Marine Biology & Oceanography


Feature Writer: John Blatchford
John Blatchford, Margaret Blatchford

Oceanographers study all aspects of the marine environment - Marine Biologists research the many diverse habitats and the plants and animals that live in the sea. Overfishing, pollution and global warming threaten many critical habitats and there is increasing awareness of the need for conservation effort in many cases.

Working from boats, diving in submersibles, using scuba gear, or simply collecting from the sea shores - professional scientists and amateur enthusiasts are building a picture of this alien world. We still know more about the surface of the moon than we do about the deep ocean!

Marine life ranges from the enormous whales to microscopic plants in the plankton and in-between we find members of every phylum.

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Research Vessel, John Blatchford
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John Blatchford

Large Plankton-eating Sharks

In: Marine Life

The biggest fish in the world feed on very small animal plankton, just as enormous whales survive on krill. more...

Aquatic Ape Theories

In: Marine Biology & Oceanography (general)

Many anatomical differences exist between modern humans and modern apes. When and why did these changes come about? more...

Digital Camera Binoculars

In: Marine Biology & Oceanography (general)

Advice about purchasing digital camera binoculars for whale watching. more...

Marine Reptiles

In: Marine Life

Living and extinct reptiles of the sea. Ogopogo and the Loch Ness Monster might even exist! more...

Vancouver Island Marine Biology

In: Marine Biology

Clayoquot Sound UNESCO Biosphere Reserve has locations of outstanding interest for naturalists keen on the sea and coastal habitats. more...

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feature blog
John Blatchford

Jul 13, 2008

Marine Reptiles and Amphibians

There are about seventy marine reptiles, but only one amphibian can tolerate estuarine conditions.


Two Types of Marine Reptile

Sea Snakes

There are over sixty species of snake that live more or less permanently in the sea. They are highly venomous and eat fish. All breathe air and need to surface at intervals (like whales), and some need to come ashore to breed.



Sea Turtles

Seven species of turtle a fully marine, but like the snakes they breathe air and come up regularly. They lay their eggs on sandy beaches, and often migrate over long distances to return to the place where they hatched.



While writing about these Marine Reptiles I began to think about marine amphibians.



One Type of Marine Amphibian

While there are a number of very well adapted sea-going reptiles (snakes and turtles) there are no truly marine amphibian – only one species of frog comes close.



Frogs and Toads



The Crab-eating Frog - Fejervarya cancrivora formerly Rana cancrivora lives in the mangrove swamps of south east Asia, and as its name suggest it will eat crabs. It is the only known modern species of amphibian that can tolerate saltwater conditions.



The Marine Toad - Bufo marinus, despite its name does not live in or near the sea. It is purely terrestrial, and goes to freshwater to breed.



(My old article about French Frogs and Toads looks at a few of the common modern ones.)



Newts and Salamanders

None of the family Salamandridae goes anywhere near the sea. Most live in or near freshwater, and a few have become terrestrial in damp places, but they cannot tolerate salt. My article about French Newts and Salamanders introduces the group.



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