Eve Coleman’s
Analysis on Nomura’s Jellyfish
Eve Coleman
My name is Eve Coleman and I live in Georgia and frequently visit beaches in Savannah and South Carolina where I first began to observe ocean ecosystems. I love traveling, hiking, and working with animals. From a young age I have been very passionate about protecting and appreciating our oceans. I want to pursue a career in international environmental law to help protect marine life across the globe! I also am very interested in working with sea animals in field biology. I love writing and am excited to spread awareness and information about our oceans through my writing!
Global Warming is an unseen phenomenon that cannot always be easily observed, but affects many of the earth's ecosystems. In one damaging example, the Yellow Sea and in Japanese waters are starting to boast unprecedented numbers of Nemopilema nomurai, some of the largest jellyfish recorded. These giant jellyfish have had a tri-fold effect on Japan's economy, their fisherman, and their ocean ecosystem.
Size
The Nemopilema nomurai, otherwise known as Nomura's jellyfish, weigh up to 440 pounds and grow up to 6 feet and 7 inches in diameter. Recorded increases of these blooms began in the early 20th century. Nomura’s Jellyfish feed on zooplankton for all their lives and eventually small fish when they grow big enough. They grow incredibly quickly, starting from the size of a grain of rice to reaching six feet in diameter within six months. Although their size is impressive, they have a number of predators including sharks, leatherback sea turtles, swordfish, and humans. In addition to their impressive size, their reproductive systems are also remarkable and have contributed to the negative effect of their overpopulation.
Getty: The Asahi Shimbun
Reproduction
Nomura’s jellyfish carry an impressive amount of eggs allowing them to lay over one billion eggs at a time. Usually, the majority of these eggs would be consumed by predators or die as polyps when the water got too cold but, overfishing and increasing ocean temperatures have gotten rid of the predators of these eggs and the majority of the eggs make it into adulthood causing an overpopulation of the species.The effects of their overpopulation have been catastrophic.
The rapid escalation in population has wreaked havoc on the natural ecosystem, and caused problems for fishermen and swimmers. The ecosystem in the Yellow Sea and parts of the Pacific Ocean are less abundant with naturally occurring planktons and fish, because the disproportionate amount of Nomura's Jellyfish are eating large amounts of the small fish and plankton. Furthermore, plankton and fish aren’t the only organisms disappearing from the Yellow Sea, several species of marine animals are suffering because of these jellyfish.
Many other animals including sharks, tuna fish, whales, and reef fish are losing their food sources because of Nomura’s Jellyfish and their populations are declining in the Yellow Sea, whether that be from permanent migration or death. This has created problems for fishermen because the fish population has shrunk which has led to a negative impact on their economy.
Junji Kurokawa / AP file
Impact on Fishermen
Additionally, due to the size and amount of Nomura's Jellyfish in the Yellow Sea and certain areas in the Pacific Ocean, fishermen unintentionally catch them in their nets which causes chaos for the crew. If a group of jellyfish over a meter get caught in the nets they can permanently damage the net as well as poison the fish that have already been caught, thus spoiling the entire day's catch. Additionally, these blooms can become so thick that fishing trolleys cannot move through the water and of course, can’t continue fishing. Fishermen must be extremely cautious when actively fishing near relatively small groups of Nomura's Jellyfish because if a group of them become entrapped in a net, the boat could potentially capsize.
In early November 2009, a ten ton fishing trawler operated by a three man crew was sunk by Nomura's Jellyfish in their nets. The fisherman had tried to bring the jellyfish back to port instead of cutting the net or releasing the entire catch; however, they were unsuccessful. The boat capsized stranding all three fishermen in the water, who were later rescued.
Not only do Nomura's Jellyfish cause problems for fishermen, they also sting swimmers in the Yellow Sea: there has been an uprising in severe envenomations caused by Nomura's Jellyfish. These stings cause itching, swelling, pain, inflammation, and death in some cases. A study exploring the internal effects of these stings found that the venom causes damage to organs such as the kidneys, heart, liver, and lungs. Though there are hundreds of thousands of stings reported annually, fatality rates aren’t relatively high.
Japanese businesses, fishermen, and citizens have been working to find a way to make the best of these jellyfish but an easy, viable solution has not yet been implemented. Many proposed solutions, specifically in the nutrition and agricultural fields, have seemed promising, but the process to prepare these jellyfish for safe consumption or use is extensive as well as expensive.
Yomiuri Shimbun/AFP/Getty Images
Tango Jersey’s Ice Cream Company has a vanilla flavor that includes these jellyfish inside. The ice cream making process involves dicing the edible portion of the jellyfish and then soaking it in milk overnight to later add into vanilla ice cream. However, the process to obtain and prepare the jellyfish is exhaustive. It requires thorough cleaning, cooking, and a well trained employee to ensure that the venom has not contaminated the product.
Another proposed solution is that these jellyfish be used as fertilizer, which is how other invasive species are dealt with. Nomura's Jellyfish found to be a suitable fertilizer but the process to transform the jellyfish into fertilizer is too difficult to become a widespread solution. The process to turn Nomura’s Jellyfish into fertilizer includes catching these jellyfish, de-salting them, drying them, and grinding them into little pieces. Due to the size of Nomura’s Jellyfish they’re almost impossible to catch and bring to shore. When caught they have been found to destroy the nets they are captured in and even sink the boat attempting to pull them up. Their size also makes the desalination and drying process longer in comparison to other jellyfish species.
Additionally, all of these methods require the jellyfish to be killed. This is difficult because Nomura's Jellyfish release their billions of eggs upon death meaning that to stop population growth they would need to be transported alive to a safe area to ensure the eggs don't end up in the ocean. Medical research has also shown that these jellyfish cannot be used to help create medicine or be used to relieve certain ailments. These jellyfish have created danger for swimmers and put fishman between a rock and a hard place when it comes to doing their jobs successfully and finding a way to limit and benefit from the increasing populations of the Nemopilema nomurai.
Clearly a solution must be met but no one has been able to successfully aid the ecosystem by limiting the Nemopilema Nomurai’s population. This is because the causes of their increasing populations are global issues. Nomura’s Jellyfish are now able to reproduce all year round because of the heating oceans. Overfishing has also played a big role in eliminating their natural predators allowing their eggs and polyps to thrive, year round, with little chance of being eaten. Global Warming has caused many of our oceans reefs, communities, and resources to become depleted and even barren.