I came across this page. If you search for "Poisson", you will see the following information:
passenger lists from the Natal Witness for the year 1886 - January to June ...
March 12 Arrival
Taymouth Castle C S S London. Warden
Passengers Mr & Mrs Poisson and 5 children ...
URL: http://archiver.rootsweb.ancestry.com/th/read/SOUTH-AFRICA-IMMIGRAN...