The effect of light intensity on development and hatching success of lingcod, Ophiodon elongatus (Girard), eggs

Abstract

The influence of incubation light intensity on development and hatching success of the lingcod (Ophiodon elongatus Girard) was studied by determining time to hatch, per cent hatch (total and viable) and per cent of deformities for embryos incubated at three different light intensities: ∼0, 1, and 563 lux. Photoperiod for the last two treatments was 16 h dark: 8 h light. Chemical parameters throughout incubation remained within acceptable ranges. Hatching in all treatments began 43 days post fertilization (353 °C days) and was complete on day 46 (377 °C days), with peak hatch for all treatments on day 44 (361 °C days). Per cent viable hatch for eggs incubated in the 1 lux treatment (88.6 ± 2.1%; mean ± SEM) was significantly greater than eggs incubated in the ∼0 lux (59.6 ± 11.3%) and 563 lux (61.4 ± 9.2%) treatments. A significantly greater per cent of deformed embryos with curled bodies occurred at 563 lux (9.5 ± 2.6%) compared with the 1-lux treatment (2.5 ± 0.6%). No significant differences for the other categories of deformities (ball, short, distended gut) were detected among treatments. Total deformities (all categories combined) for ∼0 lux (16.0 ± 4.2%) and 563 lux (17.2 ± 3.3%) were significantly greater than total deformities for 1 lux (5.0 ± 1.4%).