AGE AND GROWTH OF LARVAL ATLANTIC HERRING, CLUPEA-HARENGUS - A COMPARATIVE-STUDY

Age and growth of 1,746 Atlantic herring, Clupea harengus, larvae coll ected in the Nantucket Shoals-Georges Bank region during the autumn-wi nter seasons of 1976-77, 1988-89, 1989-90, 1990-91, 1991-92, 1992-93, and 1993-94 were determined by enumerating the daily growth increments of their sagittal otoliths. Growth with respect to length for each of the years was best described by a Gompertz curve. Owing to severe wea ther events in November, January, and February of the 1976-77 season w hich disrupted the fishes' feeding regimen, growth was much slower (0. 16 mm/d) than in more recent years. Lower daily food consumption was r eflected in the rapid and continual decrease in otolith diameter durin g the autumn and winter of 1976. Growth for the other six years was st rong, showed only minor interseasonal fluctuations (0.22-0.24 mm/d), a nd ranged intraseasonally from a high of just over 0.40 mm/d in Octobe r to a low of 0.04 mm/d in February. A general model of larval herring growth was constructed with data from six recent field seasons. Inver se regressive methods were employed to generate a composite growth cur ve with confidence Limits for predicting age (days) for a given standa rd length (mm) from hatching until the onset of metamorphosis. Analysi s of otolith growth revealed a dramatic increase in the growth rate of the lapillus at about 2.5 months (29.0 mm). It is suggested that this increase may coincide with, or immediately follow, the filling of the otic bullae with gas and may provide an easily obtainable marker for estimating the timing of this critical event. The importance of this p hase in the life of larval herring is discussed, particularly with ref erence to the 1976-77 season.