Figure 1.
Map of study area and place names referred in the text.
Continental shelf marked in grey (bottom depth <250 m). Blue polygon indicates the study area. Blue bold arrow shows the Continental shelf edge axis. Red shaded area marks the area of temperature profiles.
Figure 2.
Map of average sea surface temperature in January 1990–2011 showing the relatively warm high-saline eastern Atlantic water flowing north-eastwards on and along the continental shelf edge, flanked by cooler water masses.
Temperature measurement measured by satellite and mapped with permission from Bundesamt für Seeschifffahrt und Hydrographie, Germany (www.bsh.de).
Figure 3.
Day of Year parameter in the temperature model.
Parameter estimate (solid line) with 95% confidence interval (dashed lines) and partial residuals (dots) relative to mean predicted value.
Figure 4.
CSE parameter in the temperature model.
Parameter estimate (solid line) with 95% confidence interval (dashed lines) and partial residuals (dots) relative to mean predicted value.
Figure 5.
Year parameter in the temperature model.
Parameter estimate (solid line) with 95% confidence interval (dashed lines) relative to mean predicted value.
Figure 6.
Distance from catch position to continental shelf edge (CSE) axis.
Positive values are off the shelf. In the North Sea positive values are northeast of the axis.
Figure 7.
Hovmüller plot of mackerel distributions proxies from commercial landings in October to December (left), January to March (mid) and bottom trawl surveys in March (right).
The spatial aspect have been reduced to one dimention by projecting the catch location onto the CSE axis. Greyscale in cells range in 10%-steps from 0–10% (white), to 90–100% (black). Thick line represents position of 50% cumulative landings (left, mid) or CPUE (right) and thin line shows the center of gravity of the distances.
Table 1.
Factors affecting spatiotemporal distribution of the commercial fishery in Q3–4.
Table 2.
Factors affecting spatiotemporal distribution of the commercial fishery in Q5.
Figure 8.
Relative distribution of mackerel landings from the commercial fisheries and mackerel catches from fisheries independent bottom trawl surveys.
Data from January–March are shifted back one year to match data in the same season from October–December.
Figure 9.
Mackerel distribution and temperature trends (3y rm).
Position of 50% cumulative landings in Q4 and in survey CPUE along the continental shelf edge axis (blue) and temperature around the shelf edge in the Northern North Sea from off Shetland Is. to the western edge of the Norwegian trench in November–January (red).
Table 3.
Correlation analyses between proxies for spatial patterns of the mackerel represented by Position of 50% Cumulative Landings (Po50%CL) and modeled temperature in the shelf edge current.