Fat metabolism in fishes

IT is well known that the fat content of herring varies over a wide range and extreme values may be as low as 1 % or as high as 30 %. Lovern & Wood [1937] made a study of the seasonal nature of these variations and showed that following minimal values about April, there was a rapid rise in fat content during late May and June to maximal-values in July. After this point had been reached the length of time that a high fat content was maintained depended on when the fish spawned; relatively high values were maintained until spawning was im- minent, when cessation of feeding caused a rapid drop in the fat content. The rapid rise in June was associated with the intensive feeding which then takes place, food organisms being very abundant at that time. In winter, scarcity of food, and possibly lack of appetite, result in a steadily falling fat content to the minimum values in April.