Morphology of the Otoliths of the Atlantic Blue Marlin (Makaira Nigricans) and their Possible Use in Age Estimation

The otoliths of the blue marlin, Makaira nigricans, have not been described as they are very small and difficult to locate. In the present study, methods are provided for the extraction and observation of the otoliths. We used scanning electron microscopy (SEM) techniques to describe the morphology of the otoliths in the blue marlin. External and internal morphological features of the sagitta displayed stratifications which increased with increased body size. Otoliths have proven very useful in age and growth estimations for many fish species. It seems possible that the internal and external morphology of the Atlantic blue marlin otoliths can be employed to estimate the age and growth rate of this important recreational and commercial fish.