Shark Population Analysis

Atlantic Mako Shark Population 1951-2018

I wanted to highlight the severity of shark population declines over the last 50 years or so.

Not too long ago, I heard a wild statistic on the news. They mentioned that humans kill around 10,000 sharks every single day across the world. That really caught my attention and shocked me. So I tried to find some data tracking shark populations over the years. I found one, and I targeted the Atlantic Mako Shark because that particular species had population data going all the way back to 1951. So that seemed like a good one for me to start with.

I made two line plots showing 1. the absolute population numbers each year, and 2. the percent change in population each year.

import pandas as pd
import numpy as np
import matplotlib.pyplot as plt
import seaborn as sns
sharks = pd.read_excel('shark_population_data.xlsx', sheet_name='Sheet1')
sharks.head()

sharks.info()

fig, ax = plt.subplots(figsize=(10,6))
sns.set_style('darkgrid')
sns.lineplot(data=sharks, x='year', y='stock')
fig.suptitle('Shark Population Decline Over Time', y=0.95)
plt.show()

Annual Mako population in absolute terms

This visualization indicates that around 1980, Atlantic Mako sharks began an exponential population decline, which appears to continue to the present day.

sharks['change'] = (sharks['stock'].pct_change() * 100).round(2)
sharks

fig, ax = plt.subplots(figsize=(10,6))
sns.set_style('darkgrid')
sns.lineplot(data=sharks, x='year', y='change')
fig.suptitle('Shark Population Annual Percent Change in Population', y=0.95)
plt.show()

Annual Mako Population in relative terms

If we visualize each year as a percentage change from the previous year, we can glean some good news, in that the rate of decline is slowing. Although,the Mako population is still declining, at least the annual percentage change is not as severe in the last few years.

Conclusion

This data is discouraging. The Atlantic Mako shark population has been in an exponential decline for the last 45 years. At the current rate of decline, the Mako will not survive the next 45 years.

Notes