Salmon Escapement
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Mark and Recapture for Event Data When Reporting Probabilities Are Less Than One
No News is Good News?: Mark and Recapture for Event Data When Reporting Probabilities are Less than One. Cullen S. Hendrix Idean Salehyan* Korbel School of International Studies Department of Political Science University of Denver University of North Texas [email protected] [email protected] Abstract. We discuss a common, but often ignored, problem in event data: underreporting bias. When collecting data, it is often not the case that source materials capture all events of interest, leading to an undercount of the true number of events. To address this issue, we propose a common method first used to estimate the size of animal populations when a complete census is not feasible: mark and recapture. By taking multiple sources into consideration, one can estimate the rate of missing data across sources and come up with an estimate of the true number of events. To demonstrate the utility of the approach, we compare Associated Press and Agence France Press reports on conflict events, as contained in the Social Conflict in Africa Database. We show that these sources capture approximately 76% of all events in Africa, but that the non- detection rate declines dramatically when considering more significant events. We also show through regression analysis that deadly events, events of a larger magnitude, and events with government repression, among others, are significant predictors of overlapping reporting. Ultimately, the approach can be used to correct for undercounting in event data and to assess the quality of sources used. * We would like to thank Christian Davenport, James Nichols, and James Hines for comments on and assistance with earlier drafts. -
Snakes on a Lane
Trinity River Restoration Program Juvenile Salmonid Outmigrant Monitoring Evaluation, Phase II Final Technical Memorandum December 21, 2009 Prepared for: Trinity River Restoration Program 1313 S. Main Street P.O. Box 1300 Weaverville, California 96093 Prepared by: ESSA Technologies, Ltd. 1765 W 8th Avenue Vancouver, British Columbia V6J 5C6 Simon Fraser University Department of Statistics and Actuarial Science 8888 University Drive Burnaby, British Columbia V5A 1S6 North State Resources, Inc. 5000 Bechelli Lane, Suite 203 Redding, California 96002 (530) 222-5347 USBR TASK ORDER 06A0204097G NSR# 10116-02 © 2009 Trinity River Restoration Program Citation: Schwarz, C.J., D. Pickard, K. Marine and S.J. Bonner. 2009. Juvenile Salmonid Outmigrant Monitoring Evaluation, Phase II– December 2009. Final Technical Memorandum for the Trinity River Restoration Program, Weaverville, CA. 155 pp. + appendices. Executive Summary The Trinity River Restoration Program (hereafter called the Program) was initiated in 1984 to restore and maintain the fish and wildlife stocks of the Trinity River Basin to levels that existed just prior to construction of the CVP Trinity River Division. Using an adaptive management framework the Program hopes to determine the most effective restoration strategies to restore the Trinity River’s natural riverine processes and enhance fish and wildlife populations. The Program’s Integrated Assessment Plan (IAP) identifies key assessments that can be used to evaluate long-term progress toward achieving Program goals and objectives and/or provide short-term feedback to improve Program management actions by testing key hypotheses and reducing management uncertainties. This report addresses juvenile salmonid outmigrant monitoring (a key component of the IAP), evaluating tradeoffs between alternative monitoring methods for assessing smolt abundance, run timing, and condition. -
Juvenile Salmonid Outmigrant Monitoring Evaluation, Phase II
Trinity River Restoration Program Juvenile Salmonid Outmigrant Monitoring Evaluation, Phase II Final Technical Memorandum December 21, 2009 Prepared for: Trinity River Restoration Program 1313 S. Main Street P.O. Box 1300 Weaverville, California 96093 Prepared by: ESSA Technologies, Ltd. 1765 W 8th Avenue Vancouver, British Columbia V6J 5C6 Simon Fraser University Department of Statistics and Actuarial Science 8888 University Drive Burnaby, British Columbia V5A 1S6 North State Resources, Inc. 5000 Bechelli Lane, Suite 203 Redding, California 96002 (530) 222-5347 USBR TASK ORDER 06A0204097G NSR# 10116-02 © 2009 Trinity River Restoration Program Citation: Schwarz, C.J., D. Pickard, K. Marine and S.J. Bonner. 2009. Juvenile Salmonid Outmigrant Monitoring Evaluation, Phase II– December 2009. Final Technical Memorandum for the Trinity River Restoration Program, Weaverville, CA. 155 pp. + appendices. Executive Summary The Trinity River Restoration Program (hereafter called the Program) was initiated in 1984 to restore and maintain the fish and wildlife stocks of the Trinity River Basin to levels that existed just prior to construction of the CVP Trinity River Division. Using an adaptive management framework the Program hopes to determine the most effective restoration strategies to restore the Trinity River’s natural riverine processes and enhance fish and wildlife populations. The Program’s Integrated Assessment Plan (IAP) identifies key assessments that can be used to evaluate long-term progress toward achieving Program goals and objectives and/or provide short-term feedback to improve Program management actions by testing key hypotheses and reducing management uncertainties. This report addresses juvenile salmonid outmigrant monitoring (a key component of the IAP), evaluating tradeoffs between alternative monitoring methods for assessing smolt abundance, run timing, and condition. -
Mark-Recapture Estimates of Stickleback Population Sizes in Paxton and Priest Lakes in 2016
Mark-recapture estimates of stickleback population sizes in Paxton and Priest Lakes in 2016 Dolph Schluter, Marius Roesti, and Thor Veen Biodiversity Research Centre and Zoology Department University of British Columbia Introduction We conducted a mark-recapture survey of population (census) sizes of the stickleback species pairs in Priest and Paxton lakes in spring 2016. Trapping success over the years by the Schluter lab and people in other labs had suggested that total numbers were high. Nevertheless, current population sizes were unknown. The present project aimed to remedy this situation. Previous knowledge of population sizes of fish in these lakes comes from a mark-recapture study carried out in Paxton Lake in May, 2005 (M. Nomura and D. Schluter, unpublished). The results of this effort are shown in Table S1 of the Supplement. These estimates are now stale, being more than 10 years out of date. The estimates were based on relatively small samples, leading to highly uncertain estimates (wide confidence intervals). Population sizes of the Priest Lake (Vananda Creek) species pair have never been estimated directly (previous numbers are based on extrapolating from Paxton Lake estimates according to area differences between Priest Lake and Paxton Lake). Methods Study populations Population size was estimated in four populations from Texada Island, BC. These included the Paxton Lake Benthic Threespine (Gasterosteus aculeatus), the Paxton Lake Limnetic Threespine (Gasterosteus aculeatus), the Vananda Creek Benthic Threespine (Gasterosteus aculeatus) from Priest Lake, and the Vananda Creek Limnetic Threespine (Gasterosteus aculeatus) from Priest Lake. All four populations are federally listed as Endangered under the Species at Risk Act (SARA), Access difficulties prevented us from conducting similar studies in Spectacle (Balkwill) Lake and Emily Lake (Vananda Creek), which also contain stickleback species pairs. -
A Generalized Estimating Equations Approach to Capture-Recapture Closed Population Models: Methods and Applications
A GENERALIZED ESTIMATING EQUATIONS APPROACH TO CAPTURE-RECAPTURE CLOSED POPULATION MODELS: METHODS AND APPLICATIONS Md. Abdus Salam Akanda Thesis presented to the University of Évora to obtain the Degree of Doctor in Mathematics Area of Specialization: Statistics SUPERVISOR: Professor Russell Gerardo Alpizar Jara, PhD ÉVORA, JUNE, 2014 INSTITUTE FOR ADVANCED STUDIES AND RESEARCH Abstract Wildlife population parameters, such as capture or detection probabilities, and density or population size, can be estimated from capture-recapture data. These estimates are of particular interest to ecologists and biologists who rely on ac- curate inferences for management and conservation of the population of interest. However, there are many challenges to researchers for making accurate inferences on population parameters. For instance, capture-recapture data can be considered as binary longitudinal observations since repeated measurements are collected on the same individuals across successive points in times, and these observations are often correlated over time. If these correlations are not taken into account when estimating capture probabilities, then parameter estimates will be biased, possibly producing misleading results. Also, an estimator of population size is generally biased under the presence of heterogeneity in capture probabilities. The use of covariates (or auxiliary variables), when available, has been proposed as an alter- native way to cope with the problem of heterogeneous capture probabilities. In this dissertation, we are interested in tackling these two main problems, (i) when capture probabilities are dependent among capture occasions in closed population capture-recapture models, and (ii) when capture probabilities are heterogeneous among individuals. Hence, the capture-recapture literature can be improved, if we could propose an approach to jointly account for these problems. -
Jaguar Survey and Monitoring Techniques and Methodologies: a Review
Jaguar Survey and Monitoring Techniques and Methodologies: A Review A Submission to the U.S. Fish and Wildlife Service in Partial Fulfillment of Contract F13PX01563 © Daniel Alarcon John Polisar, Tim G. O’Brien, Sean M. Matthews, Jon P. Beckmann, Eric W. Sanderson, Octavio Cesar Rosas-Rosas, and Carlos A. López-González 27 March 2014 Table of Contents Executive Summary ...................................................................................................................... 1 Background ................................................................................................................................... 2 Survey Designs and Statistical Analyses Applied to Data Collected During Jaguar Surveys, Monitoring, and Research .................................................................................................... 5 Abundance and Occurrence ........................................................................................................ 6 Species Distribution Mapping: Modeling presence-only data .................................................... 7 Logistic Regression: Modeling presence-absence data ............................................................. 10 Occupancy: Modeling detection-non-detection data................................................................. 11 Kinds of Occupancy Models ................................................................................................. 14 Capture-Recapture Models for Density Estimation Using Replicated Count Data .................. 17 Poisson -
Olvido, AE, and LS Blumer. 2005. Introduction to Mark-Recapture
This article reprinted from: Olvido, A. E., and L. S. Blumer. 2005. Introduction to mark-recapture census methods using the seed beetle, Callosobruchus maculatus. Pages 197-211, in Tested Studies for Laboratory Teaching, Volume 26 (M.A. O'Donnell, Editor). Proceedings of the 26th Workshop/Conference of the Association for Biology Laboratory Education (ABLE), 452 pages. Compilation copyright © 2005 by the Association for Biology Laboratory Education (ABLE) ISBN 1-890444-08-1 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the copyright owner. Use solely at one’s own institution with no intent for profit is excluded from the preceding copyright restriction, unless otherwise noted on the copyright notice of the individual chapter in this volume. Proper credit to this publication must be included in your laboratory outline for each use; a sample citation is given above. Upon obtaining permission or with the “sole use at one’s own institution” exclusion, ABLE strongly encourages individuals to use the exercises in this proceedings volume in their teaching program. Although the laboratory exercises in this proceedings volume have been tested and due consideration has been given to safety, individuals performing these exercises must assume all responsibilities for risk. The Association for Biology Laboratory Education (ABLE) disclaims any liability with regards to safety in connection with the use of the exercises in this volume. The focus of ABLE is to improve the undergraduate biology laboratory experience by promoting the development and dissemination of interesting, innovative, and reliable laboratory exercises.