Thursday, April 15, 2010

Hurricane Katrina Responsible for More Dolphin Births?

Photo courtesy: fotolen

Hurricane Katrina was one of the worst natural disasters to strike the USA. The loss of life and property was inestimatible both on a human level and on a financial one.

However, it appears there was one positive result from this. A recently-published study reveals that the hurricane may have set the stage for a baby boom in the dolphin population along the Gulf coast.

During the years following Katrina, biologists observed a sharp increase in the number of bottlenose dolphin calves. Due to the storm, the local fishing industry sustained enormous damage to their commercial vessels causing fishing to decline. Scientists believe that consequently the amount of prey fish available to the dolphins increased.

The study, published in Marine Mammal Science, shows a marked spike in dolphin calf births following the hurricane. Before Katrina, the local bottlenose dolphin calf rate was 1%; but, in the years following Katrina, the numbers increased dramatically to 6%. The study suggests that since during this period 87% of the commercial fishing fleet was either damaged or destroyed, the increase in prey fish available to be eaten gave the dolphins increased energy for reproduction.

An excerpt from the report states:
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.

The scientists are also considering the fact that the hurricane was responsible for a much higher mortality rate among calves than was usual. They speculate that this could have resulted in an unusually high number of fertile females in the following mating season.

Researchers plan to continue studying the reproductive habits of bottlenose dolphins in the Gulf. It would appear that scientists now believe that we haven’t previously understood the full extent human activity has on the ecosystem.

To date, we have refused to acknowledge that the more fish we take from the ocean leaves less fish for species such as dolphins. What we have acknowledged is that reduced fishing has led to an increase in dolphin babies. Hopefully, we manage to make the leap to realization that fishing must be regulated more than it is; that somehow we must find a way to eliminate catching non-targetted species; and, somehow we must learn to live in harmony with our marine friends.

Via TreeHugger

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