by
Per Sparre
Danish Institute for Fisheries Research
Charlottenlund, Denmarkand
Siebren C. Venema
Project Manager
FAO Fisheries Department
FAO FISHERIES TECHNICAL PAPER 306/1 Rev. 2
INTERNATIONAL YEAR OF THE OCEAN '98
DANIDA
Food and Agriculture Organization of the United Nations
FAO - FIAT PANIS
Rome, 1998
|
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 92-5-103996-8
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 or otherwise, without the prior permission of the copyright owner. Applications for such permission, with a statement of the purpose and extent of the reproduction, should be addressed to the Director, Information Division, Food and Agriculture Organization of the United Nations, Viale delle Terme di Caracalla, 00100 Rome, Italy.
© FAO 1998
This electronic document has been scanned using optical character recognition (OCR) software and careful manual recorrection. Even if the quality of digitalisation is high, the FAO declines all responsibility for any discrepancies that may exist between the present document and its original printed version.
1.1 THE PRIMARY OBJECTIVE OF FISH STOCK ASSESSMENT
1.2 THE STOCK CONCEPT
1.3 MODELS
1.3.1 Analytical models
1.3.2 Holistic models1.4 ASSESSMENT OF STOCKS IN TROPICAL WATERS
1.5 DEFINITIONS OF BODY LENGTH
1.6 AGE AND RECRUITMENT
1.7 THE UNDERLYING ASSUMPTION OF RANDOM SAMPLES
1.8 THE ORGANIZATION OF THE MANUAL
1.9 FURTHER READING
2.1 MEAN VALUE AND VARIANCE
2.2 THE NORMAL DISTRIBUTION
2.3 CONFIDENCE LIMITS
2.4 ORDINARY LINEAR REGRESSION ANALYSIS
2.5 THE CORRELATION COEFFICIENT AND FUNCTIONAL REGRESSION
2.6 LINEAR TRANSFORMATIONS
3. ESTIMATION OF GROWTH PARAMETERS
3.1 THE VON BERTALANFFY GROWTH EQUATION
3.1.1 Variability and applicability of growth parameters
3.1.2 The weight-based von Bertalanffy growth equation3.2 INPUT DATA FOR THE VON BERTALANFFY GROWTH EQUATION
3.2.1 Data from age readings and length measurements
3.2.2 Length composition data (without age compositions)
3.2.3 Data from commercial catches3.3 METHODS FOR ESTIMATION OF GROWTH PARAMETERS FROM LENGTH-AT-AGE DATA
3.3.1 The Gulland and Holt plot
3.3.2 The Ford-Walford plot and Chapman's method
3.3.3 The von Bertalanffy plot
3.3.4 The least squares method3.4 ESTIMATION OF AGE COMPOSITION FROM LENGTH-FREQUENCIES
3.4.1 Bhattacharya's method
3.4.2 Modal progression analysis
3.4.3 The probability paper and parabola methods3.5 FITTING GROWTH CURVES BY MEANS OF COMPUTER PROGRAMS
3.5.1 ELEFAN I
3.5.2 The seasonalized von Bertalanffy growth equation
3.5.3 Maximum likelihood methods
3.5.4 Limitations of length-frequency analysis
4. ESTIMATION OF MORTALITY RATES
4.1 THE CONCEPT OF A COHORT AND SOME BASIC NOTATION
4.2 THE DYNAMICS OF A COHORT, THE EXPONENTIAL DECAY MODEL
4.3 ESTIMATION OF Z FROM CATCH PER UNIT OF EFFORT DATA AND THE CONCEPT OF THE CATCHABILITY COEFFICIENT4.3.1 Heincke's method
4.3.2 Robson and Chapman's method4.4 ESTIMATION OF Z FROM A LINEARIZED CATCH CURVE
4.4.1 The constant parameter system
4.4.2 The linearized catch curve equation
4.4.3 The linearized catch curve based on age composition data
4.4.4 The linearized catch curve based on age compositions with variable time intervals
4.4.5 The linearized catch curve based on length composition data
4.4.6 The cumulated catch curve based on length composition data. (The Jones and van Zalinge method)
4.4.7 Summary of the linearized catch curve methods4.5 BEVERTON AND HOLT'S Z-EQUATIONS
4.5.1 Beverton and Holt's Z-equation based on length data
4.5.2 Beverton and Holt's Z-equation based on age data
4.5.3 Beverton and Holt's Z-equation based on length-at-first-capture
4.5.4 The Powell-Wetherall method4.6 A PLOT OF Z ON EFFORT FOR SEPARATE ESTIMATES OF F AND M
4.7 NATURAL MORTALITY4.7.1 Natural mortality and longevity
4.7.2 Pauly's empirical formula
4.7.3 Rikhter and Efanov's formula
5.1 VIRTUAL POPULATION ANALYSIS (VPA)
5.2 AGE-BASED COHORT ANALYSIS (POPE'S COHORT ANALYSIS)
5.3 JONES' LENGTH-BASED COHORT ANALYSIS
5.4 THE SLICING TECHNIQUE
6.1 ESTIMATION OF TRAWL NET SELECTION
6.2 ESTIMATION OF GILL NET SELECTION6.2.1 Symmetrical selection curves
6.2.2 The product of two logistic curves6.3 DISCUSSION OF SELECTION BY OTHER GEARS
6.4 OTHER ASPECTS OF GEAR SELECTIVITY6.4.1 Knife-edge selection
6.4.2 Recruitment and selectivity
6.4.3 Selectivity as a function of age6.5 ESTIMATION OF THE RESULTANT OGIVE FROM A CATCH CURVE
6.6 GEAR SELECTIVITY AND VPA METHODS6.6.1 Gear selectivity and fishing mortality
6.6.2 Estimation of selection curves from cohort analysis6.7 USING A SELECTION CURVE TO ADJUST LENGTH-FREQUENCY SAMPLES
7.1 SIMPLE RANDOM SAMPLING
7.2 STRATIFIED RANDOM SAMPLING
7.3 PROPORTIONAL SAMPLING
7.4 SAMPLING COMMERCIAL CATCHES
7.5 ESTIMATION OF THE TOTAL CATCH IN WEIGHT OF A CERTAIN SPECIES
7.6 ESTIMATION OF THE LENGTH COMPOSITION OF A CERTAIN SPECIES IN THE TOTAL CATCH
8.1 ASSUMPTIONS AND MODELS UNDERLYING THE YIELD PER RECRUIT MODEL OF BEVERTON AND HOLT
8.2 BEVERTON AND HOLT'S YIELD PER RECRUIT MODEL
8.3 BEVERTON AND HOLT'S BIOMASS PER RECRUIT MODEL
8.4 BEVERTON AND HOLT'S RELATIVE YIELD PER RECRUIT MODEL
8.5 YIELD PER RECRUIT FROM LENGTH DATA
8.6 AGE-BASED THOMPSON AND BELL MODEL
8.7 LENGTH-BASED THOMPSON AND BELL MODEL
8.8 PREDICTION OF THE EFFECTS OF CHANGES OF MESH SIZES USING THE THOMPSON AND BELL METHOD
9. ESTIMATION OF MAXIMUM SUSTAINABLE YIELD USING SURPLUS PRODUCTION MODELS
9.1 THE SCHAEFER AND FOX MODELS
9.2 GULLAND'S FORMULA
9.3 CADIMA'S FORMULA
9.4 MSY ESTIMATORS BASED ON THE SURPLUS PRODUCTION MODEL9.4.1 Validation of estimates of MSY based on empirical formulas
9.5 MUNRO AND THOMPSON PLOT
9.6 STANDARDIZATION OF EFFORT
9.7 THE DERISO/SCHNUTE DELAY DIFFERENCE MODEL
10. MULTISPECIES/MULTIFLEET PROBLEMS
10.1 SURPLUS PRODUCTION MODELS APPLIED TO MULTISPECIES/MULTIFLEET SYSTEMS
10.2 BIOLOGICAL INTERACTION
10.3 ECONOMIC INTERACTION
10.4 TECHNICAL INTERACTION10.4.1 A yield per recruit model for mixed fisheries
10.4.2 Assessment of mixed fisheries based on length-frequency data
10.4.3 Multifleet mixed fisheries
11. ASSESSMENT OF MIGRATORY STOCKS
11.1 THE CONCEPT AND STUDY OF MIGRATION
11.2 BIAS CAUSED BY MIGRATION
11.3 THE ANNUAL-RETURN MATCHED SAMPLES METHOD11.3.1 Estimation of growth parameters by the annual-return matched samples method
11.4 THE GENERAL MATCHED SAMPLES METHOD
11.5 ASSESSMENT BASED ON TAGGING DATA
11.6 ESTIMATION OF THE GROWTH PARAMETERS OF A MIGRATORY STOCK: THE ATLANTIC MACKEREL
12. THE STOCK/RECRUITMENT RELATIONSHIP
12.1 CLASSICAL S/R CONSIDERATIONS
12.2 THE STABILITY OF RECRUITMENT
12.3 TOWARDS MODELLING RECRUITMENT
13.1 THE BOTTOM TRAWL
13.2 PLANNING A DEMERSAL TRAWL SURVEY
13.3 DATA RECORDING
13.4 DECK SAMPLING AND CATCH RECORDING PROCEDURES
13.5 THE SWEPT AREA
13.6 BIOMASS ESTIMATION BY THE SWEPT AREA METHOD
13.7 PRECISION OF THE ESTIMATE OF BIOMASS
13.8 ESTIMATION OF MAXIMUM SUSTAINABLE YIELD
14. SUMMARY OF FISH STOCK ASSESSMENT
14.1 GENERAL ASPECTS OF FISH STOCK ASSESSMENT
14.2 REVIEW OF METHODS TO BE USED ACCORDING TO THE TYPE OF DATA AVAILABLE
15. MICROCOMPUTER PROGRAM PACKAGES
15.1 THE LFSA PACKAGE
15.1.1 Length-frequency (LF) programs
15.1.2 Age/length analysis: estimation of growth parameters from age/length data
15.1.3 Miscellaneous programs15.2 THE COMPLEAT ELEFAN PACKAGE
15.3 THE FiSAT PACKAGE
15.4 OTHER FISH STOCK ASSESSMENT PROGRAMS PRODUCED BY FAO15.4.1 The ANACO package
15.4.2 The ANALEN package
15.4.3 BEAM 1 and BEAM 2
15.4.4 BEAM 3
15.4.5 BEAM 4
15.4.6 The NAN-SIS package
15.4.7 CLIMPROD
TABLE A1 - LIST OF IMPORTANT FORMULAS
TABLE A2 - METHODS BASED ON LINEAR TRANSFORMATIONS AND ORDINARY LINEAR REGRESSION ANALYSIS: y = a + b*x
TABLE A3 - IMPORTANT DATES EXPRESSED AS FRACTIONS OF A YEAR FROM 1 JANUARY
TABLE A4 - FRACTILES OF THE t-DISTRIBUTION (STUDENT'S DISTRIBUTION)