Policy Uses and Limitations of the Ecopath Suite and Approacha

CW: concerning predictions, there are two that are fairly robust: primary production limits possible total production, through it will not determine whether a system is stable or not. Here, Ecopath and its dynamic routines, Ecosim and Ecospace can help; equilibrium community composition responds to fishing: as you alter fishing mortality, a number of changes in abundance are predicted. Notably, the system will tend to become top heavy when fishing is very low. Conversely, at very high fishing mortalities, long-lived species will be lost, while the changes at intermediate level of fishing mortality are largely indeterminate, i.e., we cannot assess their reliability. In fact some of the results for intermediate levels of fishing are goofy, with several stable states of which we don’t know if they are realistic or not. But the extreme predic-