by Aidan E.
I’m not sure if it is just me, but at times, I wish things could just be left alone. Not altered, not upgraded and not moved; left alone. Our world regrettably sees the altering, upgrading and moving of many things; especially animals. At first, it may seem a formidable idea to alter an animal’s genetics or to introduce it to another country. However, in the end, it usually comes back to bite. Flying back with a dangerous sting like the Killer Bee or growing back in large numbers like the Zebra Mussel, it’s simply not a good idea. We have a name for these animals, we call them invasive species. According to the USDA, invasive species are plants, animals, or pathogens that are non-native (or alien) to the ecosystem under consideration and whose introduction causes or is likely to cause harm. This is very true and people fail to realize that it is not the animal’s fault that their eating too much plankton, growing too fast or that they’re aggressive. Would you care to guess whose fault it is? It is… Humans! Yes, with no surprise we have done something again to discombobulate nature. This is an actual issue that not only threatens animals, but us as well. We will be looking at three prime examples of marine invasive species; the sea walnut, killer allege and zebra mussels.
Do you like jellyfish? I’m sorry to say, but we will not be conversing about jellyfish today. However, we will be speaking of something very similar. It is the sea walnut. It sounds fairly cute and cuddly and its looks are almost identical to a jellyfish, but in fact it belongs to a different, but related group known as ctenophores (Youg). The sea walnut is native to the east coast of North and South America (OP). In 1982, the sea walnut was discovered in the Black Sea. During transfers to other countries, it subsequently spread to the Caspian Sea. It soon reproduced and shaped a significantly large population (OP). Feeding on fish larvae and plankton, the sea walnut possesses microscopic beating hairs called cilia to create inescapable water currents for small ecosystems. These currents rapidly draw its prey square into its transparent body (Youg). Increasing in size and ferocity, the sea walnuts were soon consuming all the plankton they could catch. The sea walnut contributed to the collapse of local fisheries and forced the local food webs to collapse (Youg). Soon, “In the Black Sea, the anchovy, an economically important species, had gone into decline and dolphins have started to vanish. In the Caspian Sea, the native seal populations have fallen too” (Youg). As obviously displayed, the sea walnut causes major changes within the ocean and economically affects humans. For this reason scientists are still hard at work trying to find a way to decrease there population within foreign waters.
Did you know that multicellular eukaryotes of the kingdom Plantae could also be an invasive species? I probably just confused you, let me rephrase. Did you know that algae can be an invasive species? Let me introduce you to killer algae. Native to the Indian and Pacific Oceans, killer algae has escaped public and private aquariums in California, Japan, Australia, and Monaco (OP). Multiplying within every muddy crevasse it parks, the killer algae sets an aggressive domain. Killer algae essentially replaces native organisms and deprives marine life of food and habitat. It has spread widely in the Mediterranean and California. “Rapid spread is one key trait of a good invader” (Jacoby). Mass production is the sole key of killer algae’s successful forays. Killer algae spreads by fragmentation. Amazingly, fragments the size of 10 millimeters in length can rapidly produce a new rhizome, attach, and grow. “The Mediterranean strain survives fragmentation better than the native strain in Florida” (Jacoby). Undeniably, a mass producing marine algae can rapidly modify the food chain and habitat of an ocean. Killer algae has become such a large problem, that the State of California has eradicated it at a considerable cost using toxic chemicals (OP). Can you start to comprehend how invasive species can be so dangerous? Let’s leave Killer Algae for the next monster movie and not our most beloved oceanic biome!
Do you like zebras? Are you inquiring to why I’m even mentioning zebras? We are going to be learning about the zebra mussel, another invasive species. “This bivalve mollusk is native to the Caspian Sea, in particular, lagoons of the Black Sea and their inflowing rivers” (OP). It resides in fresh and brackish water. In the 18th and 19th centuries, it ventured through European canals. Soon reaching the Baltic Sea, the zebra mussel soon began its exasperating reign. In 1988, it was discovered in the Great Lakes. Over the years the zebra mussel has spread to many rivers and lakes in eastern and central North America (OP). Reproducing extensively, female zebra mussels can produce 100,000 to 500,000 eggs per year. These develop into microscopic larvae. Subsequently after two to three weeks, the miniscule larvae settle and fasten to any stable surface using small fibers called “byssal threads” (DNR). Once this process is complete, they quickly transform into the creature we know as the zebra mussels. According to the Smithsonian, the mollusk has fouled power plants, water purification facilities, ships, and littered beaches with decaying mussels and sharp shells. In addition, large populations have devoured plankton and decreased the food available for commercial and game fish. Let’s leave the zebra’s to ambling about the African plains and not our wonderland of waterways! This is our third and final example.
In conclusion, invasive animals can be very dangerous and can quickly harm the habitat and ecosystems surrounding. This is a large issue that was originally sparked by humans. In order to recover from this position, do your best to leave animals where you find them, be mindful of how you move them or just leave them alone. It’s quite simple; sometimes it is best if you just leave things be.
Ed Youg. “The Stealthy Sea Walnut Sucks to Succeed – Not Exactly Rocket Science.” Not Exactly Rocket Science. N.p., 20 Sept. 2010. Web. 24 July 2015.
“5 Invasive Species You Should Know.” Smithsonian Ocean Portal. N.p., n.d. Web. 24 July 2015.
Jacoby, Charles. “Killer Algae.” (n.d.): n. pag. Http://nsgl.gso.uri.edu/flsgp/flsgpg04003.pdf. Web.
DNR. “Zebra Mussel (Dreissena Polymorpha).” Zebra Mussel. N.p., n.d. Web. 25 July 2015.
Sea Walnut: Marco Faasse, World Register of Marine Species
Killer Algae: Antoine N’Yeurt, Moorea Biocode Project
Zebra Mussel: D. Jude, Univ. of Michigan, N