Ages for Hoplostethus atlanticus were first estimated by counting growth zones in the otolith, the calcified ear stone. Because such counts can be doubted, they were checked independently by measuring the decay of lead-210 from radium-226 within the otolith core, a clock that does not depend on interpreting bands. The two methods converged on maximum ages beyond 100 years, with figures around 150 widely cited.
Late maturity compounds the problem. Orange roughy are generally reported as first spawning somewhere in their twenties to mid-thirties, so a cohort removed from a seamount aggregation is not replaced within a management cycle.
The fishery history reflects that arithmetic. Deep trawling over seamounts from the late 1970s onward produced large early catches followed by steep declines, and several stocks were closed. Some New Zealand stocks have since been assessed as rebuilt and certified, which shows recovery is possible, but on timescales set by the fish rather than by the fleet.