Partitioning survival during early marine migration of wild and hatchery-reared Atlantic salmon (Salmo salar L.) smolts using acoustic telemetry

Table 3 Watson’s U² values measuring for circular uniformity around 24 h

	Fish type	Time			Test statistic	P-value	n
		Mean	CI	Median	U²
Lake	Hatchery	12:24	08:43–16:45	12:05	0.26	< 0.03	75
Lake	Wild	Random	05:21–19:49	11:09	0.11	> 0.1	43
Estuary	Hatchery	Random	11:38–19:37	15:25	0.16	< 0.1	63
Estuary	Wild	Random	13:08 – 22:22	19:52	0.16	< 0.1	38
Marine arrays	Hatchery	13:32	10:59–16:29	13:31	0.3	< 0.01	39
Marine arrays	Wild	Random	07:43–14:57	09:54	0.19	< 0.1	22

Times presented in UTC + 1. Data in bold indicate departure from circular uniformity, i.e. Atlantic salmon (Salmo salar) smolt movements were more likely to occur at a specific time of day. ‘Random’ means the data follow a uniform distribution around the 24-h clock and ‘n’ is the total number of fish detected passing the receivers at each section. Mean and median times at which smolts left the lake, left the estuary and arrived at the final marine arrays are presented. Confidence intervals (CI) for the population mean time were calculated using a bootstrapping approach assuming an underlying von Mises distribution. Watson’s critical value is 0.19 for all sample sizes

ISSN: 2050-3385