This section discusses sustainable conservation based on the ecosystem approach as a new paradigm for risk management in fisheries. A significant positive correlation was observed between the Aleutian Low Pressure Index (ALPI) and carrying capacity at the species level. Residual carrying capacity was significantly positively correlated with body size and negatively related to age at maturity in chum salmon (O. keta) as an example of a density-dependent effect (Kaeriyama, 2008). On the other hand, the biomass of wild chum salmon populations in the 1990s decreased to 50 per cent of 1930s levels, despite a significant increase in hatchery populations (Figure 3.4.1).