Jens Anton Gjertsen when he was in norway

hello i am from norway an had an uncle who went to america back in 1889. i have searched boarding list for ships, with no success. Jens was born in Flakstad, Norway, on the farm of Qvalvik in 1863-4[?] the info i was givin by family members who are no longer living is that he was a fisherman somewhere in usa moved to Astoria[?] usa, where he worked on a trolley there. we know he had 2 daughters but not who he was married to. what i fear is that he changed his name once there or was changed by the officials of that time. i have contacted the archivist in Astoria, Oregon an he is not listed to have worked there. but there were some Gjertsens with the swedish name ending of "son". could the usa had changed his name to that. also his father was Gjert Andreassen an his mother was Kristine Tomine Gjertsdatter, also of Flakstad. thank your any help of any kind.