1) The Norse in Greenland didn't eat fish?
One Greenland archeologist (Jette Arneborg) whom Diamond quoted literally found that laughable, when she was interviewed later. The've got the fish hooks & the sinkers. Diamond points out that there are relatively few fishbones found at Norse Greenland sites, and cites the Hunting, Fishing, & Animal Husbandry at the Farm Beneath the Sands study (Inge Enghoff-I had to send to the U of Alaska to get it), ignoring the fact that the study itself points out that that's because 1) Fish bones are small (duh!), 2) Fish bones are highly perishable (duh!), and 3) The archeologists only started to use excruitiatingly thorough screening techniques part of the way through the excavation. Also despite the fact that one place Diamond went to had been named by the Norse "Salmon Stream." Besides, the theory that the Greenlandic Norse didn't eat fish: Does that even pass the smell test (so to speak)?