Length-weight relationship equation considering seasons for Japanese flounder (Paralichthys olivaceus) in northwestern Kyushu, Japan

Abstract

Japanese flounder is one of the most important fishery resources in Japan, and stock enhancements and assessments have been conducted. However, the resolution of important data such as length composition has been reduced due to factors such as survey budget and personnel shortages. On the other hand, at markets and fishing ports, weight data has been accumulated over the past years as basic data important for buying and selling fishes. Therefore, it is possible to create length compositions from weight data over the past by creating a relationship that converts weight data to length data. As a result, a model with two seasons (April-September and October-March) was adopted. The standard errors of both models were very small and were considered robust. The results of this study are expected to be used to estimated length composition with a high degree of accuracy and to contribute to improving the accuracy of stock assessment and estimating the effects of stock hatchery releases.