainbow trout (ELRT) does not exist as a self-sustaining wild population because of dependence on hatchery propagation. Habitat degradation and the presence of alien brook trout in Pine Creek, the ELRT’s principal spawning grounds, along with continued reliance on hatchery production to maintain the ELRT population will make it increasingly difficult to re-establish a wild population. Description: This subspecies is similar to other rainbow trout in gross morphology (see Moyle 2002), but differs slightly in meristic counts, especially in having finer scales than coastal rainbow trout. It is also distinctive in possessing 58 chromosomes, rather than the 60 typical of other rainbow trout (Busack et al. 1980). Taxonomic Relationships: Snyder (1917) described this trout as a subspecies of rainbow trout, Salmo gairdneri aquilarum. However, Hubbs and Miller (1948) examined Snyder's specimens and concluded that ELRT were derived from hybridization between native Lahontan cutthroat trout (presumed to have occupied Eagle Lake prehistorically) and introduced rainbow trout. Miller (1950) later retracted the hybridization theory. Needham and Gard (1959) then suggested that ELRT were descended from introduced or immigrant rainbow trout from the Feather or Pit River drainages. Behnke (1965, 1972) proposed a redband-rainbow hybrid origin, although redband trout are now considered to be rainbow trout subspecies. Busack et al. (1980), in an extensive electrophoretic, karyotypic and meristic analysis, suggested that ELRT were derived either from immigration or an unrecorded introduction of a rainbow trout with 58 chromosomes. The distinctive morphology, ecology, and physiology of this form all point to ELRT being derived from natural colonization from the Sacramento River drainage.
    [Show full text]
  • Influence of Water Temperature and Beaver Ponds on Lahontan Cutthroat Trout in a High-Desert Stream, Southeastern Oregon
    AN ABSTRACT OF THE THESIS OF Andrew G. Talabere for the degree of Master of Science in Fisheries Science presented on November 21. 2002. Title: Influence of Water Temperature and Beaver Ponds on Lahontan Cutthroat Trout in a High-Desert Stream, Southeastern Oregon Abstract approved Redacted for Privacy Redacted for Privacy The distribution of Lahontan cutthroat trout Oncorhynchus clarki henshawi was assessed in a high-desert stream in southeastern Oregon where beaver Castor canadensis are abundant. Longitudinal patterns of beaver ponds, habitat, temperature, and Lahontan cutthroat trout age group distribution were identified throughout Willow Creek. Three distinct stream segments were classified based on geomorphological characteristics. Four beaver-pond and four free-flowing sample sections were randomly located in each of the three stream segments. Beavers substantially altered the physical habitat of Willow Creek increasing the depth and width of available habitat. In contrast, there was no measurable effect on water temperature. The total number of Lahontan cutthroat trout per meter was significantly higher in beaver ponds than free-flowing sections. Although density (fish! m2) showed no statistically significant (P < 0.05) increase, values in beaver pondswere two-fold those of free-flowing sections. Age- 1 and young-of-the-year trout were absent or in very low numbers in lower Willow Creek because of elevated temperatures, but high numbers of age-2 and 3 (adults) Lahontan cutthroat trout were found in beaver ponds where water temperatures reached lethal levels (>24°C). Apparently survival is greater in beaver ponds than free-flowing sections as temperatures approach lethal limits. Influence of Water Temperature and Beaver Ponds on Lahontan Cutthroat Trout in a High- Desert Stream, Southeastern Oregon by Andrew G.
    [Show full text]
  • LAKE TROUT­ (Salvelinus Namaycush)
    LAKE TROUT­ (Salvelinus namaycush) Common Names: Lake trout, laker, grey trout, Mackinaw, Great Lakes trout Lake Michigan Sport Catch in Wisconsi n : 100,000 per year Preferred Temperature Range: 48‐52 ºF, 9‐11 ºC Predators for Adults – Sea Lamprey, humans for Juveniles – Larger carnivorous fish Eggs – Whitefish, burbot, and sculpin Length: 17‐36 inches Weight: 3‐30 pounds State Record: 9/9/46; 47 pounds, from Lake Superior State Record (Inland): 6/1/57; 35 pounds, 4 ounces, from Big Green Lake, Green Lake County Wisconsin Department of Natural Resources Bureau of Fisheries Management PUBL‐FM‐101 08 April 2008 Identification: Lake trout are distinguished by Wisconsin waters of Lake Michigan. Unfortunately, having a deeply forked tail, the inside of their successful natural reproduction of the lake trout has mouth white, and 10‐11 rays in their anal fin. The not taken place, even with many millions of fish color of the lake trout varies from light green or planted. Stocking, therefore, remains essential to grey to dark green or almost black with light spots sustain the lake trout population in Lake Michigan. and worm‐like markings on their back and sides. Eggs for the hatchery program are collected Distribution: Lake trout are native to New from mature lake trout held in hatcheries in October England, the Great Lakes area, and Canada. In the and November. The eggs incubate about 90 days Lake Michigan waters of Wisconsin, they can be before hatching. After being reared in the hatchery found in the outer half of Green Bay and along the for a year, they are stocked the following spring from entire Lake Michigan shoreline.
    [Show full text]
  • A Review of Literature on Lake Trout Life History with Notes on Alaskan Management
    A REVIEW OF LITERATURE ON LAKE TROUT LIFE HISTORY WITH NOTES ON ALASKAN MANAGEMENT R. Russell Redick , Fishery Biologist Alaska Department of Fish and Game Division of Sport Fish Homer, Alaska ABSTRACT The lake trout, Salvelinus namaycush (Walbaum) , is the largest of the chars and is distinguished from other chars by having more than 100 pyloric caeca. It is restricted to North America and chiefly inhabits oli- gotrophic lakes of Alaska, Canada, and the northern United States. Food availability rather than preference usually determines the diet of lake trout. If forage fish are available, older lake trout are piscivorous while younger fish are chiefly dependent upon invertebrates. The opposum shrimp, Mysis relicta , is important to the diet of young lake trout in many lakes. Spawning occurs over rocky shoals in the fall when water temper- atures cool to 12" C or lower. The eggs typically hatch in 135 to 145 days. The fry move to deeper water after hatching ad reside in rock crevices during their juvenile development. Growth rates and age at maturity are correlated to latitude, with northern populations growing slower and maturing later than southern populations. Most states manage their lake trout populations for recreation. However, limited commercial lake trout fisheries exist in Canada and attempts have been made to establish similar commercial fisheries in Alaska. TAX0 NO MY AND DES CRIPTIO N The lake trout is the largest of the North American chars and has been classified by some ichthyologists as the only species of the genus Cristivomer , with all remaining chars divided into the sub-genera Baione and Salvelinus .
    [Show full text]