Fig 1.
Flowchart depicting the main steps of the simulation procedure used in the present study.
Fig 2.
Estimated catch comparison and catch ratio curves (solid black line) and 95% confidence intervals (broken black lines) for cod (A and B, respectively), and for Norway lobster (C and D, respectively). Dotted grey lines represent when both gears are fishing equally efficient. Grey solid lines in A and C represents the catch length structure for cod and Norway lobster, respectively.
Fig 3.
Effect of sample size on catch ratio confidence intervals (grey band) per length class for cod (40, 65, 90 cm).
The confidence intervals shown in fig A to C are for the observed catch structure and from D to F are for the uniform catch structure scenario. The solid black line and the dotted grey line define for a specific length class the original catch ratio and when both gears are fishing equally efficient (catch ratio equal to 1), respectively.
Fig 4.
Effect of sample size on catch ratio confidence intervals (grey band) per length class for Norway lobster (35, 45, 65 mm).
The confidence intervals shown in fig A to C are for the observed catch structure and from D to F are for the uniform catch structure scenario. The solid black line and the dotted grey line define for a specific length class the original catch ratio and when both gears are fishing equally efficient (catch ratio equal to 1), respectively.
Table 1.
Power model parameters (a and b from equation 6) for the relative uncertainties and goodness of fit per sampling level, length class, species, and catch length structure.
Coefficient of determination (R2) represents the quality of the fit and ranges from 0 to 1, where 1 is a perfect fit.
Fig 5.
Cod uncertainty curves for the observed catch structure (A) and uniform catch structure (B); and decrease in relative uncertainty when sampling 100 more individuals for the observed catch structure (C) and uniform catch structure (D). Points in fig A and B represent the observed relative uncertainties.
Fig 6.
Norway lobster uncertainty curves for the observed catch structure (A) and uniform catch structure (B); and decrease in relative uncertainty when sampling 100 more individuals for the observed catch structure (C) and uniform catch structure (D). Points in fig A and B represent the observed relative uncertainties.
Table 2.
The number of individuals sampled and the associated decrease in uncertainty when measuring 100 more individuals.
Mean values for all length classes considered and their respective standard deviations (in parenthesis) are presented.