Japanese angelshark is eaten and the rough skin is made into a type of leather called shagreen for use in wood finishing. Angel sharks in general are highly threatened by commercial trawl fisheries due to their susceptibility to capture and low rate of reproduction, and angel shark species elsewhere are known to have declined markedly under fishing pressure. Trawling activity in the Yellow Sea and other parts of the northwestern Pacific is intense and, coupled with pollution, has had a serious impact on the local ecosystem. The Japanese angelshark population is suspected to have declined by up to 50% or more under
Alfred Ehrenreich placoid scales, or dermal denticles; leather made with these scales still attached is referred to as Shagreen. However, Ehrenreich had to find a way to remove these scales from the hides in order for his product to reach a wider market. Initially he tried a process patented by a Danish chemist called Kristian Bendixon. Later the company switched to a system that involved the hides being treated by acid. Two chemists came up with similar ideas, Theodore H. Kohler and Dr Allen Rogers. Once treated in this way the skin could be split into layers, to both increase the yield