A method of producing a composition comprising a high concentration of very long chain polyunsaturated fatty acids (VLCPUFAs) from natural oils such as fish oil, squid oil, algal oil and krill oil. In addition, a composition comprising a high concentration of very long chain polyunsaturated fatty acids isolated from such natural sources; as well as to a process for isolating separate fractions of very long chain polyunsaturated fatty acids having identical chain lengths but different degrees of unsaturation from such highly concentrated compositions is disclosed.