The intricate symbiotic relationship between reef building corals and algae seem to rely on a delicate communication process between the algae and the coral, where the algae is constantly telling the coral that the algae belongs inside it, and that everything is fine. Without this communication, the algae would be treated as any other invader, e.g. a parasite, and be expelled by the coral’s immune system.

Researchers now fear that increased water temperature will impair this communication system, something which might prove to be the final blow for corals already threatened by pollution, acidification, overfishing, dynamite fishing, and sedimentation caused by deforestation.

According to a new report, a lack of communication is likely to be the underlying cause of coral bleaching and the collapse of coral reef ecosystems around the world.

Reef building corals can defend themselves and kill plankton for food, but despite this they can not survive without the tiny algae living inside them. Algae, which are a type of plants, can do what corals can’t – use sunlight to produce sugars and fix carbon through photosynthesis.

“Some of these algae that live within corals are amazingly productive, and in some cases give 95 percent of the sugars they produce to the coral to use for energy,” said Virginia Weis, a professor of zoology at Oregon State University. “In return the algae gain nitrogen, a limiting nutrient in the ocean, by feeding off the waste from the coral. It’s a finely developed symbiotic relationship.

If this relationship were to collapse, it would be death sentence for the reef building corals.

Even though the coral depends on the algae for much of its food, it may be largely unaware of its presence, said Weis. We now believe that this is what’s happening when the water warms or something else stresses the coral – the communication from the algae to the coral breaks down, the all-is-well message doesn’t get through, the algae essentially comes out of hiding and faces an immune response from the coral.”

This internal communication process, Weis said, is not unlike some of the biological processes found in humans and other animals.

Researchers now hope that some of the numerous species of reef building corals found globally and their algae will be more apt at handling change.

“With some of the new findings about coral symbiosis and calcification, and how it works, coral biologists are now starting to think more outside the box,” Weis said. “Maybe there’s something we could do to help identify and protect coral species that can survive in different conditions. Perhaps we won’t have to just stand by as the coral reefs of the world die and disappear.”

The new research has been published in the most recent issue of the journal Science and was funded in part by the U.S. National Science Foundation.

Researchers at Woods Hole Oceanographic Institution (WHOI) unveiled a hazardous cocktail of pesticides when analysing the brain matter of 12 marine mammals; eleven cetaceans and one gray seal stranded near Cape Cod, Massachusetts.

This is the most extensive study of pollutants in marine mammals’ brains and it confirms suspicions of marine mammals being the carrier of a vast array of different chemicals that have found their way into marine ecosystems.

Lead author Eric Montie analyzed the cerebrospinal fluid and the gray matter of the cerebellum in the twelve animals and found them to contain a long row of different man-made chemicals, including a group of especially widespread substances labelled “the dirty dozen” by environmentalists. Many countries banned the “the dirty dozen” as early as the 1970s due to their adverse effect on human health, but they are unfortunately still present in our environment.

Montie didn’t just test for the presence of certain chemicals; he also measured their concentration and found one instance where it was surprisingly high.

“The biggest wakeup was that we found parts per million concentrations of hydroxylated PCBs in the cerebrospinal fluid of a gray seal”, says Montie. “That is so worrisome for me. You rarely find parts per million levels of anything in the brain.”

PCBs are neurotoxicants known to disrupt the thyroid hormone system. Other examples chemicals found in the tested mammals are DDT (diklorodifenyltriklorethane), which can cause cancer and disturb reproduction, and PBDEs (polybrominated diphenyl ethers); a type of flame retardants known to impair the development of motor activity and cognition.

Co-author Chris Reddy, a senior scientist in the WHOI Marine Chemistry and Geochemistry Department, describes the new study as “groundbreaking because Eric measures a variety of different chemicals in animal tissues that had not been previously explored. It gives us greater insight into how these chemicals may behave in marine mammals.”

The results of this study was published online April 17 in Environmental Pollution.

According to WWF Canada, excessive bycatch* of cod is undermining the cod moratorium imposed in 1994. On the southern Grand Banks near Canada, cod bycatch is now at least 70 percent higher than target levels and this is hampering the recovery of one the world’s best known fisheries.

WWF Canada also states that ships from the European Union are responsible for the largest proportion of the overrun bycatch.

In 2003, bycatch amounts were estimated to be over 80 per cent of the remaining cod stock which caused WWF to push for a 2008 cod recovery strategy that included setting a bycatch reduction target of 40 per cent for the southern Grand Banks at the September 2007 annual meeting of the Northwest Atlantic Fisheries Organization (NAFO).

The 40 percent target level was based on estimations of how much the cod population could endure and still have at least some chance of recovery. 40 percent is equivalent of 420 tonnes of cod, but unofficial fishing statistics for the year 2008 show that almost twice as much, 713 tonnes, was caught as bycatch last year. Of these 713 tonnes, ships from the European Union member states accounted for 444 tonnes.

It should be noted that these figures does not account for misreported bycatch and illegal fishing.

WWF Canada is now urging NAFO to adopt an effective recovery plan for southern Grand Banks cod; one hat will include immediate bycatch reduction targets as well as long-term recovery goals. Gear-based solutions need to be combined with protection of spawning and nursery areas for the plan to be effective and the arrangements must naturally be backed by efficient monitoring and enforcement to have any effect. Such a recovery plan would be consistent with the Ecosystem management approach adopted in the newly revised NAFO Convention.

“Cod and other fish stocks can never recover as long as NAFO refuses to see the urgency of the bycatch problem and acknowledge that voluntary measures are not working,” says Dr. Robert Rangeley, Vice President Atlantic, WWF-Canada. “If NAFO’s Scientific Council starts working on solutions at their June meeting then it will be the responsibility of the Fisheries Commission, in September, to impose strict management measures that will give cod recovery a chance.”

* Bycatch is here defined as unused and unmanaged catch. You can find more information about bycatch in “Defining and Estimating Global Marine Fisheries Bycatch”; a paper co-authored by WWF for the journal Marine Policy. According to this paper, the global bycatch now constitutes over 40 percent of the global reported catch.

In May this year, hundreds of Asian swamp eels were discovered in and around Silver Lake in historic Gibbsboro, New Jersey. This was the first finding in New Jersey, Asian swamp eelbut not the first finding in the United States. Unlike Florida, Georgia, and Hawaii – the three other U.S. states where this species have been discovered – New Jersey is however subjected to harsh winters and a breeding population of Asian swamp eels in New Jersey confirms the suspicion that this Asian invader has no problem adjusting to the
chilly climate of northern North America.

The Asian swamp eels were found by a local college student checking on frogs and turtles in the Silver Lake. As he spotted snake-like heads peeking from the water, he decided to photograph them and post the pictures online. This lead to the “snakes” being identified as Asian swamp eels, Monopterus albus, and prompted a call to the local authorities.

In its native environment in Asia and Australia, the swamp eel Monopterus albus inhabits gentle hill streams, estuaries and lowland wetlands, and it is a common species in rice paddies. It has developed a long row of traits that makes it an apt survivor in many different kinds of environments. Unfortunately, these traits also make it the “perfect” invasive species and biologists fear that the Asian swamp eel may wreck havoc with existing North American ecosystems, especially if the predatory species of these systems prefer to target familiar prey rather than catching the newcomers.

– The Asian swamp eel can survive long periods of drought by burrowing in moist earth, and can therefore take advantage of seasonally appearing, short-lived bodies of water.

– If its home becomes unsuitable, e.g. because of drought, this eel simply crawls ashore and make its way to a more suitable home by slithering over land, just like a snake. This makes it hard to eradicate from bodies of water using poison or similar; there is always the risk of at least two specimens getting away over land and forming a new breeding colony in nearby waters.

– The Asian swamp eel can tolerate a wide range of oxygen levels in the water since it is capable of absorbing oxygen from the air above the surface through its skin. This skill doesn’t only come in handy in oxygen depleted waters; it is also what makes it possible for the fish to travel impressive distances over land.

– This eel prefers freshwater habitats, but can tolerate brackish and saline conditions, which increases its chances of always finding a suitable home.

– It eats all sorts of prey, not only fish, crustaceans, amphibians, and other aquatic animals, but detritus (decaying organic matter) as well. Highly specialized feeders have a much harder time adjusting to new habitats and are therefore less likely to become problematic invasive species.

– This eel is a protandrous hermaphrodite, which means that it can change its sex. All specimens are born male, but can turn into females if necessary. This means that if an aquarist releases two male specimens into a lake, one of them can turn into a female to make reproduction possible.

In Georgia, the first specimens of Asian swamp eel was discovered in 1994, and three years later eels were found in Florida as well. The Hawaiian history of combating swamp eels is much longer as the first specimens are believed to have been released in Hawaiian waters about 100 years ago. In Georgia and New Jersey, biologists blame aquarists of having caused the situation by releasing their pets into the wild. In Florida and Hawaii however, Asian food markets and fish-farmers are considered more likely sources. Asian swamp eels are typically sold fresh in food markets and can be kept alive for long periods of time as long as their skin is kept moist.

New Jersey authorities are now focusing on containing the creatures while trying to figure out a way of annihilating them. “We’re not panicking yet,” says Lisa Barno, chief of the New Jersey Bureau of Freshwater Fisheries. “It’s more that it’s just an invasive species we’d rather not have. We’re still documenting the true extent of the problem, but right now it seems to be fairly contained.” One of the immediate goals is to prevent an expansion downstream to the Cooper River and a watershed leading to the Delaware River. Since May, only one Asian swamp eel has been discovered outside the Silver Lake.