For fish oil, this share could reach 41% of total production, compared with 33% in 2011-13. The use of fish by-products can affect the composition and quality of the resulting fishmeal/fish oil, because they contain, in general, less protein, more ash (minerals) and increased levels of small amino acids (such as glycine, proline, hydroxyproline) compared to fishmeal and fish oil obtained from whole fish. This difference in the composition may affect its potential for use aquaculture and livestock farming. However, this is not taken into consideration in the fish model and in the Outlook.