Environmental effects on egg development and hatching success in Jordanella floridae, a species with parental care

Male flagfish Jordanella floridae provide parental care in the form of nest guarding, cleaning and fanning. Patterns of egg development, hatching success and disease in the absence of parental care across a range of physical environments that flagfish naturally experience were observed. Egg hatching success increased with salinity but was unaffected by temperature. Egg development rate, on the other hand, increased with temperature but was unaffected by salinity. Furthermore, disease (most likely fungus on the eggs) was the primary source of mortality. Thus, the results suggest that, in this species, parental care of the eggs can only significantly increase offspring fitness by reducing disease and that the value of care will overall be reduced in saline environments because eggs hatch readily there, in the absence of care.