"In 1846 he took part in a zoological expedition around the coast of Arendal; in 1849, he collected specimens in Oslofjord. He never made such a trip to the western fjords, although he did spend some days in Sognefjord in 1847"
I have sources.
The claim probably comes from the setting of his hulder-tale, “From Sognefjord,” which many people take as autobiographical. It was not.