Drought in Northern Australia, wet and wild conditions in California, climatic disruption in South America, extreme cold in Northern Europe.
Just some of the consequences of the upwelling of exceptionally warm water in the equatorial Pacific, a phenomena known as “El Nino, ” or the “Christ Child”. The last such event was five years ago and now it looks like there might be another this autumn and winter, the result: misery for many millions of people across the world.
But how does the flood of warm water affect the marine environment and the people whose sea fishing tackle is their livelihood? Read on to find out.
Jelly fish swarms
This summer saw a biblical plague hit the Pacific coast of North America. From Southern California to British Columbia, a mega-swarm of billions of bright blue jellyfish filled the sea and littered the beaches with their rotting carcasses. The Velella Velella, or “by the wind sailor”, is a small creature with a stiff sail-like protuberance that stands clear of the water, enabling the jellyfish to go wherever the wind takes it.
Ocean warming caused by a possible El Nino event, is thought to have caused a spike in jellyfish numbers. Normally, the North Westerly prevailing wind off the coast of North America keeps the jellyfish far out to sea, but this year, strong Southwesterlies have made the Velella Velella run aground. Fortunately, though alarming to look at, the swarm is harmless to humans.
Sea lion famine
Thousands of dead and dying sea lions washed up on the shores of Southern California this summer. The problem is so bad that this spring, well over 1000 pups overwhelmed rescue centres in the area, and victims had to be taken to sanctuaries further north.
The the sea lions are victims of starvation – and El Nino may be to blame. The dissipation of shoals of anchovies and sardines caused by the sudden warming of the water off the coast of California, spells famine for sea lions and other marine mammals.
A sudden bloom of harmful algae is a natural phenomenon. Coastal upwellings of cold, nutrient rich water fuel a rapid growth of algal cells that can turn the water to a reddish brown sludge. Such blooms can be highly toxic, poisoning marine life, killing corals and devastating fishing communities. In 2001, researchers discovered a 400 km stretch of reef off Indonesia, where all the coral was dead. The cause – El Nino.
In 1997, a severe drought in Indonesia, caused by El Nino, sparked uncontrollable wildfires throughout the region. It’s thought ash from the fires drifted East, falling in the sea off the Mentawai Islands. The iron rich particles fed an algal bloom that reached truly epic proportions. The decomposing plant matter leached all the oxygen from the water, killing everything in it for hundreds of kilometers.
Where the deep ocean collides with Peru’s sharp continental shelf, an upwelling of cold, nutrient-rich water provides food for spectacular shoals of anchovies and sardines. In turn, local fishermen depend on the resource for their income. The Peruvian anchovy fishery is worth billions of dollars each year, and the ground fish meal produced by factories along the coast supplies one third of the world’s demand for the product.
But when El Nino strikes, the cold water is replaced by warm currents, and the shoals of fish upon which so many families depend, disappear, literally overnight. Leave aside the ethics of turning edible, nutritious food into pellets to feed farmed salmon, this is a disaster for sea fishing families.
Coral bleaching disaster
The coral triangle is often described as an “underwater Amazon”. It’s an area of incredible biodiversity spanning nearly six million square kilometers under the seas of Southeast Asia. El Nino is bad news for coral because warmer than average sea temperatures interfere with the coral’s ability to photosynthesize. As the thermometer rises, the coral fades to white and dies, a process called coral bleaching.
Already under pressure from global warming, the 1997/98 El Nino caused widespread coral bleaching in the region. And as environmental pressures stack up, it gets harder and harder for the delicate fauna and flora of the reefs to bounce back. Since the 1980s, experts say up to half the coral in the coral triangle has been lost and if there is an El Nino this year, some scientists predict a die off from which the reefs may never recover.