Q: What is the gray layer under the skin in salmon? Is it okay to eat?
A: Salmon (and other fish) develop a gray-brown layer of insulating fat between their skin and flesh. This is in addition to fat deposited within the flesh. For cosmetic reasons, vendors who remove the skin also take off as much of the gray fat as they can. But you may still find some of it on your salmon steaks or smoked salmon.
Yes, it’s okay to eat it, though some people dislike the intense flavor. Like the fat deposited within the flesh, this gray layer contains heart-healthy omega-3 fatty acids. But the fat in farmed salmon may also contain elevated levels of PCBs and other industrial pollutants, depending on where the fish comes from and what it was fed.
Though research is unclear as to how much of a risk farmed salmon (and other farmed fish) poses, it shouldn’t be the only fish you eat. It’s always best to vary your intake of seafood.