Jun 8

This year the Society of Biology’s amateur photography competition is inviting budding photographers to think creatively about forests, grasslands, deserts and watery environments, fitting in with the theme ‘Home, Habitat & Shelter’.

Entries can focus on any of the world’s amazing ecosystems, although as today is World Ocean’s Day we thought we would give potential entrants some inspiration from one of nature’s most mysterious and varied environments. Occupying approximately two thirds of the Earth’s surface and containing around 95 percent of the Earth’s water, the world’s oceans provide numerous habitats for a wide range of species. The oceans are divided into five distinct areas: the Pacific, Atlantic, Indian, Southern (Antarctic) and Arctic.

Oceans are divided into five layers, and each layer is designated depending on its depth, physical characteristics and biological conditions, and the richness of life within each zone can vary considerably. Oceanographers categorise the open ocean as the pelagic zone, while the far depths, including the oceanic trenches, are described as hedalpelagic. At depths between 6,000 and 11,000 metres, there is a very low density of marine-life due to the harsh physical and chemical conditions.

But even at great depths and with no direct access to sunlight, creatures have evolved to survive and thrive. The giant tube worm lives around strong flowing hydrothermal vents, which are cracks on the ocean floor from which very hot, mineral-rich water flows into the surrounding ocean water. These vents are usually found near volcanically active places and the surrounding water is heated by the magma beneath the Earth’s surface.

Giant tube worm plume – a deep-sea species

The giant tube worm lives inside thin, tube-like structures made from chitin (a hard, protective material found in the outer skeleton of some invertebrates) and can grow up to two metres long. It has an impressive, haemoglobin-rich, red plume which is extended when it is undisturbed. The highly specialised body is divided into four sections, each of which plays a role in gas exchange, structure and support, and absorption of nutrients. Like other worms, it does not have a digestive tract and relies on a symbiotic relationship with bacteria in its body tissue. The bacteria perform chemosynthesis, a process by which organic molecules are produced for the worm to feed on.

Giant tube worm specimen

The remoteness of the hydrothermal vents prevents scientists from studying the ecology and biology of this species and others that live in these deep-sea areas. So although it is clear to see they have adapted to thrive in harsh oceanic environments, other biological features such as reproduction and feeding habits are relatively unknown.

If you have been inspired to think about a creature that has developed to flourish in a unique environment or you have simply been struck by the beauty of a creature in its natural habitat, why not enter the Society of Biology amateur photography competition. Photographs could focus on biological research which helps to answer the complex question of why and how different organisms survive in diverse environments; or, could simply capture the beauty of an animal in its natural habitat.

Further details on entering the photography competition are available on the Society of Biology website

May 14

1aOur oceans are critical to our very existence; it’s a simple matter of healthy oceans = healthy people.  Besides providing us with food (today almost one in six people in the world rely on fish as their primary source of protein), oceans provide us with many other important services that our survival depends on.  They maintain our renewable supply of fresh water through the water cycle, regulate our climate, and produce more oxygen than the world’s rainforests. With growing concern over climate change, we are turning more and more towards the oceans for clean, renewable energy.

In addition to being an important source of protein, many marine organisms have been found to provide therapeutic uses in antioxidant, antiviral, anti-inflammatory, anti-fungal, or antibiotic medicines. Additionally, the marine and coastal ecosystems offer endless recreational opportunities such as sea kayaking, sport fishing, surfing, whale watching and scuba diving, activities which not only feed our souls, but also drive economic benefits through employment for local peoples.


Today almost one in six people in the world rely on fish as their primary source of protein.

Although critical to our existence, our oceans are in desperate trouble.  Depleted fishery stocks, habitat destruction, pollution, coastal development, climate change and invasive species, are some of the major issues threatening the healthy existence of our oceans.  In the Pacific Ocean for example, there is an area 1000 kilometres from the US coast which is larger than the entire land mass of South Africa and which is covered in plastic. It contains six times more plastic than plankton, and is growing all the time as more than 10 million tonnes of plastic finds its way into the sea each year.


The marine and coastal ecosystems offer endless recreational opportunities such as sea kayaking, sport fishing, surfing, whale watching and scuba diving.

This current state of affairs is largely as a result of the dilemma known as “The Tragedy of the Commons”, in which multiple individuals acting independently in their own self-interest can ultimately destroy a shared limited resource, even when it is clear that it is not in anyone’s long term interest for this to happen.

Plastic debris littered along the beachfront

Our oceans are in desperate trouble. Depleted fishery stocks, habitat destruction, pollution, coastal development, climate change and invasive species, are some of the major issues threatening the healthy existence of our oceans.

Overfishing, together with global climate change and habitat destruction, are considered as the three major risks facing our oceans. When looking at this, obviously the first thing that we have to do is to control our own levels of exploitation. That means fishing within the biological limits of a fish population and assuring that the gear that we use does not destroy habitats. Today, many stocks are just hanging on to survival because of regulations that were inadequately or not properly enforced in the past. We need to abide to these regulations and support good science that guides the future regulatory parameters around fishery off-take.


Fishing is taking place across food chains and thereby breaking down the efficiency of the oceans.

Globally, as human populations continue to grow, along with the popularity of seafood, fish stocks are coming under increasing pressure and can no longer keep up with pressure of current commercial fishing operations. A recently published report on the state of the world’s fisheries by the United Nations Food and Agricultural Organisation (FAO), estimated that approximately 80% of the world’s fisheries were fished at (52%) or beyond (28%) their maximum sustainable limits.

A small-pelagic fishing trawler at dawn and surrounded by seagul

Overfishing, together with global climate change and habitat destruction, are considered as the three major risks facing our oceans.

Increased levels of fishing do not only result in the overexploitation of our marine resources, but also results in the destruction of marine habitats. More than 50% of the world’s total marine catch (81 million tons) is harvested using towed fishing gear. Studies have shown that fishing can damage the seabed by, for example, breaking deep-water coral reefs and other fragile habitats.


The United Nations Food and Agricultural Organisation (FAO), estimated that approximately 80% of the world’s fisheries were fished at (52%) or beyond (28%) their maximum sustainable limits.

Habitat destruction is not only about the physical loss that may come from the destruction of a reef or the damming of a river, but also from pollution, diverted stream flows, and even the introduction of invasive species. Through habitat destruction, biodiversity is negatively impacted which ultimately is the cornerstone of a productive ecosystem that in turn drives the fishery resource upon which we depend. We know that 85 % of all commercially valuable fish are dependent upon wetlands and estuaries during some part of their lifecycle. Two-thirds of our estuaries and bays are already severely degraded through torrents of chemical and other poisonous runoffs and irresponsible development and agricultural practises.


Pollution is negatively impacting on the biodiversity of our oceans.

Protecting our oceans and coast is more than stopping pollution and regulating fishing. It also means controlling our activities onshore and controlling unregulated coastal development. With all of these poisonous pollutants running into the oceans, “dead zones” have been created where only some of the smallest marine organisms can survive. These areas are created in significant part by synthetic nitrogen fertilizers flowing into the sea and nourishing massive algal blooms which then decay and cause oxygen- depletion, killing everything except the hardiest in its vicinity.


We know that 85 % of all commercially valuable fish are dependent upon wetlands and estuaries during some part of their lifecycle.

Although these kinds of reports on the state of our marine resources may be disheartening, it is important for us to realize that there are solutions, and that if we all work together, we can turn things around. Marine Protected Areas are globally recognised as an essential tool for marine conservation and for helping restore the health of our oceans. They allow for the protection of habitats and provide areas where fish species can grow and breed without disturbance. As habitats are able to re-establish back to their natural state, they help in preventing damage from severe storms, reducing the impacts of pollutants while also aiding in reducing the impacts of climate change.

Blouberg Strand and Table Mountain

Protecting our oceans and coast is also about controlling unregulated coastal development.

Where fishing is concerned, it is important that all stakeholders abide by set fishing regulations and laws- we need to build a culture of voluntary compliance and self-regulation. Fisheries need to start implementing what is known as an Ecosystem Approach to fisheries (EAF), which seeks to protect and enhance the health of our marine ecosystems as a whole, to ensure the long-term survival of marine life and the communities that depend on it.

Marine Protected Area signage overlooking an estuary mouth

Marine Protected Areas are globally recognised as an essential tool for marine conservation and for helping restore the health of our oceans.

It is also important that we promote a sustainable seafood trade. By simply asking questions about our seafood and making more informed choices about the fish that we trade, buy and eat, we could make a huge impact in influencing positive change in the seafood chain of custody.  But this requires urgent and concerted effort from all parties involved- from the fishing industry all the way to the consumer.


It is important that all stakeholders abide by set fishing regulations and laws.

Our oceans are a common heritage, and we all have the responsibility and the ability to help conserve and protect them- if not for our sake, then for the sake of future generations- our children.


Support the South African Seafood Initiative (SASSI) and only eat and buy the healthiest and most well managed fish populations.

More tips on what you can do to help save the oceans:

1. Support South Africa’s Marine Protected Areas
2. Eat sustainable seafood: Support the South African Seafood Initiative (SASSI) and only eat and buy the healthiest and most well managed fish populations. For further information visit: www.wwf.org.za/sassi
3. Don’t dispose of trash or toilet waste in the ocean.
4. When enjoying recreational fishing, obey regulations and try to enjoy only catch-and-release fishing and use care when releasing fish back into the ocean. Take photos, not fish
5. Keep beaches clean. Plastics and other debris harm sea life and pollute the ocean. Clean up after yourself. Get involved! Participate in beach cleanups if you live in a coastal area.
6. Don’t purchase items that exploit marine resources unnecessarily such as shell and coral jewellery and sharks teeth.
7. Spread the word: Tell people what’s going on with the world’s oceans and what they can do to make a difference.


Peter Chadwick

Apr 20

With Easter just a hop, skip and a jump away, we thought we’d crack into the ARKive coll-egg-tion and have a scramble around to eggs-tract some egg-citing eggs to eggs-hibit in our blog. Along the way, we’ve also learned about the eggs-istence of some rather eggs-centric egg-laying and guarding habits, and we hope you’re as eggs-tatic about our finds as we are!

Gooseberry fool?

Peacock butterfly egg image

Peacock butterfly eggs look a lot like gooseberries!

While you might be forgiven for being fooled into thinking that these green globules are plump and juicy gooseberries, they are, in fact, peacock butterfly eggs. The eggs of this species are laid in groups under nettles, usually in May, and hatch two weeks later.

Sunny-side up? Over-easy? Well-done?

Emu egg image

Emu eggs come in various shades of greenish-black

However you like your eggs, there’s no denying that these ones look as though they’ve been char-grilled in their shells! But fear not, these emu eggs are supposed to look like this; they come in various shades of greenish-black and are the size of a small grapefruit. The male emu is an eggs-traordinary guardian, taking sole responsibility for incubating the eggs over the course of two months while the female wanders off to potentially find another mate, and protecting the chicks against predators for several months once they’ve hatched.

100 kids and counting…

Green turtle egg image

Green turtles can lay an impressive number of eggs per nesting season

In the UK, having more than about four siblings would constitute being part of a pretty large and impressive family, but in the world of marine turtles, this is a mere drop in the ocean. Female green turtles produce between 100 and 150 ping-pong-ball-like eggs per clutch, and can lay up to nine separate clutches per breeding season. While this may seem rather a lot, marine turtles don’t guard their nests or look after their young, and with the threat of land- and ocean-dwelling predators, the survival rate of hatchlings is very low.

High-flying hunger games…

Bald eagle egg image

Bald eagle nests are some of the largest of any bird species

Bald eagle nests, made with sticks and lined with moss, grass, seaweed and other vegetation, are some of the largest of any bird species, sometimes reaching several metres in width. These enormous nests presumably provide a comfy and snug environment for the eggs during the 35-day incubation period, yet things can soon turn ugly. By being bigger and louder, the first-born chick is often afforded more parental attention and food, and will even occasionally kill its younger siblings.

Treasures of the deep

California horn shark egg image

Shark eggs, such as this California horn shark egg, are often referred to as ‘mermaid’s purses’

A mermaid’s purse might well sound like something a sea-dwelling siren would keep her money and credit cards in, but a pilfering pickpocket could get a nasty surprise if they were to try to purloin this particular purse as it is actually a shark egg-case! Mermaid’s purses vary greatly in shape, size and colour, depending on the shark species in question.

Eggs-panding eggs


Common frog egg image

Common frog eggs are coated in a jelly-like substance

Frog egg masses, often referred to as frogspawn, tend to look rather like a gruesome collection of eyeballs. The female common frog releases between 1,000 and 2,000 eggs at a time, which are covered in a jelly-like coating. This coating expands when it comes into contact with water, providing protection for the tadpoles growing within.

Egg pasta


Sea lemon egg image

Pasta del mar – sea lemons produce somewhat pasta-like egg masses

What may look like a delectable strand of abandoned tagliatelle cast into the depths of the ocean is, in actual fact, a mass of sea lemon eggs. A common sea slug around Britain’s shores, the sea lemon produces thousands of eggs at a time which form a long, coiled, ribbon-like mass. These egg masses are produced in the spring and are attached to rocks, so if you take an Easter weekend dip in the sea and find such a structure, we would advise leaving it well alone and not adding it to your carbonara!

Ha-bee Easter!


Honey bee egg image

Honey bee egg

A supplier of sugary goodness and a harbinger of spring to many, the honey bee lays its eggs from March to October. Honey bee colonies have a complex structure, formed of the queen, workers and drones, all of which serve different functions. Worker bees have a variety of roles within the colony, with some being tasked with feeding the developing larvae which emerge from the eggs around three days after they are laid.

Eggshellent parenting


King penguin egg image

King penguins incubate their egg on their feet

King penguins appear to take parenting very seriously, with each pair keeping a close eye on their precious egg. Incubation is shared by the male and female and is split into two- or three-week cycles, and parental duties remain shared once the chick has hatched. It’s a good job that king penguins don’t let their eggs out of their sight, otherwise they may not believe the chick belonged to them…the chick looks so different to the adult that they were first described as two completely different species!

Eggs-treme monotreme

Short-beaked echidna egg

A short-beaked echidna egg

While the majority of mammals give birth to live young, there are some eggs-treme mammalian species that lay eggs! These eggs-tra special critters are known as monotremes, and the short-beaked echidna is one of them. The echidna’s leathery egg is laid into a pouch on the female’s abdomen, where it is incubated for about ten days before it hatches. The young echidna, or ‘puggle’, remains there until it is 45 to 55 days old.

We hope you’ve enjoyed these eggs-amples of awesome eggs, and that you all have a wonderful Easter weekend!

Kathryn Pintus, ARKive Text Author

Apr 11

A recent report published in the journal Nature Conservation has found that sea levels are rising at a higher rate than they have for thousands of years, putting many islands and the species living on them at risk.

Global climate change is negatively affecting the Earth and its oceans in many ways, and these impacts are predicted to be the greatest cause of future species extinctions. The increasing temperature on Earth is melting the sea ice at the North and South Poles, which is increasing the amount of water in the oceans. The temperature of the ocean is also increasing, which raises the volume of the seawater due to the molecules requiring more space to move. “Sea level rise is one of the most certain consequences of global warming, yet it remains the least studied,” the study said. “Potential effects of sea level rise are of considerable interest because of its potential impact on biodiversity and society.”

Seychelles image

The Seychelles may be one of the groups of islands at risk of flooding due to rising sea levels

Of the 180,000 islands on Earth, all low-lying islands are particularly at risk and it is thought that over 10,000 of them could disappear, along with the species that live on them, if the sea level rise predictions are correct. Islands are home to a much higher proportion of endemic species than mainland areas, with the entire population of the Alaotran gentle lemur, New Caledonia blossom bat, Seychelles frog and thousands of other species being found on just one island, or a small group of islands. The submersion of numerous islands will not just impact fauna and flora, with human populations living in coastal areas also being forced to move inland or relocate completely in response to the rising sea levels, and coastal industries being lost.

New Caledonia blossom bat

The New Caledonia blossom bat is only found in a few caves in northern New Caledonia

New Caledonia and French Polynesia are thought to be the islands most at risk of disappearing under water, with islands in the Caribbean and Mediterranean and those in close proximity to Guyana and Madagascar also under threat. The study found that, after a predicted sea rise of between 0.5 and 2.3 metres, more than 30 percent of the totally submerged islands would be in New Caledonia, 30 percent in French Polynesia and 10 percent in the Mediterranean, with the rest occurring in other regions.

French Polynesia image

It is predicted that 30 percent of French Polynesia will be under water when sea levels rise

The authors of the study said, “Considering their important contribution to global biodiversity and the threat of sea level rise for future biodiversity of some of these islands, there is an urgent need that islands feature prominently in global and regional conservation prioritisation schemes.” Less than 5 percent of the Earth’s land area is represented by islands, although they are home to around 20 percent of the world’s bird, reptile and plant species, as well as other fauna. Of all known extinctions, 80 percent have occurred on islands, and although climate change may be partially to blame, the negative effects of invasive species, deforestation, over-collection and various other threats are more prevalent in island ecosystems than on the mainland and have much greater and more severe impacts on island species.

Laysan crake image

The Extinct Laysan crake disappeared from Hawai’i due to the negative effects of invasive species

Find out more about the effects of climate change on animal and plant species

Find out more about the islands of the North Pacific, South Pacific and Indian Oceans.

Find out more about the conservation of islands

Hannah Mulvany, ARKive Content and Outreach Officer

Jan 23

A shocking one quarter of all shark and ray species are threatened with extinction, according to the results of a new study.

Great white shark image

The great white shark is classified as Vulnerable on the IUCN Red List

Threat analysis

The paper, published this week in the open-access journal eLife, analysed the threat and conservation status of an impressive 1,041 species of chondrichthyans, a fascinating group of fish species including sharks, rays, skates and chimaeras whose skeletons are made of cartilage rather than bone. The results were rather alarming, revealing that this group is among the most threatened in the animal kingdom.

The paper is the result of collaboration between more than 300 experts from 64 countries, and reports that, while no species has yet been driven to global extinction, at least 28 populations of skates, sawfishes and angel sharks are now locally or regionally extinct. In addition, several shark species have not been seen for several decades.

Reef manta ray image

Reef manta ray parts are highly valued in traditional medicine, posing a threat to this majestic species

Threat hotspots

The study highlights two areas which are currently experiencing a higher than expected level of threat: the Red Sea and the Indo-Pacific Biodiversity Triangle. The latter is considered to be among the most biologically and culturally diverse regions on the planet, yet unfortunately it is also one of the least regulated.

The authors of the paper explain that, “The Indo-Pacific Biodiversity Triangle, particularly the Gulf of Thailand, and the islands of Sumatra, Java, Borneo, and Sulawesi, is a hotspot of greatest residual threat, especially for coastal sharks and rays with 76 threatened species.”

It is feared that, should no national or international action be taken, these species could rapidly become extinct.

Shark finning image

Finning was revealed to be a major threat to many shark species

Major threats

The results of the study revealed that the main threat to chondrichthyans is overexploitation through targeted fisheries and incidental catches. Of particular concern for the future of sharks, wedgefishes and sawfishes is the process of ‘finning’, which is driven by the huge market demand for shark fin soup, a highly sought-after delicacy in China.

The authors of the new research paper state that, “Fins, in particular, have become one of the most valuable seafood commodities. It is estimated that the fins of between 26 and 73 million individuals, worth US$400-550 million, are traded each year.”

Habitat loss is a further threat to chondrichthyans, with 22 species being threatened by the destruction of estuaries and river systems for the purposes of residential and commercial development, and 12 species being placed at risk due to the conversion of mangroves into shrimp farms. In addition, pollution and climate change have been identified as major threats to sharks, rays and their relatives.

Scalloped hammerhead shark image

The scalloped hammerhead shark is classified as Endangered on the IUCN Red List

Additional factors

As well as providing a vital insight into the type and extent of threats to chondrichthyans, the paper also revealed other interesting factors which come into play. It was found that large body size and occurrence in shallow habitat are the biggest factors determining a species’ likelihood of being threatened. The results showed that with every 10-centimetre increase in a species’ maximum body length came a 1.2-percent increase in the probability that the species would be threatened. Dwellers of deep water appear to fare better than their shallow-water relatives, with a 10.3-percent decrease in the probability of being threatened for every 50-metre increase in the minimum depth limit of the species.


Read more on this story at Mongabay.com – One quarter of sharks and rays threatened with extinction.

View photos and videos of chondrichthyans on ARKive.

Read more about shark conservation and conservation in the Indo-Pacific Region.


Kathryn Pintus, ARKive Content and Outreach Officer



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