Perfilado de sección

  • Discussion: combining results 1-3,


    　We can predict that during the years when a large amount of precipitation is observed in the fall, a decrease in the amount of Ammonytes sp. is observed in the spring.

    　In these years, it may be necessary to control the catch in order to avoid overfishing.

    How is the larva density, shown in Figure 4, determined?

    　The number of eggs is generally proportional to the body weight of the female parent. Hence, if the nutritional status of the female parent is the same every year, then the number of eggs can be determined by the number of parents.

     　However, the survival rate of larvae fluctuates greatly due to natural phenomena as examined here, and there is no room for human control.

     　The very least that humans can do (aside from seedling release) is to increase the number of female parent fishes by avoiding overfishing. Furthermore, prohibiting fishing would result in the growth of older and larger parent fish, and the number of eggs spawned would also increase. At that point, we would have to wait for years when the survival rate of larvae is high.