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Metabolism
Fish Aging & Longevity
How fish age - and why some species live over 200 years while others live only weeks.
System: Skeletal Level: Intermediate Discipline: Physiology
📖 Overview
Fish lifespans span three orders of magnitude. Killifish complete their entire life cycle in 4 months. Rougheye rockfish and Greenland sharks live 200-400 years - the longest-lived vertebrates known. Because most fish grow indeterminately, an old individual may be enormous. Age is estimated from otolith rings, scale rings, vertebral rings, and (in sharks) growth bands. Long-lived fish reproduce slowly and are extremely vulnerable to overfishing.
⚙️ Mechanism
Indeterminate growth adds size throughout life. Otolith and vertebral rings record annual growth cycles. Telomere shortening is slower than in mammals in some long-lived species.
🔑 Key Concepts
Indeterminate growth, otolith aging, life history strategy, K vs r selection.
🐟 Examples
Greenland shark - 400+ years. Rougheye rockfish - 205 years. Bowhead sturgeon - 150+ years. Beluga sturgeon - 100+ years. Killifish - 4 months.
✨ Fun Fact
The oldest known vertebrate alive today is a Greenland shark - estimated at 392 years old. It was likely born during the reign of the Sun King, Louis XIV.