Science Serving Maryland's Coasts

Sarah DuBeau-Farley, Amherst College

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The Effects of Hypoxia on the Vulnerability of Named Goby Larvae and the Influence of an Alternate Prey Source


I performed predation experiments to examine how summer oxygen depletion in the Chesapeake Bay affects the trophic interactions of fish larvae. The larvae of the naked goby Gobiosoma bosci were presented to adult gobies at varying dissolved oxygen levels. The feeding rate of the adults was found to be significantly lower at 1 mg/1 oxygen than at saturation levels and showed a decreasing trend at 3.0 mg/1 and 2.0 mg/1. This was due to the fact that the larvae tended to rise in the tank as DO decreased; at levels of 1 mg/1 larvae were almost completely spatially separated from the adults. When amphipods were used as the prey item, the adult gobies ate significantly less when the DO level was 1.0 mg/I than at saturation levels. Amphipods remain on the bottom of the tank at all DO levels. Therefore this decrease in feeding was due to the adult's decreased capability. When both larvae and amphipods were used as prey, it seems that fewer larvae are eaten. However, feeding rates on both still decrease when DO level was sufficiently low. My results suggest that low dissolved oxygen has complex effects on predator prey interactions and can possibly have important effects on trophic systems.