The head of the team that discovered the wreckage of the Titan sub said one ROV was lost in the search as it couldn't handle the depth

• Ed Cassano headed the team that recovered the wreckage of the Titan sub.
• His company's remotely operated vehicle, Odysseus 6K, found the wreckage of the Titan.
• Cassano said that another ROV was lost as it was "beyond their depth capability."

The head of the team that discovered the wreckage of the Titan submersible told a press conference that another ship's remotely operated vehicle (ROV) was lost during the search as it was "beyond their depth capability," adding that this showed the "scope of the effort" that went into the recovery.

Ed Cassano, the CEO of Pelagic Research Services, said his team was part of a fleet of ships involved in the rescue search but that its ROV, Odysseus 6K, was identified as the primary asset to carry out the rescue.

Pelagic's ship was stationed around 250 feet away from Deep Energy, a Bahamian-flagged ship with two ROVs onboard. One was holding at its depth limit of 8,860 feet, while the other had been lost after attempting to send it to the seafloor, Cassano said.

The debris was uncovered near the ship's wreckage, about 13,000 feet beneath the surface in the North Atlantic

"We pushed some things, and everybody pushed some things on this response," he said.

He added that the initial preparations had been for a rescue operation, and he detailed how they planned to "integrate" a lifting line that Deep Energy with Odysseus 6K's lifting capabilities.

But he said it soon became clear that the passengers could not have survived the journey, adding that "by 12 o'clock, sadly, a rescue turned into a recovery."

"Shortly after we arrived on the seafloor, we discovered the debris of the Titan submersible," Cassano said.

Cassano appeared to hold back tears at one point while discussing the operation.

"I have to apologize, we are still demobilizing. There's a lot of emotions, people are tired," he said.

Photos of the debris recovered from the wreckage may explain what caused the submersible to suffer a "catastrophic implosion" as it descended to view the Titanic wreck. 

Jasper Graham-Jones, an associate professor of mechanical and marine engineering at Plymouth University, previously told Insider that the carbon-fiber hull likely failed first.

He said it was impossible to be certain just by looking at the photos, but the carbon-fiber hull most likely gave way under the enormous pressure of the ocean depths.

All five passengers onboard the Titan, including OceanGate CEO Stockton Rush, died during the incident.

The US Coast Guard has since said that presumed human remains had also been recovered.

The other passengers were British billionaire Hamish Harding, British-Pakistani Shahzada Dawood, his 19-year-old son, Suleman, and French sub-pilot and explorer Paul-Henri Nargeolet.