A "fisker" is someone who fish. A "fishmonger" would be a "fiskehandler", from "fisk" (="fish") and "handler" (="trader").
so then the sentence is incorrect, it should read: En fiskehandler selger fisk
The sentences only have to be grammatically correct. They don't have to be factual, make sense or be potically correct. "I am a banana" is a perfectly valid sentence for translation.
Fishermen usually only sell fish wholesale at the quayside fish auctions when they land their catch. The translation of the sentence is grammatically correct but makes little sense in English.
I'm curious about how the genders of these words relate to the gender of the person. How would one refer to a female fisher, for example? I know that one could use the masculine form because of the pronoun reform, but is there an option to use a feminine form? This question applies to all occupation nouns.
In this case, 'fisker' would be used for both fishermen and fisherwomen. Adding a feminine ending would sound wrong, and may even be taken offence at.
For some other occupations ending in -er, we have the option to add -inne:
skuespiller = male or female actor
skuespillerinne = actress
And for others again, adding -inne is the norm:
keiser = emperor
keiserinne = empress
Then, just to spice things up, some occupations ending in -er can take a -ske ending instead:
sykepleier = male or female nurse
sykepleierske = female nurse (a bit archaic)
For occupations that end in -mann, you have the option to replace that ending with -kvinne, much like in English. It is not required, unless the person you're describing prefers that term, and more commonly done with some words than others.
brannmann = male or female firefighter
brannkvinne = female firefighter, firewoman
Farfaren min var en fisker på Lake Winnipeg som solde sin egen fisk fra sin veranda butikken.
I noticed in the audio the "s" in selger sounds like a "sh", whereas in other sentences it sounds like a normal "s". Is there a set of rules for when to change it's sound to sh?
I think in this case it's because the previous word ends in "r", and when you have the "rs" combination in Norwegian the "s" gets pronounced as "sh" (assuming you read the sentence as a whole). If you read the words separately, it will probably be pronounced as a regular "s".
This also means "A fisherman is selling fish", which might make more sense to some people.
To me, a fisher is an animal. A person who fishes is a fisherman or fisherwoman.
What is the Norwegian job qualification for a hunter catching whales professionally?
"En hvalfanger", if you're looking for the occupation.
As for qualifications, I suppose you better be physically fit, up for long hours at sea, able to withstand abuse, and open to retraining. They're very much a dying breed.