tpo 26

The reading and the lecture are both about the type of shellfish that is native to Eastern Europe (zebra mussel). Whereas the author of the reading states that this marine cannot be stopped and that it makes a serious threat to the freshwater fish population in all of North America, the lecturer suggests that they can be stopped and they have some benefit for some fish. The lecturer casts doubt on the main point in the reading by providing three reasons. These reasons are about lake knowledge in past about this type of fish, they will be food sources for some species and some influence that some fish can take that from them.
First of all, according to the text, the reading explains a prime example of this fish in Eastern Europe that finally the area in North America will be colonized by them. However, the lecturer disputes this point. He says that this work happened just because they did not have enough knowledge about that.
Secondly, the reading asserts that they have dominated in the area because they do not have any predator and they have a high rate of reproduction. Nevertheless, the lecturer refutes this argument. He argues that after some days, some birds find out that this fish is a good source of food. Since the birds eat a lot of them as a food source, they cannot be able to dominate in that area.
Finally, the reading claims that zebra mussel eats plankton that many others use this food as their source so, they harm these fish. On the other hand, the lecturer believes that it is true that they eat plankton that many fish use this source but, they generate some nutritions that go to the bottom of the ocean that is good for fish in there. Moreover, the fish at the bottom of the ocean is helped by zebra mussel.
In conclusion, although the reading and the lecturer are both about the zebra mussel, the three main points made in the passage are effectively challenged by the lecturer.