Tumor disappearance in a South Maui resident sea turtle

MikeSevernsDiving Diving on Maui, Marine Life 1 Comment

Any frequent Maui diver or snorkeler has witnessed innumerable green sea turtles with tumors, some as large as a baseball, and sometimes completely covering a turtle’s eyes. It’s a painful sight, even more so because these tumors are more prevalent in areas where we humans reside, and because we are most likely responsible for their suffering. Indications are that our activities on land change the nearshore ecosystem and make it more likely that turtles will contract this disease. Turtles with tumors the size of a baseball have not been known to recover. Some of these end up stranding themselves and are euthanized, or they disappear from our reefs and we just stop seeing them.

Fortunately, not all turtles are equally afflicted. Many have tumors that do not grow to such large size. And in these turtles, some individuals actually experience tumor regression or disappearance altogether.

We have been lucky to see a few of these fortunate turtles over the years, one as recently as this summer.  In 2001 Andy Schwanke began a photo catalog of turtles that we see at the places we dive. This was possible because each turtle’s face has a unique pattern of scales.

154R_Race 2002

In 2002 Juerg Grieder photographed the above turtle at Ulua Beach with small tumors in the back corners of both eyes.

154R_Race 6_27_05 edited 2

In 2005, off Kamaole, tumors were seen in the armpit and almost covering both eyes.

Race 2013 edited 2

But In July of 2013, off Wailea Point, the right eye showed no evidence of tumors. Her eyes are closed because she is resting, and we did not want to bother her just to get a photo of her eye open, but it appears as though no tumor is present.


This is not unusual. A 2006 master’s thesis by Joseph Spring showed that 88% of nesting females at French Frigate Shoals had tumors that were regressing. In a 1999 paper by Peter and Ursula Bennett they report a 33% regression in the turtles they monitored.

So, while not unusual, she is the first turtle we know personally (and have photographed) with a good outcome from this disease. Now we will keep an eye out for her and see if she remains disease-free. She is a huge female with an easy-to-remember scale pattern on her face so she will be easy to spot, especially because in the 11 years we have known of her, she appears to have stayed within a small area between the St. Anthony wreck and Wailea Point. If we see her again we’ll keep you posted!

Comments 1

  1. That’s wonderful, and also wonderful that Mike Severns Diving boat captain, Andy Schwanke, and owner, Pauline Fiene, have identified so many turtles. It’s neat that you follow their lives, as individuals, and wonderful to learn that some of them do recover. I’ve been so sad to see some of them with such disfiguring and often incapacitating tumors. : )

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