Life History Tactics in Cohorts of a Partial Migratory Brown Trout (Salmo trutta L.) Population

Table 1

Summary of Kruskal-Wallis analyses, testing for the effect of tactic on body mass for three separate cohorts (termed Co A, Co B, and Co C) of brown trout monitored from 2001 to 2003 in Greåna River. 𝑁 is shown for the number of females and immature males (Fe+Im), number that migrated 2002 (Mig 02), 2003 (Mig 03), males maturing in 2001 (Mmale 01), 2002 (Mmale 02), and 2003 (Mmale 03). If total 𝑁<10, no Kruskal-Wallis test was conducted. A graphic illustration of changes in body mass over time is given in Figure 2.

No.	Cohort	Year	Month	Age	N							Kruskal-Wallis test
					Fe + Im	Mig 02	Mig 03	Mmale 01	Mmale 02	Mmale 03	Total	𝑋^2	𝑃
1	Co A	2001	Sep	0+	534	0	2	0	3	2	541	6.9	0.080
2	Co A	2001	Oct	0+	188	0	0	0	5	2	195	9.5	0.008
3	Co A	2002	May	1+	271	0	0	0	8	3	282	1.1	0.590
4	Co A	2002	Sep	1+	149	—	5	0	8	4	166	21.5	<0.001
5	Co A	2002	Oct	1+	147	—	4	0	9	6	166	21.0	<0.001
6	Co A	2003	May	2+	27	—	5	0	0	1	35	5.3	0.021
7	Co A	2003	Sep	2+	39	—	—	0	0	4	43	9.1	0.003
8	Co A	2003	Oct	2+	51	—	—	0	0	11	62	8.0	0.005
1	Co B	2001	Sep	1+	166	6	2	2	3	0	179	14.5	<0.006
2	Co B	2001	Oct	1+	102	6	4	2	2	0	116	18.2	0.001
3	Co B	2002	May	2+	100	20	9	0	7	0	136	27.2	<0.001
4	Co B	2002	Sep	2+	31	—	9	0	8	0	48	7.4	0.025
5	Co B	2002	Oct	2+	43	—	9	0	9	0	61	12.7	0.002
6	Co B	2003	May	3+	12	—	14	2	3	2	33	8.3	0.011
7	Co B	2003	Sep	3+	4	—	—	1	0	1	6	—	—
8	Co B	2003	Oct	3+	4	—	—	0	2	3	9	—	—
1	Co C	2001	Sep	2+	41	6	0	5	2	0	54	11.4	0.010
2	Co C	2001	Oct	2+	23	12	0	3	1	0	39	9.7	0.021
3	Co C	2002	May	3+	26	23	0	0	4	0	53	22.7	<0.001
4	Co C	2002	Sep	3+	16	—	0	0	5	0	21	2.5	0.066
5	Co C	2002	Oct	3+	15	—	0	0	7	0	22	6.3	0.012
6	Co C	2003	May	>3+	2	—	0	0	0	0	2	—	—
7	Co C	2003	Sep	>3+	4	—	0	0	0	1	5	—	—
8	Co C	2003	Oct	>3+	3	—	0	1	0	0	4	—	—