Alligator doubled in size: Is invasive fish fueling gator growth spurt in Mississippi?

A 12-foot-1 alligator killed Sept. 3 in Mississippi is captivating state wildlife experts, not for how big it is, but for how big is used to be.

It more than doubled in size since being fitted with a research tag in 2011, according to the Mississippi Department of Wildlife, Fisheries and Parks.

That growth spurt begs for explanation and state officials have a surprising theory: Mississippi’s alligators may be getting bigger feasting an invasive Asian carp.

“Nationally, it is rare to document alligators of this size class with annual growth rates of this magnitude, but (such cases) are always associated with habitats with abundant and exceptional prey resources,” the department said in a Sept. 9 Facebook post.

“It is worth noting, since the time 2003-2005 this area of the Mississippi Delta has seen a tremendous increase in the Asian carp population. The MWDFP Wildlife Bureau has documented alligators feeding on the Asian carp on many occasions. ... Alligators in this part of the state (tributaries of the MS River) have significantly more body mass than alligators anywhere else in the state.”

Mississippi is plagued with multiple species of invasive carp, some of which grow to 60 inches and weigh more than 110 pounds, according to the National Park Service. Invasive silver carp are capable of jumping 10 feet out of the water, the U.S. Geological Survey reports.

The 12-foot-1 alligator was killed by a hunter in the Forest Home Chute area, just off the Mississippi River, officials said on Facebook. The name of the hunter was not released.

In 2011, the gator was measured at 76.375 inches in length, or just over 6 feet, officials said. It grew by more than 77 inches in the years since, the post said.

That growth rate is nearly an inch bigger per year than the average of 5 to 8 inches, the state said.

Mississippi estimates as many as 38,000 alligators live across 408,000 acres of wetlands.

Alligator season opened in Mississippi on Aug. 28 and ended Sept. 7, the state reports. More than 840 alligators were harvested this season, 13 of which had state tags, officials said.

At least three alligators killed this season exceeded 12 feet in length, including one that was 13-feet, 8 inches long, reported the Clarion Ledger on Aug. 29.

This story was originally published September 10, 2020 at 2:07 PM with the headline "Alligator doubled in size: Is invasive fish fueling gator growth spurt in Mississippi?."