Otoliths - "earstones" - are small white bony structures found in the head of all fish other than rays, sharks & lampreys. They provide a sense of balance in much the same way that the inner ear provides balance in humans. They also aid in hearing. In some fish, the otolith is connected through fine hairs to the swim bladder & this aids the fish to hear behind itself.
Growth rings, much like those of a tree, record the age & growth of a fish from the date of hatch to the time of death in such detail that everything from the year of hatch, the migration pathways & the temperature of the water can be analysed from the otolith.
1 comment:
Great word, Mark. Reminds me of something I read years ago, about the ocean floor of the northern Pacific, where, in sediment metres deep, the only organic remains are 'shark's teeth & the earbones of whales'. but then, a whale is not a fish?
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