Observations on effects of feeding level on growth and reproduction in haddock, Melanogrammus aeglefinus (L.) in captivity

Individual haddock, Melanogrammus aeglefinus (L.) were maintained at different feeding levels in an aquarium from November until the completion of spawning. The mean duration of spawning was 33.2 days (range 19–59) during which an average of 16.6 (range 10–25) batches of eggs were produced. The size and dry weight of the eggs declined during the spawning period. Egg production and feeding level were correlated positively. There was some suggestion that when female haddock received low rations (< 5 kcal day^-1) a lower proportion spawned, and the dry weights of the eggs were lower compared with females on high rations (> 13 kcal day ^-1). The relation between daily growth in wet weight, g, and daily surplus energy intake, kcal, was: G =(0.295 E )— 0.328. When food energy is restricted, haddock appear to achieve a balance between somatic growth and reproduction.