Table 5. Size trends: most important taxa characterizing groups ‘I’,‘D’ and‘S’ by SIMPER analysis.

GROUP	Taxon	Average frequency of occurrence	Contribution (%)	Cumulative Sum (%)
D	T. min. capelanus	0.273	10.01	10.01
	Scorpaena spp.	0.154	8.29	18.30
	S. vulgaris	0.070	7.07	25.37
	P. erythrinus	0.070	7.07	32.44
	M. merluccius	0.149	5.80	38.24
S	S. cretense	0.125	4.71	4.71
	M. surmuletus	0.160	4.60	9.31
	Loligo spp.	0.082	4.16	13.47
	S. officinalis	0.069	4.10	17.57
	S. mantis	0.102	4.01	21.58
I	S. pilchardus	0.964	18.83	18.83
	P. erythrinus	0.497	14.21	33.04
	P. kerathurus	0.300	8.69	41.73
	A. antennatus	0.235	7.32	49.05
	Mullus spp.	0.688	6.64	55.69

The fish taxa are listed in decreasing order of their importance in typifying the groups ‘INCREASE’ (‘I’), ‘DECREASE’ (‘D’) and‘STABLE’ (‘S’) by SIMPER analysis performed on presence/absence data. Cut off for low contributions: 90.00%. ‘I’ vs‘D’ overall between group dissimilarity 76.85; ‘D’ vs‘S’ overall between group dissimilarity 73.81; ‘S’ vs‘I’ overall between group dissimilarity 76.96