3.3 δ13CEAA fingerprints
across Baltic regions
The δ13CEAA fingerprints of clupeids
from the four Baltic Sea regions show region-specific clustering of most
herring and sprat specimens (Fig. 5A and 5B). The separation was
stronger for herring (Pillai’s Trace = 1.05, F6,32 =
5.9; P < 0.001) than for sprat (Pillai’s Trace = 0.90,
F6,32 = 4.4; P < 0.01) due to larger principal
component variability of the Arkona Basin specimens. The region-specific
separation becomes weaker when joining the two clupeid species (see Fig.
S1). To assess how ontogentic factors may have influenced the observed
δ13CEAA fingerprints, we incorporated
mass of individual specimens as a covariate using MANCOVA. The
significance of these tests are practically similar to those obtained
with MANOVA for both herring (Pillai’s Trace = 1.06,
F6,30 = 5.6; P < 0.001) and sprat (Pillai’s
Trace = 0.94, F6,30 = 4.4; P < 0.01).