Linking water quality to larval survival: predation mortality of fish larvae in an oxygen-stratified water column

Low dissolved oxygen concentrations can affect growth rates, distributions and predator-prey interactions of aquatic organisms. Each of these potential effects is generally examined separately in laboratory and field studies. As a result, it is often difficult to determine the net influence of low oxygen on survival and which individual effect of low oxygen contributes most to mortality. We used a spatially explicit individual-based predation model to predict how effects of low dissolved oxygen on vertical distributions, predation rates, and larval growth combine to influence survival of estuarine fish larvae in a water column where the subpycnocline (bottom) and pycnocline layers are subject to oxygen depletion. We analyzed simulations involving 3 predators (scyphomedusae based on Chrysaora quinquecirrha, and fish that were relatively sensitive to, or tolerant of, low dissolved oxygen), water columns that differed in the relative thickness of the subpycnocline layer, and bottom dissolved oxygen concentrations ranging from