Nudibranch Diving & Tide Pool Experience

2026/04/18

Nudibranch Diving & Tide Pool Adventure in Kushimoto

Yesterday the ocean was calm, but today the swell from the typhoon returned.

Even at deeper depths, we could feel a bit of movement. However, visibility was good and the water temperature was around 20°C, so the conditions were still comfortable.

Today’s plan was a combination of nudibranch diving and tide pool photography.

Despite the swell, we were able to find and observe a variety of small marine life.

First, let’s start with some tiny species.

We found Mnestia girardi, about 2mm in size.

If you look closely, you can even see its eyes. It’s a very cute member of the sea slug group, although its shape is quite different from typical nudibranchs, so it’s easy to miss.

Next, we finally found Placida babai.
This species appears more often in spring, but numbers have been low this year. Today, we were lucky to find two individuals, each about 2mm.

Moving on to slightly larger ones, around 1cm in size.

We encountered Thecacera pacifica, which has also been rare recently. It was great to see one again after a while.

We are still hoping to find even smaller individuals, but they have been hard to locate this season.

Lastly, we observed Longibranchus putnami laying eggs.
The nudibranch itself was about 1cm, but the eggs next to it were only millimeters in size.

From these tiny eggs, many larvae will hatch and grow. Although we cannot observe them during their drifting stage, we hope they will grow safely and return to delight us again.

During the dive, we also encountered many flatworms, including Thysanozoon nigropapillosum.
They were gathered in several spots, possibly feeding together.

Their colorful patterns are very beautiful, especially when photographed up close. The yellow dots look like stars in the night sky.

We visited the tide pools as well.

Today’s low tide was even lower than yesterday, making access easier.

We discovered a new area where Barred-chin blenny can be found.

These fish live in very shallow water, less than 10cm deep, so you can photograph them without fully entering the water.