Ecophysiological constraints on the larvae of Pleuroncodes monodon and the implications for its reproductive strategy in poorly oxygenated waters of the Chile-Peru undercurrent.

Pleuroncodes monodon is a conspicuous component of the Humboldt Current ecosystem. Benthic adults south of ∼22°S are associated with low temperature (T) ∼11°C and low dissolved oxygen (DO) (<0.5 mL L⁻¹) waters during the hatching period. Because P. mondon inhabits an oxygen minimum zone and larval release is assumed to match most favorable environmental conditions, larval performance under cold hypoxic conditions and its implications have not yet been assessed experimentally. We quantitatively assessed the effect of DO and T within environmental ranges, and initial starvation on survival, developmental time, and growth of P. monodon zoeae. Molting success from zoea I to zoea II was significantly and positively dependent on DO rearing levels. Age at molting was a negative power function of oxygen concentration. Initial exposure to low DO increased larval mortality by 3% per day of exposure. After ∼4 and ∼1.5 days of starvation after birth under normoxia and hypoxia, respectively, 50% of larvae failed to molt to zoea II. Rearing in 1 mL L⁻¹ DO produced 50% lighter larvae after molting into zoea II. Mortality of larvae reared at 11°C was 40% higher than that at 15 and 20°C. Functions for development time and growth negative/positive dependence on temperature were also fitted. Pleuroncodes monodon zoea I are highly tolerant of low oxygen when compared with other crustacean. Nevertheless, DO and T conditions during hatching season are suboptimal for development. Early larval survival as an ultimate cause of reproductive/environmental coupling in this case should be critically revised.