Ccxlviii. New Zealand Fish Oils

IT has been suggested by Lovern [1932 et seq.] that the fats of freshwater fish are, within comparatively small limits, characteristic for that class and quite distinct as regards the relative proportions of component fatty acids from marine fats. So far as the authors are aware the data on this subject have been derived almost entirely from species inhabiting the Northern Hemisphere. The present work, however, suggests that this important generalisation with regard to the composition of freshwater fats can be extended to include species inhabiting the Southern Hemisphere. In most parts of New Zealand, eels are the predominant freshwater fish. The two species known respectively as the short-finned or northern eel (Anguilla australis) and the long-finned or southern eel (Anguilla aucklandii) are noted for their large size when mature; specimens weighing 35 lb. or more being occasionally caught. The composition ofNew Zealand eel oil does not seem to have been previously determined. Wiehr [1934] reports that the fat from A. vulgaris yielded 86-5% fatty acids of which the solidacids separated by Farnsteiner's method comprised 20*3 %, whilst Ono [1935] gives qualitative data for the composition of Japanese eel oil. The general characteristics of various eel oils determined by previous investigators are given in Table I.