Egg mass gelatinous envelopes of yellow goosefish Lophius litulon protect the internal eggs and larvae from salinity stress and desiccation

Some teleosts, including yellow goosefish Lophius litulon, spawn gelatinous egg masses, but the biological function of the gelatinous matrix remains poorly understood due to limited experimental access. This study tested whether the gelatinous membrane of L. litulon egg masses, which naturally float just below the sea surface in coastal areas, protects eggs and larvae from abiotic stress. Salinity stress experiments using 782 and 605 eggs were conducted. Embryos retained within gelatinous membranes maintained high survival and normal growth after 45 and 90 h of exposure to 50% diluted salinity, whereas those removed showed significant reductions (two-way ANOVA; p < 0.001 and = 0.015, respectively). Additionally, experiments using 449 and 599 larvae examined responses to 24-hour exposure under desiccation and elevated temperature conditions (2-3 °C above the appropriate temperature). The gelatinous matrix retained moisture, showing stable survival and growth (two-way ANOVA; p = 0.838 and 0.804, respectively), although heat stress reduced survival (two-way ANOVA; p < 0.001). These results indicate that the gelatinous matrix offers physical protection from some types of environmental stress, likely an adaptive trait for survival in variable coastal habitats. This study provides the first experimental evidence of such protective functions in gelatinous egg masses of marine fishes.