Chapter 18: Long-term Trends in the Fish Community of Oneida Lake: Analysis of the Zebra Mussel Invasion
Brian J. Irwin, Lars G. Rudstam, James R. Jackson, Anthony J. VanDeValk, and John L. Forney
Ecosystem-level study and ecosystem-based fishery management are being increasingly emphasized as important frameworks for understanding and maintaining the use of aquatic resources (Carpenter et al. 1995; Link 2002; Pikitch et al. 2004). The recent acceleration of this movement is due, in part, to a recognition that a more holistic approach to assessment is required because many fish species are being heavily overexploited (Pauly et al. 2000), targeted fishing still affects multiple species (through bycatch, habitat alterations, or restructuring a community), regime shifts are resulting from human-induced ecological change and spread of invasive species (Carpenter 2003; Scheffer and Carpenter 2003), and the effects of a perturbation can be mediated through food-web interactions. In aquatic ecosystems, the drivers of change can arise either rapidly (e.g., invasive species) or through a more incremental change over a longer term (e.g., global warming). In addition to differences in their operative time scales, stressors can induce indirect shifts through multiple interacting components of an ecosystem, thus complicating estimation of their effects. This capacity for cascading effects combined with the limited recovery potential of some low-density populations may prevent a return to prior conditions, even if a stressor is successfully removed (Botsford et al. 1997; Carpenter 2003). Ultimately, understanding how relationships in complex food webs have changed due to previous perturbations can improve assessments by reducing areas of uncertainty, promoting precautionary management, and enhancing the ability to predict and respond to future stressors (e.g., ecosystem forecasting; Botsford et al. 1997; Link 2002).