Sockeye spawning activity occurred within a 21-day period.
Females first began nest construction on 8 August (12 females
within our twenty-four 5-m2 sampling sites) and the last breeding
female on the beach was noted on 29 August. After 8
August, the density of breeding females increased rapidly,
with most females completing spawning between 9 and 17
August (Fig. 1B). Peak densities of breeding females of about
13 per 25 m2 occurred on 11 and 13 August, just 3 and 5 days
after the commencement of spawning. After these dates, the
number of spawned-out females rose rapidly, with virtually no
females remaining alive on the beach by the end of August
(Fig. 1C).