| Last updated
Husband and wife Lakyn and Stephen have since apologised for their actions, saying they hadn't meant to offend anyone.
In a TikTok video, Lakyn could be seen approaching the seal at a Kauai beach back in June, touching its back while posing for the camera.
The seal, however, didn't look too happy about the incident, and suddenly jumped up - reaching its head towards her hand.
Lakyn then jumps back and runs away across the beach as the camera pans around to film her leaping through the sand.
According to official estimates, there are just 1,100 Hawaiian monk seals left in the Northwestern Hawaiian Islands and 300 in the main Hawaiian Islands.
Under state and federal laws, it is a crime to touch or harass them, with penalties of up to five years in prison and a $50,000 (£36,000) fine.
The National Oceanic and Atmospheric Administration (NOAA) contacted the couple over the weekend and handed them an undisclosed fine, the Honolulu Star-Advertiser reports.
Dominic Andrews, a spokesman for NOAA's Office of Law Enforcement, confirmed that an investigation was underway, but declined to comment further.
The couple have since 'sincerely' apologised for what happened, after the clip went viral online - having been shared by various accounts across several social media platforms.
Lakyn's TikTok account, where the video was originally posted, has also been set to private.
Speaking to the Honolulu Star-Advertiser on Monday, Stephen said: "We're deeply sorry.
"We love Hawaii and the culture. We didn't mean to offend anyone. We respect the culture."
Stephen explained that NOAA authorities had contacted he and Lakyn on Sunday and assessed an undisclosed fine.
He continued: "We sincerely apologise if we offended any locals. The last thing we want to do is disrespect anyone or anybody's culture or lifestyle. That's something we're really, really sorry about."
Stephen added: "We're animal lovers. We weren't trying to cause any harm or threaten or scare any animals.
"We're deeply sorry. We'll learn from this mistake."
He also said he and his wife had received death threats online after the footage went viral, asking that their full names were not given.
LADbible has contacted NOAA for a comment.
Chosen for YouChosen for You
Most Read StoriesMost Read