Figure 3
Breakpoints in Western Baltic cod stock functioning. (a) Apparent hysteresis in the relationship between spawning stock biomass (SSB) and fishing mortality (F); red vertical and horizontal lines indicate biomass reference level Blim and fishing mortality (F) reference point FMSY; vertical grey shaded area represents F management range. (b) Effect of scaled exploitation pressure, i.e. fishing mortality relative to recruitment (R, i.e. year-class strength at age 1) on SSB; horizontal line indicates biomass reference level Blim; black dashed line indicates alternative linear model (fitted to the data excluding 2007 and 2015 considered as outliers). (c) Effect of SSB on R; red vertical and horizontal lines indicate biomass reference level Blim. (d) Effect of sea surface temperature (SST) on R. (e) Effect of SSB on productivity (R/SSB). (f) Effect of SST on productivity; black dashed line indicates alternative spline model. Coloured points and lines indicate regime-dependent linear models from breakpoint analysis.
