Erucic acid (13-22:1) occurs naturally in fish oils and in small amounts in thephospholipids of animal tissues (often with some 15-22:1), but it is probably best known as the major component (up to 66%) of the total fatty acids in rapeseed oil. 5-22:1 is present in meadowfoam oil.
Other cis-octadecenoic acids, such as 7-, 13- and 15-18:1, are occasionally seen in lipids of fish or marine invertebrates. 5-18:1 is a minor component of the seed oil of meadowfoam and of a few other plant species, and it is encountered in the lipids of sponges
11-cis-Eicosenoic acid is a common if minor constituent of animal tissues and fish oils, often accompanied by the 13-isomer. It is also found in rapeseed oil and seed oils of related species.Cis-5-20:1 can amount to 67% of the total fatty acids in meadowfoam oil (aocs.org).