The researchers studied the lipids and carotenoprotein in the prawn Penaeus japonicus. They found that the hepatopancreas stored most of the lipids, while the muscle mainly contained phospholipids. The major fatty acids in both organs were palmitic, oleic, eicosapentaenoic, and docosahexaenoic acids. They also discovered a blue carotenoprotein with astaxanthin in the prawn's hypodermis, which had a unique molecular weight and specific characteristics. The astaxanthin in the carotenoprotein was identified as the main component, along with an epimer and a cis-isomer.