Dr. Pennisi may love bats, but I adore jellyfish so I'm going to tell you a little bit about them. There are over 350 different species of jellyfish (some scientists contest there may be as many as 2,000 individual species) ranging from the minuscule Irocongi (about the size of your pinky fingernail) to the Lion's Mane Jellyfish (about the size of a refrigerator) . Jellyfish are about 95 - 98% water and have no bones, internal organs, blood, or really anything that would qualify them as an animal and yet they are a viable and necessary component of aquatic habitats. There are over 280 types of fish and other species such as leatherback sea turtles that eat jellyfish. Jellyfish reproduce asexually, and some species can live for so long in an environment that scientists have no way to gauge their lifespan.
So what, why is it important to know about jellyfish? Well it is important to understand the jelie's roll in marine ecosystems because it can help dictate whether or not our fishing industries can survive. In 2011 there was a blooming swarm of Nomura jellyfish (~440 lbs, 6 ft long) along coastal Japan. Millions of these jellyfish became entangled in fisherman's nets and with their massive weight ripped through most of them - creating millions of dollars worth of damages and causing a shut down of 90% of fishing industry in Japan which significantly impacted their economy. This has not been the only example of jellyfish swarming in such large quantities - with reasons estimated for their populace ranging from increasing sea temperatures due to global warming, to losing natural predators from over fishing. Jellyfish are incredibly resilient creatures - they can thrive in poor water quality, consume nearly anything of an appropriate size, can regrow appendages or parts of their body if injured, and when reproducing can do so in thousands at a time.
One of the most concerning factors about these jellyfish swarms is their effect on the fishing industry. Jellyfish typically feed on plankton - the same food that many commercially consumed fish eat as well. Because of over fishing by humans in the oceans there have been fewer and fewer fish to compete with for their food source so jellyfish are taking over the seas - and by doing so hinder the ability of fish populations to regain stability. What we need to take away from this is that our blatant overuse of commercial fishing has a significant impact on the marine ecosystems. As much as I love and admire these creatures it is not overall healthy for our oceans to be dominated by them. Pollution hurts our ecosystems and the fish and other marine species we want to preserve are more hurt by this than the jellyfish are as well.
~Brooke Welsh-Appleby
Did you find any articles or research on an estimate of when this started? I guess I'm just wondering if the 2011 swarm off of Japan was the first observed or if we have seen this occur before. Thanks!
ReplyDeleteI'm very glad to see the overpopulation of jellyfish being mentioned at the end of the blog. The take-home message that the seas are being over-fished is very correct and I feel needs to be brought to light. I have made the personal choice to not eat seafood because of the over fishing of the seas, much like a vegetarian chooses not to eat meat because of the mistreatment of livestock and other environment affects large livestock operations pose. The habitats in the ocean are some of the most endangered habitats on the planet.
ReplyDeleteIn this article, http://www.bbc.co.uk/news/uk-scotland-north-east-orkney-shetland-21313702 , it talks about how Iceland's government has announced that it is lowering its mackerel fishing quota for 2013 by 15%. This violated policies it had with a european union Iceland is a part of. Iceland is now following recommendations presented by international scientists in regards to how much mackerel it takes from the ocean. I thought the article to be an example of what more countries need to do to reduce their taking from the ocean.