In terms whether the zebra muel will exert negative influence on North American, the paage and lecture are contradictory to each other.The author believes that zebra muel might do harm the local species as they arrived while the lecturer holds a different opinion.
First of all, the author makes a point that the history events suggest the zebra muel\'s invasion is unstoppable.In the past, human transportation makes it poible for zebra muel spread around the whole Europe and it is likely to happen again in North American.However, the lecturer demonstrates a different idea that a change made in the \"ballast water\" will prevent the invasion of zebra muel from continuing.He says that if we refill the \"ballast water\" with ocean water, the muel will no longer survive because the saline water might probably kill them all.
Second, contrary to the belief in the paage that zebra muel is able to conquer the new habitat due to their high reproduction rates and adaptation ability, as well as lacking predator, the lecturer says that the hypothesis made by author is not true.He mentions that there are many local bird will eat the zebra muel as a major prey.As a result, the zebra muel is unlikely to dominate the new habitat.
Finally, regarding whether the zebra muel will cause the decline in the fish population since they may compete for food such as plankton with fish species.The author thinks it is a poible consequence brought by zebra muel.However, the lecturer refutes it that the muel can\'t reduce the fish population because they provide enough nutrient for bottom living fish.
