AGE DETERMINATION OF ANGUILLA ANGUILLA (L) AND RELATED SPECIES
	CONTENTS

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MARKING AND TAGGING METHODS APPLIED TO EEL, ANGUILLA ANGUILLA (L.)

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PREPARATION OF THIS DOCUMENT

These two reviews were presented at the meeting of the EIFAC Working Party on Eel in Bristol (UK) 1988. Thereafter they were finalized for publication.

The Ministry of Agriculture and Fisheries -the Netherlands- kindly offered to print the report.

AGE DETERMINATION OF ANGUILLA ANGUILLA (L.) AND RELATED SPECIES

LEIF ASBJØRN VØLLESTAD

Østfold County, Environmental Administration, Moss, Norway, and Department of Biology, University of Oslo, Oslo, Norway.

RAYMONDE LECOMTE-FINIGER

Universite de Perpignan, Laboratoire de biologie Marine, Perpignan Cedex, France

BERT STEINMETZ

Ministry of Agriculture and Fisheries, Directorate of Fisheries, The Hague, The Netherlands.

ABSTRACT

This report presents a description and discussion of the different methods used in eel ageing studies during the last decade. Four main types of techniques are used: 1) grinding or slicing; 2) burning and cracking; 3) clearing of whole otoliths in alcohol; and 4) methods using advanced technology. Grinding and slicing is the most common with almost all institutes introducing their own modification of the general method. In very few cases has the validity of the method been documented. The available evidence indicate that burning and cracking give a good approximation of true age. This method has proved to be accurate in a number of tests. Other method have proved useful in specific cases, but further studies are necessary.

FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS Rome 1988
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CONTENTS

1.   INTRODUCTION

2.   DEFINITIONS

3.   DESCRIPTION OF METHODS

3.1   Grinding and sliceing

3.2   Burning and cracking

3.3   Whole otoliths

4.   COMPARISON OF METHODS

5.   DISCUSSION

6.   CONCLUSIONS

7.   ACKNOWLEDGMENTS

8.   REFERENCES

Introduction

Marking

Tagging

Conclusions and recommandations