The line graph compares the number of two sea animals and a land animal from January to June. Overall, it is clear that the population of bear increased, while whale decreased slightly, and dolphin became extinct over the timeframe.
At the beginning of the period, the total population of dolphins was above 140, which was the highest of that period. However, this number experienced a slight decline to below 80 in February, followed by a more moderate decrease of less than 20 in April, and almost became extinct at the end of the period. Furthermore, the number of whales started the period at 80, half of that of dolphins. Whales population dropped to less than 60 in Feb, followed by some fluctuation, and finished at less than 80.
In contrast, the land animal, bears, which were less than 20, rose steadily to more than 80 in March. April saw a more moderate climb in bears population, and hit a high of above 180, which was the highest at the end of the period.