The Effects of Black Gill Disease on the Respiration of Penaeus setiferus, the Atlantic White Shrimp, during Activity and Hypoxia: Treadmill Studies.

Abstract

AbstractThe Atlantic white shrimp, Penaeus setiferus, is a commercially important species that is abundant along the United States' east coast and Gulf of Mexico. Like other similar organisms, this species is vulnerable to black gill disease, where gills become heavily melanized as part of an immune response associated with gill irritants or parasitic infection. The melanization blackens the gills, making the disease obvious. Black gill is thought to be stimulated by high temperature, high salinity, and low oxygen. In this study, we investigated whether the presence of black gill influences the ability of shrimp to take up oxygen across the gills. Shrimp were made to exercise on an underwater treadmill while measurements of oxygen uptake were made. Measurements were made in well-oxygenated water (100% air saturation) and moderate (50% air saturation) and severe (30% air saturation) hypoxia. In quiescent animals, there was no difference in oxygen uptake between control shrimp with no black gill and those with obvious black gill infections. Oxygen uptake increased by as much as twofold when shrimp were active on the treadmill. In both control and black gill groups, oxygen uptake declined in hypoxia, but the decline was greater in black gill shrimp, suggesting an impairment to taking up oxygen. Thus, black gill significantly impairs the ability of shrimp to take up oxygen under hypoxic conditions when shrimp are active. These results provide a mechanistic basis for potential negative impacts of shrimp populations suffering with outbreaks of black gill.