Credit: Kat Brown

Japanese Puffer & Underwater Circles

Japanese puffer fish are among the most controversial and enigmatic species of fish found in the waters of Japan. The species is primarily known for the intricate circles that the fish create at the bottom of the ocean – which have actually been discovered by startled researchers only a few years ago. The circles have, at first, been a topic of great distress in the scientific community, due to their remarkable resemblance to modern day crop circles, but have subsequently been linked to the intricate mating rituals of the puffer fish.

Also known as blowfish, puffer fish have a few unique traits that set them apart from many other types of underwater species. This type of fish can commonly be found in the waters of Japan and is known mostly for its characteristic slow movements that often make it vulnerable to predators. To counter for that disadvantage, puffer fish have developed remarkably flexible stomachs and an ability to ingest a large amount of water – or air, when needed. They basically end up transforming into an inedible “balloon” that predators can no longer pick on, and some species even feature spines that would further discourage even the most relentless predators from trying any tricks.

Another unique trait of the Japanese puffer fish is their uncommon mating ritual. Discovered in 1995, the “underwater crop circles” that male Japanese puffer fish put together are actually designed to attract mates. Males essentially swim along the bottom of the sea, and use their fins to disrupt the sand and sediments to create some remarkably intricate and geometrically correct patterns. The circular shapes generally measure about 7 feet in diameter, and when they are finished, they are usually inspected by females, who will choose to reproduce with the “best” circle makers, laying their eggs in the center of the circular shape.

The unique circles that the puffer fish construct can range between basic, crater shaped mounds, to highly intricate circular patterns of intermittent lines and shapes, such as radially aligned valleys and ridges. In many cases, the males that build these shapes go through a lot of trouble attempting to make them more enticing, in some cases even bringing fine sediments and fragments of seashells to add to the aesthetic appear and create intricate shadow and color patterns. A curious fact about the building process is that the males themselves use a circular pattern that also uses water currents to help bring finer sediments closer to the center of the pattern.

Although highly fascinating and intricate, the circles are somewhat curious due to their enigmatic nature. Most researchers will admit that, while it is somewhat clear that females will examine various circles and choose the one that “works” best for them, it is entirely unclear as to what criteria they actually use when choosing a circle. According to some scientists, the various designs, shapes and angles are not even an issue, since the females are usually more interested in the fine sand in the center. The behavior of Japanese puffer fish is still worth investigating closely, and the “artistic” skills of these cute fish have definitely managed to take the world by storm.

Blane Perun

Diver - Photographer - Traveler

Whale in Ocean