While Hurricane Katrina may have been among the most devastating natural disasters to strike the US, a recently published study reveals that the storm may have lead to a baby boom for dolphins along the Gulf coast. In the years following Katrina, biologists observed a sharp increase in the number of bottlenose dolphins calves--and suspect that all the damage to the fishing industry may have had something to do with it. With human activity being relentless in so many ecosystems, sometimes it takes a crippling disaster to measure the extent of our impact.The study, which was published in the journal Marine Mammal Science, shows a spike in dolphin calve numbers following the hurricane--from 1 percent of dolphins observed before Katrina to 6 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.
According to the report:
Commercial fisheries landings and recreational fisheries landings decreased by 48% and 42%, respectively between 2005 and 2006 for Gulfport and Biloxi harbors. This decrease in recreational and commercial fishing, similar to the effects of creating a marine reserve, could have resulted in increased prey availability for dolphins within the area.
Another factor that may have contributed to the baby boom is a potential jump in the number of reproducing females following the storm. The hurricane 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.
To better understand the full extent human activity has on their ecosystem, researchers plan to continue studying the reproductive patterns of bottlenose dolphins in the Gulf. From our lofty position on the food-chain, it's often difficult to grasp the extent our appetite has on native species who, unfortunately for them, share a similar taste. But, even in just a brief period of reduced fishing which resulted from damage caused by a hurricane, scores of newborn dolphins hint that what's bad for the fishing industry may be good for everything else.