After the Storm
Dolphin reproduction in Mississippi Sound spiked after Hurricane Katrina
Sightings of Atlantic bottlenose dolphin calves in the Mississippi Sound increased two years after Hurricane Katrina, suggesting that the storm’s fall-out may have encouraged more dolphins to reproduce.
Katrina struck the Gulf Coast in August 2005, wiping out commercial fishing boats and reducing recreational fishing as well. Researchers speculated that the downturn might have spurred more reproduction among dolphins, which could take advantage of increased fish populations. And calves may have died during the storm, they note, causing female dolphins to become fertile the following season.
The team monitored Atlantic bottlenose dolphins (Tursiops truncatus) in the Mississippi Sound for three years, scanning each encountered group for calves. The average number of calves seen per kilometer travelled by the team increased by more than four times between the summers of 2005 and 2007, according to the study in Marine Mammal Science. While the proportion of calves to other dolphins was around 1 percent immediately before Katrina, it went up to about 7 percent by spring 2007.
The fishing reprieve may have given female dolphins more food to feast on, boosting their chances of successful reproduction, the authors say. And since dolphins can expend energy avoiding boats, the dip in recreational fishing might have allowed the animals to focus on hunting prey instead. – Roberta Kwok
Source: Miller, L.J. et al. 2010. Potential effects of a major hurricane on Atlantic bottlenose dolphin (Tursiops truncatus) reproduction in the Mississippi Sound. Marine Mammal Science DOI: 10.1111/j.1748-7692.2010.00371.x.
Image © cpurser, iStockPhoto.com
