Ever wonder how old the fish are that you are catching? This has been an important aspect of the research that we have been doing on Lake Ontario bass populations. To date, our oldest largemouth from this project has been 18 years old and our oldest smallmouth has been 17 years old. Bass can be aged by counting the annual growth rings in several hard structures (scales, otoliths, dorsal spines), but otoliths are the best structure for old fish.