A recently published study has revealed that Hurricane Katrina, one of the most devastating natural disasters to strike the US several years back may have lead to an increase in the bottlenose dolphin population along the Gulf coast, the reason being a decline in commercial fishing. The study, published in the journal Marine Mammal Science, shows an increase in dolphin calve numbers following the hurricane, from one percent of dolphins observed before Katrina to six percent in the years following.

One reason for this increase, the study suggests, is that during this period 87% of commercial fishing vessels were damaged or destroyed by the hurricane, which means more fish for dolphins and more energy to reproduce. Another factor that may have contributed to more dolphin babies was the jump in number of reproducing females following the hurricane which resulted in a higher mortality rate among calves, meaning there might have been an unusually high number of fertile females for the following mating season. Dolphins are known to become and remain fertile for extended periods of time following the loss of a calf.

The researchers plan to continue studying the reproductive patterns of the bottlenose dolphins in the Gulf, looking at how does decreasing commercial fisheries intake affect dolphin populations and also how does the number of boats or density of boats affect the populations.It's not yet clear if the increase in dolphin births since Katrina is likely to lead to an overall dolphin population increase, or if it's unlikely to be sustained over time but the increase in available food will decrease likely once fishing activity increases.