Top 10 Mysterious Ocean Secrets
Trivia Top 10 Mysterious Ocean Secrets



Top 10 Mysterious Ocean Secrets

VOICE OVER: Rebecca Brayton WRITTEN BY: Dylan Musselman
What lies in the deepest depths of the ocean? For this list, we'll be looking at some of the most mysterious phenomena, creatures, and places in the sea. Our countdown includes Giant Squid, The Milky Sea Phenomenon, Giant Cannibal Shark, and more!

Top 10 Unexplored Ocean Secrets

What lies in the depths? Welcome to WatchMojo, and today we’ll be counting down our picks for the Top 10 Unexplored Ocean Secrets.

For this list, we’ll be looking at some of the most mysterious phenomena, creatures, and places in the sea. The ocean covers over 70% of our planet’s surface; but there’s still a LOT we don’t know! Without further ado, let’s dive in.

#10: Giant Oarfish

The Giant Oarfish is something out of a nightmare. It’s the world’s largest bony fish, with the longest confirmed specimen measuring 26 feet. As if that’s not scary enough, there are unverified claims of giant oarfish up to 56 feet! It’s thought that they might be responsible for sightings of “Sea Serpents” throughout history. We’ve rarely spotted these fish in their natural habitat, aside from a few lucky instances. For the most part, what we do know about this species is the result of their bodies washing ashore after death, to the horror and fascination of beachgoers. How do they reproduce? Are they solitary? We can’t be certain. For now, more is unknown than known about these creatures.

#9: The Milky Sea Phenomenon

If you’re ever at sea and find yourself surrounded by a strange blue glow, take comfort that you’re not alone in being confused. Sailors have reported this Milky Seas effect for hundreds of years, but only in the last few decades have we had evidence to explain it. Based on water samples and satellite images, the current hypothesis is that the glow is created by bioluminescent bacteria. That being said, it would take an extraordinary amount of them to produce such light. So even if it is bacteria, what’s causing them to group together on the surface like that?

#8: Stronsay Beast

In 1808, the body of a strange creature washed up on the shores of Scotland’s Orkney Islands. A long necked sea creature described to have a small head, bristly mane, and three pairs of legs, it was dubbed Halsydrus pontoppidani. It was allegedly 55 feet long and was thus labeled a sea monster by the locals. The best that people can guess is that it was a basking shark, but there’s definitely some disconnect in the descriptions, even when taking into account decomposition. Others believe it to resemble a Plesiosaur, a reptile that used to roam the oceans in the Triassic Period. But Plesiosaurs went extinct millions of years ago. So what was this beast? A mystery, that’s what!

#7: Giant Cannibal Shark

In 2003, scientists tagged a 9-foot great white shark so that they could keep track of it to study. Several months later, the tag washed up on shore. When they checked the data from the device, they saw something strange - the shark plunged deep underwater and experienced a sudden surge in temperature, which remained the same for over a week. The only reason that experts could think of, is that the shark had been eaten. But what hunts a 9 foot great white? Possibly another, even larger cannibal shark, one that has never been seen to this day but terrifies us nonetheless.

#6: Hadal Zone

Named after Hades, the Greek god of the underworld, the Hadal zone is every bit as daunting and mysterious as its namesake suggests. The zone refers to the very deepest parts of the deepest trenches. It begins at a depth of roughly 20,000 feet and continues down to 36,000 feet. The conditions present this far below the sea make it challenging to explore these areas with our current technology. So for now, we can only imagine what strange, unworldly creatures live in such an extreme environment.

#5: The Immortal Jellyfish

Turritopsis Dohrnii, commonly known as the Immortal Jellyfish, actually lives up to its name. When this jellyfish is put in danger, it can reverse its development back into that of a polyp, starting its cycle of growth again. In essence, these jellyfish are somehow able to completely recycle their cells. This makes them essentially immortal, though not invincible, as they can still fall victim to predators or disease. These jellyfish are of great interest to scientists, who hope to one day harness this incredible ability and use it to extend human life expectancy.

#4: The Abyssal Zone

The Abyssal Zone is the oceanic depth that ranges from 6,000 to 20,000 feet below sea level. So while it might not be as deep as the Hadal Zone, it’s actually the single largest habitat for life on our planet. The vast majority of this area remains unexplored, but scientists already know that there are strange species and specimens that are endemic to this region - meaning they live only here. What other mysteries lie in wait in this massive part of our oceans? Unfortunately, given current technological limitations, it might be some time before we can study these depth.

#3: The Purple Orb

Jokingly referred to as Blobbus Purpulus, this strange object looks like some alien egg or sci-fi artifact. Discovered in 2016 in the Channel Islands off California, the odd purple orb understandably generated a lot of interest. But even upon closer inspection, scientists were just as puzzled as they were upon first sight. They think it might be a pleurobranch (also known as a sea slug), or a velutinid (a type of snail), but none that they know of are purple. This is the only such object/creature that’s been found like this and remains a mystery to scientists.

#2: Giant Squid

All hands on deck! Taking second place is the legendary kraken, or the more realistically, Giant Squid. Giant Squid were thought to be a tall tale for many years, but a photo of one emerged in 2004. Although we’ve pieced together a bit more footage since then, almost everything about these strange creatures remains elusive. We don’t even know how big they can actually get. If they can truly reach massive sizes, then perhaps this creature gives some credence to the Kraken stories of old, long thought to be mere legend.

Before we unveil our top pick, here are a few honorable mentions.

The Yonaguni Monument
Are These Strange Structures Near Japan Man-Made or Natural Formations?

The Cursed Gulf of Mexico Shipwreck
Every Attempt to Investigate This Mysterious Shipwreck Has Gone Wrong

Phantom Island of Bermeja
This Island Is on Several 16th Century Maps, But Is Nowhere to Be Seen

The Julia Recording
Is This Deep Sea Recording a Sea Monster or an Iceberg?

#1: The Mariana Trench

The deepest known point on Earth, this region descends to almost seven miles below sea level and stretches over 1,500 miles along the seafloor. You could drop Mount Everest in this trench and not even be able to see its peak from the surface. Only a few people have ever been down here to investigate, where the pressure is 8 tons per square inch and the temperature is just above freezing. Very little is known about life this deep in the ocean. It’s thought that the pressure is too much for calcium, and therefore bones, to form. Yet, fish have reportedly been spotted. The deepest and most inaccessible point on Earth remains one of the planet’s most enduring mysteries.