Assessment of Arctic Grayling in Selected Streams and a Survey of Salmon Lake, Seward Peninsula, 1994
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Fishery Data Series No. 95-19 Assessment of Arctic Grayling in Selected Streams and a Survey of Salmon Lake, Seward Peninsula, 1994 bY Alfred L. DeCicco September 1995 Alaska Department of Fish and Game Division of Sport Fish FISHERY DATA SERIES NO. 95-19 ASSESSMENT OF ARCTIC GRAYLING IN SELECTED STREAMS AND A SURVEY OF SALMON LAKE, SEWARD PENINSULA, 1994 Alfred L. DeCicco Division of Sport Fish, Fairbanks Alaska Department of Fish and Game Division of Sport Fish, Research and Technical Services 333 Raspberry Road, Anchorage, Alaska, 99518-1599 September 1995 The Fishery Data Series was established in 1987 for the publication of technically oriented results for a single project or a group of closely related projects. Fishery Data Series reports are intended for fishery and other technical professionals. Distribution is to state and local publication distribution centers, libraries and individuals and, on request,to other libraries, agencies,and individuals. This publication has undergoneeditorial and peerreview. Alfred L. DeCicco Alaska Department of Fish and Game, Division of Sport Fish, Region III, 1300 College Road, Fairbanks, AK 99701-1599,USA This document should be cited as: DeCicco, A. L. 1995. Assessment of Arctic grayling in selected streams and a survey of Salmon Lake, Seward Peninsula, 1994. Alaska Department of Fish and Game, Fishery Data Series No. 95-19, Anchorage. The Alaska Department of Fish and Game administers all programs and activities free from discrimination on the basis of sex, color, race, religion, national origin, age, marital status, pregnancy, parenthood, or disability. For information on alternative formats available for this and other department publications, contact the department ADA Coordinator at (voice) 907-465-4120, or (TDD) 907-465-3646. Any person who believes s/he has been discriminated against should write to: ADF&G, PO Box 25526, Juneau, AK 99802-5526; or O.E.O., U.S. Department of the Interior, Washington, DC 20240. TABLE OF CONTENTS Page LIST OF TABLES .. .. .. .. .. .. .. .. ii LIST OF FIGURES. .. .. .. .. .. .. .. .. .. .. .. .. ............... .. ii LIST OF APPENDICES ................. ....................................................................................................................... ii ABSTRACT . .. .. .. .. .. .. .. .. .. .. .. .. 1 CHAPTER 1: ARCTIC GRAYLING STUDIES IN SELECTED STREAMS ......................................................... 1 Introduction ........................................................................................................................................................... 1 Methods................................................................................................................................................................. 4 Sampling Gear and Techniques......................................................................................................................... 4 Population AbundanceEstimates.. ..................................................................................................................... 7 Age Composition............................................................................................................................................... 8 Length Composition.......................................................................................................................................... 9 Mean Length-at-Age ......................................................................................................................................... 9 Age Validation. ................................................................................................................................................. 9 Results................................................................................................................................................................. 10 Population AbundanceEstimates ..................................................................................................................... 10 Snake River ................................................................................................................................................................. 10 Pilgrim River ............................................................................................................................................................... 12 Age Composition............................................................................................................................................. 12 Length Composition........................................................................................................................................ 12 Mean Length-at-Age....................................................................................................................................... 19 Eldorado River Age Validation ........................................................................................................................ 19 Discussion ........................................................................................................................................................... 19 CHAPTER 2: FISHERIES SURVEY OF SALMON LAKE.. ...... ......................................................................... 23 Introduction ......................................................................................................................................................... 23 Methods............................................................................................................................................................... 23 Results.................................................... ............................................................................................................. 25 Catch Per Unit of Effort.. ................................................................................................................................. 25 Biological Data................................................................................................................................................ 29 Discussion .................... .................................................................................................................................... 33 ACKNOWLEDGMENTS ......................... ........................................................................................................ 34 LITERATURE CITED.. .. .. 34 APPENDIX A . .. .. .. .. .. .. 37 APPENDIX B . .. .. .. ...................... 43 i LIST OF TABLES Table Page 1. Estimated freshwatersport fish harvests(catches are in parentheses)for SewardPeninsula and Norton Soundstreams, 1980-l 993... .. .. .. .. 2 2. Estimated proportion and abundanceof Arctic grayling in the Snakeand Pilgrim rivers by age class, 1994. .. .. .. .. .. .. .. 14 3. Estimated proportion and abundanceof Arctic grayling in the Snakeand Pilgrim rivers by 25 mm FL increments, 1994.. .. .. .. .. .. .. .. .. 16 4. Estimated proportion and abundanceof Arctic grayling in the Snakeand Pilgrim rivers by RSD category, 1994.. .. .. .. .. .. .. .. .. .. .. ........... 18 5. Length distribution in 25 mm incrementsof Arctic grayling >lOl mm FL sampledfrom Seward Peninsularivers during 1994... .. .. .. .. 20 6. Mean fork length-at-ageof Arctic grayling in SewardPeninsula rivers sampledduring 1994 . .2 1 7. Median gillnet catchesby speciesin SalmonLake . .. .. .. 28 8. Number and size of fish caught by different gillnet mesh sizesin SalmonLake . .. .. .. .. 30 LIST OF FIGURES Figure Page 1. The southernSeward Peninsula showing roadsand road accessiblewaters. .............................................. 3 2. The SnakeRiver with area sampledduring 1994...................................................................................... 5 3. The Pilgrim River with areasampled during 1994.................................................................................... 6 4. Cumulative length distribution plots (tests 1 and 2) of Arctic grayling > 249 mm FL sampledfrom the SnakeRiver in 1994............................................................................................................................... 11 5. Cumulative length distribution plots (tests 1 and 2) of Arctic grayling > 269 mm FL sampledfrom the Pilgrim River in 1994....................................................... ...................................................................... 13 6. Age compositionestimates of Arctic grayling from the Snakeand Pilgrim rivers in 1994....................... 15 7. Length composition estimatesin 25 mm incrementsof Arctic grayling sampledfrom the Snakeand Pilgrim rivers in 1994............................................................................................................................ 17 8. SalmonLake with bottom contours......................................................................................................... 24 9. SalmonLake showing the location of gillnet sets.................................................................................... 26 10. SalmonLake showing the location of hoop trap and minnow trap sets.................................................... 27 11. Length frequenciesof fish capturedin SalmonLake. .............................................................................. 31 12. Length-weight relationship for round whitefish sampledfrom SalmonLake ........................................... 32 13. Length-weight relationship for least cisco