The breeding and growth of whiting, Merlangius merlangus in captivity

Data are presented on the spawning of whiting in captivity. The females were found to have a high fecundity, each shedding numerous batches of eggs over a spawning period that lasted for many weeks. Batch size tended to diminish throughout the spawning season. Measurements of the diameters and dry weights of eggs collected at different times from the commencement of spawning showed that eggs shed at the beginning of the season were both larger and heavier than those shed later. The possible significance of this phenomenon is discussed. It is shown that spawning imposes a greater physiological strain on females than on males. It was estimated that spawning caused losses in the body weight of females that ranged from 0.03% to 0.40% per day.