Supplementary material.Model fits to data.
S2.1. Model fit to landings data (in ‘000s of tonnes) for ages 1 to 6. Points show observed values, the blue line the fitted values and the blue shading shows the 95% credible interval.
S2.2. Model fit to discard data (in ‘000s of tonnes) for ages 1-2. Points show observed values, the blue line the fitted values and the blue shading shows the 95% credible interval. The poor fit to the age 2 data reflects the small but highly variable number of fish discarded at this age.
S2.3. Model fit to combined landings and discards for recent years S2.1. Points show observed values, the blue line the fitted values and the blue shading shows the 95% credible interval.
S2.4.Model fit to Scottish quarter 1 survey.S2.1. Points show observed values, the blue line the fitted values and the blue shading shows the 95% credible interval. Intermediate ages are fit best as they are sampled more consistently than young ages while older ages are subject to small sample sizes.
S2.5. Model fit to Scottish quarter 4 survey. Points show observed values, the blue line the fitted values and the blue shading shows the 95% credible interval. Intermediate ages are fit best as they are sampled more consistently than young ages while older ages are subject to small sample sizes.
S2.6. Model fit to Irish survey. Points show observed values, the blue line the fitted values and the blue shading shows the 95% credible interval. Overall fit to this survey is poorer than the Scottish surveys as sample sizes are much smaller. Because the negative log likelihood component of surveys that are less well fit is small relative to the better surveys they contribute less weight to the estimates of stock size etc.
S2.7. Model fit to seal catch compositions in two years of sampling. Points show observed values, the blue line the fitted values and the blue shading shows the 95% credible interval.
S2.8. Model fit to total seal consumption. Points show sampled values in 1985 and 2002 while the line shows the median fitted value. Shaded area is the 95% credible interval.
S2.9. Model estimates of seal attack rate, q, over time. Line shows the median and the shaded area the 95% credible interval.
S2.10. Model estimates of misreported catch (in tonnes) compared to ICES estimates. In some years reported catches are believed to be biased low as a result of catch restrictions. The model uses survey data to try to impute “missing” catch. The ICES estimates of misreported catch are not included in the model and therefore offer an external check of consistency. Overall the model estimates are close to the ICES estimates.