Investigators expect to get information about the plane’s speed, altitude, point of impact and other details about the incident.
The NTSB is still working on formal interviews with flight crew and anticipates conducting those Sunday. The investigation will also looking at the pilot's experience.
Officials said that human life was their first priority after the crash, but there were multiple attempts to check for crates. Naval Air Station Jacksonville said that crews checked the cargo bay for pets but did not see or hear animals or crates in that initial response.
Related: Rescuers tried to get pets of submerged airplane several times, commanding officer says
Kaylee LaRocque, a spokeswoman for the U.S. Navy in Jacksonville, confirmed to USA Today that each of the at least four pets checked into the luggage department are presumed dead.
“There’s water in the cargo hold," LaRocque said. “We are so sad about this situation, that there are animals that unfortunately passed away."
Update 6:30 p.m. EDT May 4: In a press briefing Saturday afternoon, National Transportation Safety Board Vice Chairman Bruce Landsberg said that the 737-800 overran runway 10 and it had no history of accidents or incidents.
Landsberg said that the NTSB is now looking into the aircraft, captain’s background and experience as well as the weather conditions and if runway condition affected crash landing.
Miami Air had an incident in 2005 with a different aircraft that made a hard landing in Pennsylvania.
Update 2:30 p.m. EDT May 4: Officials with the National Transportation Safety Board have made it to the site of the crash. A 16-person Go Team is currently investigating, NTSB Vice Chairman Bruce Landsberg told reporters in a brief press conference.
Another press conference will be held at a time to be announced on the Twitter page, @NTSB_Newsroom.
Update 8:27 a.m. EDT May 4: Capt. Michael Connor, the commanding officer at the Jacksonville Naval Air Station, told CNN he expected officials from the National Transportation Safety Board to arrive in Florida between 9 a.m. and 10 a.m. to inspect the plane that skidded off Runway 10 and into the St. Johns River.
Connor said the plane landed on the longer of the two runways at the airport. Runway 10 is 9,000 feet long, he told CNN, and there was 8,000 feet of landing distance. He said that heavy thunderstorms in the area could have impacted the plane’s attempted landing.
“Under normal conditions there is plenty of runway,” Connor told CNN.
Update 7:34 a.m. EDT May 4: Officials with the Jacksonville Naval Air Station said they are hoping to board the plane that skidded off the runway this morning to retrieve pets still on the aircraft, WJAX reported in a tweet. There was no indication of how many pets were on the plane and what their conditions were.
Update 5:50 a.m. EDT May 4: A woman who was a passenger on the plane that skidded off a Jacksonville runway into the St. Johns River told CNN the landing "didn't feel right."
Cheryl Bormann, a civil defense attorney said passengers were confused and afraid as the Boeing 737 aircraft slid off the runway at the Jacksonville Naval Air Station.
"The plane ... literally hit the ground and then it bounced," Bormann told CNN. "It was clear that the pilot did not have complete control of the plane because it bounced some more, it swerved and tilted left and right," she said. "The pilot was trying to control it but couldn't, and then all of a sudden it smashed into something."
Update 2:08 a.m. EDT May 4: Tom Francis, a spokesman with the Jacksonville Fire and Rescue Department, said he was relieved to hear there were no critical injuries.
“To say that I was wiping sweat off my brow would be, of course, an understatement,” Francis said at a news conference early Saturday.
Francis, a 30-year veteran firefighter, was asked if he had ever remembered an incident of this magnitude in the Jacksonville area.
“Well, obviously, if I could remember something like that, that would make Jacksonville something along the lines of a city prone to an attack from Godzilla and from other science fiction components, and Hollywood scenarios,” Francis told reporters. “Because no, obviously, I don’t.
“(In) 30 years on the job, (other events) don’t compare to to something of this magnitude when it comes to the lives and the souls, etc.. that are potentially involved.”
Francis would not characterize the lack of fatalities as a miracle, however.
“Oh, I don’t take that kind of approach to anything, I’m more of a secular kind of guy,” he told reporters.
Update 12:45 a.m. EDT May 4: NAS Jacksonville issued a statement confirming there were 136 passengers and seven crew members aboard the Boeing 737 aircraft. There were minor injuries reported and several people were treated at the scene. There were no fatalities.
Update 12:40 a.m. EDT May 4: The Jacksonville Sheriff's Office tweeted that 21 people were taken to local hospitals.
Update 12:10 a.m. EDT May 4: Jacksonville Mayor Lenny Curry posted on Twitter that teams were working to control jet fuel in the water.
Update 11 p.m. EDT May 3: The Federal Aviation Administration told WJAX-TV that the Boeing 737-800, a military contract flight operated by Miami Air International from Guantanamo Bay Naval Base, skidded off the runway. The nose is in the mud of the river.
There are at least two minor injuries.
The Jacksonville Sheriff’s Office Marine Unit responded to the partially submerged aircraft.
The mayor of Jacksonville also confirmed the incident on Twitter: