Graphs for whales

These four graphs indicate how many whales were killed from 1950 to 1985. First graph is showing about number of the biggest whales killed which are Blue whales. According to first graph, the number of Blue whales killed at the peak of 1951, and had sharply decreased until they were extinct in 1969. The second largest whales, Fin Whales, were killed the most from 1954 to 1961. During the period, Number of the whales killed was flattening and abruptly fell down at the point of 1961. As far as I can see, the number of Sperm whales killed relatively fluctuated evenly from 1950 to 1975. In forth graph, I can see sharp equally line of mountain which is the peak in 1967. Thirty thousands of Sei whales which are the smallest whales were killed to the maximum in 1967. In my analysis, the smaller whales are, the later they were killed. As we know from four graphs, the biggest whales are extinct. Moreover, the other three whales are almost extinct in 1985. We did not have good enough tool to find and catch whales. It was relatively easy to find large whales at that time. However, the more progress technology for fishing, the easier to catch even small whales.