Relationship of Otolith Lengths and Weights in the Haddock Melanogrammus aeglefinus (L.) to the Rate of Growth of the Fish

Abstract

Haddock otolith lengths decline from over 5% of the total length of the fish at 14 to 17 cm. to almost 3% at 74 to 77 cm. The otolith lengths of slow-growing haddock decline less rapidly than those of fast-growing haddock. Little difference was found between otolith lengths in male and female haddock of the same length.Slow-growing haddock both from the Grand Bank and from St. Pierre Bank have heavier otoliths than fast-growing haddock at the same fish lengths. This is true not only for fish of different year-classes in the same year but also for fish of the same year-class in different years.The otoliths of male haddock of the Grand Bank exceed progressively in weight the otoliths of females of the same length after the males become sexually mature. The relative increase in otolith weight of the male fish is attributed to a probably slower growth rate after sexual maturity, which occurs earlier than in females. Similarly, the heavier otoliths of mature fish in sizes overlapping with immature fish are due to a greater age of the mature fish at these sizes. Otolith weight relative to fish weight decreased considerably with increase in fish size, and no distinct differences were apparent between otolith weights as a percentage of fish weights in slow-growing and fast-growing fish of the same length.