GROWTH AND OVARIAN DEVELOPMENT OF MAUROLICUS-MUELLERI DURING SPRING

The size, fecundity and gonad development of Maurolicus muelleri (Gmel in) were studied in Herdlefjorden, western Norway, from January to Jun e 1994. In January, the two age groups formed separate sound-scatterin g layers (SSL). Juvenile 1-group fish found to form the upper SSL, whi le adult 2+ individuals inhabited the lower, these distributions refle cting the different feeding to fitness functions of these two age grou ps. In June there was only one SSL, and in March and May some 2+ were also found in the upper SSL. Growth of the younger fish to 2+ fish siz e was observed over the period, and it was found that M. muelleri matu re after 1 yr, although size at maturity was lower than found in previ ous studies. Growth of the 2+ fish changed as the period progressed, t o allow gonadal development after a winter of low feeding. Increased i nvestment in development of the gonads was also observed in the 1-grou p fish over the study period, but substantial maturation only occurred from May to June. Absolute fecundity was size dependent, although hig h variability was found in the larger size ranges. Oocyte development occurred in discrete batches, although lack of gonadal synchrony betwe en individuals means that spawning is continuous in the population as a whole, once the spawning period begins. Batch fecundity was found to be similar to previous studies, and 2+ fish were found to start spawn ing earlier, and with an increased intensity, than the 1-group fish.