The elasmobranchs includes the fishes like the sharks and rays. There are certain products which are produced in the fishes of this group. The urea and the methylamines are produced in these fishes. The methylamine named as TMAO (trimethylamine oxide) is considered as a chemical which makes the food unpalatable. The chemical is considered as toxic to the health of the humans. There is a very high concentration of this chemical present in the fishes of this group. Thus, the fishes are not used as a source of food.