(CNN) Endangered seals are baffling conservationists with an unlikely predicament -- getting eels stuck up their noses.

The Honolulu-based Hawaiian Monk Seal Research Program (HMSRP), part of the United States' NOAA Fisheries agency, posted a photo on its Facebook page Monday that showed a seal with the slippery creature lodged firmly in its right nostril.

This undignified incident is just the latest in a long (and wriggly) line of eel invasions to strike the Hawaiian monk seals -- a phenomenon that was first spotted in the summer of 2016 off Hawaii's Lisianski Island.

"Mondays ... it might not have been a good one for you but it had to have been better than an eel in your nose," the HMSRP joked on its Facebook page.

The Hawaiian monk seal is one of the rarest seal species in the world and is classed as endangered in the US. The majority of the population lives around eight remote islands of the Northwestern Hawaiian Islands, and it was estimated in 2016 that only 1,427 animals remain.

Scientists are concerned the eels could carry infections and may hamper the seals from diving.

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