Category: Estuaries


Underwater Fact 151

Spiny Gurnards feature large colourful fins and venomous spines that help searching for food.

Eastern Spiny GuarnardEastern Spiny Gurnard   © Klaus Stiefel

Gurnards, also called Sea Robins, are recognised by their beautiful large pectoral fins which they flap like wings, opening and closing them while swimming. This colourful display is mainly intended to distract predators.
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Underwater Fact 141

Bottlenose Dolphins give each other names by calling out to each other in individual whistling tunes.

Bottlenose Dolphin   © Flip Nicklin

Out in the pristine waters of Sarasota bay in Florida, scientists from Mote Marine Lab have spent the past thirty years studying the local residents – Bottlenose Dolphins.
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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 113

The New Zealand Longfin Eel utilises special tubes that channel water into its nose, which enables this species to have a greater sense of smell than Great White Sharks.

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Underwater Fact 111

One of the largest freshwater fish in the world is the Giant Freshwater Stingray. Its poison is most like that of a Rattlesnake.

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Underwater Fact 109

Cannibalistic Cephalopods can be a real danger to each other. That’s why the common male octopus has a special “arm” for mating called a hectocotylus which is used to maintain a safe breeding distance from his partner.
But there is one species of octopus that mates in a completely different and unusual way.

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Underwater Fact 102

Mudskippers are able to breathe out of water by retaining water in their gill cavities and refreshing it as necessary. It is also thought that like amphibians, some species are able to absorb oxygen through their skin.

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Underwater Fact 84

Otters are the smallest of all marine mammals in the world.

An Otter can remain under water for up to 4 minutes with feeding dives up to 75m (250ft) deep.
These animals can consume up to 25% of their body weight daily. When a female is nursing she will consume even more than that. About 5 hours a day are spent in search of food.

 Sea Otter   © Sophia Volzke

Most species spend the majority of their time on land with one exception: the Sea Otter.

Sea otters have webbed feet, water-repellent fur to keep them dry and warm, and nostrils and ears that close in the water.
They sleep while floating on their back, often gathered in groups. Sometimes they anchor themselves in sea weeds or kelp to protect them from floating in a current.
Sea Otters are the only species that have more than one pup at a time which they also give birth to in the water. They hold infants on their chests to nurse them, and quickly teach them to swim and hunt.

They can thrive in warm and cold waters, along coastlines or out in the deep. Their bodies are made up of around 95 percent water. Even though they have no brains, jellyfish have somehow been smart enough to survive for over 500 million years.

Blubber Jellyfish   © Samuel J Shelton

The Blue Blubber Jellyfish (Castostylus mosaicus) is common along the east coast of Australia from shallow seas to estuarine waters. Their recognized blue color comes from their symbiotic relationship with algal plant cells that are kept inside its body.

Underwater Fact 59

Over millions of years sharks and rays have evolved to become perfectly adapted to the ocean environment. However, some of the traits that have helped them become so successful have also made them vulnerable to human impacts.

Shovelnose Ray   © Sophia Volzke

The Giant Shovelnose Ray seems to be the visualisation of the fact that sharks and rays fall into the same class of species.

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