Another oarfish carcass has washed up on the shores of Southern California, puzzling marine life experts as to why the rare and little-understood fish has turned up in the region twice in less than a week.

Oarfish -- pug-faced, eel-like creatures as big around as grown man's waist -- are marked by their shocking length. They routinely measure more than a dozen feet long. The first of the most recently washed-up pair was 18 feet long and weighted 400 pounds. The second in the back-to-back pair, measuring 14 feet long, was found Friday.

Oarfish, which can be found in temperate to tropical waters around the world, are able to dive 3,000 feet below the water's surface. It is believed they typically dwell at such great depths, which is one of the primary reasons the fish seem so rare -- we hardly ever see them and they remain largely unstudied.

The elusive nature of the oarfish makes the duel wash-up mystifying for experts.

"It may have happened some place on Earth before but it certainly doesn't happen very often," Milton Love, a research biologist at the University of California in Santa Barbara, told Reuters.

Love told Reuters that oarfish are not strong swimmers and that the fish may have been pulled ashore by powerful currents and battered to death by strong waves close to shore, adding that there may be even more carcasses in 50 to 100 feet of water off shore that no one will ever know about.

Earlier last week a group of snorkelers found the first of the pair while exploring the waters off of Catalina Island. The second oarfish was found on a beach in Oceanside, which is about 40 miles north of San Diego.

The oarfish's carcass is being preserved in ice, and tissue samples are being collected by the Catalina Island Marine Institute, CNN affiliate WTKR reported. The institute has been sending some tissues and other samples to marine scientists, including Love, who will study the oarfish's DNA and diet.

Recently, the first video of a live oarfish swimming in the sea was recorded in the Gulf of Mexico by researchers at Louisiana State University.