Ecological consequences of biological invasions: three invertebrate case studies in the north-eastern Baltic Sea

Table 1 Statistics of fish samples where at least one fish contained Cercopagis pengoi in the stomach

	L _min with Cerc.	L _mean with Cerc.	L _mean without Cerc.	Difference^b	Percentage of fish with Cerc. in stomach	Percentage of Cerc. in stomach (wet wt.)	N
Herring (1+)		14.0	13.3	P<0.05	53.6	45.7	256
0-Group	4.1	5.2	5.1	NS	7.7	1.4	40
Larvae^a	2.2
Smelt (1+)		13.1	10.5	P<0.001	25.0	40.8	78
0-Group	7.3	8.1	7.9	NS	33.3	33.7	60
3-Spined stickleback	4.1	5.0	5.3	P<0.05	25.0	26.9	94
9-Spined stickleback	3.4	4.3	5.0	P<0.001	51.1	44.7	60
Bleak	6.2	9.8	10.2	NS	93.4	85.7	70

Samples collected in the main feeding areas of the Gulf of Riga during the main feeding period (June–September) in 1994–1998. Fish length (total length, L) is given in centimetre
^aSingle finding of Cercopagis pengoi in the larval fish intestine in Pärnu Bay (NE Gulf of Riga) in 2004
^bDifference between the mean length of fish with and without Cercopagis pengoi in stomach (P significance level, NS not significant)

ISSN: 1438-3888