GUIDELINES FOR SAMPLING FISH IN INLAND WATERS |
EIFAC Technical Paper No. 33 | EIFAC/T33 |
edited by
Tadeusz Backiel | Robin L. Welcomme |
Inland Fisheries Institute | Senior Fishery Resources Officer |
05 500 Piaseczno | Fisheries Department, FAO |
Poland | Rome, Italy |
FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS
Rome 1980
The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Food and Agriculture Organization of the United Nations concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries.
M-43
ISBN 92-5-100973-2
The copyright in this book is vested in the Food and Agriculture Organization of the United Nations. The book may not be reproduced, in whole or in part, by any method or process, without written permission from the copyright holder. Applications for such permission, with a statement of the purpose and extent of the reproduction desired, should be addressed to the Director, Publications Division, Food and Agriculture Organization of the United Nations, Via delle Terme di Caracalla, 00100 Rome, Italy.
PREPARATION OF THIS DOCUMENT
The European Inland Fisheries Advisory Commission (EIFAC) is a regional commission of the Food and Agriculture Organization of the United Nations (FAO). The Commission organized a symposium on methodology for the survey, monitoring and appraisal of fishery resources in lakes and large rivers, which preceded its Eighth Session held from 6 to 10 May 1974. The Symposium1 reviewed a wide variety of methods used in sampling fish in inland waters and it was considered that the information on these methods can form the basis for a manual on sampling methodology. Thus, the Eighth Session of EIFAC recommended that a manual be prepared and Dr. T. Backiel was appointed to coordinate the work.
After preliminary discussions an outline of the manual was prepared and circulated among about 20 experts in March-April 1975, but due to various circumstances a considerable time elapsed between the submission of the first contribution, which was received by the Coordinator in October 1976, and the last, requested rather late to fill a gap, which came in November 1978.
The content of all contributions differed from what was originally envisaged. Thus, the manual has been entitled “Guidelines” to indicate that the work is not so extensive in scope and not so thorough in its content as a manual should be.
At the Eighth Session of EIFAC in 1974, another recommendation was formulated which is closely related to that on the manual. It was suggested that due to current lack of information of gears relative to the population sampled or to other methods of sampling the same population, “… the member countries be invited to carry out test fishing for intercalibration of various gears”. The then Chairman of EIFAC, Prof. Dr. K. Tiews, took the initiative in organizing an intercalibration exercise, having taken advantage of the generous offer of the Finnish delegates to make three lakes available for such an international venture. After some discussions and planning and after considerable preparatory work done by the Finnish experts and with the help of German (R.F.) specialists the exercise was performed from 23 August to 4 September 1976. The analysis of the great amount of data collected therefrom was entrusted to Dr. T.B. Bagenal (U.K.). The results of this experiment have not been incorporated into these guidelines, but it is highly recommended that the reader of this work acquaint himself with these results.
Editors: T. Backiel
R. Welcomme
For bibliographic purposes this document should be cited as follows:
Backiel, T. and R.L. Welcomme (eds), Guidelines for sampling fish in inland waters. EIFAC 1980 Tech.Pap., (33):176 p.
© FAO 1980
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1.2 Sampling fish and using commercial or sport catches
1.3 Evaluation of sampling techniques
2. GENERAL CONCEPTS OF SAMPLING FISH
2.2.1 Objectives - qualitative and semi-quantitative information
3. SAMPLING EGGS, LARVAE AND JUVENILE FISH
3.3 The spawning behaviour and habitats of fish
3.5.1 Distribution of fish larvae in inland waters
3.7 Notes on methods used by marine biologists
3.8 Notes on accuracy and precision
4.1.2 Each mesh size catches fish of a narrow size range
4.1.3 Larger-meshed nets are more efficient
4.1.4 When many mesh sizes are used, adequate samples are difficult to obtain
4.4 Epilogue: The need for more selectivity studies
5.2 Permanent and semi-permament traps used for catching migrating fish
5.2.4 Some general conclusions
5.3 Portable traps mainly used for resident species
5.3.1 Trap nets and pound nets
5.3.3 Other small entrapment devices
5.3.5 Some general conclusions
6.3.1 Where trawls can be used
6.3.2 Main difference between bottom and midwater trawls
6.5 General limitations, selectivity and efficiency of active gears
7. THE USE OF ELECTRICAL FISHING FOR ESTIMATING STOCKS OF FRESHWATER FISH
7.3.2 Behavioural considerations
8.3.2 Standing waters - cove sampling
8.3.3 Standing waters - complete poisoning
8.4 Recovery of fish and efficiency of sampling
8.5 Consequences of use of poisons
8.7 Relative merits of the use of poisons
9.2 Some elementary hydroacoustic relationships
9.4 The field data acquisition systems
9.5.1 Visual counting of fish targets on echograms
9.5.3 Computer processing of fish signals
9.6 Applications and sampling strategy
9.7 Other techniques and future development
9.8 References and relevant literature
10.2 Use of upstream fish passage facilities
10.3 Use of downstream fish passage facilities
10.4 Use of sampling traps and fish weirs
10.5 Use of acoustic, radio telemetry and coded wire microtags
11.2 Sampling upstream-migrating small eels
11.3 The behaviour and sampling of adult eels
11.4 A review of fishing gears
11.4.13 Poisoning or chemical stunning
12. SOME STATISTICAL CONSIDERATIONS IN RELATION TO SAMPLING POPULATIONS OF FISHES
12.2 Biological and statistical populations
12.3 Sources of variation among samples
12.4 On selection of a sampling programme
12.4.2 Estimates of probable variance
12.4.3 Other problems of experimental design
12.5.1 The selectivity of sampling gears
12.5.2 Stratification to improve homogeneity
12.5.3 Patchiness and other kinds of inhomogeneity in space or time