A study examined the effects of chronic exposure to low doses of the insecticide chlorpyrifos on the lake skygazer (Culter dabryi), a common predator in lakes in China.[2][1] In lakes with persistent low exposure, fish had shortened telomere lengths and the population consisted predominantly of younger individuals.[2][1] Laboratory experiments have confirmed that chronic exposure to low doses of chlorpyrifos causes telomere degradation and decreases fish survival in a dose- and physiological-age-dependent manner.[2][1] Acute exposure to high doses did not cause telomere shortening or accelerated aging.[3][2] Exposure to doses of 10 ng/L or 50 ng/L for four months increased signs of cellular senescence, with greater effects at the higher dose.[4] These findings show that chronic low exposure reduces life expectancy and population viability by accelerating physiological aging.[2]