The Mitsui & Co. Environment Fund

Introduction to Grant Projects

Kitakyushu City Institute of Environmental Sciences Manager Yoko Kajiwara

Improvement of water quality and changes in occurrence of sessile animals in Dokai Bay

Research grant

Project Description

Dokai Bay, on the City of Kitakyushu, used to be called the "Dead Sea" for its level of water contamination. Efforts to clean the water, however, led to a revival in marine organisms into the 1990s. This said, eutrophication was still well advanced at this point, and organisms within the bay remained weak and sparse. Here, it is presumed that as water quality continued to improved, there has been a change in the composition of such organisms and an associated increase in diversity. In this study, we survey the condition of sessile animals and assess the degree of environmental recovery of the bay from the aspect of its ecosystem.

Marine resources/foodPreservation of biodiversity and ecosystem
Grant year
FY2009 Research Grants
Grant term
3 years
April 2010 - March 2013
Grant amount
6,909,000 yen
Activity region
City of Kitakyushu
Sampling of purple clam (Solerellina diphos) within Dokai Bay

Overview of the Organization

Yoko Kajiwara, Manager
Yoko Kajiwara, Manager
Specialty field
Environmental sciences
Affiliated academic society
The Sessile Organisms Society of Japan
Obtained a Master degree from the Faculty of Agriculture at Kyushu University in 1983. Afte graduating in 1983, joined the Pollution Control Bureau, City of Kitakyushu. In 1987 joined the Institute of Environmental Sciences in the same position. In 1995, joined the Environment Bureau. In 1997, moved to the Public Health and Welfare Bureau. In 2001 was appointed Manager at the Institute of Environmental Sciences.
Collaborating researchers
Akiko TERASHI, testing/research leader, Institute of Environmental Sciences, City of Kitakyushu; Junko HIROSE, Institute of Environmental Sciences, City of Kitakyushu; Machiko YAMADA, Professor, Fukuoka Women's University
Research record
  • (1) Comprehensive survey of Dokai Bay, Report III, Kitakyushu City Institute of Environmental Sciences, 1994
  • (2) Yoko KAJIWARA, Machiko YAMADA. "Study on Occurrence Characteristics of Sessile Animals and Classification of Eutrophic Level in Dokai Bay." Journal of Japan Society on Water Environment 20 (3), 185-192, 1997.
  • (3) Takeshi KOHAMA, Shigeru MONTANI, Yoko KAJIWARA, Machiko YAMADA. "Population dynamics of sessile bivalves Mytilus galloprovincialis and Xenostrobus securis in hyper eutrophicated bay, Japan." Journal of Japan Society on Water Environment 67 (4), 664-671, 2001.
  • (4) Yoko Kajiwara, Nobuhisa Kashiwagi, Kiwao Kadokami: Nationwide study of dioxins in the freshwater fish Carassius auratus (gibelio) langsdorfii (crucian carp) in Japan: Concentrations and estimation of source contribution ratios, Chemosphere 69,1177-1187,2007