Freshwater Fisheries Conservation Lab

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Fish Age

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.

                      





         Otolith from a 17 year old Smallmouth Bass that weighed                                 2.12  kg (4.7 lbs) and was 485mm (19 inches) long.



 Otolith from an 18 year old Largemouth Bass that weighed 1.5kg (3.3 lbs) and was 450mm (17.7 inches) long.