Japan’s Toyama Bay: Mystical Home of Squids Big & Small

Many people outside Japan have probably never heard of Toyama or even know where it is exactly, but the ocean enthusiasts who have heard of it probably associate Toyama with squids, both big and small. The video of a 10-meter-long giant squid filmed in Toyama Bay by the owner of the dive shop Kaiyu Toyama during Christmas 2015 went viral globally—such sightings are rare, but these squids pop up on an average of once a year in the bay. 

Text and photos by Martin Voeller

During early spring of each year, the firefly squids ascend to the surface and put on a transcendental show of their own—their luminous organs glowing bright blue as they spawn and are agitated by waves on the ocean surface near the shoreline. This results in the shorelines being blanketed in blue jewels at night, a scene that attracts many people each year for this special, mystical encounter.

Squids are not the only attraction of Toyama, however. The ocean here is unique in its own right, and although I secretly wished for an encounter with a giant squid like in Jules Verne’s Twenty Thousand Leagues Under the Sea, I reached out to Mr Akinobu Kimura of Kaiyu Toyama to guide and show me what this mystical ocean offers.

Juxtaposing a natural fish tank with the Japanese Alps

Toyama Bay is located in the center of the Sea of Japan and is affected by the Tsushima Current. Whereas the Kuroshio Current brings up warm water filled with tropical fish and exotic sea creatures to Izu Peninisula from the Pacific Ocean (see my previous article in issue #95 on diving in Izu), the Tsushima Current is the northeastward-flowing branch of the Kuroshio along the western coast of Japan, which reaches down to 300m from the sea surface. This current affects the bay typically during the warm summer months, where the sea temperatures can go up to 30°C (86°F). Sea life which prefers warmer waters thrive in this zone, but during the winter months when this current is absent, the sea temperatures near the surface can dip down to 8°C (46°F). That is a whopping 22 degrees difference between the two opposite seasons.

One distinct marine feature of Toyama Bay is its steep terrain. Toyama Bay is 1,200m deep, and this depth can be observed just a short distance away from the coast—because of the steep slope to the ocean floor, the bay quickly becomes very deep. The upwelling currents from the sea floor bring exotic, cold-dwelling, deep-sea creatures from the bay’s dark depths, and because this is so near the coast, it is not uncommon for divers to encounter such marine life. And due to this close proximity from the port, the bay is like a fish tank for the local fishermen. Some species, like broad velvet shrimp and firefly squid, can only be caught here, and they are local delicacies. Also popular from the bay as seafood are the red snow crabs and yellowtail fish. 

Opposite the bay lies mountainous terrain, which is part of the Japanese Alps, and the mountain ranges covered in snow on a clear, winter day will take your breath away. Snow, which falls on these 3,000m high mountains, eventually melts and becomes part of the seven rivers that pour into Toyama Bay. 

Freshwater pouring into ocean water creates water of different salinities. As a result, the visibility can become blurry near the surface. Yet, this fast-flowing and nutrient-rich mixture is the reason why the bay has such a fertile marine environment. Out of the 800 species found in the Sea of Japan, 500 can be found in Toyama Bay—the biodiversity is exceptional and unique here.