Bioenergetic responses of Chesapeake Bay white perch to nursery conditions of temperature, salinity, and dissolved oxygen

Abstract

Changes in the physical and chemical structure of estuaries affect the habitat availability for anadromous species. White perch, an estuarine species, are among the most abundant and important fishes in the Chesapeake Bay. Here, I evaluate nursery quality for juvenile white perch by measuring metabolic and growth responses over a range of environmental conditions such as salinity, temperature, and dissolved oxygen. Rearing white perch in 10-d trials varying in temperature, salinity and dissolved oxygen conditions, I estimated growth rates, feeding rates, gross growth efficiency, and routine metabolism. Juveniles experienced higher feeding and growth rates in warmer, more oxygenated waters. In hypoxic environments (<40% saturation), metabolic rates increased as much as 4-fold while growth decreased 3-fold and feeding decreased 2-fold. My results indicate that while white perch are well suited to the saline and thermal conditions present in the Bay, nursery habitat value can be substantially curtailed by hypoxia.