Assessment of the Status of the Sport Fishery for Walleye at Pinehurst Lake, 1997
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Assessment of the Status of the Sport Fishery for Walleye at Pinehurst Lake, 1997. Conducted as part of the Walleye Monitoring Program (Project No. H96010) Prepared by Bill Patterson, Fisheries Section, Northeast Boreal Region, Alberta Conservation Association and M. G. Sullivan, Fisheries Section, Natural Resources Service, Alberta Environmental Protection March, 1998. ABSTRACT To recover or maintain Alberta's walleye fisheries, a new walleye management strategy was implemented in 1996. In 1996 the walleye fishery at Pinehurst Lake was classified as stable and a 43 cm (total length, TL) size limit in walleye was implemented in the sport fishery. In order to monitor the status of the walleye fishery at Pinehurst Lake, a creel survey was conducted during May to August 1997. Prior to this survey, the last creel survey at Pinehurst Lake was conducted during May to August 1994. The angling effort from 1994 to 1997 decreased 41% to 6.8 hours / ha. The estimated number of anglers declined 46% since 1994 to 7930 in 1997. The harvest of walleye from 1994 to 1997 decreased 51% to 2807 walleye. The catch rate on legal-sized walleye (>43 cm TL) had decreased from 0.127 walleye kept / hour in 1994 to 0.089 walleye kept / hour in 1997. The catch rate on sub-legal walleye (<43 cm TL) was estimated (utilizing a test fishery) to be moderate, at 0.44 walleye caught / hour. Evidence of recruitment is moderate. The strength of these young year-classes is likely a response due to the 43 cm TL minimum size limit. Based on the criteria used to classify walleye stocks in Alberta, the fishery at Pinehurst Lake should be reclassified from “stable” to “vulnerable”. The walleye population in Pinehurst Lake is responding to increased protection. There is a high potential for recovery of this fishery if the protected year-classes survive in strong numbers to spawning age and produce recruits. The regulation recommended in Alberta’s walleye management strategy for a walleye fishery with a “vulnerable” status is a 50 cm TL minimum size and a 3 fish daily bag limit. This regulation update would reduce harvest by 72% but only affect 16% of all anglers. i ACKNOWLEDGEMENTS Roger Korth and Michael Blackburn distinguished themselves by successfully completing a creel survey at Pinehurst Lake. Without their devotion, abilities to handle the volume of anglers and data, and their lack of cynicism, the survey would have certainly suffered. The Walleye Monitoring Program would also like to recognise volunteer anglers Nicole Poirier, Al and Duncan Baldwin (from England), Dave Majeau, Craig Johnson, Darryl Kublik and multiple Northeast Boreal Region NRS and ACA Fisheries Staff who all contributed both time and expense toward the test fishery. The Alberta Conservation Association (ACA) would like to acknowledge the co-operation from Alberta Environmental Protection, Natural Resources Service (NRS), Northeast Boreal Region, Fisheries Management Section staff that was received throughout the course of the program. The assistance from NRS staff and the use of NRS equipment is greatly appreciated. ii TABLE OF CONTENTS Page ABSTRACT i ACKNOWLEDGEMENT ii LIST OF TABLES iv LIST OF FIGURES iv LIST OF APPENDICES v INTRODUCTION 1 METHODS 1 1.1. Study Site Description 1 1.2. Methods of Study 2 RESULTS 5 Angler Survey 5 Compliance Parameters 5 Status of the Walleye Fishery 8 1. Age-class Distribution 8 2. Age-class Stability 8 3. Index of Growth 10 4. Catch Rate 10 5. Age-at-Maturity 10 DISCUSSION 13 LITERATURE CITED 14 APPENDICES 15 iii LIST OF TABLES Table Page 1. Observed catch rates of anglers; Pinehurst Lake, 1985, 1989, 1992 - 1994 and 1997. 6 2. Angler survey summary; Pinehurst Lake, 1997. 6 3. Non-compliance with size limits; Pinehurst Lake, 1997. 7 4. Criteria for classifying status of walleye fisheries; Pinehurst Lake, 1997 9 LIST OF FIGURES Figure Page 1. Illegal harvest of walleye from Pinehurst Lake, 1997. 7 2. Encounter rate of anglers possessing a sub-legal walleye from Pinehurst Lake, 1997. 7 3. Exaggeration rate of anglers releasing sub-legal walleye from Pinehurst Lake, 1997. 8 4. Age-class histogram of walleye from Pinehurst Lake, 1997. 10 5. Fork length histogram of walleye from Pinehurst Lake, 1997. 11 6. Length-at-age of walleye from Pinehurst Lake, 1997. 11 7. Age-at-maturity of walleye from Pinehurst Lake, 1997. 12 iv APPENDICES Appendix Page 1. Angler survey data; Pinehurst Lake, 1997. 1.1. Daily summary of angler survey data. 15 1.2. Catch frequency distribution of harvested walleye. 16 1.3. Catch frequency distribution of released walleye. 16 1.4. Methods of angling and catch statistics for walleye. 17 1.5. Skill levels of anglers and catch statistics for walleye. 17 1.6. Target species of anglers and catch statistics for walleye. 17 1.7. Anglers use of electronic gear and catch statistics for walleye. 17 2. Biological data from sport-caught walleye; Pinehurst Lake, 1997. 2.1. Weight histogram of walleye. 18 2.2. Length-at-maturity of walleye. 18 2.3. Summary of biological data from walleye. 19 3. Biological data from test-caught walleye; Pinehurst Lake, 1997. 28 4. Biological data from sport-caught pike; Pinehurst Lake, 1997. 44 5. Biological data from sport-caught perch; Pinehurst Lake, 1997. 47 6. Creel survey form; Pinehurst Lake, 1997. 48 v INTRODUCTION Walleye (Stizostedion vitreum) populations in Alberta have been subjected to heavy fishing pressure for many years. Most populations show signs of over-harvest, with some experiencing significant declines. Previous management strategies have focused on province- wide regulations designed to manage the walleye harvest at an average fishery. Fisheries receiving heavier than average exploitation have not been adequately protected with these regulations and consequently many have declined or collapsed. To recover these fisheries and to maintain the stable fisheries, a new walleye management strategy was implemented in 1996 (Berry 1995). This strategy requires that each walleye population is evaluated as to its degree of exploitation and is then placed in one of these categories: collapsed, vulnerable, or stable. The fishery is assigned a standard sport fishing regulation based on this status (Sullivan 1994). In early 1996, the walleye fishery at Pinehurst Lake was assigned a stable status. A 43 cm total length (TL) minimum size and a 3 fish daily bag limit on walleye was therefore implemented at the fishery. This report describes the creel survey conducted at Pinehurst Lake during the summer of 1997. The purpose of the survey was to monitor the walleye sport fishery and verify the status of the population and fishery. METHODS Study Site Description Pinehurst Lake (TWP 65, RNG 10, W4M) is approximately 45 km southeast of the town of Lac La Biche. Pinehurst Lake Recreation Area includes a basic campground and day-use area. Alberta Provincial Park staff maintain the recreation area. Pinehurst Lake Wilderness Cabins are located on a section of privately owned beach along the east shore of the lake. The trophic status of Pinehurst Lake is eutrophic. Pinehurst Lake has a surface area of 4115 hectares and a maximum depth of approximately 24 metres. Pinehurst Lake is in the Beaver River Basin, and is feed by five intermittent inlet streams and drained by Punk Creek. A more complete description of the physical, chemical and biological characteristics may be found in Mitchell and Prepas (1990). 1 Methods of Study One creel survey crew (two technicians) collected information from both Pinehurst Lake and Touchwood Lake between 17 May - 17 August 1997. The crew was stationed at the Pinehurst Lake Recreation Area. A schedule of 5 survey days at Pinehurst Lake (Wednesdays through Sundays) was preceded by 5 survey days (Fridays through Mondays) at the alternate site (Touchwood Lake). This cycle was repeated 7 times during the study. The survey technicians interviewed each angler returning to the survey site during all survey days (24 h survey). Anglers were approached and asked a series of questions concerning their time spent angling, the numbers of each species caught or released, species sought, their gear types, and their use of electronic equipment. A subjective evaluation of their skill level was also made. Children and anglers with little equipment, knowledge or seriousness were considered to be novice anglers. Professional anglers demonstrated clear superiority in equipment and knowledge (and usually had their sponsors emblazoned on their hats, coats and boats). All other anglers were classified as having a moderate skill. As time permitted during the survey period, sport fish retained by anglers was sampled for biological information. The fork length of each fish was recorded to the nearest millimetre; the weight was recorded to the nearest ten grams; and one or more skeletal structures were removed to determine the age of the fish. For this purpose, the left pelvic fin and operculum of walleye, the left cleithrum of northern pike (Esox lucius), and the operculum and or anal fin of yellow perch (Perca flavescens) were collected. Ages were determined following Mackay et al. (1990). Sex and state of maturity of each fish was determined following Olynyk (1980). Stomach contents were removed and classified as to number and species of vertebrates, and approximate number and order of invertebrates. The complete biological data set for walleye is reported in this study. Biological data for other species are partially reported in the Appendices, with the full data set stored in the Alberta Conservation Association (ACA) Fisheries Section and the Alberta Natural Resources Service (NRS), Fisheries Management Branch files, Edmonton Metropolitan office. In the Alberta Guide to Sportfishing Regulations, the size limits for walleye are described in terms of natural total length. A fork length (FL) - natural total length (TL nat) conversion was necessary to determine the number of legal and sub-legal walleye in the creel and the test fisheries.