Figure Captions
Figure 1. Posterior predictive distributions of time series
data on the winter North Atlantic Oscillation (NAO) index. The units are
based on the difference of
normalized sea
level pressure
between Lisbon, Portugal and Stykkisholmur/Reykjavík, Iceland.
Differently shaded series of data
represent different regimes. The shaded area represents the 68% central
probability interval (CPI) of the posterior predictive distribution;
thus, it includes uncertainty about the mean and the variance.
Horizontal lines in each shaded region represents the mean. M is
the minimum regime length (in years) and λ is the ‘hazard’ rate in the
change point prior, i.e., the expectation of the frequency of a regime
shift (a λ value of 20 would imply an expectation that regime shifts
occur every 20 years).
Figure 2. Posterior predictive distribution of juvenile
Atlantic cod catch rate (number of juvenile cod per beach-seine
haul). See the caption for Figure 1 for explanations of the shaded
regions of the data.
Figure 3. Posterior predictive distributions of data on the
abundance of Calanus finmarchicus as estimated from the
Continuous Plankton Recorder Survey (area C1). Data have been pooled for
the months of March through August. Keeping M constant at 10 yr,
model output is shown for λ values of (a) 10, (b) 20, (c) 25, and (d) 50
years. See the caption for Figure 1 for explanations of the shaded
regions of the data.
Figure 4. Posterior predictive distributions of data on sea
surface water temperatures measured at Flødevigen Research Station for
the months of January through December at a hazard rate (λ) of 25 years
(M = 10 years). See the caption for Figure 1 for explanations of
the shaded regions of the data.
Figure 5. Posterior predictive distributions of estimates of
instantaneous rate of fishing mortality (F ) for cod aged
2-4 yr in the North Sea. Hazard rate (λ) is 10, 20, 25, and 50
years; M is held constant at 6 years. See the caption for Figure
1 for explanations of the shaded regions of the data.
Figure 6. The timing of regime shifts in cod catch rate, NAO,
water temperature, and abundance of Calanus finmarchicus . Each
arrow identifies the beginning of a regime. The direction of the arrow
indicates the change in the mean value of the data following each regime
shift. The timing of regime shifts is shown in relation to changes in
fishing mortality and spawning stock biomass of North Sea cod (each of
which is expressed relative to its respective limit reference point; the
limit fishing mortality is 0.54, the limit spawning stock biomass is
107,000 tonnes). (a) This panel identifies regime shifts in climate and
environmental indices that do not appear to have influenced regime
shifts in cod catch rate (i.e., were not followed within 5 years by a
cod regime shift). The water temperature regime in 1988 is for January
through June; the regime shift in 2005 is for November temperatures. (b)
This panel identifies regime shifts in climate and environmental indices
that do appear to have influenced regime shifts in cod catch rate (i.e.,
were followed within 5 years by a cod regime shift). The water
temperature regime shifts are for the months of August (1994), September
(1996), July (1997), and October (1999).