Early life history of the American conger eel ... - ResearchGate

481Fig. 3A–D Conger oceanicus. SEM micrographs showing theotolith microstructure of an early metamorphosing conger eelleptocephalus (total length: 96.0 mm; preanal length/total length:0.63): A whole view (boxes with letters correspond, respectively, topanels B, C and D); B otolith core and surrounding zone; Cboundary between the developing leptocephalus growth andmetamorphic zones; D otolith edge (P primordium; HC hatchcheck; DLGZ developing leptocephalus growth zone; WIZ wideincrement zone; ICTZ increment countable terminal zone)until a relatively constant minimum value (0.65 lm) wasreached, at about 80 days (phase II). This inner portionof the otolith’s ICZ, which includes phases I and II, isnamed the developing leptocephalus growth zone(DLGZ) (Fig. 3C). In a third phase, the incrementswiden abruptly (to a maximum of 1.20–1.50 lm); thisphase, depending on the specimen, could occur between70 and 120 days. This wide increment zone (WIZ) occurredover about 20–40 days, after that the incrementwidth decreased (increment countable terminal zone,ICTZ) (phase IV) (Fig. 3C, D). In the late metamorphicleptocephali (PAL/TL