TOSHIO Katsukawa

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 We developed a stage-structured model to describe optimal energy allocation among growth, reproduction, and survival. Our model includes stochastic fluctuations in survival rate at age 0 but constant survival rate at older ages. Many mammals and birds cease to grow after maturity (i.e., determinate growth), whereas organisms in a number of other taxa grow(More)
Southern bluefin tuna (SBT) were heavily depleted in the mid-1980s, and the fishing quota has been restricted since 1985. As a result of this restriction and protection of immature individuals, spawning stock biomass (SSB) recently has shown a slight increase. The Commission for the Conservation of Southern Bluefin Tuna (CCSBT) has the target of recovering(More)
To avoid overfishing, we must maintain sufficient productivity of the fish population. Threshold or limit reference point management is widely used for this purpose. In many cases, a minimum biomass level is used in conjunction with other management measures that control exploitation above the threshold (Myers et al., 1994). In this study, I explore a(More)
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