Evaluation of periodic and aperiodic otolith structure and somatic-otolithscaling for use in retrospective life history analysis of a tropical marine goby, Bathygobius coalitus

increment formation in sagittal otoliths, scaling between otolith and somat ic growth, and the temporal Link between settlement and formation of a sett lement mark in otolith structure were evaluated for their use in reconstruc ting aspects of the early life history of the basalt goby Bathygobius coali tus. Formation of daily increments was validated in sagittae of fish rangin g in Life history stage from new recruits to sexually differentiated males and females. Total length (TL) was proportional to other measures of body l ength, width, and depth, and Linearly proportional to sagitta radius for fi sh between 8 and 40 mm TL. Somatic-otolith scaling became more curvilinear in larger fish due to declining growth rate of otoliths relative to TL, esp ecially in fish collected during warmer sea surface temperatures. For fish 8 to 40 mm TL, somatic-otolith scaling was not affected by differential som atic growth rates nor by seasonal water temperature. A settlement mark, cle arly identifiable as a distinct and abrupt shift in optical focal plane, co ntrast, and width of daily increments, was verified to coincide with settle ment. Wider post-settlement increments abruptly followed narrower pre-settl ement increments across the settlement mark. These results support the use of daily increments, somatic-otolith scaling, and a settlement mark for rec onstruction of hatch and settlement dates, mean daily pre- and post-settlem ent growth rates, size and age at settlement, and post-settlement size-at-a ge histories for the basalt goby.