Histological observations on the reproductive biology of the haddock, Melanogrammus aeglefinus (L.)

Histological observations were made on the changes occurring in the haddock ovary during maturation. The influence of varying food rations on the numbers of eggs released was considered. Oocyte development was found to be a continuous asynchronous process until the beginning of spawing, i.e. stage V when vitellogenesis became synchronized and there was no further initiation of new development. It is suggested that the upper limit of potential fecundity was determined before stage II, however the actual numbers of eggs spawned could still be reduced during later stages in response to a poor food supply.