HA3 Effects of Multiple Stressors on Marine Resources
254 Portland Ballroom
8:00 AM - 12:00 PM, Thursday
() Effects of multiple stressors in an estuarine system: influence of hypoxia and habitat.
Adams, S1, 1 Oak Ridge Natl. Lab, Oak Ridge, TN, USA
ABSTRACT- Marine ecosystems, and particularly estuaries,are subjected to a variety of natural and anthropogenic stressors which can impair the health and fitness of resident biota. Multiple stressors including pollutants, nutrients, hypoxia, turbidity, and altered habitat and hydrologic regimes can impact resources through single, cumulative, or synergistic processes. Because many marine systems are relatively variable and complex and are subjected to multiple stressors, multiple lines of evidence are needed to understand relationships between stressors and effects on important marine resources and to minimize the probability of false negatives when assessing causality. Multiple indicators of environmental stress (bioindicators) were used to assess the effects of flooding from three sequential hurricanes on the health and condition of two important estuarine fish species in Pamlico Sound, NC. A wide variety of bioindicators ranging from the biochemical to the reproductive and organism-level were used to assess the health of southern flounder and spot in Pamlico Sound compared to the health of these species sampled from a relatively unaffected reference site. Many of the physiological,reproductive,immunological, histopathological and general condition measures suggested that both species from Pamlico Sound were sublethally stressed and in relatively poor condition. The major stressors causing these sublethal stress responses in Pamlico Sound fish appear to be those related to episodic hypoxic exposure and/or a combination of factors associated with hypoxic conditions such as alterations in preferred habitat and food availability. Although fish populations in Pamlico Sound do not appear to be severely damaged or impaired at this time, organisms that are sublethally stressed can incur increased vulnerability to additional or future environmental stressors. Because of the low flushing rate(1 yr) of Pamlico Sound, recovery rate may be exceptionally slow, prolonging any adverse effects of hypoxia on the health and fitness of fish populations.
Key words: hypoxia, multiple stressors, fish health, bioindicators