Coral reefs can undergo relatively rapid changes in the dominant biota, a phenomenon referred to as phase shift. Degradation of coral reefs is often associated with changes in community structure towards a macroalgae-dominated reef ecosystem due to the reduction in herbivory caused by overfishing. We investigate the coral-macroalgal phase shift due to the effects of harvesting of herbivorous reef fish by means of a continuous time model in the food chain. Conditions for local asymptotic stability of steady states are derived. We have shown that under certain conditions the system is uniformly persistent in presence of all the organisms. Moreover, it is shown that the system undergoes a Hopf bifurcation when the carrying capacity of macroalgae crosses certain critical value. Computer simulations have been carried out to illustrate different analytical results.

珊瑚礁的优势生物区会发生相对快速的变化，这种现象称为相移。由于过度捕捞引起的草食动物减少，珊瑚礁的退化通常与社区结构向以藻类为主的礁石生态系统的变化有关。我们通过食物链中的连续时间模型来研究由于收获草食性礁鱼而产生的珊瑚-微藻相变。推导了稳态局部渐近稳定的条件。我们已经表明，在某些条件下，系统在所有生物体的存在下都是一致持久的。此外，还表明当大型藻类的承载能力超过某个临界值时，系统会经历霍普夫分支。