Presentation Information
[O08-03]Diversity of Marine Environments and Sustainability of Food Culture in Shimokita Geopark: Blessings from Three Distinct Marine Areas and Responses to Global Environmental Change★Invited Papers
*Kenichi Sasaki1 (1.Japan Agency for Marine-Earth Science and Technology)
Keywords:
Shimokita Geopark,Marine Environments,Global Environmental Change
The Shimokita Geopark, certified by the Japan Geopark Network (JGN) in 2016, encompasses five municipalities on the Shimokita Peninsula in Aomori Prefecture. This region consolidates the four major geological units related to the formation of Northeast Japan within an area of approximately 60 km square, and is characterized by its unique "broadaxe-shaped" topography. Due to these topographical characteristics, the peninsula is bordered by three marine areas: Mutsu Bay, the Tsugaru Strait, and the North Pacific Ocean. Their distinct properties fostering diverse food cultures and human activities adapted to each specific marine environment.
This presentation focuses on the physical and chemical oceanographic characteristics, as well as their fluctuations, which support the marine resources forming the foundation of Shimokita’s food culture.
The characteristics of the three sea areas are summarized as follows. The Tsugaru Strait (maximum depth approx. 450 m) is dominated by the Tsugaru Warm Current, yet exhibits complex dynamics due to the inflow of the Coastal Oyashio current from the Pacific side during winter. Mutsu Bay (maximum depth approx. 75 m) connects to the Tsugaru Strait via the Tairadate Strait; it is a highly enclosed inner bay environment comprised of water masses originating from the Tsugaru Warm Current, while on the Pacific Ocean, water masses from both warm and cold currents approach the this environmental diversity yields a wide variety of fishery resources, including Pacific bluefin tuna, scallops, Japanese flying squid, monkfish, and Pacific cod.
In recent years, Shimokita's marine areas have undergone significant transformations as the global environment has changed, becoming a "reality" perceivable through direct experience. For instance, rising sea temperatures have caused significant impact including the mass mortality of farmed scallops in Mutsu Bay in FY2025 (with mortality rates exceeding 80%), as well as a shift in what fish species are landed in local waters. These shifts directly threaten the sustainability of the Shimokita region's food culture. Furthermore, the progression of ocean acidification due to increasing atmospheric CO2 concentrations is a concern, posing a potential negative chain reaction for future resources. However, our recent research reveals that the complex seafloor topography of the Tsugaru Strait maintains a positive influence on the fishery resources of the area.
In this report, we introduce scientific findings regarding the marine environment and discuss the sustainability of "Geopark Gastronomy" in Shimokita.
This presentation focuses on the physical and chemical oceanographic characteristics, as well as their fluctuations, which support the marine resources forming the foundation of Shimokita’s food culture.
The characteristics of the three sea areas are summarized as follows. The Tsugaru Strait (maximum depth approx. 450 m) is dominated by the Tsugaru Warm Current, yet exhibits complex dynamics due to the inflow of the Coastal Oyashio current from the Pacific side during winter. Mutsu Bay (maximum depth approx. 75 m) connects to the Tsugaru Strait via the Tairadate Strait; it is a highly enclosed inner bay environment comprised of water masses originating from the Tsugaru Warm Current, while on the Pacific Ocean, water masses from both warm and cold currents approach the this environmental diversity yields a wide variety of fishery resources, including Pacific bluefin tuna, scallops, Japanese flying squid, monkfish, and Pacific cod.
In recent years, Shimokita's marine areas have undergone significant transformations as the global environment has changed, becoming a "reality" perceivable through direct experience. For instance, rising sea temperatures have caused significant impact including the mass mortality of farmed scallops in Mutsu Bay in FY2025 (with mortality rates exceeding 80%), as well as a shift in what fish species are landed in local waters. These shifts directly threaten the sustainability of the Shimokita region's food culture. Furthermore, the progression of ocean acidification due to increasing atmospheric CO2 concentrations is a concern, posing a potential negative chain reaction for future resources. However, our recent research reveals that the complex seafloor topography of the Tsugaru Strait maintains a positive influence on the fishery resources of the area.
In this report, we introduce scientific findings regarding the marine environment and discuss the sustainability of "Geopark Gastronomy" in Shimokita.