Spawning Locations, Seasonal Distribution, and Migratory Timing Of

Fishery Data Series No. 12-65

Spawning Locations, Seasonal Distribution, and Migratory Timing of Kuskokwim River Sheefish using Radiotelemetry, 2007–2011 Final Report for Study 10-305 USFWS Office of Subsistence Management Fisheries Division

by Lisa Stuby

November 2012 Alaska Department of Fish and Game Divisions of Sport Fish and Commercial Fisheries Symbols and Abbreviations The following symbols and abbreviations, and others approved for the Système International d'Unités (SI), are used in Division of Sport Fish Fishery Manuscripts, Fishery Data Series Reports, Fishery Management Reports, and Special Publications without definition.

Weights and measures (metric) General Mathematics, statistics, fisheries

centimeter cm All commonly accepted e.g., Mr., Mrs., alternate hypothesis HA deciliter dL abbreviations. a.m., p.m., etc. base of natural e gram g All commonly accepted e.g., Dr., Ph.D., logarithm professional titles. R.N., etc. hectare ha catch per unit effort CPUE

kilogram kg And & coefficient of variation CV kilometer km At @ common test statistics F, t, χ2, etc. Compass directions: liter L confidence interval C.I. meter m east E correlation coefficient R (multiple) metric ton mt north N correlation coefficient r (simple) south S milliliter ml Covariance cov millimeter mm west W degree (angular or ° Copyright  temperature) Weights and measures (English) Corporate suffixes: degrees of freedom df cubic feet per second ft3/s Company Co. divided by ÷ or / (in foot ft Corporation Corp. equations) gallon gal Incorporated Inc. Equals = inch in Limited Ltd. expected value E mile mi et alii (and other et al. fork length FL ounce oz people) greater than > pound lb et cetera (and so forth) etc. greater than or equal to ≥ quart qt exempli gratia (for e.g., harvest per unit effort HPUE example) yard yd less than < id est (that is) i.e., less than or equal to ≤ latitude or longitude lat. or long. logarithm (natural) ln monetary symbols $, ¢ logarithm (base 10) log Time and temperature (U.S.) logarithm (specify base) log2, etc. day d months (tables and Jan,...,Dec degrees Celsius °C figures): first three mideye-to-fork MEF degrees Fahrenheit °F letters minute (angular) ' hour h number (before a # (e.g., #10) multiplied by X minute min number) not significant NS second s pounds (after a number) # (e.g., 10#) null hypothesis HO registered trademark  percent % Trademark  probability P Physics and chemistry United States U.S. probability of a type I α all atomic symbols (adjective) error (rejection of the null hypothesis when alternating current AC United States of USA America (noun) true) ampere A U.S. state and District use two-letter probability of a type II β calorie cal of Columbia abbreviations error (acceptance of direct current DC abbreviations (e.g., AK, DC) the null hypothesis when false) hertz Hz horsepower hp second (angular) " hydrogen ion activity pH standard deviation SD parts per million ppm standard error SE parts per thousand ppt, ‰ standard length SL volts V total length TL watts W variance Var

FISHERY DATA REPORT NO. 12-65

SPAWNING LOCATIONS, SEASONAL DISTRIBUTION, AND MIGRATORY TIMING OF KUSKOKWIM RIVER SHEEFISH USING RADIOTELEMETRY, 2007–2011

by Lisa Stuby 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

November 2012

ADF&G Fishery Data Series was established in 1987 for the publication of Division of Sport Fish technically oriented results for a single project or group of closely related projects, and in 2004 became a joint divisional series with the Division of Commercial Fisheries. Fishery Data Series reports are intended for fishery and other technical professionals and are available through the Alaska State Library and on the Internet: http://www.adfg.alaska.gov/sf/publications. This publication has undergone editorial and peer review.

Lisa Stuby, Alaska Department of Fish and Game, Division of Sport Fish, 1300 College Road, Fairbanks, AK 99701-1599 USA

This document should be cited as: Stuby, L. 2012. Spawning locations, seasonal distribution, and migratory timing of Kuskokwim River sheefish using radiotelemetry, 2007-2011. Alaska Department of Fish and Game, Fishery Data Series No. 12-65, Anchorage.

The Alaska Department of Fish and Game (ADF&G) administers all programs and activities free from discrimination based on race, color, national origin, age, sex, religion, marital status, pregnancy, parenthood, or disability. The department administers all programs and activities in compliance with Title VI of the Civil Rights Act of 1964, Section 504 of the Rehabilitation Act of 1973, Title II of the Americans with Disabilities Act (ADA) of 1990, the Age Discrimination Act of 1975, and Title IX of the Education Amendments of 1972. If you believe you have been discriminated against in any program, activity, or facility please write: ADF&G ADA Coordinator, P.O. Box 115526, Juneau, AK 99811-5526 U.S. Fish and Wildlife Service, 4401 N. Fairfax Drive, MS 2042, Arlington, VA 22203 Office of Equal Opportunity, U.S. Department of the Interior, 1849 C Street NW MS 5230, Washington DC 20240 The department’s ADA Coordinator can be reached via phone at the following numbers: (VOICE) 907-465-6077, (Statewide Telecommunication Device for the Deaf) 1-800-478-3648, (Juneau TDD) 907-465-3646, or (FAX) 907-465-6078 For information on alternative formats and questions on this publication, please contact: ADF&G, Division of Sport Fish, Research and Technical Services, 333 Raspberry Rd, Anchorage AK 99518 (907) 267-2375. TABLE OF CONTENTS Page LIST OF TABLES...... ii LIST OF FIGURES ...... ii LIST OF APPENDICES ...... ii ABSTRACT ...... 1 INTRODUCTION ...... 1 OBJECTIVES ...... 4 METHODS ...... 4 Study Design ...... 4 Capture and Tagging ...... 5 Radiotracking Equipment and Tracking Procedures ...... 6 September Sampling in Upper Kuskokwim River Spawning Areas and Kongeruk River ...... 7 Data analysis ...... 8 RESULTS ...... 8 Spawning Locations, Frequency, and Timing ...... 10 Sampling in Upriver Sheefish Spawning Areas ...... 18 Winter and Summer Distribution and Movements ...... 19 Fall Sampling of Kongeruk River Sheefish ...... 22 Length Composition ...... 27 DISCUSSION ...... 27 ACKNOWLEDGEMENTS ...... 32 REFERENCES CITED ...... 33 APPENDIX A MAPS SHOWING LOCATIONS OF RADIOTAGGED SHEEFISH DURING THE AERIAL TRACKING FLIGHTS CONDUCTED DURING JULY 2008–2011 ...... 37 APPENDIX B MAPS SHOWING LOCATIONS OF RADIOTAGGED SHEEFISH DURING THE AERIAL TRACKING FLIGHTS CONDUCTED DURING SEPTEMBER AND OCTOBER 2008–2011 ...... 43 APPENDIX C MAPS SHOWING DETAILS OF VISITS TO UPPER KUSKOKWIM SHEEFISH SPAWNING AREAS TO SAMPLE SHEEFISH FOR SPAWNING READINESS ...... 49 APPENDIX D SPAWNING CHARACTERISTICS OF FISH FROM SPAWNING AREAS ON THE BIG RIVER, MIDDLE FORK OF THE KUSKOKWIM RIVER, AND THE KONGERUK RIVER AND ENVIRONMENTAL DATA ...... 55 APPENDIX E JULY TO OCTOBER 2008–2011 AMBIENT AIR TEMPERATURES FROM MCGRATH STATION ...... 61

i LIST OF TABLES Table Page 1. List of possible fates of radio-tagged sheefish in the Kuskokwim River...... 9 2. Assigned fates of sheefish in 2011 that were radiotagged during 2007 and 2008...... 11 3. Numbers of radiotagged sheefish located at 3 spawning areas of the Kuskokwim River during 2007– 2011...... 11 4. Number of radiotagged sheefish by spawning location and spawning frequency, 2008–2011...... 13 5. Overwintering locations of sheefish during the winters of 2007–2011...... 20 6. Feeding area fidelity for radiotagged sheefish from 2008–2011...... 23 7. Number and location of sheefish that spent the summers of 2008–2011 in the Lower Kuskokwim River by tagging location and year of tagging...... 25

LIST OF FIGURES Figure Page 1. Map of the Kuskokwim River showing approximate overwintering, feeding, and spawning locations for sheefish as noted in this study...... 2 2. Locations of radiotagged sheefish in spawning areas on the Big River and Middle Fork of the Kuskokwim River during 2008–2011...... 12 3. Map showing locations of radiotagged sheefish near the mouth of the East Fork of the Kuskokwim River and Tonzona River during September and October 2008–2011...... 14 4. Cumulative arrival and departure dates for radiotagged sheefish that migrated to upriver spawning areas on the Big River and Middle Fork of the Kuskokwim River during 2008–2011...... 16 5. Cumulative downriver passage dates for spawning and non-spawning radiotagged sheefish during 2008, 2010, and 2011...... 17 6. Upriver migration times of radiotagged sheefish during 2009 and 2010...... 21 7. Map of the Holitna River drainage showing primary concentrations of radiotagged sheefish during July, September, and October 2008–2011...... 24 8. Map showing sheefish that were located near the mouth of the Johnson River during July and late summer/early fall up the Kongeruk River, 2008–2011...... 26 9. Cumulative length frequency distributions comparing radiotagged sheefish that were assumed to have spawned in the Upper Kuskokwim River and the 11 sheefish that were assumed to not have spawned during 2008–2011...... 28

ii LIST OF APPENDICES Appendix Page A1. Map showing the locations of radiotagged sheefish during the 20–22 July 2008 aerial tracking flights. . ... 38 A2. Map showing the locations of radiotagged sheefish during the 3–4 July 2009 aerial tracking flights...... 39 A3. Map showing the locations of radiotagged sheefish during the 5–7 July 2010 aerial tracking flights...... 40 A4. Map showing the locations of radiotagged sheefish during the 4–5 July 2011 aerial tracking flights...... 41

B1. Map showing the uppermost locations of radiotagged sheefish during the 23–25 September and 8–9 October 2008 aerial tracking flights...... 44 B2. Map showing the uppermost locations of radiotagged sheefish during the 9–11 September and 9, 11– 12 October 2009 aerial tracking flights...... 45 B3. Map showing the uppermost locations of radiotagged sheefish during the 19–21 and 29 September 2010 aerial tracking flights...... 46 B4. Map showing the uppermost locations of radiotagged sheefish during the 26–28 September 2011 aerial tracking flights...... 47

C1. Substrate descriptions, set net sites, locations where other species of whitefish were observed spawning, and extent of effort to capture and sample sheefish for spawning readiness during a visit to the Big River during 13–16 September 2010...... 50 C2. Location where 52 sheefish were captured with hook-and-line techniques and examined for spawning readiness on the Big River and sites where environmental data was recorded during 24–26 September 2011...... 51 C3. Location where 36 sheefish were captured with hook-and-line techniques on the Middle Fork of the Kuskokwim River and examined for spawning readiness, sites where environmental data was recorded, and extent of set net effort to capture and sample sheefish during 20–22 September 2011...... 52 C4. Set net sites and extent of effort to capture and sample sheefish for spawning readiness during a visit to the mouth of Highpower Creek, 17–19 September 2010...... 53 C5. Location where 4 sheefish were captured with hook-and-line techniques on the Kongeruk River and examined for spawning readiness, sites where environmental data was recorded, and extent of set net effort to capture and sample sheefish during 7 September 2011...... 54

D1. Spawning readiness of sheefish captured and sampled at the Kongeruk River, Middle Fork of the Kuskokwim River, and Big River during September 2011...... 56 D2. Environmental characteristics recorded at the Kongeruk, Middle, and Windy forks of the Kuskokwim River, and Big River...... 59

E1. Daily sheefish upriver migration and corresponding daily average ambient temperatures from McGrath Station encompassing the maximum and minimum dates for spawning radiotagged sheefish that migrated upriver past the stationary tracking station located on the Middle Fork of the Kuskokwim River near the mouth of Big River...... 62 E2. Daily sheefish downriver migration and corresponding daily average ambient temperatures from McGrath Station encompassing the maximum and minimum dates for spawning radiotagged sheefish that migrated downriver past the stationary tracking station located on the Middle Fork of the Kuskokwim River near the mouth of Big River...... 63 E3. Daily average temperatures of Big River recorded by an Onset HOBO Water Temperature sensor and corresponding daily average ambient temperatures from McGrath Station during 16 October 2010 to 18 September 2011...... 64

iii

ABSTRACT This study was initiated in 2007 to expand our understanding of spawning locations, seasonal distribution, and movements of sheefish, or inconnu, Stenodus leucichthys in the Kuskokwim River drainage. Radio transmitters were surgically implanted into sheefish during 2007 (9) and 2008 (110). Radiotagged sheefish were tracked using a combination of 7 stationary tracking stations and 3 aerial tracking flights that were conducted each year during July, late September, and early October. During fall 2007–2011, 63 radiotagged sheefish migrated to 3 spawning areas, many of them over multiple and consecutive seasons. Approximately 80% were located in a 20 km section within the Big River where spawning activity had been previously documented. Much smaller numbers migrated to areas on the Middle and East Forks of the Kuskokwim River; areas previously undocumented for spawning activity. Migratory timing profiles illustrated that sheefish arrived at their spawning areas during late July through mid- September and spawned during late September through early October. Post-spawning outmigration occurred during a 1 to 1.5 week period in mid-October. The majority of sheefish, spawners and non-spawners, migrated downstream to the Lower Kuskokwim River to overwinter. A much smaller number of sheefish overwintered in the Middle Kuskokwim River and Holitna River. During the summer, sheefish traveled to and between mouths of major Kuskokwim River tributaries to feed and showed a high degree of fidelity to these areas. Sheefish were sampled for spawning readiness (condition) during late September 2011 at the Big River and Middle Fork Kuskokwim River to verify spawning locations identified from aerial tracking flights. An attempt was made to sample sheefish at the mouth of Highpower Creek, in mid-September 2010 without success. None of the radiotagged sheefish were detected there throughout this study, however, sheefish in spawning condition were captured here during the early 1970s. In addition, basic environmental and habitat data were recorded at spawning areas and compared with other studies in Alaska and Canada. Key words: Kuskokwim River, Holitna River, Big River, Middle Fork Kuskokwim River, East Fork Kuskokwim River, aerial tracking flight, sheefish, seasonal movements, spawning areas, Stenodus Leucichthys, radio transmitter, stationary tracking stations. INTRODUCTION The Kuskokwim River is the second largest drainage in Alaska. From its headwaters in the Alaska Range, the Kuskokwim River drains approximately 130,000 km2 along its 1,130 km course to the Bering Sea (Figure 1). This drainage supports 5 species of Pacific salmon as well as numerous resident species, including inconnu Stenodus leucichthys, commonly called sheefish in Alaska.

Sheefish are a highly migratory whitefish found in large northern rivers and associated lakes of northwestern North America and northern Eurasia (McPhail and Lindsey 1970). Sheefish, like other whitefish, are known for their high phenotypic plasticity (Behnke 1972). Most sheefish in Alaska are estuarine anadromous, whereas much smaller numbers are nonanadromous. Sheefish undertake migrations related to feeding, spawning, and overwintering, with estuarine anadromous sheefish undertaking the longest migrations (Howland et al. 2000). Prior to this study, documented knowledge of sheefish in the Kuskokwim River was based almost entirely on work by Alt (1987) in the 1970s and early 1980s, and on information from other systems.

Currently and historically, the greatest use of sheefish in the Kuskokwim River drainage has been for subsistence. Between 2002 and 2004 an average of 678 sheefish were harvested annually in the lower river near Bethel (Fall et al. 2003; Brown et al. 2005; Fall et al. 2007) and approximately 661 in major villages below Bethel (Ray et al. 2010). In the middle river near Aniak, sheefish are harvested throughout the year and annual harvests averaged 995 in 2001– 2002, 573 in 2002–2003, and 667 in 2009 (Krauthoefer et al. 2007; Brown et al. 2012).

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Figure 1.–Map of the Kuskokwim River showing approximate overwintering, feeding, and spawning locations for sheefish as noted in this study. In addition, map includes the locations of stationary tracking stations.

The majority of sheefish are harvested in the lower river during the early spring as the fish migrate upriver. The residents of Nikolai and Telida in the upper drainage report that sheefish are one of the first fish to return to the area in early spring and they provide a source of fresh fish prior to the salmon runs. Residents of Nikolai will travel to and harvest sheefish at the mouth of Big River in June. Present and former (currently living in Nikolai) residents of Telida also harvest sheefish in late August and early September at the mouth of Highpower Creek (Williams et al. 2005). Sheefish are also an important species targeted by sport fishers in streams and tributaries within the Kuskokwim River drainage with the largest fishery occurring in the Holitna River (Chythlook 2011). Between 2005 and 2010, estimated sport harvest of sheefish within the Kuskokwim River drainage varied from 997 in 2005 to 67 in 2010. Sport harvest estimates in the Holitna River drainage varied from 349 in 2005 to 12 in 2010, and comprised 8% to 100% of the total estimated sport harvest of sheefish within the entire Kuskokwim River drainage (Jennings et al. 2009a, 2009b, 2010a, 2010b, 2011a, 2011b). The primary objective of this project has been to document spawning locations of sheefish in the Kuskokwim River drainage. Alt (1987) documented 2 spawning areas: the lower 200 m of Highpower Creek near Telida and a 20 km section of the Big River beginning at approximately 64–67 rkm (Figure 1). During the current study, the Big River spawning area was confirmed and 2 undocumented and probable spawning areas were identified in the Middle and East Forks of the Kuskokwim River. Since this project’s inception in 2007, the majority of radiotagged sheefish have migrated to the Big River to spawn. Smaller numbers were observed at the Middle Fork Kuskokwim River, just above the confluence with Windy Fork and another small aggregation was located at the confluence of the East Fork of the Kuskokwim River with the Tonzona River. (Figure 1). Throughout this study none of the radiotagged sheefish have been located at or near Highpower Creek during the typical spawning period. This project was initially funded as a 3-year study beginning in 2007 (Stuby 2010), but funding was extended for 2 additional years of data collection from the 119 sheefish that were radiotagged during 2007 (9) and 2008 (110) to cover the life span of the radio tags. This additional effort has provided refined information on spawning locations, spawning frequency, fidelity to spawning and feeding areas, and migratory timing to and from spawning, overwintering, and feeding areas. A necessary component to identifying potential sheefish spawning habitat was establishing criteria for sheefish detected by aerial and ground receiving stations as to whether or not these sheefish may have been spawning in a particular location. Directly sampling sheefish at their spawning areas, which was a new component of this project extension, has helped better define and describe the habitat characteristics of these areas. Overall, this project has provided a greater understanding of sheefish life history in the Kuskokwim River drainage, which will be important to future management efforts.

OBJECTIVES The main objective of this project was: 1. document spawning stocks and spawning locations of sheefish in the Kuskokwim River drainage by: a. locating radiotagged sheefish during the likely spawning period; and, b. capturing sheefish at spawning areas inferred from the locations of radiotagged sheefish during the spawning period and assessing their spawning readiness (condition) to verify that spawning was occurring there. Secondary objectives of this project were: 1. determine the migratory timing of mature sheefish to their spawning, overwintering, and feeding areas; 2. identify summer feeding and overwintering areas used by spawning and nonspawning sheefish; 3. collect tissue samples from each sheefish captured at spawning areas for future genetic stock identification analysis; 4. record and describe habitat characteristics such as channel characteristics, water temperature, spawning substrate, flow, depth, and/or turbidity while visiting the spawning areas; and, 5. assist with the U.S. Fish and Wildlife Service (USFWS) whitefish telemetry project (FIS Study 06-303) by incorporating whitefish frequencies during aerial tracking flights and in the stationary tracking stations.

METHODS STUDY DESIGN Since the project’s inception, we tracked 119 sheefish that were captured and surgically implanted with radio transmitters in 2007 (9) and 2008 (110) (Stuby 2008, 2009, 2010, 2011). Movements and migratory timing were recorded for the radiotagged sheefish during the open water periods from fall 2007 through fall 2011. Radio transmitters were guaranteed by the manufacturer to transmit for 3 years (majority through April 2011) and theoretically transmit until fall 2011. In fact, 5 of the 7 radiotagged sheefish that survived tagging and handling during 2007 continued to transmit through fall 2011. Due to the migratory nature of sheefish, this study has encompassed virtually the entire drainage of the Kuskokwim River. Seven stationary tracking stations located between Aniak and the mouth of the Big River (Figure 1) were used to record movements and timing of the radiotagged sheefish during their upriver and downriver migrations. Aerial tracking flights were conducted during July throughout the Kuskokwim River drainage to locate sheefish in summer feeding areas. Data collected from the stationary tracking stations and the aerial tracking flights were used to ascertain year-to-year fidelity to these areas. During late September and early October similar methods were used to document spawning areas and determine fidelity. The number of

sheefish located during aerial tracking flights varied from year to year and month to month, as did the number of sheefish recorded on a particular stationary tracking station. Locating aggregations of radiotagged sheefish during the spawning period does not necessarily provide conclusive evidence of spawning in a particular location. Verification of spawning areas required site visits to those areas to sample sheefish and assess their spawning condition. In 2010 and 2011, we visited suspected or potential spawning areas on Big River, Middle Fork Kuskokwim River, Highpower Creek, and Kongeruk River and utilized set nets and hook-and line methods to capture and examine sheefish. At these locations sheefish were captured and examined, tissue samples were collected from documented spawning stocks for genetic baseline development, and habitat characteristics were described and recorded. CAPTURE AND TAGGING A crew of 3 persons captured and tagged sheefish during 14 August–6 September 2007. From 14 to 31 August, we fished primarily at the following upper river locations: the mouth of the Katlitna River, which is located approximately 36 rkm downriver from McGrath; the mouth of the Takotna River, which is located directly across from McGrath; the mouth of Nixon Fork, which is located at 23 rkm of the Takotna River; and the mouth of Grayling Creek, which is located 43 rkm upriver from McGrath. From 2–3 September we fished near and at the mouth of the Big River (Figure 1). During 2008, fishing for sheefish commenced downriver from Bethel immediately after break up in mid-May as soon as the Kuskokwim River near Bethel became safe to travel. Prior to capture operations, 7 sheefish that survived capture and tagging in 2007 were located during an aerial tracking flight of the Lower Kuskokwim River. The locations of these fish were used to guide fishing effort. The upstream migration of these fish also provided information about how long to sample downriver before moving upriver with the spring migration. Because of the uncertainties in timing of the upstream migration, the rate of migration, and where and how much time the migrating sheefish would spend at the mouths of the major tributaries, we were flexible in our approach to fishing locations and how much time was spent at each location. A total of 5 people on 2 crews were used to capture and tag sheefish at the mouth of the Johnson River and near Bethel during 22–29 May 2008. Once this downriver sampling was complete, 1 crew of 3 people travelled upriver and attempted to capture and tag sheefish near the mouths of the Kwethluk, Tuluksak, and Aniak rivers for approximately 1 week. Afterwards, the same crew of 3 people continued upriver to set up a base camp at Barge Slough on the Holitna River. From the base camp, the crew fished the mouths of the George, Holitna, Stony, Swift, and Tatlawiksuk rivers for approximately 2 weeks. The mainstem Kuskokwim River is glacially occluded and water clarity at the mouth of the Johnson River was poor due to tidal and mainstem influences. As a result, gillnets with 6 in mesh size were used to capture sheefish. Upriver fishing was conducted at the mouths of large tributaries and utilized hook-and-line methods. Lures had single, barbless hooks in order to minimize injury. Regardless of capture method, fish were retrieved into the boat with a rubber landing net that was designed to minimize damage to fish during catch-and-release practices. Attempts were made to inflict the least amount of stress and injury to each captured fish. Fish that showed signs of stress and/or injury due to capture (bleeding from hooks, ripped fins, lethargy, etc.) were released without receiving a radio transmitter.

Radio transmitters were surgically implanted following the methods detailed by Brown et al. (2002). For each sheefish that was captured and implanted with a radio transmitter, data collected included: measurement of fish length to the nearest 5 mm FL, gender, location (river mouth, mainstem GPS coordinate), transmitter frequency and code, date of capture, and any notable condition information. A small pelvic fin clip was collected from each radiotagged sheefish. Each tissue sample was cleaned and immediately placed in an individually labeled vial filled with 100% ethanol and stored in a cool, dark place. These samples were sent to the United States Fish and Wildlife Service (USFWS) Conservation Genetics Laboratory in Anchorage. These samples will be used to establish a genetic baseline for sheefish from the Yukon and Kuskokwim Rivers for OSM project 12-700. The original study design called for radio transmitters to be implanted into sheefish that were greater than 750 mm FL, as fish of this size were likely to be mature (Brown 2000, Taube and Wuttig 1998). However, achieving this objective was difficult, especially at the downriver fishing locations, so we relaxed the criteria and sheefish as small as 640 mm were radiotagged. Once daily catches increased markedly in the middle of June, especially on the Holitna River, only sheefish >750 mm FL were radiotagged. RADIOTRACKING EQUIPMENT AND TRACKING PROCEDURES Sheefish were surgically implanted with 3V micro-coded radio transmitters that were 1.5 cm in diameter, 5 cm long, with a wire whip antenna about 42 cm long (Lotek1 model MCFT-3A), and were programmed with a 3 s burst rate. Each radio transmitter was distinguishable by a unique frequency (149.200, 149.040, and 149.580 MHz) with 30 and 45 (latter two) encoded pulse patterns for a total of 120 uniquely identifiable transmitters. The transmitters were programmed to operate for 7.5 months (April through mid-November) and then shut off for 4.5 months in order to conserve battery power. Stationary tracking stations were used to record the upstream and downstream migrations of radiotagged sheefish to feeding, spawning, and overwintering areas. In addition, information recorded by the stations was used to allocate aerial radiotracking effort. The stationary tracking stations were operated similar to that described by Eiler et al. (2004). Four stations had Lotek SRX_400 receivers and 3 had SRX_600 receivers with attached satellite modems. Each station was powered by four 12 V deep cycle batteries that were charged with solar arrays. A water- resistant steel box covered with a fitted tarp housed the components. Two, 4-element Yagi antennas were mounted on a mast elevated 2–10 m above the ground depending on the elevation of the site above the river. One antenna was aimed upstream and the other downstream. The receivers were programmed to scan through the frequencies at 8 s intervals, and receive from both antennas simultaneously. When a signal of sufficient strength was encountered, the receiver paused for 6 s on each antenna, and then transmitter frequency, transmitter code, signal strength, date, time, and antenna number were recorded on the data logger. The relatively short cycle period minimized the chance that a radiotagged fish migrated past the receiver site without being detected.

1 Lotek Wireless, Inc., Ontario, Canada.

The 7 stationary tracking stations were located: 1) on the Kuskokwim River above Aniak; 2) on the Kuskokwim River below Red Devil; 3) at the mouth of the Holitna River; 4) on the Kuskokwim River at Sinka’s Landing across from the mouth of the Swift River; 5) on the Kuskokwim River a few bends upriver from McGrath; 6) on the Kuskokwim River at Medfra; and, 7) on the Middle Fork Kuskokwim River just below the confluence with the Big River (Figure 1). The tracking stations located near McGrath, Aniak, and Big River had a satellite modem incorporated. The modem allowed the project biologist to directly contact the receiver using a laptop computer with an analog telephone line. The stationary tracking stations were maintained by Alaska Department of Fish and Game (ADF&G) and Kuskokwim Native Association (KNA) personnel. All stations were programmed with the sheefish frequencies and USFWS whitefish frequencies. During 2007–2010 the stations operated through late October/early November until the batteries lost their charge. Given that spawning activities were usually concluded by late October, the tracking stations would have detected most of the outmigrating sheefish before the batteries lost their charge and/or the radio transmitters switched off for winter. The majority of batteries were recharged by May with the increasing daylight and ambient temperatures, and subsequently the receivers resumed scanning for radio transmitters. Aerial tracking flights were conducted with one fixed-wing aircraft, one person (in addition to the pilot), and utilized one Lotek SRX_600 receiver/scanner that was actively listened to by the project biologist and one SRX_600 that passively scanned and recorded any sheefish that the project biologist may have missed. All frequencies (including those from the USFWS whitefish study) were loaded into the receiver prior to each flight. Dwell time on each frequency was 4 s. Flight altitude ranged from 100–300 m above ground. Two H-antennas, one on each wing strut, were mounted such that the antennas received signals perpendicular to the direction of travel. During each flight, sheefish were tracked along the mainstem Kuskokwim River from Kuskokwim Bay upstream past Telida. We covered as much of the upper drainage as feasible depending on weather, pilot availability, and funding constraints. Annual (2008–2011) aerial tracking flights were conducted in July to locate summer feeding areas and in late September and early October to locate potential spawning activity. The main purpose of the October flights was to look for radiotagged sheefish that were missed during the previous September flight and to observe and record any changes in individual sheefish locations since the earlier flights. Assessing whether a sheefish was in a spawning area based on data acquired from the aerial tracking flights and stationary tracking stations was subjective. The following criteria was considered when evaluating whether a sheefish was in a spawning area: 1) it was located during the likely time of spawning; 2) it was located in habitat consistent with spawning areas described by observations from past research; 3) it was located in close proximity to 1 or more other radiotagged sheefish; 4) it was located among a large aggregation of sheefish; and, 5) there was a directed (probably upstream) migration immediately prior to being located in the fall aerial tracking flights. SEPTEMBER SAMPLING IN UPPER KUSKOKWIM RIVER SPAWNING AREAS AND KONGERUK RIVER Using aerial tracking data as a guide, during mid-to-late September 2010, we visited the purported spawning areas on the Big River and the mouth of Highpower Creek. During late September 2011, we returned to Big River and visited the Middle Fork of the Kuskokwim River. On September 7, 2011 we visited the Kongeruk River. Attempts were made to capture and

assess the spawning status (either pre-spawning, actively spawning, post-spawning, or non- spawning) from a minimum of 10 sheefish in each location using set nets and hook-and-line gear. Following capture, attempts were made to express gametes with light finger pressure. Extrusion of gametes confirmed spawning readiness and most fish were released alive. A small proportion of captured sheefish were sacrificed and the gonads were visually inspected. Gonadosomatic indices (GSI) were calculated from each female sheefish sacrificed with gonad weight expressed as a percentage of body weight (egg weight/whole body weight) X 100 (Snyder 1983). Saggital otoliths were removed for age and strontium distribution microchemistry analysis and fin tissue was removed from each fish for genetic analysis. Spawning habitat characteristics were measured using a YSI 556© handheld multiprobe flow meter and a HACH HQ Series portable meter to acquire water temperature, dissolved oxygen, pH, and conductivity. Flow was measured with a Flow Probe FP101 and a Secchi disk was used to discern water transparency. In the Big River and Highpower Creek, Hobo v2 temperature data loggers were deployed to record temperatures before, during, and after the spawning period. Most were lost due to ice scouring during spring break up; however, one was retrieved on the Big River during 2011. During September 2011, 3 additional temperature data loggers were deployed and will be retrieved in 2012. Substrate descriptions were based on Compton (1962). DATA ANALYSIS Sheefish spawning and summer feeding locations recorded by aerial tracking methods were consolidated, examined, and plotted using ArcGIS 10 (Appendix A1–A4; B1–B4). To facilitate data analysis, all radiotagged sheefish were assigned one or more “fates” (Table 1). Fates were determined from a combination of information collected from tracking stations, aerial tracking flights, and harvested fish for which radio transmitters were returned. Cumulative frequency distribution plots were used to describe migratory timing of sheefish moving past stationary tracking stations during their upriver and downriver migrations to feeding, spawning, and overwintering areas. Comparisons of length distributions of spawning and non-spawning sheefish were conducted using the Kolmogorov-Smirnov (KS) two-sample test (Conover 1980). RESULTS One hundred nineteen radio transmitters were deployed during 2007 and 2008. Nine sheefish were captured and implanted with radio transmitters during mid-August through early September 2007 and the remaining 110 were deployed during May and June 2008. During 2007, sheefish were captured in the Upper Kuskokwim river drainage between the Katlitna and Big rivers (Figure 1). During 2008, sheefish were captured in the lower to middle portions of the Kuskokwim river drainage between the Johnson and Tatlawiksuk rivers. Of the 9 sheefish captured during 2007, three were identified as gravid females, 1 as a ripe male, and the gender of the remaining fish was uncertain. For the 4 sheefish where gender was positively identified, developed testes or eggs were easily observed through the incision. Sheefish tagged during 2008 were captured in late spring and early summer and their gender could not be discerned because their gonads were insufficiently developed. Stuby (2010) details when, where, and how many transmitters were deployed at each tagging location during 2007 and 2008.

Table 1.–List of possible fates of radio-tagged sheefish in the Kuskokwim River. Fate Fate Description Spawning Status Spawner Sheefish located on a spawning areaa during late September/early October. A sub fate will be assigned to each of these fish indicating the specific area where the fish spawned. Non-Spawner Sheefish located during late September/early October but not on a spawning area. Unknown Spawning Status Sheefish not located during late September/early October. Summer Feeding Status Summer Feeders Sheefish was located during summer feeding period. A sub fate will be assigned to each of these fish indicating the specific area where the fish was located. Unknown Summer Sheefish was not located during summer feeding period. Feeding Status Overwintering Status Overwintered in Lower Sheefish traveled downriver past stationary tracking station located at Aniak Kuskokwim River during fall and traveled back upriver during early spring. Overwintered in Upper Sheefish detected in the fall aerial tracking flights upriver of the stationary Kuskokwim River tracking station at Sinka’s Landing near the mouth of the Swift River in the fall and not detected by the stationary tracking stations to leave this area until after ice out in the spring. Overwintered in Middle Sheefish detected in the fall aerial tracking flights upriver of the Aniak stationary Kuskokwim River tracking station and downstream of the station at Sinka’s Landing in the fall and not detected by either station to leave this area until after ice out in the spring. Overwintered in Holitna Sheefish documented in Holitna River during fall aerial tracking flights and not River detected by the stationary tracking stations to have left in fall and/or winter. Unknown Overwinter Sheefish was not located during fall aerial survey or detected by a stationary Location tracking station during the fall or spring. Mortality Tagging Mortality Sheefish died in response to handling and transmitter implementation. Fish not seen to move within one year after tagging. Harvest Mortality Project biologist contacted by fisher that a radio-tagged sheefish has been harvested. Or, during multiple aerial tracking flights, project biologist documents radio transmitter signal clearly emanating from a village or fish camp. Natural Mortality Sheefish survived tagging and handling, but not seen to move in over a year and is not located near human settlements. a Spawning areas were determined using the criteria listed in the Radio-Tracking Equipment and Tracking Procedures section.

Fifteen of the 119 radiotagged sheefish were assumed to have died as a result of capture and tagging. Two sheefish were presumed dead soon after capture and tagging during 2007 and 13 sheefish were presumed dead in 2008 (Table 2). Through fall 2011, twenty sheefish were known (fisher contacted ADF&G personnel) or assumed (strong tag signal coming from a fish camp or village) to have been harvested in the subsistence fishery, 3 fish were assumed to have died as a result of natural mortality, and the fates of 3 fish remain unknown (Table 2). Because the transmitters were guaranteed by the manufacturer to operate for 3 years and theoretically up to 4 years, it was expected that those transmitters deployed during 2007 would cease transmitting by fall 2011. However, 5 of the 7 radiotagged sheefish from 2007 were detected throughout 2011. Seventy-one radiotagged sheefish from 2008 were thought to have survived through 2011: 44 were located and 27 were not detected (Table 2). SPAWNING LOCATIONS, FREQUENCY, AND TIMING Annual totals of 1 (2007), 33 (2008), 20 (2009), 24 (2010), and 17 (2011) radiotagged sheefish migrated upriver in the fall to a 20 km section of the Big River that Alt (1987) had noted to be a spawning area (Table 3, Figure 2, Appendix B1–B4). These fish exhibited both sequential and non-sequential spawning. Of the sheefish migrating to the Big River spawning area, 4 individuals spawned there each year from 2008–2011, 8 fish spawned there 3 of the 4 years, 9 fish spawned twice, and 7 sheefish spawned only once. Of the sheefish spawning only once, most did so during 2010. During the time of spawning, radiotagged sheefish were located farther up the Big River in 2008 compared to previous years (Figure 2). Radiotagged sheefish were tracked to a previously undocumented spawning location on the Middle Fork of the Kuskokwim River above the confluence with the Windy Fork during late September and early October 2008–2011 (Figure 2). The number of radiotagged sheefish that migrated to this area ranged from 1 to 6 (Table 3, Appendix B1–B4). Two sheefish travelled to the Middle Fork spawning area for the first time in 2011, including one fish that was captured and tagged during 2007. One sheefish spawned for 3 subsequent years beginning in 2009 (Table 4). Two sheefish spawned in 2008 and returned again in 2011. Similar to the Big River, radiotagged sheefish were located farther up the drainage during the time of spawning in 2008 than in previous years (Figure 2). Interestingly, during 2010, a sheefish that had travelled to Big River the previous year was recorded on the Middle Fork. Similarly, during 2011, a sheefish that had travelled to Big River during 2008 was recorded on the Middle Fork in 2011. A 1–2 km area at the confluence of the East Fork of the Kuskokwim River and the Tonzona River was also identified as a potential spawning area. Four radiotagged sheefish were detected during the time of spawning at this area, 1 in 2008, 1 in 2009, and 2 in 2010 (Figure 3, Table 3, Appendix B1–B4). One sheefish was located there during 2009 and 2010 (Table 4). No radiotagged sheefish were noted in this area during 2011. During the 19–21 September 2010 aerial tracking flights we were able to fly a few hundred feet above this area and circled several times. The 2 radiotagged sheefish appeared to be at the confluence of the Tonzona and East Fork of the Kuskokwim rivers, but we were unable to visually locate sheefish from the air due to occluded water conditions. Given that 3 different radiotagged fish migrated to the same location during the time of spawning in subsequent years, it is likely that this area is in fact a spawning location.

Table 2.–Assigned fates of sheefish in 2011 that were radiotagged during 2007 and 2008. 2011 Known and Suspected Mortality Detected Suspected Transmitters not detected Year Alive and and known Captured Moving harvest in and Total throughout Tagging subsistence Natural During During Before Unknown Tagged Tagged 2011 Mortality fishery Mortality 2011 2010 2010 Fate 2007 9 5 2 0 0 2 1 0 0 2008 110 44 13 20 3 27 13 3 3 Total 119 49 15 20 3 29 14 3 3

Table 3.–Numbers of radiotagged sheefish located at 3 spawning areas of the Kuskokwim River during 2007–2011. Year Tagged Spawning Location 2007 2008 Total 2007 Big River 1 - 1 Middle Fork 0 - 0 East Fork/Tonzona River 0 - 0 Total 1 - 1 2008 Big River 2 31 33 Middle Fork 0 4 4 East Fork/Tonzona River 0 1 1 Total 2 36 38 2009 Big River 2 18 20 Middle Fork 0 1 1 East Fork/Tonzona River 0 1 1 Total 2 20 22 2010 Big River 2 22 24 Middle Fork 0 4 4 East Fork/Tonzona River 1 1 2 Total 3 27 30 2011 Big River 2 15 17 Middle Fork 1 5 6 East Fork/Tonzona River 0 0 0 Unknowna 0 1 1 Total 3 20 23 a Fish travelled past stationary tracking station located on Middle Fork near mouth of Big River but not detected during 24 and 28 September 2011 aerial tracking flights so final spawning location unknown.

Figure 2.–Locations of radiotagged sheefish in spawning areas on the Big River and Middle Fork of the Kuskokwim River during 2008–2011. The map on the right illustrates the spawning areas in 5X more detail.

Table 4.–Number of radiotagged sheefish by spawning location and spawning frequency, 2008–2011.

Spawning Frequency (Number of Times)

Spawning Location One Two Three Four Never Spawned

Big River 7 9 8 4 -

Middle Fork 2 2 1 0 -

Big River/Middle Fork 0 2 0 0 -

East Fork/Tonzona River 1 1 0 0 -

Unknowna 1 0 0 0 -

Total 11 14 9 4 11 a Fish swam past stationary tracking station located on Middle Fork near mouth of Big River but was never detected in a spawning area.

= 23 Sept.; 8 Oct 2008 = 9,11 Sept.; 9,11 Oct 2009 = 21,29 Sept. 2010

Telida

1cm = 3km 14

Medfra

1cm = 7km

Figure 3.–Map showing locations of radiotagged sheefish near the mouth of the East Fork of the Kuskokwim River and Tonzona River during September and October 2008–2011. The smaller map in the upper left-hand corner illustrates this area in more detail.

None of the radiotagged sheefish have been located at Highpower Creek or been detected up the Swift Fork into which it flows during the 4 years of the study (Figure 1, Appendix B1–B4). Test netting conducted by Alt (1987) from 19–28 September 1971 revealed the presence of “large numbers” of spawners in Lower Highpower Creek and it was speculated that spawning was occurring there. Radiotagged sheefish bound for spawning areas in the Big River and Middle Fork of the Kuskokwim River arrived over an approximately 2-month period during 2008–2011 (Figure 4). During 2008, the earliest date that a sheefish was detected at the stationary tracking station near Big River was 23 July, the latest arrival was on 19 September, and the average arrival date was 25 August. For 2009, the earliest arrival date was 7 August, the latest 14 September, with an average arrival date of 24 August. For 2010, the earliest arrival date was 11 July, the latest arrival date was 17 September with an average arrival date of 26 August. In contrast, during 2011, one radiotagged sheefish entered the Big River on 3 July. However, similar to previous years the latest arrival date was 15 September with an average arrival date of 21 August. Many of these sheefish, especially the earlier arrivals, spent weeks moving back and forth across the stationary tracking station located near the mouth of Big River on the Middle Fork of the Kuskokwim River. During 2008–2010, the 4 radiotagged sheefish that migrated to the East Fork spawning area were recorded upriver past Medfra tracking station (134 km downstream) on 29 August 2008, 1 September 2009, 31 August 2010, and 9 September 2010. Downriver migration of post-spawning sheefish was more compressed than the upriver migration prior to spawning (Figure 4). During 2008, one sheefish was recorded leaving the Big River/Middle Fork of the Kuskokwim as early as 23 September. However, for 2009, 2010, and 2011 the earliest a sheefish was recorded leaving this system was 5, 6, and 7 October, respectively. The latest a fish was recorded leaving the area was 24 October in 2008, 13 October in 2009, 18 October in 2010, and 19 October in 2011. The average dates of departure for sheefish past the Big River tracking station was 15 October 2008, 9 October 2009, 13 October 2010, and 12 October 2011 (Figure 4). During 2009, radiotagged sheefish were recorded leaving the Big River/Middle Fork drainages approximately 6 days earlier than in 2008 but over a similar time span. Departure dates for 2010 and 2011 were between those observed in 2008 and 2009 (Figure 4). Similarly, sheefish were noted to pass by the stationary tracking station at Medfra on their way downriver from the East Fork on 4 October 2008, 12 October 2009, and 14 October 2010. Timing of upriver and downriver migrations for the radiotagged sheefish showed a small negative correlation (-0.153 upriver and -0.155 downriver) with respect to ambient air temperature at McGrath, which may have influenced annual in- and outmigration timing differences (Appendix E1 and E2). In 2008 and 2010, the majority of non-spawning sheefish that spent the summers between the George and Tatlawiksuk rivers began their downriver migration during mid-October. In general, non-spawning sheefish were recorded past the Aniak tracking station approximately 1 week earlier on average than that of post-spawning sheefish (Figure 5). In 2010, 7 fish began their fall downriver migration much earlier during late August through late September (Figure 5). During 2011, non-spawning sheefish passed the stationary tracking station near Aniak primarily during the first week of October, which was approximately 15 days, on average, earlier than post spawning sheefish. A mistake in downloading the Aniak tracking station negated acquiring downriver migration information for 2009.

Upriver Migration Recorded at Tracking Station Near Big River

100%

75%

50%

25% Cumulative PercentCumulative Frequency 0%

Date Downriver Migration Recorded at Tracking Station Near Big River 100%

75%

50%

25% Cumulative Percent Cumulative Frequency 0%

Date

2008 2009 2010 2011

Figure 4.–Cumulative arrival and departure dates for radiotagged sheefish that migrated to upriver spawning areas on the Big River and Middle Fork of the Kuskokwim River during 2008–2011.

Downriver Migration of Post-Spawning Sheefish Recorded at Tracking Station near Aniak 100%

75%

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25% Cumulative Percent Frequency Frequency Percent Cumulative

Date

Downriver Migration of Sheefish Not Known to Spawn Recorded at Tracking Station near Aniak 100%

75%

50%

25% Cumulative Percent Frequency Frequency Percent Cumulative

Date

2008 2010 2011

Figure 5.–Cumulative downriver passage dates for spawning and non-spawning radiotagged sheefish during 2008, 2010, and 2011. Station data for 2009 are missing.

Sampling in Upriver Sheefish Spawning Areas During mid-to-late September 2010, we attempted to capture and sample sheefish for spawning readiness at an area on the Big River where spawning sheefish were located during the early fall aerial tracking flights (Appendix B1–B4, Figure 2). Due to unseasonably warm weather during mid-September, the spawning migration of sheefish was delayed and none were captured when we visited this location (Appendix C1). Although we did not capture any sheefish, several whitefish and other resident and anadromous species were sampled and their spawning readiness was noted (Stuby 2011). Sheefish were captured and sampled at both the Big River and Middle Fork of the Kuskokwim River during September 2011 (Appendix C2, C3). Fifty-two sheefish were captured on the Big River during 24–26 September (Appendix D1). Thirty-six sheefish were captured on 22 September 2011, primarily at the confluence of the Middle and Windy forks of the Kuskokwim River (Appendix D1). No fish were captured in set nets placed farther up the Middle Fork on 20– 21 September 2011 where sheefish were noted during the 2008–2010 fall aerial tracking flights, but sheefish were detected at these locations by the aerial tracking flight on 29 September 2011. All sheefish captured on the Big River and Middle Fork of the Kuskokwim River were in spawning condition. Eggs and milt could be expressed with little pressure. Thirteen sheefish were sacrificed on the Middle Fork and 10 were sacrificed on the Big River. Of these, female GSI values averaged 23 (Appendix D1). Eggs were approximately 2.5 mm in diameter. In contrast, 2 non-spawning females that were captured on the Holitna River on 18 August 2009 as part of the Anadromous Water Catalog sampling event on this drainage (Stuby 2010) had GSI values of 1.2 and 1.4. Another non-spawning female captured on the Kongeruk River on 7 September 2011 had a GSI value of 1.5 (Appendix D1). Basic environmental data were recorded at the Big River during 14–16 September 2010. The pH was 8.06 and conductivity was approximately 370-375 µS/cm (Appendix C1, D2). Water temperature varied from 9.21oC on 14 September to 7.71oC on 16 September. The 0.1m extinction turbidity secchi disk reading on 14 September fell by 7 mm over the same time period. Flow rate was approximately 1.07 m/sec. Values of environmental variables recorded during September 2011 did not significantly change on the Big River from those measured in 2010. Environmental characteristics were recorded at 3 locations on 25 September (Appendix C2, D2). The pH values ranged between 8.29 and 8.37 and conductivity values were similar to 2010. Measurements were taken approximately 1 week later than in 2010, and consequently the water temperature was lower. Temperature, dissolved oxygen, and conductivity values were slightly lower for the Middle Fork of the Kuskokwim River compared to the Big River (Appendix C3, D2). However, pH values of the Middle Fork were similar to what was observed on the Big River. Substrate within the extent of the sampling area at Big River was noted in detail during 2010 and described using the Wentworth grain-size classification scheme (Compton 1962, Appendix C1). The substrate on the shore was examined because diving underwater in a swift glacial river to observe the substrate where sheefish are spawning was impractical. However, substrate observed on shore is a good proxy and is commonly used to approximate actual spawning habitat (Joe Buckwalter, Alaska Department of Fish and Game, Anchorage, personal communication). Spawning substrate on the Middle Fork of the Kuskokwim River between the upper and lowermost sampling areas (Appendix C3) appeared similar to what was noted for the Big River. 18

After 2 years of attempts, a temperature data logger was retrieved during the 2011 visit to the Big River. Previous data loggers deployed during 2009 and 2010 were destroyed or taken from their anchoring points by ice during spring break-up. It is assumed that the logger may have been out of water and encased in snow and ice during 11 October 2010 through 5 May 2011 (Appendix E3). However, values acquired during the time of spawning during late September and early October 2010 were considered valid. Water temperature fell sharply during 22–25 September and remained near 0oC for the duration of the spawning period until 11 October (Appendix E3). On 17–19 September 2010, we travelled to and fished at the mouth of Highpower Creek, but were unable to capture sheefish (Appendix C4). Alt (1987) noted that sheefish prefer to spawn in locations with substrates composed of varying sized gravel, like what was seen on the Big River. The mouth of Highpower Creek is composed of very fine, organic material, unlike that seen on Big River. Highpower Creek is tannic and relatively slow-moving (0.46 m/sec) compared to the Swift Fork of the Kuskokwim River into which it flows. The secchi disk went extinct at 11 in on Highpower Creek, but went extinct at 6 in at the confluence with the Swift Fork. Sediment and hydrology on the Swift Fork near the mouth of Highpower Creek and upriver as observed on the 29 September aerial tracking flight appears similar to that observed for the Big River. WINTER AND SUMMER DISTRIBUTION AND MOVEMENTS The majority of radiotagged sheefish spent the winters from 2007 through 2011 in the Lower Kuskokwim River (downstream from Aniak). Because the radio transmitters were programmed to be inactive during the winter, exact overwintering locations could not be discerned. Overwintering sheefish migrated upriver soon after spring ice out, including fish that migrated to upriver spawning areas the previous year (Table 5). One fish was recorded past the Aniak tracking station on 10 May 2008, which was the day that the Kuskokwim River broke up at this location. Near the mouth of the Johnson River, the mainstem Kuskokwim River broke up on 14 May 2008, so this sheefish had migrated upriver under the ice. The earliest radiotagged sheefish detected past the Aniak tracking station was on 16 May for 2009 and 13 May for 2010 (Figure 6). Both of these fish appeared to migrate upriver soon after break up, but not before. Due to power issues with the stationary tracking station located above Aniak, upriver migration data was unavailable for 2011. Although the majority of radiotagged sheefish spent the winters in the Lower Kuskokwim River, a much smaller number spent the winter in mainstem locations near McGrath or in or near the Holitna River. Based on information from tracking stations and aerial tracking flights, 3 sheefish overwintered near McGrath during the winter of 2008/2009 (Table 5). Also, during the winters of 2008/2009 and 2009/2010, a total of 14 and 13 sheefish, respectively, were located in or near the Holitna River. These fish were among the 62 that were captured and tagged in the Lower Holitna River during early to mid-June 2008. Six out of the 13 sheefish that overwintered in the Holitna River in 2009/2010 returned to the Holitna River soon after spawning in mid-October 2010. In 2011, two fish were detected on the Big River and 1 on the Middle Fork of the Kuskokwim River during the time of spawning that also returned to overwinter in the Holitna River. Many of the fish that overwintered in the Holitna since 2008 continued to do so in 2011. However, one fish that was detected overwintering in the Holitna River since 2008 was detected in the mainstem near Aniak in 2011.

Table 5.–Overwintering locations of sheefish during the winters of 2007–2011.

Year Tagged Overwintering behavior 2007 2008 Total

Winter 2007/2008 Overwintered in Lower Kuskokwim River 7 - 7 Overwintered in or near the Holitna River 0 - 0 Spent winter near McGrath 0 - 0

Winter 2008/2009 Overwintered in Lower Kuskokwim River 7 60 67 Overwintered in or near the Holitna River 0 14 14 Spent winter near McGrath 0 3 3

Winter 2009/2010 Overwintered in Lower Kuskokwim River 7 53 60 Overwintered in or near the Holitna River 0 13 13 Spent winter near McGrath 0 0 0

Winter 2010/2011 Overwintered in Lower Kuskokwim River 6 47 53 Overwintered in or near the Holitna River 0 12 12 Spent winter near McGrath 0 0 0

Upriver Migration Recorded at Tracking Station near Aniak

100%

75%

50%

25% Cumulative PercentCumulative Frequency

Date

2009 2010

Figure 6.–Upriver migration times of radiotagged sheefish during 2009 and 2010.

Sheefish showed varying degrees of fidelity to summer feeding areas at the mouths of major tributaries of the Kuskokwim River during 2008–2011. For 2009–2011, more than 50% of the sheefish radiotagged at locations where they were assumed to have been feeding returned to the river mouths where they were captured and tagged (Table 6). In fact, 1 fish that was tagged at the mouth of Nixon Fork in mid-August 2007, a tributary of the Takotna River, migrated upriver soon after ice out and spent entire summers back at the mouth of Nixon Fork during 2008–2010 until mid-October when it began its downriver migration. In 2011, this fish travelled during late summer to the Middle Fork of the Kuskokwim spawning area. Other radiotagged sheefish, in particular those tagged in the Lower Holitna River (Appendix A1–A4), showed similar summer site fidelities. However, not all sheefish returned to their areas of capture/feeding during 2008– 2011 (Table 6). Sheefish have also migrated to other tributary mouths and mainstem locations to feed in addition to their capture locations. Radiotagged sheefish have been consistently found concentrated in particular locations within the Holitna River drainage during the July–October aerial tracking flights since 2008 (Figure 7). Alt (1981) also noted these primary areas of concentration as well as additional concentrations farther up the drainage. Sheefish captured and radiotagged in 2008 had stomachs full of outmigrating juvenile salmon as well as lamprey and other small fishes. The three sheefish captured and sacrificed during an Anadromous Waters Catalog survey of the Holitna River drainage during mid-August 2009 had stomachs full of juvenile whitefish. To date, no sheefish have been detected upriver of Titnuk Creek on the Holitna River or Townsite Creek on the Hoholitna River. Approximately 50% of the sheefish that were captured and radiotagged at the mouth of the Johnson River and near Bethel during 2008 spent one or more summers downriver of Akiak, which is located near the mouth of the Kisaralik River (Figure 1, Table 7). Upon capture in 2008, all fish had stomachs full of anadromous smelt. During 2009, seven sheefish that were captured and tagged at the mouths of the George, Holitna, and Tatlawiksuk rivers during 2008 spent the summer below Akiak, most in the Johnson/Kongeruk and/or Kialik rivers (Table 7). Similarly, 8 sheefish tagged at these upriver locations spent the summer of 2010 below Akiak, as did 3 in 2011. Ten fish that have spent one or more summers downriver of Akiak travelled to upriver spawning areas during 2007–2011 (Table 7). Fall Sampling of Kongeruk River Sheefish During each year from 2008–2011, a small number of radiotagged sheefish spent the summer feeding in the Johnson River before migrating upstream to the Kongeruk River during late summer/early fall. The Kongeruk River is a tributary of the Kuskokwim River that is located approximately 9 km upriver from the Johnson River mouth (Figure 8, Table 7, Appendix A1–A4 and B1–B4). The number of sheefish that were tagged in the Johnson River and displayed an upriver migration to the Kongeruk River ranged from 1 in 2011 to 4 in 2008 and 2009 (Table 7). This pattern was also displayed by radiotagged sheefish from the George River in 2009 (2) and 2010 (3). Another sheefish spent the summer of 2010 in the Kialik River before migrating up the Kongeruk River in late summer. This fish spent the previous 2 summers near the mouth of the George River where it was tagged in 2008 (Table 7). Two sheefish that had been tagged at the mouth of the Johnson River during 2008 and had repeated this pattern in 2009 and 2010 travelled upriver instead in 2011: one to spawn on the Middle Fork of the Kuskokwim River and the other was detected near the mouth of the George River.

Table 6.–Feeding area fidelity for radiotagged sheefish from 2008–2011.

River Mouth of Tagging in 2007 River Mouth of Tagging in 2008

Katlitna Takotna Blackwater Total George Holitna Johnson Tatlawiksuk Total a Number captured and tagged 4 1 1 6 12 62 8 14 96

2008 Located at tagging area 4 1 0 5 - - - - - b Not located at tagging area 0 0 0 0 - - - - - Clearly spent 2008 at different locationc 0 0 1 1 - - - - -

2009 Located at tagging area 0 1 0 1 4 30 5 4 43 b Not located at tagging area 3 0 1 4 6 16 2 6 30 Clearly spent 2009 at different locationc 2 0 1 3 1 7 1 3 12 23

2010 Located at tagging area 1 1 1 3 3 26 3 5 37 b Not located at tagging area 1 0 0 1 6 11 1 3 21 Clearly spent 2010 at different locationc 1 0 0 1 4 4 1 2 11

2011 Located at tagging area 2 0 0 2 2 14 3 3 22 b Not located at tagging area 1 1 0 2 2 9 2 2 15 Clearly spent 2011 at different locationc 1 0 0 1 0 1 2 2 5 d Unknown 0 0 0 0 1 4 0 0 5 a Excludes the fish that was tagged near the mouth of Big River during 2007. This fish was in spawning condition and travelled to the Big River spawning area. b Due to limited number of aerial tracking flights and stationary tracking stations, fish could have visited their feeding areas and not have been detected. c This number is a subset of “Not located at tagging area during 20xx”. d Fish detected at Big River/Middle Fork Spawning areas in early fall that were not recorded by stationary tracking stations located at and below Sinka’s landing and by the July 2011 aerial tracking flight.

Figure 7.–Map of the Holitna River drainage showing primary concentrations of radiotagged sheefish during July, September, and October 2008–2011. Also noted are locations where Alt (1981) captured sheefish, although no radiotagged fish from this study were found.

Table 7.–Number and location of sheefish that spent the summers of 2008–2011 in the Lower Kuskokwim River by tagging location and year of tagging. Also noted are the numbers of radiotagged fish that travelled to a spawning location during 2007–2011.

Lower Kuskokwim River (Akiak Spent summer in Johnson River and and downriver) travelled to Kongeruk River in fall Kialik River Tagging Location and Spawned during

Date 2008 2009 2010 2011 2008 2009 2010 2011 2008 2009 2010 2011 2007–2011

Big River (2007) 1 0 0 0 0 0 0 0 0 0 0 0 1

Katlitna River (2007) 0 0 0 1 0 0 0 0 0 0 0 0 0

Johnson River (2008) 8 6 4 3 4 4 3 1 2 1 1 0 2

Kuskokwim River near Bethel (2008) 4 2 0 0 0 0 0 0 0 0 0 0 1

George River (2008) 0 2 3 0 0 2 3 0 0 0 1a 0 2

25 0 3 3 1 0 1 0 0 0 1 1 0 2 Holitna River (2008)

0 2 2 2 0 0 0 0 0 1 1 1 2 Tatlawiksuk River (2008)

Total 13 15 12 7 4 7 6 1 2 3 4 1 10

a Fish spent majority of summer in the Kialik River and then swam up the Kongeruk River during late summer .

` July 2008 Atmautluak July 2009 July 2010 July 2011

Sept/Oct 2008 Sept/Oct 2009 Sept/Oct 2010 Sept/Oct 2011 N 4 0 4 Km

2.5 0 2.5 Miles Bethel River 26

Napakiak

Napaskiak

Figure 8.–Map showing sheefish that were located near the mouth of the Johnson River during July and late summer/early fall up the Kongeruk River, 2008–2011.

The Kongeruk River was the only drainage in addition to the upriver tributaries used for spawning where a dedicated migration was noted from summer to fall. Because of this seasonal migration and suspicions of possible spawning activity, we visited the Kongeruk River on 7 September 2011 to sample sheefish for spawning readiness and record environmental characteristics. Four sheefish were captured using gillnets and sacrificed. One sheefish was a mature, non-spawning female and the other three were immature and gonads were so small gender could not be discerned (Appendix D1). All sheefish sampled had stomachs full of 3 spine stickleback (Gasterosteus aculeatus) and 9-spine stickleback (Pungitius pungitius), several of which showed spawning characteristics. While setting gillnets we noticed sheefish surfacing/feeding behavior. In contrast to the upriver spawning areas, the Kongeruk River is underlain by sand and silt, and the pH and conductivity is much lower (Appendix C5, D2). In addition, the water clarity and dissolved oxygen levels were comparatively lower. LENGTH COMPOSITION Length compositions of the radiotagged sheefish differed between spawners and non-spawners. The average length of 21 sheefish considered immature and tagged downriver and near Bethel was 705 mm. The average length for 63 sheefish that migrated to upriver spawning areas during 2008–2011 was 769 mm, and the average for 11 sheefish that were assumed to not have spawned during the same time period was 699 mm. Their cumulative length distributions were also significantly different (D=0.648, P<0.001, Figure 9). The average length of all the tagged fish (119) was 750 mm with a minimum of 640 mm and a maximum of 910 mm. The smallest sheefish that migrated to the spawning areas was 670 mm and largest was 910 mm. DISCUSSION Throughout the project, many of the fates initially assigned to radiotagged sheefish changed as more information was acquired. Each year some fish were captured in the commercial, sport, and subsistence fisheries and others died due to natural causes. Some sheefish that were thought to have died in 2008 travelled to spawning areas in 2009 and 2010 (Stuby 2011). In 2010, fourteen radiotagged sheefish that were alive and moving in 2009 were not detected throughout the summer by the tracking stations or from the aerial tracking flights. This number almost doubled in 2011. The inability to detect radiotagged sheefish could have been a result of unreported harvests or transmitter failure. The transmitters were programmed to shut off in mid- November to conserve battery power. Theoretically the transmitters could transmit for up to 4 years and many of the transmitters deployed in 2007 and 2008 were detected into fall 2011. Alt (1977) noted that a sheefish tagged 32 km up the Holitna River in 1968, was recovered below Nulato in the Yukon River in 1973. Whether any of these undetected fish migrated to a different drainage is unknown. Sheefish spawn in very few locations in the Kuskokwim River drainage. To date, only 4 spawning areas have been described for the entire Kuskokwim River sheefish population. Fall locations of radiotagged sheefish in this study have confirmed spawning was occurring in sections of the Big River and Middle Fork and likely occurring in a third area at the confluence of East Fork and the Tonzona River. A fourth area in Lower Highpower Creek was inferred as a spawning area by Alt (1987), but has not been verified in this study. Because sheefish are iteroperous broadcast spawners, it can be assumed that spawning should take place in a relatively small area within a short time frame. Indeed, the spawning areas on the Big River (~25 km), Middle Fork (~7 km), and East Fork/Tonzona River (~2 km) are relatively small and the spawning time frame is relatively short. 27

100%

75%

50% KS Test:

Spawning vs. non-Spawning 28 D = 0.648

Cumulatie PercentCumulatie Frequency 25% P < 0.001

Length (mm)

Spawned Not Observed to Sapwn

Figure 9.–Cumulative length frequency distributions comparing radiotagged sheefish that were assumed to have spawned in the Upper Kuskokwim River and the 11 sheefish that were assumed to not have spawned during 2008–2011.

Spawning activity was confirmed in a previously undocumented area on the Middle Fork of the Kuskokwim River. The spawning females at the Middle Fork and Big River had egg masses that were almost a quarter of their total body weight. Bond and Erickson (1985) noticed that the eggs of nonspawning female coregonines usually have GSI values less than 3, which will increase to 20 or more by the fall spawning period. In addition, the eggs and milt were easily expressed with light pressure, which is also a characteristic of spawning activity. Lastly, during the time of spawning, sheefish eggs will grow in diameter to approximately 2.5 mm as noted in other spawning populations in the Yukon River drainage (Alt 1987) which is consistent with egg diameters measured from this site. The sheefish noted at the confluence of the East Fork of the Kuskokwim River with the Tonzona River during the time of spawning are assumed to represent another undocumented spawning population. Five sheefish in pre-spawning condition were captured and sacrificed in 1996 at the mouth of the East Fork during early August 1996 (John Burr, personal communication, ADF&G fisheries management biologist, Fairbanks, Alaska). We plan to visit this potential sheefish spawning area in late September 2013 and sample sheefish for spawning readiness to verify spawning is occurring there (FIS project 12-312). Mature prespawning sheefish began migrating to their respective spawning tributaries up to 2 months or more prior to spawning in late September. However, these fish did not arrive at their spawning areas until late September. On the Middle Fork of the Kuskokwim River sheefish were observed milling near the mouth of Windy Fork prior to spawning. Similarly, Alt (1987) noted that sheefish will congregate in deep water holding areas in the vicinity of spawning grounds and as spawning time approaches move upstream or downstream to spawning areas. This is a characteristic strategy of broadcast spawners that have to be together in the same place at the same time to maximize spawning success. During low-level flights of the area, the mouth of the East Fork of the Kuskokwim River appeared to be underlain by finer sediments compared to the Tonzona River. The Tonzona River, which empties into the East Fork, has the preferred substrate as seen on the Big River and Middle Fork. Perhaps sheefish are not spawning at the confluence, but farther up the Tonzona River. Future studies in this area, including FIS 12-312, may provide additional refinement of the description of this potential spawning area. Spawning sheefish in the Big River and Middle Fork of the Kuskokwim River were located farther up the drainages in 2008 than during 2009–2011. Gerken (2009) and Alt (1987) noted that sheefish spawn in the evening. However, all aerial tracking flights had to be conducted during the daytime. They also noted that spawning sheefish will break the water surface and make rapid movements to expel their eggs and milt. This same behavior was observed at night at the Big River camp site but was not seen or heard during daylight hours. Where sheefish rest during the day in between night spawning efforts may have been arbitrary and could have accounted for the variations in where sheefish were located during the aerial tracking flights. Sheefish have specialized spawning habitat needs that are similar amongst different tributary systems. During the September 2010 and 2011 sampling efforts at the Big River spawning area, substrate habitat characteristics were noted and compared to other systems. According to Gerken (2009), sheefish spawning presence on the Sulukna River, a tributary of the Yukon River, was more likely if small cobble was the dominant substrate and gravel was the subdominant substrate. This was similar to what we and Alt (1987) noted for the Big River and Middle Fork, where the shore substrate is composed of differentially sized gravel with varying degrees of sorting, sizes, and percentages of cobble, gravel, and sand. 29

Sheefish appear to select spawning areas with fairly specific geologic features, which in turn are associated with specific water quality parameters (pH, temperature, and conductivity). Geology of headwater regions of the Big River and Middle Fork are primarily comprised of Paleozoic limestone that represent former alternating deep-marine and shallow-marine depositional environments in addition to mudstone and shale (Decker et al. 2004). Sulukna River geology is characterized by limestone, dolomite, and sandstone. This combination is common to other known sheefish spawning areas such as the Alatna, Selawik, and Kobuk Rivers (Beikman 1980). The surficial and bedrock geology affects surface and ground water quality (Brabets et al. 2000). Gerken (2009) noticed that pH on the Sulukna River tended to be 8.0 or above, similar to what was recorded on the Big River and Middle Fork of the Kuskokwim River. The pH in nearby Kuskokwim River tributaries during September is unknown. Gerken (2009) also noted that specific conductivity tended to be higher on the Sulukna River compared to other systems, specifically above 200 µs/C, which is consistent with what was observed on the Big River and Middle Fork of the Kuskokwim River. Other water quality parameters such as water temperature and flow may restrict establishment of sheefish spawning areas. Alt (1987) and Howland (2005) noted that preferred water temperatures for spawning tended to vary between 0oC and 6oC. Gerken (2009) observed that spawning within the Sulukna River began on 23 September when the mean water temperature was 4.5oC. In general, sheefish prefer habitat with fast-flowing, shallow water (Alt 1987, Howland 2005). In this study, early fall water temperatures as well as flow data on the Big River corresponded to previous work in other systems. The Lower Highpower Creek environment is very different from the Big River, Middle Fork of the Kuskokwim River, and sheefish spawning locations in other drainages. According to Alt (1972) the substrate near the mouth of Highpower Creek was composed of differentially sized gravel. During the 2010 reconnaissance of this area, we noted the substrate to be primarily composed of fine, organic material that suggests the habitat has changed in the past 40 years. The Swift Fork of the Kuskokwim River, into which Highpower Creek flows, does have the preferred substrate and conditions previously described and if this spawning population is still viable it is likely they are spawning in this drainage near or upriver from Highpower Creek. According to Alt (1972), an area approximately 24 km upstream of Highpower Creek on the Swift Fork had the right combination of gravel size, water depth, and current for sheefish spawning. However, few sheefish were observed here and it was assumed that most spawning took place downstream. The status of this spawning population will be better understood with the attempted deployment of radio transmitters into sheefish at Highpower Creek and downriver during 2012 (OSM Project 12-312). Since 2008, radiotagged sheefish have consistently displayed a prolonged migration on the way to their spawning grounds that begins approximately 1–2 months before spawning takes place. In contrast, they exhibit a relatively abrupt post-spawning outmigration. Howland et al. (2000) noted similar in-and out-migration timing and patterns for sheefish in the Mackenzie River system in the Yukon Territory, Canada. Likewise, Underwood (2000) noted that the post- spawning migration on the Selawik River occurred between 27 September and 19 October, with the peak on 14 October. According to Gerken (2009) sheefish began spawning in the Sulukna River in both 2007 and 2008 on 23 September. The post-spawning migration for the Sulukna River sheefish began on 5 October with departure completed by 10 October. Non-spawning sheefish usually began their downriver migrations during a similar time period as spawning

sheefish. Non-spawning fish migrated past the Aniak tracking station earlier because their outmigration originated near or below the mouth of the Tatlawiksuk River, and thus they had less distance to travel than upriver spawning sheefish. Mean departure dates from the Upper Kuskokwim River spawning areas to overwintering areas varied during 2008–2010. The average date of the post-spawning migration of sheefish occurred approximately 1 week earlier in 2009 than 2008, with 2010 and 2011 values in between. According to the National Weather Service, Fairbanks Forecast Office (http://pafg.arh.noaa.gov/), the Upper Kuskokwim River was experiencing record high temperatures and precipitation in early October 2009. The exact correlation between air temperature or precipitation and water temperature is not known, but it is plausible that the warmer, wetter fall in 2009 contributed to warmer water temperatures in the Big River and an earlier outmigration for sheefish. Through fall 2011, eleven radiotagged sheefish that were alive and moving had not yet migrated to an upriver spawning area. It is likely that many of these sheefish were immature at the time they were tagged. Upon capture, most of these fish were less than 750 mm FL which is the length at which most sheefish populations mature (Brown 2000, Taube and Wuttig 1998). During each year of the study there has been at least 1 fish that was located on upriver spawning areas that did not previously spawn. During 2011 there were 3 such fish. If any of the transmitters that were deployed in 2008 are still operational in 2012, it is likely that a proportion of the 11 fish that have not yet spawned will be located in spawning areas as they continue to grow and mature. This study has documented both sequential and non-sequential spawning for male and female sheefish. Sheefish are iteroperous, but it has been noted from past studies that after spawning, females may not spawn again for 2 or more years (Reist and Bond 1988), whereas males are more likely to spawn during sequential years (Underwood 2000). A known female that migrated to the Big River spawning area during 2007 was recorded travelling to this location 3 years in a row during 2009–2010. Sequential year spawning has been recorded at all 3 spawning areas to varying degrees. Even though 6 sheefish spawned 3 sequential seasons on the Big River and 4 sheefish spawned 4 sequential seasons, the gender of these sheefish was unknown. However, it is likely both sexes were represented. Savereide (2010) also documented sequential year spawning in radio-tagged female sheefish (19 of 61 sequential spawners) as well as males on the Kobuk River. The majority of spawning sheefish showed fidelity to their spawning areas. However, over the course of the study 2 sheefish spawned on the Big River one year and on the Middle Fork of the Kuskokwim River a different year. The Big River is a major tributary of the Middle Fork and conceivably sheefish migrating upriver may have followed a group of other sheefish heading to a different tributary to spawn. No straying was noted between the East Fork/Tonzona Rivers and Big River and the Middle Fork. If the mouth of Highpower Creek became unsuitable for spawning it’s plausible that sheefish may travel to different parts of the Swift Fork of the Kuskokwim River to spawn. Information collected to date indicates that the majority of Kuskokwim River sheefish exhibit a high degree of fidelity to summer feeding areas, although this study was not designed to rigorously track sheefish during summer. With the exception of those sheefish that eventually migrated to upriver spawning areas, most of the sheefish that were tagged in 2008 at the mouths

of the George, Holitna, and Tatlawiksuk rivers returned to these areas during 2009–2011. Unless migrating to a spawning area, sheefish generally did not move far from the tributary mouths. During spring and summer most of the major Kuskokwim River tributary mouths are a good source of outmigrating salmon smolt. During mid-May 2008, one capture mortality at the mouth of the Johnson River had a stomach full of anadromous smelt. An examination of stomach contents from 3 capture mortalities in June 2008 at the mouths of the Tatlawiksuk and Holitna rivers contained outmigrating salmon smolt as well as a few juvenile resident species such as lamprey Lampetra japonica and burbot Lota lota. During late August 2009, three sheefish captured on the Holitna River had stomachs that contained juvenile whitefish and juvenile salmonids. The Holitna River is a very productive system for salmon and subsequently large numbers of sheefish are found in this system throughout the summer. Alt (1981) noted that during June and July, feeding fish included pre-spawning fish, immature fish, and non-spawning mature fish (also noted in this study). Alt also noted that sheefish in areas on the Holitna and Hoholitna rivers congregated by size and state of maturity. The Kongeruk River is the only other drainage where a dedicated fall migration was noted during 4 years of the study. From the air, the Kongeruk River, similar to the Johnson River into which it flows, appears to be underlain by fine sediments and has a relatively slow current compared to upriver spawning locations such as the Big River. Other environmental parameters which may be important for spawning were also different from that recorded in the upriver drainages such as pH and conductivity. Given the absence of spawning sheefish in our gillnet samples, differences in spawning habitat, and 1 sheefish that spent early fall in the Kongeruk River during 2008–2010 and travelled upriver to spawn on the Middle Fork in 2011, the Kongeruk River is not believed to be a sheefish spawning location. Instead, this drainage is considered a feeding area where fall spawning 3- and 9-spine stickleback concentrate. According to Ball et al. (2007), sticklebacks that were sampled between June and August in the Yukon-Kuskokwim Delta were energetically dense with 9-spine stickleback containing approximately 24% lipid and 3-spine stickleback containing approximately 11% lipid. Although the majority of sheefish spent the winter in the Lower Kuskokwim River, a much smaller proportion spent the winter in the Holitna River and upper reaches of the mainstem Kuskokwim River, including several sheefish that spawned upriver and returned to the Holitna River afterwards. In addition, over the 4 years of the study, a few sheefish that overwintered in the Holitna River for one or more seasons were then noted to travel downriver and overwinter elsewhere. According to Chythlook (2009) sheefish are caught occasionally through the ice during the winter in the Middle and Upper Kuskokwim River. Whether these fish represent a stock that is distinctly different from those wintering in the lower river is doubtful. As sheefish are broadcast spawners and spawn in relatively small locations, it is likely that spawning aggregations include fish from multiple overwintering areas. ACKNOWLEDGEMENTS The U.S. Fish and Wildlife Service, Office of Subsistence Management, provided $106,777 in funding support for 2010 and 2011 through the Fisheries Resource Monitoring Program, under agreement number 70181AJ030. During 2010 and 2011, John Chythlook, John Burr, and James Savereide assisted in sheefish sampling efforts on the Big River, at the mouth of Highpower Creek, and the Middle Fork of the Kuskokwim River. Mike Thalhauser and Melissa Smith of KNA helped download and maintain the stationary tracking stations and provided general

support. Dan Reed provided biometric support. James Savereide proofread the report and provided valuable edits and comments. This study has been conducted cooperatively with Ken Harper’s United States Fish and Wildlife Survey (USFWS) study, “Telemetry studies of humpback and broad whitefish in the lower Kuskokwim River (06-303).” As such, Ken Harper, Frank Harris (USFWS), and Mike Thalhauser (KNA) included the frequencies from the radiotagged sheefish in their aerial tracking flights and forwarded sheefish data from their stationary tracking stations. REFERENCES CITED Alt, K. T. 1972. Sport fish investigations of Alaska: A life history study of sheefish and whitefish in Alaska. Alaska Department of Fish and Game, Division of Sport Fish, Annual Performance Report, 1971-1972, Project F-9-4, Vol. 13, R-11, Juneau. Alt, K. T. 1977. Inconnu, (Stenodus leucichthys), migration studies in Alaska 1961-74. Journal of the Fisheries Research Board of Canada. 34(1): 129-133. Alt, K.T. 1981. A life history study of sheefish and whitefish in Alaska. Alaska Department of Fish and Game, Division of Sport Fish, Annual Performance Report 1980-1981, Project F-9-13, Vol. 22, R-II-A&B, Juneau. Alt, K. T. 1987. Review of sheefish (Stenodus leucichthys) studies in Alaska. Alaska Department of Fish and Game, Fishery Manuscript No. 3. Juneau. Ball, J. R., D. Esler, and J. A. Schmutz. 2007. Proximate composition, energetic value, and relative abundance of prey fish from the inshore eastern Bering Sea: implications for pisciverous predators. Polar Biology. 30: 699-708. Behnke, R.J. 1972. The systematics of salmonid fishes of recently deglaciated lakes. Journal of the Fisheries Research Board Canada 29:636-671. Beikman, H. M. 1980. Geologic Map of Alaska: Special publication SG0002-1T and Sg0002-2T, U. S. Government Printing Office, Washington, D. C. U. S. Geological Survey. Bond, W. A., and R. N. Erickson. 1985. Life history studies of anadromous coregonid fishes in two freshwater lake systems on the Tuktoyaktuk Peninsula, Northwest Territories. Canadian Technical Report of Fisheries and Aquatic Sciences 1336. Brabets, T. P., B. Wang, and R. H. Meade. 2000. Environmental and hydrologic overview of the Yukon River basin, Alaska and Canada. Water-Resources Investigations Report 99-4204. U. S. Geological Survey, Anchorage, Alaska. Brown, C. L. J. S. Magdanz, D. S. Koster and N. M. Braem, editors. 2012. Subsistence harvests in 8 communities in the central Kuskokwim River drainage, 2009. Alaska Department of Fish and Game, Division of Subsistence Technical Paper No. 365. Fairbanks, Alaska. Brown, C. L., D. Caylor, J. Dizard, J.A. Fall, S. Georgette, T. Krauthoefer, and M. Turek. 2005. Alaska subsistence salmon fisheries 2003 annual report. Alaska Department of Fish and Game, Division of Subsistence Technical Paper No. 316. Juneau. Brown, R. J., C. Lunderstadt, and B. Schultz. 2002. Movement patterns of radio-tagged adult humpback whitefish in the Upper Tanana River drainage. Alaska Fisheries Data Series Number 2002-1, U. S. Fish and Wildlife Service, Fairbanks. Brown, R. J. 2000. Migratory patterns of Yukon River inconnu as determined with otolith microchemistry and radio telemetry. Master’s thesis, University of Alaska Fairbanks. Chythlook, J. 2009. Fishery Management Report for Sport Fisheries in the Kuskokwim-Goodnews Management Area, 2007. Alaska Department of Fish and Game, Fishery Management Report No. 09-45, Anchorage. Chythlook, J. 2011. Fishery Management Report for Sport Fisheries in the Kuskokwim-Goodnews Management Area, 2009. Alaska Department of Fish and Game, Fishery Management Report No. 11-48, Anchorage.

REFERENCES CITED (Continued) Compton, R. R. 1962. Manual of Field Geology. John Wiley & Sons, Inc. pp 212-216. Conover, W. J. 1980. Practical nonparametric statistics 2nd ed. John Wiley & Sons, New York. Decker, J., S. C. Bergman, R. B. Blodgett, S. E. Box, T. K. Bundtzen, J. G. Clough, W. L. Coonrad, W. G. Gilbert, M. L. Miller, J. Murphy, M. S. Robinson, and W. K. Wallace. 2004. Geology of Southwestern Alaska. [In] Plafker, G., and Berg, H. C., editors. The geology of Alaska. Volume G-1. Geological Society of America, Boulder, Colorado. Eiler. J. H., T. R. Spencer, J. J. Pella, M. M. Masuda, and R. R. Holder. 2004. Distribution and movement patterns of Chinook salmon returning to the Yukon River basin in 2000-2002. U. S. Department of Commerce, NOAA Technical Memorandum NMFS-AFSC-148. Fall, James A., C.L. Brown, D. Caylor, S. Georgette, T. Krauthoefer, and A.W. Paige. 2003. Alaska Subsistence Fisheries 2002 Annual Report. Alaska Department of Fish and Game, Division of Subsistence Technical Paper No. 315. Juneau. Fall, J. A., D. Caylor, M. Turek, C. Brown, T. Krauthoefer, B. Davis, and D. Koster. 2007. Alaska subsistence fisheries 2004 annual report. Alaska Department of Fish and Game, Division of Subsistence Technical Paper Nol. 317. Juneau. Gerken, J. D. 2009. Identification and characterization of inconnu spawning habitat in the Sulukna River, Alaska. MS Thesis, University of Alaska, Fairbanks. Howland. K. L., R. F. Tallman, and W. M. Tonn. 2000. Migration patterns of freshwater and anadromous inconnu in the Mackenzie River system. Transactions of the American Fisheries Society. 129: 41-59. Howland, K. L. 2005. Population differentiation if inconnu, Stenodus leucichthys, in the Mackenzie River system. Doctoral Thesis. University of Alberta, Edmonton, Alberta. Jennings, G. B., K. Sundet, and A. E. Bingham. 2009a. Estimates of participation, catch, and harvest in Alaska sport fisheries during 2005. Alaska Department of Fish and Game, Fishery Data Series No. 09-47, Anchorage. Jennings, G. B., K. Sundet, and A. E. Bingham. 2009b. Estimates of participation, catch, and harvest in Alaska sport fisheries during 2006. Alaska Department of Fish and Game, Fishery Data Series No. 09-54, Anchorage. Jennings, G. B., K. Sundet, and A. E. Bingham. 2010a. Estimates of participation, catch, and harvest in Alaska sport fisheries during 2007. Alaska Department of Fish and Game, Fishery Data Series No. 10-02, Anchorage. Jennings, G. B., K. Sundet, and A. E. Bingham. 2010b. Estimates of participation, catch, and harvest in Alaska sport fisheries during 2008. Alaska Department of Fish and Game, Fishery Data Series No. 10-22, Anchorage. Jennings, G. B., K. Sundet, and A. E. Bingham. 2011a. Estimates of participation, catch, and harvest in Alaska sport fisheries during 2009. Alaska Department of Fish and Game, Fishery Data Series No. 11-45, Anchorage. Jennings, G. B., K. Sundet, and A. E. Bingham. 2011b. Estimates of participation, catch, and harvest in Alaska sport fisheries during 2010. Alaska Department of Fish and Game, Fishery Data Series No. 11-60, Anchorage. Krauthoefer, T., J. Simon, M. Coffing, M. Kerlin, and W. Morgan. 2007. The harvest of non-salmon fish by residents of Aniak and Chuathbaluk, Alaska, 2001-2003. Alaska Department of Fish and Game, Technical Paper No. 299. Anchorage, Alaska. McPhail, J. D., and C. C. Lindsey. 1970. Freshwater fishes of northwestern Canada and Alaska. Fisheries Research Board of Canada Bulletin 173. Ray, L., C. Brown, A. Russell, T. Krauthoefer, C. Wassillie, and J. Hooper. 2010. Local knowledge and harvest monitoring of nonsalmon fishes in the Lower Kuskokwim River Region, Alaska 2005-2009. Final report to the U.S. Fish and Wildlife Service, Office of Subsistence Management, to fulfill obligations for Study No. FIS 06 351. Alaska Department of Fish and Game Division of Subsistence Technical Paper No. 356, Fairbanks. Reist, J. D. and W. A. Bond. 1988. Life history characteristics of migratory coregonids of the lower Mackenzie River, Northwest Territories, Canada. Finnish Fisheries Research. 9: 133-144.

REFERENCES CITED (Continued) Savereide, J. W. 2010. Spawning location, run timing, and spawning frequency of Kobuk River sheefish. USFWS OSM Annual Report for Study 08-103. Snyder, D. E. 1983. Fish eggs and larvae. Pages 165-197 [In] L. A. Nielsen, D. L. Johnson, and S. S. Lampton, editors. Fisheries techniques. American Fisheries Society, Bethesda, Maryland. Stuby, L. 2008. Spawning Distribution and Migratory Timing of Kuskokwim River Sheefish using Radiotelemetry, 2007-2009. USFWS OSM Annual Report for Study 06-305. Stuby, L. 2009. Spawning Distribution and Migratory Timing of Kuskokwim River Sheefish using Radiotelemetry, 2007-2009. USFWS OSM Annual Report for Study 06-305. Stuby, L. 2010. Spawning locations, seasonal distribution, and migratory timing of Kuskokwim River sheefish using radiotelemetry, 2007-2009. Alaska Department of Fish and Game, Fishery Data Series No. 10-47, Anchorage. Stuby, L. 2011. Spawning Distribution and Migratory Timing of Kuskokwim River Sheefish using Radiotelemetry, 2010. USFWS OSM Annual Report for Study 10-305. U.S. Fish and Wildlife Service, Office of Subsistence Management, Fairbanks. Taube, T. T. and Wuttig, K. 1998. Abundance and composition of sheefish in the Kobuk River, 1997. Alaska Department of Fish and Game, Fishery Manuscript Report No. 98-3, Anchorage. Underwood, T. J. 2000. Abundance, Length Composition and Migration of Spawning Inconnu in the Selawik River, Alaska. North American Journal of Fisheries Management 20: 386-393. Williams, L., C. Venechuk, D. L. Holen, and W. E. Simeone. 2005. Lake Minchumina, Telida, Nikolai, and Cantwell subsistence community use profiles and traditional fisheries use. Alaska Department of Fish and Game, Technical Paper No. 295, Juneau, Alaska.

APPENDIX A MAPS SHOWING LOCATIONS OF RADIOTAGGED SHEEFISH DURING THE AERIAL TRACKING FLIGHTS CONDUCTED DURING JULY 2008–2011

Appendix A1.–Map showing the locations of radiotagged sheefish during the 20–22 July 2008 aerial tracking flights. All mortalities up to the July 2008 aerial flight were deleted from map.

Appendix A2.–Map showing the locations of radiotagged sheefish during the 3–4 July 2009 aerial tracking flights. All mortalities up to the July 2009 aerial flight were deleted from map.

Appendix A3.–Map showing the locations of radiotagged sheefish during the 5–7 July 2010 aerial tracking flights. All mortalities up to the July 2010 aerial flight were deleted from map.

Appendix A4.–Map showing the locations of radiotagged sheefish during the 4–5 July 2011 aerial tracking flights. All mortalities up to the July 2011 aerial flight were deleted from map.

APPENDIX B MAPS SHOWING LOCATIONS OF RADIOTAGGED SHEEFISH DURING THE AERIAL TRACKING FLIGHTS CONDUCTED DURING SEPTEMBER AND OCTOBER 2008–2011

Appendix B1.–Map showing the uppermost locations of radiotagged sheefish during the 23–25 September and 8–9 October 2008 aerial tracking flights. All mortalities up to September 2008 aerial flight were deleted from map.

Appendix B2.–Map showing the uppermost locations of radiotagged sheefish during the 9–11 September and 9, 11–12 October 2009 aerial tracking flights. All mortalities up to September 2009 aerial flight were deleted from map.

Appendix B3.–Map showing the uppermost locations of radiotagged sheefish during the 19–21 and 29 September 2010 aerial tracking flights. All mortalities up to September 2010 aerial flight were deleted from map.

Appendix B4.–Map showing the uppermost locations of radiotagged sheefish during the 26–28 September 2011 aerial tracking flights. All mortalities up to September 2011 aerial flight were deleted from map.

APPENDIX C MAPS SHOWING DETAILS OF VISITS TO UPPER KUSKOKWIM SHEEFISH SPAWNING AREAS TO SAMPLE SHEEFISH FOR SPAWNING READINESS

Area 1: Very course pebble gravel and cobble to very fine sand and silt. Gravel sub-rounded to rounded and moderately to poorly sorted (Sorting is degree sediment has been reworked by transporting agents and the degree to which the sediment particles approach being similar in size).

Area 2: Compared to Area 1, see more large cobbles. Sand/silt fills the interstities between cobbles. Mixture is poorly sorted. N Area 3: Sediments become better sorted moving down sandbar towards camp. Also see coarse pebble gravel. However, with a lower energy environment towards bend, sediments become silitier and sandier with less cobble and pebble gravel.

Area 4 (Camp): Location of temporary Area 1 field camp. This is a higher energy area

50 and see larger cobble gravel with silt and sand in the interstities. Moderately to very Area 2 Area 3 Set net locations Area 4 (Camp) Extent of Ken Alt's visit in 1971 Extent of our sampling effort in 2010

Whitefish observed spawning

0 0.25 0.5 1 miles

00.25 0.5 1 kilometers

Appendix C1.–Substrate descriptions, set net sites, locations where other species of whitefish were observed spawning, and extent of effort to capture and sample sheefish for spawning readiness during a visit to the Big River during 13–16 September 2010.

Recorded Environmental Data Camp Site #1 Sheefish Capture Location 51

Site #3

Site #2

0.5 Kilometers 0.5 Miles

Appendix C2.–Location where 52 sheefish were captured with hook-and-line techniques and examined for spawning readiness on the Big River and sites where environmental data was recorded during 24–26 September 2011. Environmental data values corresponding to each “Site” can be found in Appendix D2.

Site #2

Site #3

Gillnet Sampling Extent Recorded Environmental Parameters

52 Camp Site #1 Sheefish Capture Locations

1 Kilometers 1 Miles

Appendix C3.–Location where 36 sheefish were captured with hook-and-line techniques on the Middle Fork of the Kuskokwim River and examined for spawning readiness, sites where environmental data was recorded, and extent of set net effort to capture and sample sheefish during 20–22 September 2011. Environmental data specifics corresponding to each “Site” can be found in Appendix D2.

Upper Telida Lake N

Capture location for 1 gravid least cisco. 53

Uppermost Extent of our sampling effort in 2010

Set net locations

00.25 0.5 1 mile 00.25 0.5 1 kilometer

Appendix C4.–Set net sites and extent of effort to capture and sample sheefish for spawning readiness during a visit to the mouth of Highpower Creek, 17–19 September 2010.

Site #1

Site #2

Gillnet Sampling Extent Recorded Environmental Parameters Sheefish Capture Location

1 Kilometers 0.75 Miles

Appendix C5.–Location where 4 sheefish were captured with hook-and-line techniques on the Kongeruk River and examined for spawning readiness, sites where environmental data was recorded, and extent of set net effort to capture and sample sheefish during 7 September 2011. Environmental data specifics corresponding to each “Site” can be found in Appendix D2.

APPENDIX D SPAWNING CHARACTERISTICS OF FISH FROM SPAWNING AREAS ON THE BIG RIVER, MIDDLE FORK OF THE KUSKOKWIM RIVER, AND THE KONGERUK RIVER AND ENVIRONMENTAL DATA

Appendix D1.–Spawning readiness of sheefish captured and sampled at the Kongeruk River, Middle Fork of the Kuskokwim River, and Big River during September 2011.

Sacrificed Fishb

Length Spawning Fish Weight Gonad Weight a Date (mm) Gender Ready (kg) (kg) GSI (Female) Kongeruk River 7-Sep-11 775 F NO 5.727 0.085 1.5 7-Sep-11 635 U NO 2.948 0.028 7-Sep-11 620 U NO 2.778 0.028 7-Sep-11 570 U NO 2.240 0.028

Middle Fork of the Kuskokwim River 22-Sep-11 700 M YES 22-Sep-11 705 M YES 22-Sep-11 710 M YES 22-Sep-11 710 M YES 22-Sep-11 680 M YES 22-Sep-11 745 M YES 22-Sep-11 665 M YES 22-Sep-11 780 M YES 22-Sep-11 740 M YES 22-Sep-11 670 M YES 22-Sep-11 690 M YES 22-Sep-11 690 M YES 22-Sep-11 710 M YES 3.110 0.050 22-Sep-11 720 M YES 3.629 0.057 22-Sep-11 680 M YES 3.090 0.057 22-Sep-11 750 M YES 3.969 0.085 22-Sep-11 675 M YES 3.118 0.085 22-Sep-11 685 M YES 3.118 0.113 22-Sep-11 790 M YES 4.621 0.113 22-Sep-11 740 M YES 3.884 0.085 22-Sep-11 660 M YES 2.977 0.057 22-Sep-11 780 M YES 4.536 0.113 22-Sep-11 750 M YES 3.884 0.057 22-Sep-11 790 F YES 5.046 0.964 19.1 22-Sep-11 740 M YES 22-Sep-11 775 M YES 22-Sep-11 910 F YES 22-Sep-11 665 M YES -continued

Appendix D1.–Page 2 of 3.

Sacrificed Fishb Length Spawn ing Fish Weight Gonad Weight GSI Date (mm) Gender Readya (kg) (kg) (Female) Middle Fork of the Kuskokwim River 22-Sep-11 720 M YES 22-Sep-11 660 M YES 22-Sep-11 675 M YES 22-Sep-11 705 M YES 22-Sep-11 675 M YES 22-Sep-11 865 F YES 6.634 1.588 23.9 22-Sep-11 760 F YES 22-Sep-11 800 F YES

Big River 24-Sep-11 740 M YES 3.544 0.085 24-Sep-11 895 F YES 6.605 1.588 24.0 24-Sep-11 810 F YES 5.982 1.531 25.6 24-Sep-11 755 F YES 4.366 0.907 20.8 24-Sep-11 810 M YES 4.848 0.142 24-Sep-11 795 M YES 5.188 0.142 24-Sep-11 800 M YES 4.734 0.113 24-Sep-11 795 M YES 5.160 0.142 24-Sep-11 770 M YES 4.536 0.113 24-Sep-11 735 M YES 3.629 0.113 24-Sep-11 635 M YES 24-Sep-11 800 M YES 24-Sep-11 775 M YES 24-Sep-11 795 M YES 24-Sep-11 765 M YES 24-Sep-11 795 M YES 24-Sep-11 765 M YES 24-Sep-11 850 M YES 24-Sep-11 740 M YES 24-Sep-11 830 F YES 25-Sep-11 785 F YES 25-Sep-11 820 M YES 25-Sep-11 825 M YES 25-Sep-11 790 M YES 25-Sep-11 745 M YES -continued

Appendix D1.–Page 3 of 3.

Sacrificed Fishb Length Spawning Fish Weight Gonad Weight GSI Date (mm) Gender Readya (kg) (kg) (Female) Big River 25-Sep-11 925 F YES 25-Sep-11 785 M YES 25-Sep-11 830 M YES 25-Sep-11 785 M YES 25-Sep-11 710 M YES 25-Sep-11 770 M YES 25-Sep-11 810 M YES 25-Sep-11 795 M YES 25-Sep-11 815 M YES 25-Sep-11 795 M YES 25-Sep-11 730 M YES 25-Sep-11 775 M YES 25-Sep-11 945 F YES 25-Sep-11 775 M YES 25-Sep-11 775 M YES 25-Sep-11 825 F YES 25-Sep-11 835 M YES 25-Sep-11 830 M YES 25-Sep-11 760 M YES 25-Sep-11 740 M YES 25-Sep-11 710 M YES 25-Sep-11 680 M YES 25-Sep-11 720 M YES 25-Sep-11 715 M YES 26-Sep-11 785 M YES 26-Sep-11 780 M YES 26-Sep-11 770 M YES

Appendix D2.Environmental characteristics recorded at the Kongeruk, Middle, and Windy forks of the Kuskokwim River, and Big River.

DO Temperature Conductivity Secchi Depth Flow Rate

Date/Time Sitea mg/L % pH oC us/cm m m/sec Comments

Kongeruk River 9/7/11 13:35 1 9.87 90.5% 7.52 11.1 76.1 0.23 0.46

9/7/11 15:05 2 10.07 91.7% 7.61 10.9 78.6 0.30 0.70

Middle Fork of the Kuskokwim River 9/21/11 12:20 1 11.22 92.5% 8.27 4.9 356 1.78 0.54

9/21/11 15:25 2 11.21 94.4% 8.26 5.7 357 0.61 0.71 9/22/11 11:22 3 11.51 92.6% 8.13 4.7 358 0.61 0.15 Confluence of Middle and Windy Forks 59

9/22/11 11:22 3 8.21 1.37 Windy Fork Mouth

Big River 9/14/10 14:45 1 11.41 99.5% 8.06 9.21 375 0.10 -

9/16/10 9:20 1 - - - 7.71 370 0.09 1.07 pH probe not working 9/25/11 15:53 1 11.64 99.1% 8.29 7.1 380 0.84 1.01

9/25/11 17:00 2 11.63 99.2% 8.37 7.1 380 0.61 0.83

9/25/11 17:40 3 11.60 98.8% 8.34 7.1 379 0.76 0.36 a Site locations are shown on maps in Appendices C2, C4, and C5.

APPENDIX E JULY TO OCTOBER 2008–2011 AMBIENT AIR TEMPERATURES FROM MCGRATH STATION

Daily Average Ambient Temperature from McGrath Station and Number of Sheefish Recorded During Inmigration at Tracking Station Near Big River 6 25

5 20

4 C o 15

3 62

10 Numberof Fish 2 Temperature,

5 1

0 0

Date 2008 2009 2010 2011 2008 2009 2010 2011

Appendix E1.–Daily sheefish upriver migration and corresponding daily average ambient temperatures from McGrath Station encompassing the maximum and minimum dates for spawning radiotagged sheefish that migrated upriver past the stationary tracking station located on the Middle Fork of the Kuskokwim River near the mouth of Big River.

Daily Average Ambient Temperature from McGrath Station and Number of Sheefish Recorded During Outmigration at Tracking Station Near Big River 8 20

7 15

6 10 C

5 5 o

4 0 63

Numberof Fish 3 -5 Temperature, Temperature,

2 -10

1 -15

0 -20

Date 2008 2009 2010 2011 2008 2009 2010 2011

Appendix E2.–Daily sheefish downriver migration and corresponding daily average ambient temperatures from McGrath Station encompassing the maximum and minimum dates for spawning radiotagged sheefish that migrated downriver past the stationary tracking station located on the Middle Fork of the Kuskokwim River near the mouth of Big River.

Average Daily Temperature Variations of the Big River

Probe suspected to be out of water and encassed in

ice and snow 10 C o Time Time of Spawning

0 64

Temperature, Temperature, -10

-20

-30

-40 Date

Water Temperature Ambient Temperature (McGrath Station)

Appendix E3.–Daily average temperatures of Big River recorded by an Onset HOBO Water Temperature sensor and corresponding daily average ambient temperatures from McGrath Station during 16 October 2010 to 18 September 2011. Sensor assumed to be out of water and values unreliable during 11 October 2010 to 5 May 2011.