Environmental Science 15th Edition by Scott Spoolman,Tyler Miller

Exercise 10

A fishprint provides a measure of a country's fish harvest in terms of area. The unit of area used in fishprint analysis is the global hectare (gha), a unit weighted to reflect the relative ecological productivity of the area fished. When compared with the fishing area's sustainable biocapacity (its ability to provide a stable supply of fish year after year, expressed in terms of yield per area), its fishprint indicates whether the country's annual fishing harvest is sustainable. The fishprint and biocapacity are calculated using the following formulas:
Fishprint in (gha) = metric tons of fish harvested per year/productivity in metric tons per hectare × weighting factor
Biocapacity in (gha) = sustained yield of fish in metric tons per year/productivity in metric tons per hectare × weighting factor
The following graph shows the earth's total fishprint and biocapacity between 1950 and 2000. Study it and answer the following questions.

Based on the graph,
a. In what year did the global fishprint begin to exceed the biological capacity of the world's oceans?
b. By how much did the global fishprint exceed the biological capacity of the world's oceans in 2000?