TPO 26 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 stopped and that it pos

The reading and the lecture are both about The zebra mussel fish which moved from Eastern Europe to North America eventually. More specifically, in regard to the passage, the writer presents three theories about the risk of these fish on the other fish population. The lecturer disputes the claims made in the article. His position is that The zebra mussel effect is not clear and they will not make any serious threat to the other fishes.

First and foremost, the author of the reading states The zebra movement will not stop because of its background history and its transport using human tools like ships and boats, so these fish will dominate into any new habitat. The article mentions that these fish will colonize all of North America. This argument is challenged by the lecturer. He claims that in the past there was no control because human knowledge was limited but now there are new effective ways to stop the spread of this fish.

Secondly, the author suggests by moving to a new habitat the fish will dominate it and can adapt to any hard condition. In the article, it is said that there are no predators for these fish in the new places, so they will have a high reproduction rate. Again, the professor specifically addresses this point when he states there is a predator for the fish like the birds in Europe because after moving these fish to the new habitat, birds found a new source of food which is zebrafish. He goes on to say that the fish started to move to other places, so it is unlikely to dominate new habitats.

Finally, the author brings his argument to a close by suggesting that zebra mussels will cause a decrease in the population of the other fishes because they will compete with other fishes for the same resources of food. Not surprisingly, the lecturer takes issue with this claim by contending that it is true they have negative impacts on some fishes, but also they have a positive impact on other fishes. He notes that zebra mussels take nutrients to the bottom of the lake which means new food for the other fishes.