QI plot related to PCA factor coordinates.

<p>Each plot shows the observed QI curve (solid line), its CI (dashed lines), and the frequency histogram of the considered environmental variable. The dotted line in each plot indicates the value QI = 1. For a correct interpretation factor variables correlation relative to PCA (Tab. 5) must be considered.</p

Distribution maps (2006 year) of Chl_sat, POC, CDOM, PAR, UML thickness and BL temperature highlighting the differences in distribution patterns between the two areas.

<p>Black areas correspond to the selected ranges in each area.</p

Anchovy distribution maps in the North Aegean Sea (upper part) and in the Strait of Sicily (lower part).

<p>Symbols size is proportional to the abundance of strictly positive values, while zero values are omitted.</p

QI plots related to depth for <i>Engraulis encrasicolus</i> (left) and <i>Sardina pilchardus</i> (right) in both study areas.

<p>Each plot shows the observed QI curve (solid line), its CI (dashed lines), and the frequency histogram of depth. The dotted line in each plot indicates the value QI = 1.</p

Sardine distribution maps in the North Aegean Sea (upper part) and in the Strait of Sicily (lower part).

<p>Symbols size is proportional to the abundance of strictly positive values, while zero values are omitted.</p

Study areas and sampling design in the Strait of Sicily (A, C, E) and in the North Aegean Sea (B, D, F).

<p>Study areas and sampling design in the Strait of Sicily (A, C, E) and in the North Aegean Sea (B, D, F).</p

Quotient curves related to satellite data for <i>Engraulis encrasicolus</i> and <i>Sardina pilchardus</i> in both study areas.

<p>Each plot shows the observed QI curve (solid line), its CI (dashed lines), and the frequency histogram of the considered environmental variable. The dotted line in each plot indicates the value QI = 1.</p

Pearson correlation coefficient between bathymetry in both study areas and the considered environmental variables.

<p>Only significant values (p<0.001) are reported. ns: non significant.</p

Factor variables correlation relative to PCA carried out on the environmental variables most influencing anchovy and sardine population.

<p>The analysis was performed separately on each area in order to maximize the comprehension of environmental process affecting each area. Values in bold represent the variables most related to each PCA axis.</p

Median values of the <i>in situ</i> and satellite variables in the two study areas.

<p>Median values of the <i>in situ</i> and satellite variables in the two study areas.</p