TPO 26 ZEBRA MUSSELSReading The zebra mussel a freshwater shellfish native to Eastern Europe has long been spreading out from its original habitats and has now reached parts of North America There are reasons to believe that this invasion cannot be sto

In the reading, the author explains that the zebra mussels are a serious threat to the North American fish population and there are several reasons that these are unstoppable and have many negative effects on the freshwater fish population. On the contrary, The professor explains that there are many ways to stop the population of zebra mussels and can be manageable and they are not a serious threat to the North American fish population.

First, as the author says that history indicates that the zebra mussels are the dominant species and their invasion was unstoppable. History of Europe also indicates that they will quickly colonize North America. The professor says yes that's true that past people could not able to control the population of zebra mussels and it is because they do not have enough knowledge to control them. As the author says they can be transferred by the freshwater like ballast water of the ship, there are ways to drain the ballast water by draining the water in the salty ocean water and fill the ship with saltwater. The salty ocean water kills the zebra mussels. Hence, control the population of zebra mussels

Secondly, as the author mentions that the zebra do not have any predator when they arrived in the new habitat so they reproduce rapidly and dominate the area and affect the other species of that habitat. On the other hand, the professor says the author did not see through the information is that this happens only because the other species did not the zebra mussels as a food source at the beginning. After a while, the other species came to know about the new food source that is zebra mussels and quickly change their habitat and as a predator especially the birds eat them as a food source. As a result, they control their population

Third, the author mentions that other freshwater fish populations decline because of zebra mussel especially the plankton-eating fish because there is a competition of food source that is plankton between the mussels and the other fish. The professor says it happens only to plankton eaten fishes, not on the other fishes. So it does have a negative effect on plankton eaten but the positive effect on the fishes who live at the bottom and instead of plankton they eat mussels. Therefore, no competition of food so their population increases.