What is Marine Life? Basically anything that lives in the oceans, any of the seas or even brackish water areas – as distinct from fresh water areas - is classed as Marine Life - or Sea Life.

The range of creatures living in our seas is huge and the subject of much scientific research.

Much of that research is commerce based, for the oceans are home to vast supplies of minerals and chemicals which have medicinal and other scientific supplies awaiting the prospectors!

That which lives in freshwater is normally classified as ‘Aquatic’ in the broadest sense.

Marine Biology is the classification and scientific study of organisms that live in the oceans, sea and other brackish waters.

Sometimes confused with marine ecology, the biological science is associated with the actual study of the specific organism and not how they interact with each other.

Our Planet’s marine life provides support and natural resources around the globe such as food, medicine, raw materials and even helps to support tourism and other recreations in many parts of the world.

The Earth’s oxygen process, our climate and even the shorelines are affected by the delicate interaction and behavior of our marine life.

From microscopic zooplankton to gigantic whales (cetaceans), marine biology covers an intricate bio-diversity of plant life and animal life upon which the continued existence of our planet is dependent.

Biological studies and taxonomy include tiny biotic components that may be trapped in surface water, to deep ocean trenches that descend more than 10,000 meters below sea level.

In Scuba Diving, we are privileged to see, admire and sometime interact with various creatures that live in on or below our seas. Without sea life, there would not be the vast interest in scuba and snorkeling.

Marine Biology observes the habitats of our huge open oceans, known as the pelagic zone, to kelp forests and coral reefs in the shallows of our warmest oceans. Our Oceans cover approximately 71% of the surface of our planet and they contain a large proportion of Earth’s natural life and there are new ocean species beneath the surface of the oceans that are still waiting to be discovered.

Whilst our earth mineral surface life is generally but a few meters deep, the oceans and the life within, extend down several thousand meters into depths so far uncharted, and unexplored.

Some of the known species that Marine Biology covers are found in the three categories of marine life below;

  1. Marine Invertebrates - more than 98% of species on earth don’t have a typical backbone
  2. Marine Vertebrates - Birds, Fishes, Reptiles, Sharks and Rays
  3. Marine Mammals - Seals, Sea lions, Whales and Dolphins


Invertebrates are one of the main attractions to scuba divers, including coral reefs, underwater creatures such as Octopus, Squid and Cuttlefish. Marine life forms and fish seek shelter in our coral reefs.

The same coral reefs extend a welcome to scuba divers and snorkelers alike - providing water-based recreation for divers and snorkelers - as well as medicines for the human race. Corals can generally be grouped by two forms, namely hard corals and soft corals, and surprisingly they can be found in both shallow and deep water.

As divers, we are normally only aware of the visual aspects of the oceans and the life they hold of course. There are more ‘not yet found’ or ‘invisible’ invertebrates that live in the oceans than we will ever see in a lifetime of diving.

> Marine Invertebrates: List of Examples


The Invertebrates that interest most scuba divers include Fish such as Jacks, Parrot fish, Angelfish, Barracuda, Moray Eels and Sea horses. Sharks and Rays also tend to fascinate divers. For the uninitiated divers, the reputations of sharks and rays often cause concerns!

These include the majestic Whale Sharks, the awe inspiring Bull Sharks, the graceful manta ray and one of the most common sighting for scuba divers, Nurse Sharks.

> Marine Vertebrates: List of Examples


Mammals that live in the sea are also attractions for seasoned divers - as well as beginners. We are constantly overawed by the sights, the sheer beauty, and the diversity of life down in the depths - whether at 2 meters or 30 meters – which is generally accepted as being the lower depth of basic deep diving.

Marine mammals include the larger specimens such as whales and dolphins, together with seals and otters in some areas.

> Marine Mammals: List of Examples

Related Links |> Coral Reefs |> Marine Reserves |> Marine Vertebrates |> Marine Invertebrates

Whilst the Whales and Dolphins are totally dependent upon the oceanic life for food and other bio-diverse well-being, the otters are happy to wander into the sea or freshwater in search of food and for normal life. Seals are more dependent upon the sea – but not totally!

Future projects include Animals l Birds l Fish l Mammals l Reptiles l Fungi l Plants and algae l Microscopic life.

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