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?