Table 2.

Focusing within areas, harbour porpoise mass is still predicted by the presence and absence of bottlenose dolphin ‘predation’ (see values in italics) around (a) Scotland (N=299, adjusted R²=0.82) and (b) the North Sea (N=408, adjusted R²=0.80). (GLM of factors predicting mass variation, dependent variable is body mass. Parameter estimates given are for mortality other than physical trauma (fixed factor: cause of death; presence of dolphin ‘predation’ (dolphin predation); juveniles (age class); females (sex).)

source of variation	sum of squares	d.f.	F	p	parameter estimate±s.e.
(a)
body length	23 425	1	804.2	<0.001	0.59±0.02
cause of death	1198	1	41.1	<0.001	−4.69±0.73
dolphin ‘predation’	123	1	4.2	0.041	−1.50±0.73
age class	68	1	2.3	0.127	−1.27±0.83
sex	6	1	0.2	0.661	−0.29±0.66
month	311	11	1.0	0.472
model
explained	39 246	16	84.2	<0.001
residual	8214	282
total	47 460	298
(b)
body length	33 347	1	1114	<0.001	0.60±0.02
cause of death	2560	1	85.5	<0.001	−5.44±0.69
dolphin ‘predation’	138.7	1	4.6	0.032	−1.22±0.57
age class	31	1	1.0	0.311	−0.78±0.77
sex	3	1	0.1	0.743	0.19±0.57
month	229	11	0.7	0.743
model
explained	47 736	16	99.7	<0.001
residual	11 704	391
total	59 440	407