What's an otolith??? A fish's age is a valuable tool for proper population management. The way ODWC Fisheries staff estimate age is through the counting of rings found on an inner bone called an otolith. Much like the rings on trees, these rings present themselves as ringed layers, made up of calcium. Fish have periods of fast (spring) and slow (winter) growth.
These are depicted as bright white rings for slow growth (or annuli AKA "birthdays") and cloudy broad spaces for fast growth. Once collected biologists use microscopes to count these rings and estimate the age of the fish. This coupled with length and weight gives us valuable information about fish growth, spawning success, and overall population health.
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