Drastic changes in the life history of an individual are reflected by measurable changes in its otolith micro-increment data as seen in our analyses of age groups 0-VI. Micro-increment measurements and analyses are relatively simple to do by light and scanning electron microscopy and by using micro-densitometer and digitizing equipment. The otolith micro-increment analysis is capable of establishing the age of an icefish by relating the daily micro-increment count to the life history of the fish. Changes in otolith morphology and mass correlate with fish size and age group.
We describe a method of reading daily micro-increments in connection with shape, size and mass analyses of the otoliths of the South Georgia icefish Pseudochaenichthys georgianus. Icefish ages must therefore be estimated from otoliths. georgianusīetween the Antarctic Peninsula and South Georgia.Īging Antarctic icefish is difficult because of their lack of scales and poorly calcified bones. Our results indicate a single population of P. As the fish age beyond group III, individual otolith variability The next drastic change in otolith shape and daily micro-increments occurs when ~7 cm longįish shift from pelagic to benthic habitats. Micro-increment shapes and periodicities occur in connection with the hatching period of the icefish. DrasticĬhanges in the life history of an individual are reflected by measurable changes in its otolith microincrementĭata as seen in our analyses of age groups 0−VI. Micro-increment measurements and analyses are relatively simple to do by light and scanningĮlectron microscopy and by using micro-densitometer and digitizing equipment. The age of an icefish by relating the daily micro-increment count to the life history of theįish. The otolith micro-increment analysis is capable of establishing Changes in otolith morphology and massĬorrelate with fish size and age group. South Georgia icefish Pseudochaenichthys georgianus. We describe a method of readingĭaily micro-increments in connection with shape, size and mass analyses of the otoliths of the
Aging Antarctic icefish is difficult because of their lack of scales and poorly calcifiedīones.
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