Fishery stock assessment and management system in Japan
Tetsuichiro Funamoto
Hokkaido National Fisheries Research Institute, Fisheries Research Agency, Kushiro, Hokkaido, Japan
E-mail: tetsuf@fra.affrc.go.jp
For marine fisheries resources around Japan, stock assessment is conducted for 84 stocks of 54
species based on a Japanese control rule for acceptable biological catch (ABC). This rule shows
how to calculate ABC for each stock according to amount of available information. For example,
when biomass is estimated, a type-I rule, which setd fishing mortality (F) at an appropriate level,
such as Fmed and F0.1, is applied to determine ABC. In addition, this type-I rule specifies the
establishment of a recovery reference point called Blimit, and if biomass (or spawning stock
biomass) falls below Blimit, then ABC is calculated based on reduced F. Virtual population
analysis is the main stock assessment model used in Japan, and this model was applied to 28
stocks in fiscal year 2013. In recent stock assessments in Japan, vigorous efforts have been made
to: (1) work with fisherman to attain consistency of stock assessment results with fishermen’s
observations about stock status, (2) develop ABC estimation methods that are robust under data
poor situations, and (3) exploration of recruitment estimation methods to improve the accuracy
of future stock projections. Current issues for fish stock assessment in Japan include:
(1) modification of stock assessment approaches in consideration of ecosystem-based
management, (2) introduction of an observer program to understand actual discards, and
(3) translation of stock assessment reports into English so that stock assessment results are
available to the global fisheries community.