When I ate Rotten Shark, I thought that this might be a metaphor! As you can see it is not. If you look carefully at the dinner at the end -Rotten Shark is not the only testing item on the menu. You will see a man eating the eye from a sheep's head. Also on the menu - testicles in fermented whey!
You might ask what was the origin of this meal? I think it is this. Food on Iceland was always hard. You wasted nothing. So if you caught a huge shark that could not be eaten as is - you found a way of eating it. Testicles? Delicious! Eyes? Yummy.
I am pretty adventurous when it comes to food - but I have to admit defeat here. I did eat my bit of shark - I gagged. I did eat a sheep's head but passed on the eye. I passed on the the testicles. I ate a lot of bread and potatoes.