Natural Environment Blog

A million tonnes of fish and other marine life caught in the North Sea is thrown overboard every year, according to a new study by WWF-Germany.

The resulting report, entitled “Sea Creatures Are Not Rubbish”, says that one-third of all North Sea catch ends up back in the sea. In other words, for every tonne that ends up at the fishmonger, two tonnes were thrown back into the ocean. 

The discarded creatures are usually referred to as “bycatch”. Bycatch is any species caught in a fishery that wasn’t supposed to be - often because it’s the wrong species or it’s too small. 

The main problem with bycatch is that, most creatures are dead or close to death by the time they’re thrown back into the ocean. This represents a huge threat to marine life all over the world. Each year, millions of turtles, whales, dolphins, sharks, and seabirds, right through to juvenile fish, corals, crabs and starfish etc are killed and tossed back into the ocean.

And it’s not just a conservation problem. It’s also a problem for the fishers themselves.

“Bycatch costs fishers time and money,” says Amanda Nickson, Head of WWF’s Bycatch Initiative. “It contributes to the already critical problem of over-fishing, it jeopardizes future revenue, jobs and long-term food security.”

“It is also a major killer of marine wildlife. How many more reasons do you need to change the way we fish?” she adds.

Different target species result in different degrees of bycatch. For example, the report says that for every kilogram of Dover sole (Solea solea) that found its way to the fishmonger, six kilograms of bycatch had been thrown overboard. The study also found that every kilogram of Norwegian lobster or scampi results in five kilograms of bycatch.

WWF says that every year several million sharks and up to 250,000 sea turtles are killed in fishing operations designed to catch other species.

“Bycatch is an incredible waste and one of the largest threats to many sea creatures,” said Karoline Schacht, Fisheries Policy Officer, WWF-Germany. “The drama happens far away at sea but this unseen wastefulness must come to an end.”

WWF has been working on the bycatch issue arround the world, and currently has 70 bycatch projects in over 40 countries.

Here’s the full report (written in German): Sea Creatures Are Not Rubbish [PDF, 1.03 MB]

The Wildlife Trust of India (WTI) is about to implement a satellite tracking program for the whale shark (Rhincodon typus).

The program, believed to be the first of its kind in India, will involve monitoring of whale sharks along the Gujarat coast. The sharks will have a tag implanted in their dorsel fin, which will be able to rely important information to satellites about the movements of the fish.

In particular, the satellite tracking will provide scientists with information about the migration, breeding, water temperature and deep movement among other parameters of the fish and its habitat.

Often referred to as the "gentle giant", the whale shark can grow up to 12.2 m. (40 ft.) in length and can weigh up to 13.6 tonnes (15 short tons).

Although this is the first time satellite monitoring will be used for whale sharks in India, its not the first time the country has used satellite tracking on marine life. India has used satellite tracking on sea turtles and other marine species. 

“We do not have any population specific data about the species. One of the greatest constraints of the conservation of the fish is poor knowledge about the life and biological parameters such as growth, reproduction, distribution and movement,” coordinator of the project Dhiresh Joshi said.

The data provided by the program will help in designing conservation projects for the whale shark, which has been listed on the International Union for Conservation of Nature’s (IUCN) Red List as vulnerable since 2000.

The whale shark is often killed for meat, liver oils, fins, frozen meat that are in huge demand in the south Asian countries.

Previous Satellite Monitoring

The U.S. and China have already been tagging whale sharks, with some interesting results. Satellite monitoring in the U.S. and South China sea have revealed that whale sharks can travel thousands of kilometers over many years. 

About the Whale Shark

Often referred to as the “gentle giant”, the whale shark can grow up to 12.2 m. (40 ft.) in length and can weigh up to 13.6 tonnes (15 short tons). The giant fish can be found in warmer, tropical oceans, usually between latitudes 30°N and 35°S, and is often seen in the waters of Australia, India, the Maldives, South Africa, Belize, Mexico, the Galapagos Islands, Southeast Asia and Indonesia.

A whale shark can live for as long as 70 years (if its not hunted and killed beforehand).

Although the whale shark was first discovered in 1828, it is believed to have been around for at least 60 million years.

Australian scientists have made an exciting discovery in the oceans, just off southern Australia.

The CSIRO scientists have discovered 338 marine species previously unknown to science in the southern ocean, just off southern Australia. 

They also found 86 species previously unknown in Australian waters and 242 previously studied species.

The discovery resulted from a project to monitor the Commonwealth Marine Reserve Network off southern Tasmania, Australia. 

The CSIRO scientists worked with Geoscience Australia, Museum Victoria, and the Queensland Museum to analyze the findings.

The research also resulted in the discovery of a further 80 seamounts (underwater mountains). This brings the total number of known seamounts in the region to 144, which makes it the highest concentration of seamounts in Australian waters.

Most of the seamounts are actually extinct volcanoes. Some are up to 25 kilometers across at the base, and rise 200 to 500 meters from the seabed.

They also discovered 145 under sea canyons, bringing the total in the region to at least 276.

So, in summary, they discovered:

• 338 marine species previously unknown to science
• 86 species previously unknown in Australian waters
• 80 previously undiscovered seamounts
• 145 under sea canyons

The discovery is a result of seafloor sampling, taken in November 2006 and April 2007, as well as two surveys undertaken using multibeam sonar and underwater video transects.

These days, we hear a lot about the tragic consequences of plastic bags on the environment. In particular, plastic bags are causing significant damage to our oceans and marine life. But what about other plastic items?

In today’s world, we are surrounded by plastic. We live in a plastic world. What’s more, we throw out most of our plastic products at an alarming rate. Some plastic items, such as packaging, won’t even last a day before it’s tossed into the bin - or even worse, discarded onto the street or ocean. Other items - you know, those items that are supposed to last a long time - might be lucky to reach their 2nd birthday! Occasionally, we might purchase a plastic item that we keep for say, 5 - 10 years.

The ironic thing about this is that, one of plastic’s outstanding benefits has always been it’s incredible resilience and durability - plastic will last for hundreds of years. Yet, we throw it out, sometimes within a day of product purchase.

The fact that plastic doesn’t break down for hundreds of years causes a major issue for the environment. In particular, plastic is killing thousands of animals around the world every day.

Here are some (grim) facts/statistics on the impact that plastic is having on our oceans.

• Plastic causes the deaths of more than a million seabirds every year
• Plastic causes the deaths of more than 100,000 marine mammals each year
• About 90% of the rubbish floating in the ocean is plastic
• According to estimates by the UN Environment Programme in 2006, every square mile of ocean contains 46,000 pieces of floating plastic
• Hundreds of millions of nurdles (plastic pellets) find their way into the oceans each year. These nurdles act as a chemical sponge - they attract man-made chemicals, such as hydrocarbons and pesticide DDT. This makes them even more toxic. The nurdles then find themselves into marine creatures, then onto our dinner plate. We are indirectly eating our toxic waste.
• Plastic photodegrades. This means that it breaks down into much smaller parts. These smaller parts are continuously being eaten by marine creatures, who mistaken them for food. Many marine creatures actually feed their young on plastic items - again mistaking it for food. One turtle found dead in Hawaii had over a thousand pieces of plastic in its stomach and intestines.
• Floating plastic can sometimes transport marine life to a new location - one of which is outside their normal habitat. This can result in the migrant becoming a pest in the new habitat.
• Not all plastic floats. Much of it - up to 70% - ends up on the ocean floor. This ends up killing the marine life which is found there. Dutch scientists estimate that there’s up to 600,000 tonnes of plastic on the sea bed of the North Sea alone.
• The Pacific Ocean has a garbage dump twice the size of continental United States. The dump is so large that scientists believe it would be impossible to clean it up. Most of this gigantic dump consists of plastic.

If I told you the world’s largest garbage dump was almost twice the size of continental United States would you believe me?

Well, that’s how big the Great Pacific Garbage Patch is. The Great Pacific Garbage Patch is the collective name for two gigantic masses of garbage floating in the Pacific Ocean. The two masses are known as the Western Pacific Garbage Patch and the Eastern Pacific Garbage Patch.

The Great Pacific Garbage Patch has been described as a “plastic soup”. It consists of about 100 million tons of garbage, extending up to 100 feet below the surface, all being held together by the swirling currents of the ocean. The mammoth garbage patch is a result of general litter from both sea vessels and land. Here’s an animation showing the movement of the currents surrounding the Great Pacific Garbage Patch.

Curtis Ebbesmeyer, an oceanographer, has compared it to a living entity, “moving around like a big animal without a leash”. Ebbesmeyer, who has tracked the build-up of plastics in the seas for more than 15 years, says that when the animal comes close to land “…the garbage patch barfs, and you get a beach covered with this confetti of plastic”. Some beaches in Hawaii have been known to be buried in 10 feet of plastic garbage!

The Great Pacific Garbage Patch was discovered in 1997 by Charles Moore, an American oceanographer. He came across it by chance while taking a short cut home from a Los Angeles to Hawaii yacht race. After steering into the North Pacific gyre, he found himself surrounded by garbage. Not just a little bit of garbage, but a virtual continent of garbage. All day, every day, for about a week, his vessel sailed through a sea of garbage. Moore said “Every time I came on deck, there was trash floating by”.

Following this alarming discovery, Moore sold his oil business and became an environmental activist.

What’s being done about it?

Unfortunately, many scientists believe that it’s pretty much impossible to clean up the Great Pacific Garbage Patch. They have also said that attempts to do so could actually do more harm to plankton and other marine life. In any case, the US government recently passed legislation to increase funding so that more clean up work can be done.

Image courtesy of Greenpeace