Was the spike due to the disappearance of the fishing boats or because the hurricane disrupted things in other ways?
For example a hurricane would increase the amount of biomass washed from the shores. The direct disruption of the oceans by a major storm probably affects all the hormones and life cycles of the critters in the deep blue sea.
there are more theories as always, but the most accepted is that because of less fishing the population of fish increased so dolphins had a nice feast. Nature always finds a balance:)