Low grade fishmeal consists of the trimmings and leftover of fish. It goes through the standard fishmeal manufacturing process (chopping, cooking, extraction of oils) removal of stick water (used to reduce to fish emulsions), hot dry heating and grinding.
Our fish powder is made with whole fresh fish that is sun dried and then grounded. The entire process is natural. The whole fish is used. No oils, collagen or proteins are removed. You can see a Chart explaining the differences in the Sigma Fish Powder Page