Zusammenfassung: This formula is based on the Richards formula, which includes well-known growth formulae, and is invariant for allometry. It is expanded by exchanging the independent variable from time to its function, in other words the cumulative water temperature. This standard formula includes the method of substituting values for the cumulative water temperature into the time term, the mathematical model of adding sine functions to the time term, and switched growth rate models. This standard model is given by general theory, which makes the character of parameters clear and helps to analyze the growth formula statistically.

Zusammenfassung: The statistical model used is extended to estimate abundance from commercial catch-at-age data for many of the major commercial fish species in the world. The model combines commercial catch-at-age data and research survey estimates of fish abundance; extends the model to allow correlated errors among ages within a year for the survey estimates of fish abundance. Method is formulated for modeling the fishing mortality on the oldest ages of the fish caught. Estimates are obtained using maximum likelihood. The level of correlation among ages is sufficiently large to produce large biases in the standard methods for some stocks. The statistical model that includes correlated errors greatly reduces bias and increases efficiency if the correlation in the estimation error is large.

Zusammenfassung: The statistical model for extraction is a binomial distribution. The conventional method for employing this binomial model is based on approximation to a normal distribution. The Bayesian statistical method, which assumes that the prior distribution of parameters is uniform, is preferable to the conventional method, and two theorems demonstrate that this model corresponds well with the conventional method. Furthermore, this model is simpler to understand and easier to calculate by micro-computer than the conventional method.

Zusammenfassung: The purpose of this study is to construct a model that can predict the impact on fisheries caused by coastal development activities. To accomplish this, many species of fish must be incorporated in the model, because each type of fish has a different value as a fishery resource and a different behavior for the same impact. In addition the effect of fish swimming must be considered because even when the total resource amount of fish does not change, fish may still disappear from the object area. These factors make the model structure complicated. Meanwhile, a new concept called “object oriented programming” (OOP) is attracting the attention of modellers. In this paper, we have constructed a model called the “shallow-sea ecological model” (SSEM), by using Smalltalk, which is representative of the OOP language. This showed that the fishing ground environment are expressed very flexibly and plainly by Smalltalk.

Zusammenfassung: The method of guaranteed estimation is used to estimate the unknown parameters of two nonlinear regression models. The first describes the relations between the body size structure of zooplankton and the biomass of planktivorous fish. The second estimates time-lag between the dynamics of cladoceran egg production and dynamics of phytoplankton.