FMS Products
Earliest References to Age Determination
of Fishes and Their Early Application
to the Study of Fisheries
James R. Jackson, Department of Natural Resources, Cornell University
An article originally published in Fisheries (2007), Volume 32, Number 7 [reprinted with permission from AFS].
Abstract: Age data are routinely used in fish population studies today. While
various works have touched upon aspects of the history of fish aging techniques,
there does not appear to be a single source that attempts to summarize the earliest
literature on age determination of fishes in a broad historical context. The Fisheries
Management Section formed the ad hoc Assessment of Fish Aging Techniques
Committee in 2006, with development of such a review as a goal. The earliest
references to rings on the hard structures of fish by Leeuwenhoek and Hederström
date to the seventeenth and eighteenth centuries. Scientific validation of annuli on
the scales of fish did not take place until the late 1800s, with the work of Hintze and
Hoffbauer. The work of Reibisch on otoliths and Heincke with other hard structures
quickly followed. These later studies on fish aging techniques came at a time when
large-scale studies of fish populations were gaining momentum. While the new aging
methods were adopted rapidly by many fisheries workers, debates about their validity
were not uncommon. A notable example took place between Hjort and Thompson,
centering on Thompson’s doubts concerning the validity of scale-based ages in
Hjort’s seminal 1914 paper.
Current Status and Review of Freshwater Fish Aging
Procedures Used by State and Provincial Fisheries
Agencies with Recommendations for Future Directions
Michael J. Maceina, Jeff Boxrucker, David L. Buckmeier, R. Scott Gangl, David O. Lucchesi,
Daniel A. Isermann, James R. Jackson, and Patrick J. Martinez
An article originally published in Fisheries (2007), Volume 32, Number 7
[reprinted with permission from AFS].
Abstract: In 2006, the Fisheries Management Section of the American Fisheries Society formed the ad hoc Assessment of Fish Aging
Techniques Committee to assess the current status of aging freshwater fish in North America. For seven species groups that included black
bass (Micropterus spp.), crappie/sunfish (Pomoxis spp./Lepomis spp.), catfish (Ictaluridae), morinids, percids, salmonids, and esocids, a survey of
U.S. and Canadian fisheries agencies (N = 51 agencies responding) revealed that scales, otoliths, and spines were the most common structures
used to age fish. Latitudinal clines existed for some of the structures that were examined, with scales typically used more in northern latitudes
than otoliths. Many agencies conducted some validation of age estimation techniques and most assessed precision at least for some of the age
samples collected. Providing personnel with training to age fish was common. Reasons for the structures used and the types of inferences and
information generated from age data were reported. Scales were the most common structure used to age esocids, black bass, crappie/sunfish,
and moronids, but only 27% of all respondents felt that scales accurately aged fish to the maximum age. Alternatively, most agencies felt that
otoliths provided accurate estimates. From a review of published papers, otoliths were more accurate when compared to other aging structures
and showed higher precision. Most agencies conducted back-calculation of lengths from annuli that provided additional information on
growth, even though back-calculation procedures contain complex and inconsistent interpretation and computation issues. Currently, many
studies are being conducted where known-age fish were chemically or physically marked, stocked, then recaptured after a number of years
which can furnish data for age validation. Recommendations include the development of a known-age reference database to allow sharing of
information, publication of validation studies, and careful considerations for conducting back-calculation of lengths from presumed annuli.
Power and Sample Size Estimation Techniques for Fisheries Management: Assessment and a New Computational Tool
Kenneth G. Gerow, Department of Statistics, University of Wyoming
Abstract: Formulae for sample size calculations in the literature are often predicated on unrealistic assumptions (e.g. equal variances) or unrealistic, or simply undesirable, designs (two independent samples of the same size). In addition, sample size and power calculations usually involve repeated use of any given formula, as the researcher works through varying inputs (alpha, power choices, design choices, etcetera), making the process of considering sample size and power issues unpleasantly tedious and error-prone. I survey formulae currently in the fisheries literature, describing deficiencies. I then discuss sample size formulae that correct these deficiencies, and describe a freely available Excel tool that enables the calculations.
“Dilemma” and “Epilogue”
Robert W. Wiley, retired, Wyoming Game and Fish Department
An article originally published in Fisheries (1987), Volume 12, Number 6
[reprinted with permission from AFS], with an epilogue added in 2006.
Trout Stocking Rates: A Wyoming Perspective
Robert W. Wiley, Fisheries Biologist, Retired, Wyoming Game and Fish Department
Trends in Agency Use of Propagated Fishes as a Management
Tool in Inland Fisheries
James Jackson, Jeff Boxrucker, and David Willis
An overview paper presented at the Propagated Fishes in Resource Management meeting in 2003.
Fisheries Management Section Brochure
A three-page brochure describing the history, objectives, and information needed to join the AFS Fisheries Management Section.
Burbot: Biology, Ecology and Management
Publication Number 1, Fisheries Management Section, American Fisheries Society V.L. Paragamian and D.W. Willis, editors.
Fish Sampling and Data Analysis Techniques Used by Conservation Agencies in the U. S. and Canada
Fisheries Techniques Standardization Committee
In 1985-86, the Fisheries Techniques Standardization Committee of the Management Section, American Fisheries Society conducted a survey to determine how conservation agencies In the U.S. and Canada routinely sampled 15 sport fish in four water types (lakes and Impoundments less than 500 acres, lakes and impoundments 500 acres and larger, streams, and rivers). Data analysis techniques were also surveyed. This document summarizes findings of the survey and provides a reference to fish sampling and data analysis techniques used by conservation agencies in the U.S. and Canada.
During the fall of 1983, the Management Section of the American Fisheries Society established as one of its objectives, "Promoting sound fisheries management practices and developing new management concepts and techniques." One of three tasks Identified to accomplish this objective was to, "Establish a committee to review fisheries data collection and analysis techniques and explore feasibility of standardizing techniques." In 1984, Individuals from the U.S. and Canada volunteered to be members of this committee.
The first activity of the Fisheries Techniques Standardization Committee was to develop a survey that sought information on how conservation agencies in the U.S. and Canada collected and analyzed data for 15 sport fish in four water types. Results of the survey are the subject of this report. This report is intended to have at least two values. First, it identifies states and provinces that shared the use of common techniques. This will hopefully facilitate communication among agencies regarding comparative results. Secondly, this report will allow conservation agencies to compare their techniques with those of their neighbors and even with those used by others in more distant geographical areas. Environmental conditions dictate appropriate sampling and analysis techniques; however, data Interpretation would be enhanced if techniques were standardized over the broadest geographic areas possible. This report is intended to help stimulate such action.