The book of Honu: Pioneering citizen-based science

51jwm6pamdl-_sx348_bo1204203200_
Image source here

We began as two sport divers with an interest in underwater photography. We weren’t marine biologists and had no background in conservation. We knew nothing about the Hawaiian green turtle, or honu as the Hawaiians call them.

Peter Bennett and Ursula Keuper-Bennett start their book with these phrases. Originally from Canada, Peter and Ursula had their first underwater experience with a sea turtle in 1998, on the reefs of Honokowai, in the Hawaiian island of Maui. They named her Clothahump. The Bennets kept returning back to Maui every year up until today (at least I hope-their last video in their youtube channel is from 2013). All these years, they have spent countless hours observing and documenting the local Hawaiian green sea turtle population in a dedicated and consistent way, that probably very few – if any – people had done before them. They summarised their accumulated knowledge in their book, The book of Honu: Enjoying and learning about Hawai’i’s sea turtles, published by the University of Hawai’i’ Press in 2008.

This book is a treasure. Really. They provide highly detailed information about the underwater life and habits of the Honus like no other before, scientist or not. Not any modern and fancy sea turtle behaviour study technique like GPS fine scale tracking, accelerometers, remotely operated vehiclescameras attached to sea turtles, or even, the so popular these days, use of drones, can provide such a great insight into the daily routine of sea turtles that resulted from their dedication and enthusiasm for more than 2 decades. (the linked studies and videos however provide very useful insights of different nature and they are highly recommended!). It is not surprising that

We attended the 13th annual sea turtle symposium in Georgia. Once the turtle specialists heard that we’d been observing turtles underwater for years, they began asking us questions: How did we tell them apart, whether they got along together, if they had favorite spots, just what is it that they did all day long-the same sort of queries that everyone had.

The Bennetts give many answers (or at least insights) to questions of the above type in their book.

  • “Upon approach from humans, young turtles are caught up in a delicate dance between curiosity and caution”.
  • “Juvenile turtles seem to enjoy play. A dance of round-and-round where one would try to nip the tail of the other”.
  • “Male-male mounting turns out to be so common. Perhaps it is a dominance behaviour”.
  • “Some honu occupy exactly the same spot year after year. Some have 2 or 3 favorite places, while others are content to stay in the same small area”.
  •  “They scratch the tops and bottoms of their shells, their throats, their heads”.
  • “We’ve concluded that the honu create their own cleaning stations”.
  • “They mostly do the same things we do at home: eat and sleep”.
  • “They don’t seem to have a pecking order. We have never seen one honu consistently dominating another. Even size is not a reliable predictor of which turtle will prevail in a confrontation. At times, we’ve seen the smaller honu chase off the larger”. I can personally confirm this last one.
img_4587
A honu cleaning station on Maui island. 

The book is full of descriptions of the above style. Notice the absence of dry scientific language. In fact positive, turtle-huggy emotions are overflowing:

There is no better experience – no happier time – for us than resting with old friends on the ocean bottom.

But that should not discourage people, even highly qualified marine biologists, to read this book and take its content into serious account. Of course sea turtle behaviour of the above kind is hard to quantify and it is open to many explanations – even I disagree with a couple of their interpretations. But if I was writing a book about my own underwater sea turtle encounters, I hardly imagine I would use a much different tone.

Photo identification

One of the first questions that people ask after hearing about our turtle experience, is “How do you tell them apart?”

The Bennetts were among the first people (if not the first) who consistently used photo id techniques to distinguish individuals: their facial scales (scutes) are practically unique, like a human fingerprint. Until the end of 2004, they had logged more than 750 unique individuals. They gave names to turtles that were repeatedly observing and naturally they became attached to them. It is really enjoyable, to read their narrations about the lives of known turtles, how they first met, how they were reacting in their presence as well as with other turtles, and about their transition from being young juveniles to mature adults. This emotional attachment however sometimes came with a cost.

Fibropapilloma

fib
Example of a Hawaiian green turtle with fibropapilloma tumours. This is an alive turtle basking on a beach.

Seeing an afflicted turtle will probably disturb you. It certainly upsets us.

Fibropapillomatosis (FP) was firstly recorded in Florida, in 1938 and in Hawaii in 1958. It is a disease that gives the turtles nasty external and internal tumours that can be more than 10cm large in diameter. The tumours grow steadily, sometimes, blinding the turtle, while the tumours on the skin, neck and plastron, make swimming difficult. The cause and how FP spreads still remains a great mystery. Some healthy turtles have remained healthy even if they live close to infected ones. A herpesvirus seem to play a role in the disease, as well as poor quality of water, even though infected turtles have been found in clean waters. The Marine Turtle Specialist group consider FP as one of the key unsolved mysteries of sea turtle biology.

The Bennetts were unfortunate to see many of their friends dying from the disease, including Clothahump itself.

We saw her only once in 1993. The white spots had mushroomed into tumors. We both cried underwater. That day, we vowed to tell Clothahump’s story and somehow help the ocean community on her reef.

And so they did. Their long term observations of affected turtles led to a better understanding on how the disease appears, progresses and disappears. They discovered that the tumours start from the eyes, and in general one can tell the severity of an affected turtle, by assessing the eye tumours. They also discovered that it affected primary young turtles, and that most adult turtles recover within 3 or 4 years. They collaborated with George Balazs, an expert on Hawaiian sea turtles, and they published a series of scientific papers and reports, like this one and this one (page 37) (also available here).  The Bennetts comforted their readers:

Our records and other studies show that FP isn’t nearly as deadly as was first feared. FP related deaths are not affecting the chances for survival of the whole population. It certainly kills some, but others live and grow to reproduce and replenish the population. There’s comfort in knowing that.

Nevertheless, for these two people that see turtles as individuals and not as part of a population, many sea turtle deaths were like losing a friend.

In a population level things are looking great till today indeed.

newgen
The future looks very optimistic for the sea turtles of Hawaii. The population is increasing and very recently it was characterised as least concern by the IUCN.

Peter and Ursula have contributed a lot in our knowledge of sea turtle biology with their observations. But they have inspired us even more with their passion…

Peter and Ursula’s webpage (made in 1995!)

Peter and Ursula’s youtube channel

 

Advertisements