Sea Cows Extinction

There is a disagreement between the passage and the lecture concerning possible explanations of sea cow's extinction, one kind of marine animal. The reading passage represents 3 theories about the extinction. However, the lecture casts doubt on it, and gives contradicting evidence.
First of all, the reading states that native Siberian people over-hunted sea cows, eventually resulting in the extinction of them. The lecturer, on the other hand, disputes it with the statement that the sea cow was so enormous that few of them provide a village with sufficient meat to live for months, and Siberia was not populous. Thus, they did not need many cows.
Furthermore, it is said in the passage that the number of the kelp, fundamental food source of cows,
But, the lecturer again dissents from the reading. He claims that if any upheaval had occurred, it would have affected the other animals like whale, and yet there was not any change in the environment reported. Then, food scarcity explanation cannot be plausible.
Finally, the author argues that the sea cows were exterminated by the European fur traders coming after 1741. On the contrary, the professor concludes that the eradication of sea cows did not take place because of the traders. When the traders arrived, the population of the cows had already been meager, which means something severe happened to them.

Finally, the author argues that the sea cows were exterminated by the European fur traders coming after 1741. On the contrary, the professor concludes that the eradication of sea cows did not take place because of the traders. When the traders arrived, the population of the cows had already been meager, which means something severe happened to