可持续捕捞的概念意味着，如果每年通过自然死亡，捕捞和产卵繁殖补充，使得鱼群能够在每年年初捕捞开始时保持平衡不变，那么这样的捕捞策略就可以年复一年地一直持续下去，因此可持续捕捞的鱼群应该是模型（6）（7）（8）的平衡解，即模型不依赖于时间的-the concept of sustainable fishing, and if each year through natural causes, fishing and breed added, fish can be made in the beginning of each year fishing at the beginning balance unchanged then the fishing strategy, year after year, to be continued indefinitely. therefore sustainable harvesting of fish should be model (6) (7) (8), the equilibrium solution that model is not dependent on time