Humans feeding wild sea turtles: different aspects.

Conservationists and biologists have been always uncomfortable – if not categorically against – with the idea of humans feeding animals in the wild. Sometimes the reasons are obvious especially when human safety is compromised: you really don’t want to start feeding a polar bear, a lion or a great white shark. Beyond safety issues there can be other concerns of course, like the health of the animal itself (when it is fed food that is not used to) as well as changes in its habits and its behaviour. Of course, it all depends on the scale that this feeding take place. In this post we will focus on feeding wild sea turtles and in particular as this takes place around a very specific area in the greek island of Zakynthos, an area that I have been closely observing for the last years. Before we start, we should stress that feeding sea turtles is not illegal in Greece.

Agios Sostis is located on the west part of Laganas bay, Zakynthos, within the limits of the National Marine Park of Zakynthos. We are going to focus on 3 specific areas around Agios Sostis: A small port that local fishermen regularly use, a patch near the shore that a few of the all year-round resident loggerhead sea turtles naturally forage, and the marine area between these spots. This marine area is characterised by turtle spotting boat activities, especially during August and September. This is due to the fact that the area has relatively high density of resident loggerheads, who, in contrast to the actively reproductive females, do not migrate to any distant foraging grounds.  See here for photos of some of the resident turtles of the area.

The little port is used daily from local fishermen, who after returning from the night’s fishing, they are typically cleaning off their nets, discarding any unwanted bycatch. A male loggerhead, named Sotiris, who has been possibly around for more than 15 years now, started to take advantage of this discard. Thus, an interesting relationship started between him and the local fishermen who sometimes just throw fish, crabs squid etc in the water or other times feed him directly in the mouth. It is clear that the scale of this feeding is very small.  As far as this specific turtle itself is concerned, Sotiris has also been observed foraging naturally in several occasions.

Sotiris, one of the long term residents, is being fed some squid from local fishermen.

As a conservationist, I always found it very hard to come up with arguments against that type of feeding. For me, it has always symbolised an alternative relationship, between turtles and fishermen, a relationship very often devastating for the animal as the interaction with the fishing industry has always been considered the number one anthropogenic threat for the sea turtles worldwide. One should never forget that many people, including fishermen, view marine life in a completely different way, than others who, for example, have grown up with David Attenborough documentaries. As we will also stress in a future blog post, understanding people’s relationship with animals is crucial for conservation. Not all people make the discrimination between not wild and wild animals (the ones that “shouldn’t be fed”).  One does not have to look too far in order to see that other people can categorise animals differently: useful for humans, dangerous for humans, animals that do harm with one way or another, animals that are indifferent to humans.

Loggerhead interactions

Even though, it could have always been the case, the first time it came to my attention that more turtles are entering the port, seeking for food, was in 2011. In this video (3:42-7:44), another resident-to-be male loggerhead turtle, Agisilaos, makes one of his first appearances in the port. It is interesting how the french narrator of this particular documentary, also describes the story with great amounts of romanticism. Until today, Sotiris and Agisilaos are the two turtles that regularly occupy the port, with other resident turtles appearing from time to time. When two turtles meet at the port, a fight between them starts. Typically, one turtle is the attacker, the other being the offender, and the fight typically consists of head to tail circling and several attempted bites (we should note that the loggerheads have pretty good defensive skills against these bites).

The two main male loggerheads that are present in the port: Sotiris (top) is attacking Agisilaos (down). See the full fight in this video
Sotiris is attacking another resident turtle of unidentified sex.
Agisilaos is attacking a resident male inside the port.

These type of fights however do not occur only in the port but also in a nearby foraging ground. Only a few meters away from the part, there exists a patch of relatively small size where most turtles are observed foraging on a sponge from the phylum Porifera. Regular fighting is observed among turtles that have never been observed to be involved in a human feeding incident. In fact, one can identify specific individuals that occupy the patch more often than others and also being the most aggressive.

Antagonistic interaction between loggerhead turtles in a natural foraging ground. For a comprehensive video that depicts this type of behaviour click here.

It is safe now to conclude, that loggerheads can exhibit some territorial behaviour, defending their foraging grounds, by attacking other turtles that are trying to be there as well. Moreover there are indications that the more spatially restricted the foraging place is, the more aggressive these interactions become. Even though, it is not easy to quantify, the interactions inside the port seem to be more aggressive and last longer than the ones in the natural foraging ground, where the food is more available and spread out. In fact in this one of a kind video, shot by Giannis Xenos, one can see a long term resident male loggerhead looking for molluscs, in a very wide sandbank area, while being followed closely by another resident. No aggressive interaction occurs between the two turtles whatsoever, possibly having to do with the fact that the food in this case is scarce and spread out. However, one should also not underestimate the personality factor, it is true that different turtles react differently in similar situations.

More research is required to see if this feeding can indeed result to increased antagonistic interactions and how this affects the welfare of the turtles, see also this interesting preliminary study from the nearby island of Kefalonia. Again, it all depends on the scale of the feeding. It seems to be the case that in Kefalonia this is more intensive and tourists are even encouraged to buy fish from the fishermen in order to feed the turtles themselves. Here the issue loses its romantic flavour and becomes more complicated.

Turtles being fed by or for tourists

Apart from Kefalonia, Zakynthos recently experienced a similar issue. Last summer, it became somehow a trend, to feed with tomatoes a specific turtle, right near the port and the foraging ground. This feeding was coming from both turtle spotting and private boats. Interestingly only one turtle seemed to be involved, Achilles, a young male loggerhead also a long term resident.

Achilles being fed with tomatoes on several occasions during the summer of 2016.

Having been observing Achilles for the last 5 years, I could say that his habits were a bit different this year. He was slightly more aggressive, mostly swimming around the area, and not spending as much time naturally foraging on sponges as the year before (he did not quit doing this however). It could be the case that this had something to do with this feeding in which he was continuously involved. The National Marine Park of Zakynthos and Archelon released a joint public statement about this issue (greek version, english version, article in a Zakynthian newspaper in greek).

Encouraging tourists to feed sea turtles is problematic. On one hand the scale of this activity increases a lot, more turtles can be involved also for a larger amount of time and as we have explained this can potentially have a negative impact on their welfare. On the other hand, it gives the wrong messages to the visitors of the island, about how to treat wildlife. I can understand that the word “wrong” here can be debated by people who see wildlife in a different way. However I would encourage the Zakynthians involved in sea turtle spotting to think what they would like to see in their island:

  • Sea turtle tours that look like visits to the zoo or a farm.


  • Sea turtle tours that promote nature in its pure and untouched form.

Even though, I don’t want to tell people what to do, I hope they go for the second option and encourage others to do the same.


The book of Honu: Pioneering citizen-based science

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.
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.


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.

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