Photos of a bull shark got a lot of people taking on Wednesday. But can bull sharks swim inland?
Jared Moser says he found the dead shark while four-wheeling in Kenefick Tuesday. The decomposing shark was located some 40 miles north of Galveston Bay off the Trinity River near Liberty, Texas.
Texas Game Warden Randy Button went to check it out early Wednesday and said the 5-foot-shark was clearly dumped. Button said you could see the tracks where the shark was dragged into the water. There was also evidence of a hook in its mouth.
Although the evidence suggests the shark did not swim up the Trinity River, experts say it could have.
“Bull sharks are one species that we actually classify as marine and fresh water,” said Professor Jaime Alvarado in the ocean and coastal studies department. “They venture into waters that are extremely warm and they can move into much colder waters.”
Alvarado told us bull sharks, in particular, can sustain themselves for long periods of time in fresh water.
“As a matter of fact, in Lake Nicaragua, we have occurrences that last for years,” said Alvarado.
Closer to home, bull sharks have been documented in the Mississippi River a thousand miles from the Gulf of Mexico.
And, in Texas, there have been reports of bull sharks being caught below the Lake Livingston Dam, above Houston.
“It’s a species of shark that can cover long distances,” said Alvarado. “They can cover perhaps 200 miles overnight.”
So, while the unfortunate fish found dead off the Trinity River didn’t swim there, we verify that bull sharks are able to survive in fresh water many miles inland.
Here’s additional information from Texas Parks & Wildlife:
“Bull sharks do have the ability to survive in freshwater. Unlike most other sharks, they can retain salts while excreting excess water when they are in freshwater. The farthest inland a bull shark has been encountered was in the Mississippi River by Davenport, Iowa. Bull sharks are the most common species found in Texas, and our bays serve as nursery areas for the juveniles. They are found in coastal waters worldwide. In Texas, there have been unverified reports of bull sharks being caught below the Lake Livingston Dam, above Houston.
Interesting fact: The sharks in Lake Nicaragua are bull sharks, and that is a landlocked lake. The Zambezi River sharks in Africa are also bull sharks.”
Aubry Buzek, Press Office at Texas Parks & Wildlife Department
Non-profit oceanic organization Wild Aid
The Texas Parks & Wildlife Department