Well, the title, I admit, probably is in a way slightly misleading. Anyways, this question sort of came up over a time period, so as to the info, please bear with me. A lot of what I am going on is remembered from Tonmocon, and therefore probably riddled with holes. Basically, first of all there was that talk on D. gigas (I think), at tonmocon, and one of the things brought up was how there was a population that were migrating through extremely oxygen-deprived areas between two locations. As I remember it, there wasn't an answer at the time as to how. Recently, I was looking up Hemacyanin (which is a quarter as efficient as hemoglobin but can flow freely as apposed to in cells, thereby allowing greater concentrations of it in blood--note: I'm not telling you this because I think you don't know it, I just want to make sure it's correct.), and I happened to ask my dad about it and he said that if he remembered correctly, hemacyanin held on to oxygen tighter than hemoglobin. Well, I was wondering, could increased levels of hemacyanin affect it? Just curious.