1. CONSEQUENCES RELATED TO THE CHOICE OF BIOLOGICAL PARAMETERS
Stock assessment
CONSEQUENCES RELATED TO THE CHOICE OF BIOLOGICAL PARAMETERS
A.Abella ARPAT-Livorno, Italy

2. age
Size
age N

3. Biomass T*

4. FAST
GROWING

5. SLOW
GROWING

6. …what happens when we use different growth parameters and M, but “consistent” among them? Is the perception of the current situation similar?
M from Pauly’s equation (1980)

7. 1/2 max
1/8 max
30% SSBo
10%
SSBo

8. Assessment di Merluccius merluccius inTuscany (multigear fishery)

9. M variabile
M costante
Lower numbers by size
Major proportion removed

10. variable M
costant M
Different contribution of each single gear to F by size

11. variable M
costant M

12. Mortality estimates keeping lenght frequencies separated by sex

13. Estimation of Z with length converted catch curve

14. By sex
merged

15. M F
Total
Data structured by age
Simulated data>>>

16. Males
Females

18. with SURBA the same overestimation will occur...

19. Size of first maturity