Invasive Species: The Asian Carp

Throughout human history, we have witnessed a variety of habitat degradations and fragmentations caused by the introduction of invasive species. Identifying invasive species and taking early action are important and necessary as it helps eradicate damaged effects to the environment. While more attentions are paid to invasive animals living in terrestrial ecosystem, the most serious species that leaves environmentalists a lot of concerns belongs to the aquatic environment: the Asian Carp. In this report, I will describe this species and do further research into its impacts before suggesting potential solutions to eliminate the species.

Asian Carp is a type of freshwater fish which has small eyes, thick lips, two barbels at each end of their mouth, heavy body and intramuscular bones. This species can weigh up to 60-110 pounds and grow up to 50 inches if raised in prosperous environment. Carp has a long lifespan averagely from 15 to 24 years and their hatching is is quite rapid and easy, only within two days. There are estimately ten different types of Carp such as common carp, grass carp, silver carp, crucian carp, black carp, bighead carp, Amur carp, goldfish, largescale silver carp, and mud carp. The colour of carp also vary; it can be yellow, white, black, silver or orange depending on where they are grown.

According to IUCN/SSC Invasive Species Specialist Group (2010), carp originates from Asia and lives in still or slowly flowing waters, lakes, and permanent wetlands. This invasive species can be found at low altitudes, especially coastal lakes and favors habitats that contain abundant aquatic vegetation. The reason why carp can survive in high salinities and polluted, degraded areas is that they have a high reproductive ability and tolerance rate. Additionally, they are likely to be spotted in streams and substantial runoff from rural Asian agricultural land such as rice field sewage water due to the properity of aquatic organisms. A

sian Carp is believed to bring about various uses for human, from food consumption to recreational fishing industry. In fact, unlike other common fish species, carp have white mild flesh and are a rich source of protein and nutrition for many parts of the world. Koi, an ornamental type of carp, are very expensive and specially popular for aquarium show because of their appealing appearance and sense of entertainment. Therefore, although carp is non-native to the North American aquatic ecosystem, they have been introduced here for over 100 years for their various utilities. Not only provide a huge amount of human food, carp are also seen as a method to manage nuisance algal blooms in wastewater treatment plants, aquaculture ponds, and boost harvests from catfish ponds in the United States (Michigan Sea Grant). However, it only takes a little time for ecologists to detect Carp’s threats to the new introduced environment. Michigan Sea Grant also found that silver carp and bighead carp grow so rapidly in number they disrupt the native aquatic species’ food web at multiple levels and also compete with them in terms of habitat. Moreover, this species is notorious for leaping high into the air from 8-10 feet when they are disturbed by big sounds. If introduced carp hear boat motors they may jump out of the water and frighten surroundings, sometimes they can cause injuries to boaters in connecting waterways. Based on the US Geological Survey, the consequences caused by Asian carp in the Great Lake have elevated significantly in the past decade, estimately cost the fishing industry around $7 billion a year. Hence, urgent and effective measures have been taken continuously in an attempt to completely eradicate the invasive carp from the US aquatic ecosytem.

One of the most prevalent preventative approaches in action includes using electric barriers, harvesting, traps and water level manipulation. Ecologists and national agencies have cooperated to build an absolute aquatic separation so that the spread of Asian carp is limited between oceans. The second method of controling carp is using chemicals such as rotenone and pheromones. Both chemicals are proved safe and have come into use widely in the US for adjusting fish behaviours and sex hormones. The third measure is biomanipulation, which aims at manipulating the interrelationships among plants, animals, and their environment in an attempt to reach a new ecological balance.

Another potential way of managing the number of carp is the application of immunocontraception. In this method, a gene is delivered to block reproduction of the fish, making them infected by a recombinant virus. Last but not least, sterile feral is one of the most useful methods taken to lower the population of carp by using an inducible sterility gene that modulates the hatching practice of Asian carp. The more rapidly number of carp grow, the more disastrous consequences are ensued to the ecosystem.

From my perspective, in comparison with the merits carp bring, their impacts are believed to be considerably more damaging to the introduced environment. Human food and recreational fishing industry may vary in many aspects and carp can be replaced by other types but it is truly impossible to let the ecological system be disrupted and biodiversity is gradually lost by invasive effects of Asian carp. Over the years, they have caused a great deal of alternations to the natural development of other native species regarding food web and their habitat. Therefore, immediate actions should be taken to first regulate the population growth of invasive carp and then completely eliminate them from the places they have been introduced. Thereby, we could maintain a sustainable development of the natural ecosystem, bring down economic costs, and reduce the risks of losing precious animals. To recapitulate, it seems to me that even though Asian carp are introduced to North America for human food and recreational fishing activities.