Lake sturgeon (Acipenser fulvescens) growth and longevity estimated from adult capture-mark-recapture data

Effective fishery management policy depends on accurate life-history data, particularly for harvested species. Longevity is a core life-history trait that is directly related to annual survival and lifetime reproductive potential, but fish longevity is generally not well documented, particularly for long-lived species. We used capture-mark-recapture data spanning 44 years as an alternative method to estimate sex-specific adult lake sturgeon (Acipenser fulvescens) average annual growth and longevity for five populations in the Laurentian Great Lakes. We determined individual fish average annual growth and fit population and sex-specific exponential lines for average annual growth as a function of fish length at initial capture. We used the exponential equations to estimate age for 180 cm fork length (FL) female and 160 cm FL male lake sturgeon from each population by sequential subtraction of annual growth increments and assuming age at onset of sexual maturity of 24 and 15 years for females and males, respectively. Average annual growth estimates varied between sexes and among populations and ranged from 0.26 to 1.15 cm year^-1. Estimated ages also varied among populations. Age estimated for a 160 cm FL male lake sturgeon across the five populations ranged from 90 to 279 years. Age for a 180 cm FL female across populations ranged from 99 to 427 years. Our data suggest lake sturgeons live much longer than currently believed. High longevity and inferentially higher adult survival have important implications for sturgeons in general and support conservative harvest regulations for lake sturgeon fisheries.