Marine Wildlife Center of Japan

Ecosystems That Begin With Drift Ice

The Okhotsk Sea is a unique body of water—the southernmost in the world where drift ice arrives. When the drift ice that covers the sea throughout winter begins to melt with the coming of spring, phytoplankton living within the ice (ice algae) are released into the surrounding waters. This triggers a rapid, large-scale bloom known as the ice-edge bloom.

The massive increase in phytoplankton provides essential nutrients for zooplankton such as krill and copepods. In turn, fish, seabirds, and marine mammals gather in these waters to feed on them. In the Okhotsk Sea, a vast ecosystem thrives—one that begins with drift ice and connects life from one level to the next in an unbroken chain.

Learn The Role of Top Predators

The Okhotsk Sea is a region where the assemblage of marine mammals changes dramatically with the seasons. Different life cycles unfold and overlap throughout the year, shaping the rich ecosystem unique to this sea. We focus on these seasonal changes and conduct ongoing surveys of marine mammals, examining their population density, distribution, behavior, and diet. Clarifying how living organisms interact with their environment is one of our key roles. In recent years, the decline in the volume of drift ice and the earlier timing of its retreat have raised concerns about their impacts on marine mammals. To ensure that we stay abreast of these changes, we carry out long-term monitoring and continue to document what is happening now in the Okhotsk Sea.

Share Let’s Explore the Sea Together! (Abashiri Nature Cruise)

We invite you to see and experience firsthand the pinnipeds, cetaceans, seabirds, and the environment of the Okhotsk Sea in which they live. By observing the scenes through direct experience, you can truly appreciate how vital drift ice is to this sea. Using the survey data we have accumulated over the years, we encourage you to think together with us. Why not board our research vessel Chipashiri and experience some of our ongoing research activities? Abashiri Nature Cruise offers a rare opportunity to be close to the front lines of scientific research and to enjoy a truly special experience.
Abashiri Nature Cruise

Our current research projects

  • Drift-Ice Season Surveys

    Look for seals on the drifting ice!
    During the season when drift ice spreads across the sea, we head out by boat to quietly search for and observe seals resting on the ice. While experiencing the harsh yet beautiful winter environment of the Okhotsk Sea, we study the ecology of seals in ways only possible here.

  • Marine Environment Surveys

    Explore the marine environment and its connection with living organisms!
    We regularly collect seawater to measure temperature and salinity, observe ocean fronts and surface conditions, and record the appearance of small marine organisms such as krill and jellyfish. By accumulating environmental data, we explore the relationships between the sea and its living organisms.

  • Fin Whale Surveys

    Identify individual fin whales!
    We photograph the area around the dorsal fins of fin whales to identify individuals and use drones to measure body length. Each data point provides an important clue to understanding fin whale behavior and growth, helping us gain a deeper insight into their ecology.

  • Acoustic Surveys

    Locating whales and dolphins through sound!
    Using microphones, we investigate where cetaceans are and what kinds of sounds they produce. Even when animals are out of sight beneath the surface, sound allows us to study their lives—making acoustic research an indispensable tool.

  • Sato’s Beaked Whale Surveys

    Waiting for Sato’s beaked whales to surface!
    We record the time these whales spend at the surface and underwater to clarify their diving patterns. Using drones, we photograph individuals for identification and record their vocalizations with underwater microphones. This research brings us closer to understanding the still-mysterious lives of Sato’s beaked whales.

Act How Should We Protect the Okhotsk Sea? How Should We Live with It?

As the Okhotsk Sea continues to change all the time, how should we address these changes in the years ahead? Climate change and shifts in drift ice patterns are steadily transforming the marine environment. Observing and accurately understanding these changes is an urgent task. Based on field surveys and data accumulated over many years, we strive to convey the present state of the Okhotsk Sea and propose concrete actions that can only come from our perspective and experience. In our aim for a future where we live in harmony with the sea, we reflect on what each member of society can value and how we can engage with this remarkable environment.