Tide Pool Exploration at Jogashima: The Beginning of my Passion.

Jogashima, a small island off the coast of Kanagawa Prefecture, is known for its rugged coastline, wide views of the Pacific, and hidden tide pools teeming with beautiful marine life.

(more info here!)

It’s a place where rocky outcroppings meet the sea in dramatic distinction, creating pools that reveal entire miniature ecosystems at low tide. The air is usually fresh with a slight ocean cold, and on clear days, you can even catch a glimpse of Mt. Fuji in the distance! It’s an ideal spot for any ocean lover, and for beginners like my friend and me, it was the perfect playground to discover marine life up close, without venturing too deep into the open sea…

On a cold Wednesday morning, November 29th, 2023, we arrived at Jogashima by 9 a.m., ready to snorkel and explore the intertidal zone. The conditions were perfect for a day of tide pool exploration: the sea temperature was at 18°C, while the air was a brisk 13°C. With visibility stretching to 8 meters and a gentle southwest breeze, we were treated to a clear, expansive view of the pools. The spring tide had exposed a large area for us to explore, bringing out a bloom of marine life just waiting to be discovered. We’d even sipped on hot cocoa beforehand, hoping the cacao polyphenols would give us a bit of warmth as we prepared for the cold-water experience ahead.

As beginner marine enthusiasts, we were both excited and a bit nervous. The intertidal pools offered a safe zone where we could observe marine life without worrying about currents or deep waters. I felt fortunate to have a friend who shared my curiosity and enthusiasm, especially since it’s rare to find someone willing to brave the ocean in late November! Her companionship made this experience even more meaningful. :)

After suiting up, my friend in a 5mm wetsuit and me in a 3mm, we gradually entered the water. The cold shocked our bodies but soon passed as we began to explore. The tide pools were alive with all kinds of creatures. Sea hares (Aplysiida) glided gracefully across the sandy bottoms. They have an incredible sense of smell and can follow even the lightest scent using their ear-like structures, called rhinophores. Various crustaceans scurried in and out of the rocks, while countless blennies darted around in their shallow, rocky habitats. A few vibrant nudibranchs caught our attention, and we even spotted a pair of youjiuo, or seaweed pipefish (Syngnathus schlegeli), moving through the pools! These demersal fish, meaning they live and feed near the sea bottom, can grow up to 30 centimeters (12 inches) in length.

We swam around for two to three hours, completely absorbed by the beauty (and the freezing temperature) of this hidden world. As the day wore on, we finally climbed out of the water, chilled to the bone. We warmed up with a hearty sashimi teishoku lunch, the perfect way to celebrate our time in the ocean.

With renewed energy, we decided to explore more of the island, stopping by Akabane Kaigan. This beach had unique, dark, pebble-like sand, giving us yet another peek at the diverse landscapes around Jogashima. My friend discovered what looked like a piece of an animal’s backbone, adding a bit of mystery to our find. Nearby, we stumbled upon a massive net washed ashore, a reminder of the impact of marine debris on coastal environments. Despite our best efforts to lift it, the net stayed anchored in place.

Eventually, the sun began to set, and we boarded the bus home. As I sat looking out the window, I felt a growing sense of appreciation, not only for the beauty of the ocean but for the shared passion and curiosity that had brought me here. That day marked the beginning of a deeper connection with the ocean for me, a spark that has only grown since. ★