Every day is not like Friday the 13th. We have so few lucky and unlucky days in western tradition. But this one has taken on a great tradition since the 19th century. It is thought to have originated with the story of Jesus' last supper in which there were 13 individuals in the Upper Room on the 13th of Nisan Maundy Thursday the night before his death on Good Friday.
In Spanish-speaking countries it is Tuesday the 13th that is considered a day of bad luck. Tuesday is considered dominated by the influence of Ares, the god of war. And Friday the 17th is considered a day of bad luck in Italian popular culture.
This salmon expired earlier in the week on Forty Creek in Grimsby. There were still a few swimming salmon moving upstream, but many more have expired completing their journeys.