Category: Shallow Coast


Underwater Fact 153

Despite its name the ‘Common Skate’ is nowadays extremely rare.

Common SkateCommon Skate   © Oceana.org

Skates are found in most parts of the world, from the shallow waters on the coast to depths of 2700 metres. They are flattened fish that look very similar to their well-known relatives: the rays.
The major difference between rays and skates is their reproductive strategy. Rays are live bearing (viviparous) while skates are egg-laying (oviparous).

The Common Skate or Blue Skate (Dipturus batis) is the largest skate in the world attaining a length of more than 250cm.
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Underwater Fact 152

The Veined Octopus or Coconut Octopus is the only invertebrate known to use tools, and one of only two octopuses known to exhibit bipedal behaviour by “walking” on two of its legs.

Coconut octopus in Lembeh   © Marco Carnovale

Originally discovered in 1964, Amphioctopus marginatus lives in the tropical waters of the western Pacific Ocean.
The species is commonly known as Veined Octopus, named after the distinct dark brown lines that branch over the mantle and down the arms of the animal. The edges of their arms are often darkened in contrast to the white-blue suckers.

Coconut Octopus   © franklin tom

Another common name for these molluscs is Coconut Octopus, which relates to a very peculiar and interesting behaviour of the species: it carries coconut shells and clam shells across the ocean floor and uses them to build fortresses.

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Underwater Fact 150

Lionfish are venomous, not poisonous – there is a difference.

Pterois640Lionfish   © Sophia Volzke

Although both venomous and poisonous animals produce a toxin that can be harmful to other organisms, the method of delivery is different. Venomous organisms use a specific apparatus like spines or teeth to inject their toxin. Poisonous organisms, on the other hand, require their victim to ingest or absorb the toxin.

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Underwater Fact 146

Octopuses have the largest brains of any invertebrate.

Common Octopus   © ARKive

The fact that these creatures, whose ancestors diverged from the lineage that would lead to ours roughly 500 to 700 million years ago, have developed intelligence, emotions, and individual personalities is challenging our understanding of consciousness itself.

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Underwater Fact 139

The Jellyfish population in Japanese waters is 100 times greater than 20 years ago.

Nomura’s Jellyfish swarm   © Amazing Story’s

Nomura’s Jellyfish are in the same size class as the lion’s mane jellyfish, the largest jellyfish in the world.
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Underwater Fact 135

Turritopsis Nutricula is a species of Jellyfish that can age backwards.

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Underwater Fact 133

Sand Tiger Sharks are the only sharks known to come to the surface and gulp air. They store the air in their stomachs, which allows them to float motionless in the water while hunting.

Sand Tiger Shark   © Mark Fox

This Shark is not related to the Tiger Shark (Galeocerdo cuvier) however, it is a cousin of the Great White Shark (Carcharodon carcharias).
Despite its fearsome appearance and strong swimming ability, it is a relatively docile and slow-moving shark that will only attack a human when threatened.

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Underwater Fact 132

The Christmas Frigatebird is a highly endangered species of sea bird that only breeds on Christmas Island in the Indian Ocean.

Male Christmas Frigatebird   © Save Nature Save Human

Male Christmas Frigatebirds begin their mating displays in late December, inflating their scarlet throat pouches during courtship.

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Underwater Fact 126

Horseshoe crabs have ten eyes – the largest pair is used only for finding mates.

Horseshoe Crab – Vision   © Sophia Volzke

A quick glance at the horseshoe will show the crab’s two compound lateral eyes.
This is unusual because no other living animal from the Crab’s sub-family, Chelicerate, possesses compound eyes.
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Underwater Fact 115

A species that is actually benefiting from climate change with its geographic range expanding: the Bigfin Reef Squid.

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