holy fish!

Photo Courtesy: www.treehugger.com

You may have read recently about a Japanese trawler capsizing as the fishermen were hauling up a catch of jellyfish. Scoff if you will, but the Nomura jellyfish or the 'giant' jellyfish can grow over 6ft wide and weigh up to 450lbs. They are one of around 200 species of coastal jellyfish that exist around the world.

Jellyfish swarms have been occurring with increasing frequency in the recent years. These swarms are detrimental to the fishing industry and already there have been numerous cases of financial loss. Entire catches of fish have had to be discarded because jellyfish poison makes it unsaleable. The invasions cost the Japanese fishing industry up to $332 million a year. Increasingly polluted waters off China boost the growth of microscopic plankton that the jellies feed on. Additionally construction around the harbours provide a safe-haven for jellyfish larvae to cling to. As adults they swim on the currents flowing in from China causing major problems for Japanese fishermen. Similar such spawns of Mediterranean jellyfish have also affected salmon farms in Ireland, causing large scale financial loss.

Climate change has resulted in the warming of oceans and has allowed some of the almost 2000 jellyfish species to expand their ranges. They have also started appearing earlier in the year and increase their overall numbers. This same phenomenon has also been observed in ticks, bark beetles and other pests which have spread to new latitudes, increase in number due to warming of temperature.

Increase in jellyfish numbers indicate an unhealthy ocean. It means that the predator-prey balance has gone awry. Overfishing has eliminated many of the jellyfish's natural predators - animals like whales, sea turtles etc which feed on jellyfish and actively reduce their numbers. Overfishing also means that there is more plankton available for the jellyfish to feed on thereby earlier maturity times and increase in their numbers.

In order to alleviate this problem there needs to be stricter laws concerning fishing and pollution control. Active culling of the jellies is a solution that attacks the symptom but not the root cause of the problem. Ocean ecosystems world over are under tremendous stress and unless the fishing industry, governments and consumers grasp this - problems much worse than this will prevail.

On the flip side, innovative entrepreneurs are trying to process and market the Nomura jellyfish as appetizing food choices. Would you eat a giant jelly?

rebirth of the primordial soup?

One of the most devastating effects of global warming is how it affects the oceans and seas of the world. In order to understand how climate change affects the oceans, it is essential to know how oceans affect global weather.

Oceans dominate the movement of water, supplying most of the water vapour in the atmosphere by evaporation. Of this, 91% is returned to the oceans as precipitation, the remainder is transported and precipitated over landmasses. Runoff and groundwater from land flow back to the oceans.

The oceans and the atmosphere are tightly linked, and together form the most dynamic component of the earth’s climate system. Oceans store heat. When the earth’s surface cools or is heated up by the sun, the temperature change is greater and faster over land than over the oceans.

Winds and currents are constantly moving the ocean’s waters. The Gulf Stream Drift, for example, is powered by cold, dense, salt-laden water sinking off the north polar coastal regions and moving south in the depths, pushing the surface warm water from the tropical and subtropical Atlantic (including some from the Gulf of Mexico) up north to bathe the shores of Western Europe, producing a climate that is surprisingly mild for that latitude.

Global warming and melting of the polar ice-caps freshens the surface water, reducing its density and preventing it from sinking. As a result, the Gulf Stream slows down, or may even reverse, bringing severe winters to northern Europe while the rest of the earth heats up.

All over the world ocean waters are warming as a result of global warming putting stress on marine ecosystems and sea life, already under siege from pollution, overfishing and habitat destruction. Warmer oceans also mean that ice caps are going to be melting faster, the rising sea-level will put underlying coastal areas at risk of being submerged. Sea levels are predicted to rise 7 to 23 inches by the end of the century, plus 4 to 8 inches if recent melting in Greenland and Antarctica continues. Many scientists consider these conservative estimates.

Apart from this there is going to be a direct influence on global weather patterns with increase in hurricanes and typhoons. We have already seen evidence of this. Additionally, winters in northern Europe and Scandinavia have grown wetter, while those in southern Europe and the Middle East have become dryer. European farmers have encountered an earlier and longer growing season. The habitats and life cycles of many marine and terrestrial species have changed. There have been changes to the monsoon in India and the Pacific Southwest as well.

Food for thought: The planet's weather not only supports its varied species of life, it also supports global economy. The biggest economic sectors directly affected by climate change are agriculture and the fishing industry. The warming up of our oceans is a bigger threat to human survival than anything else we currently face. A continued increase in ocean temperatures will see the top predator species of the food chain extinct with oceans reverting back to the primordial soup stage of early creation.