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Emergency Surgery Saves Hooked Hawaiian Monk Seal

With just 1,100 Hawaiian monk seals alive in the wild today, every individual matters. That’s why an expert from The Marine Mammal Center leapt into action to save one of these critically endangered animals after it swallowed a fishing hook.

June 3, 2015

An endoscope is used to observe the surgical procedure on Hawaiian monk seal RF28.
© NOAA NMFS Permit 16632-00 and 932-1905-01MA-009526-1

When Dr. Shawn Johnson got the call about a critically endangered Hawaiian monk seal in need of emergency surgery, he told the veterinarian on the other line that he’d be on the next plane. And he meant it.

Within hours, Dr. Johnson, the Director of Veterinary Science at The Marine Mammal Center, was en route from San Francisco to Honolulu. He arrived at noon local time and by 1 p.m., he was easing the seal into an anesthesia-fueled slumber.

The Hawaiian monk seal on the operating table was a young male known to researchers as RF28. He was rescued on a beach in Kauai after being spotted with fishing tackle near his mouth but no fishing line (or hook) present.

An X-ray of the animal’s throat and chest, taken with a portable Vet Rocket X-ray machine, had confirmed that the seal had ingested a large fishing hook, which had become embedded in the lining of his esophagus.

The veterinary team examines RF28.
© NMFS Permit 16632-00 and 932-1905-01MA-009526-1

The veterinary team examining RF28, led by Dr. Gregg Levine and other experts from the NOAA Fisheries Hawaiian Monk Seal Research Program, knew that the ingested hook would be deadly if not removed. After stabilizing the sleeping seal, they moved quickly but carefully as they began the de-hooking procedure.

Hawaiian monk seals have a fairly tough esophagus because they are accustomed to swallowing fish whole, so the team was hopeful that they could remove the hook by pulling it out through the seal’s mouth rather than having to open his body cavity, a much riskier procedure.

Using an endoscope that allowed the team to see what they were doing inside the seal’s throat, they were able to snake a de-hooking tool down the esophagus to locate and dislodge the hook.

After several hours of delicate maneuvering, the two-inch hook was successfully removed. But the surgery—and the danger to the monk seal—wasn’t over yet.

An X-ray of the fishing hook that was removed from HMS RF28.
© NMFS Permit 16632-00 and 932-1905-01MA-009526-1

One of the most dangerous parts of a major surgery like this is the anesthesia, and that is especially true for seal patients. These animals are adapted to life in the ocean, including the ability to dive deep and hold their breath for a long time. Without assistance, they may not breathe under anesthesia at all.

After receiving an initial dose of medication that will slow them down enough to be handled and then a special gas to start the anesthesia process, seals must be placed on a ventilator that will regulate their breathing. Just getting these animals intubated, or fitted with a tracheal tube, is no easy task.

Lucky for RF28, Dr. Johnson has had many years of surgical experience working with marine mammals, including a special fellowship in anesthesia. With Dr. Johnson’s help, RF28 woke up safely after his three-hour surgery.

After a few days of observation, RF28 was released back into the wild near the spot where he was rescued. He returned to a growing population of about 200 seals in the main Hawaiian Islands.

Spotting Trouble in the Distance
Meanwhile, about 1,000 miles away in the middle of the Northwestern Hawaiian Islands, researchers have been monitoring a larger, but declining population of monk seals.

Researchers estimate that about 900 Hawaiian monk seals live on the atolls in this archipelago extending northwest from the main Hawaiian Islands. But fewer than one in five pups in this area survive their first year due to threats like entanglement in ocean trash, changes in the food chain and predation.

Dr. Michelle Barbieri, The Marine Mammal Center’s conservation medicine veterinarian based in Hawaii, and our Ke Kai Ola hospital operations manager, Deb Wickham, joined NOAA biologists on an extensive research trip to study these animals and provide life-saving medical care to sick, entangled or injured seals.

Former patient Meleana is resighted hauled out on a beach.
© Deb Wickham NMFS Permit 16632-00 and 932-1905-01MA-009526-1

They’ve also been able to check up on the progress of previous patients, such as Mele and Pua, who were spotted looking healthy on beaches near where they were released earlier this year after spending several months rehabilitating at our Ke Kai Ola hospital on the island of Hawaii.

Says Dr. Johnson, “No matter the effort involved—whether it’s a three-hour surgery or a three-month rehabilitation process—every Hawaiian monk seal we save is a huge success story for this critically endangered species.”

Watch a dramatic (and graphic) video about the surgical procedure to remove the hook from the seal's esophagus.

You Can Save a Species
Help provide the emergency care that Hawaiian monk seals like these need to survive as a species. Your support goes a long way to help all of our patients get a second chance at life.




Read about the new Hawaiian Monk Seal Hospital.

Learn about Hawaiian monk seals!

Learn about Ocean Trash and how to prevent it!


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