Many people have heard about the hatching of Hawksbill sea turtles here at the Underwater Observatory Park, but few know the complexity entailed in a process the beginning of which is hard to predict and where the success of the release is only known in the future. I was one of those privileged to have the opportunity to actively participate in all phases of a new generation at the observatory, from preparation through breeding and brief encounters on the high seas.
We will follow the growth and release of turtle “5 red” (the names will be explained below).
Hatching date: 28.08.1999
Hatching weight: 17 grams
Shell length: 4.2 cm
Shell width: 3 cm
Health status: good
The process began at the beginning of the February 1999. In preparation for the mating season, we isolated Zachary, a male Hawksbill turtle. Zachary had lived for a year in the adult turtle pool, shared by the females Hawksbills. The purpose of the isolation was to change Zachary’s orientation to cause a kind of “nostalgia” for the female turtles. At the same time, we checked the sand in the island of the adult turtles’ pool. The composition of the sand plays a major role when female turtles dig their nest. The sand must be damp to some degree, so that the future mothers are able to dig a nest and lay their eggs.
The second step is the hatching period. Moisture, density, composition and salinity are all factors that determine the state of the sand.
We found the sand unsuitable, so it had to be replaced. After two months of isolation and the replacement of sand on the island, it was time for Zachary to return to the females in the main pool. The day he returned I was anxious. Where two months in isolation enough? Were the females ready for mating?
In the wild, the Hawksbill turtle lives in permanent territories, with each female occupying an area of a few miles along the reef. Each of these female “plots” is dominated by a male.
Breeding begins in the spring, when the male impregnates the females in his territory. Adult male and female turtles can be easily distinguished by the length of their tail; the female’s tail is short, the male’s long. However, when turtles are young, this distinction cannot be made, the reason being that puberty lasts between five to seven years and only then is the difference in tail size evident. In extreme cases a blood test can be done to identify the gender.
The big moment arrived, and without delay Zachary was placed back in the pool with the females. Funally “let loose”, Zachary pounced on the female turtle, Tyson, and bit her neck. But there was nothing to fear, this is a natural part of courtship and mating. (Tyson got her name after biting the ear of one of the divers, Gadi, a short while after boxer Mike Tyson did this to rival Evander Holyfield.). At this point, Zachary “sat” on Tyson’s back with his front limbs hugging her hard shell close to her neck, and his back limbs hugging the side of her shell. Stuck to her shell in this way, he started mating.
At this point, the female must carry the male, whose full attention is on mating and not swimming. Hawksbill turtles belong to the family of marine reptiles which spend most of their lives in water. However, they breathe air above the surface through the mouth and must come up for air every few minutes. The ability of turtles to hold their breath is interesting, and while resting, they only need to surface every half hour. Yet when active, such as catching prey or mating, they need to surface more frequently. So denying them their privacy, we all looked on with expectation as Tyson carried Zachary on her back for the next four hours.
As we continued to monitor the activity in the pool over the following days, Zachary maintained his strength and impregnated the remaining females in the pool.
At this point, there is nothing more to do but wait for the egg-laying season, which takes between several weeks to several months, due to the female’s ability to retain sperm, and she will only fertilize her eggs when she feels ready.
For the next month, we daily examined the state of the sand in the island, and wet it from time to time so as to maintain the required moisture level. We also raked and smoothed the sand every day so we would know if Tyson had been to the island to start digging.
I tried to dig a nest with my hands the size and depth of a turtle nest. This is a great way to simulate the female experience of digging. I dug a nest relatively easily, and if I had succeeded, then maybe Tyson would follow suit.
“Tyson is digging,” the urgent message came through while I was eating lunch. I immediately went to the adult turtle pool. Indeed, Tyson was busy digging her nest in the center of the island. Digging a nest requires much effort. Adult females in nature do not always manage to return to sea after spawning because they are exhausted from the effort and in a few cases they eventually die. This did not happen in our case because we were able to help Tyson return to the water. We watched as Tyson dug with her hind feet, and with each dig, one of her feet served as a kind of spade that removed the sand from the hole. After an hour of digging, Tyson had completed building the nest. (Was it fatigue or dissatisfaction with the sand?) After a nerve-wracking 10 minutes – bingo, Tyson began to lay her eggs. I was so happy and from a distance observed the nest slowly filling with eggs. At first, the eggs came out in pairs and then one by one. By the end, there were 55 to 60 eggs in the nest. Tyson covered the nest with sand and camouflaged the area to prevent potential predators from identifying its location. This task can be compared to a child in a sandbox who throws the sand in all directions.
Once she was done, Tyson tried to regain her strength and return to the water. After a 10 minute rest, she crawled back into the pool.
At this point, Tyson had completed her role as a mother and would have no further contact with the nest or her babies. We marked the location of the nest for future examination.
For the next two months the nest received the required heat from the sun for the eggs to develop. The sun actually incubates the island. The time of spawning is important and needs to be in early summer to ensure the nest is exposed to the sun during the warmest period. Here in Eilat, the hot season is exceptionally long and therefore the timing is less important than elsewhere in the world, where if even a few days are lost, the eggs in most cases will not hatch.
During the next two weeks, the other female turtles climbed onto the island, dug a nest, spawned their eggs, covered the nest and returned to the pool.
Again, we needed patience and I couldn’t wait until the hatching season.
At the beginning of the hatching season we prepared the island for hatching. A low fence was built around the island to prevent the young turtles from reaching the pool.
The night watchman gets ready for hatching, and most of his time is spent monitoring the island.
A midnight call woke me up and Shaul, the watchman, shouted into the phone, “We’ve got turtles, we’ve got turtles.” I gave out a long screech and woke my wife. “We’ve got turtles, we’ve got turtles,” I shouted, repeating his words. Without delay, we made our way to the Observatory and immediately gathered the turtles in a special container prepared in advance. We counted 43 in all – an outbreak of turtles!
Newborn turtles leave the nest in a group. The first turtles to hatch climb to the top of the nest and stop at a waiting point for the remaining turtles to hatch and join them, before seeking the sea. The reason for this is the fear of potential predators on land and in the sea (birds, crabs, small mammals and fish are just some of the predators). By departing the nest together, the turtles confuse predators and increase their chance of survival. Studies and observations carried out in nature show that only one in every thousand eggs reaches adulthood.
We head home, happy and tired.
The first thing I did the following day was to uncover the nests on the island, because sometimes some of the turtles don’t manage to leave the nest with the others. I dug carefully and discovered a turtle among the eggshells that had hatched but hadn’t made it out of the nest. I placed it in the container along with its siblings.
We began taking care of the turtles. First, we marked the turtles to enable us to monitor each one individually. Turtles have a hard heart-shaped protective shell made of 13 overlapping plates. Using different colored nail polish, we marked a plate on each turtle with a number of 1 to 13. The turtle I dug out of the nest was named “5 red”. While marking the turtles, we gave it a general examination: skin, eyes, claws (Hawksbill turtles have two claws on each forearm that are used to cut food) and tail. Then we weighed each turtle and daily updated their data on the computer. To our delight, all the turtles had a normal weight of between 16 to 21 grams. For the first few days, the turtles fed on protein leftover in their bodies since spawning. The turtles are isolated to prevent the spread of infectious diseases and biting. Each container had a water spout. After a few days, the turtles started to eat from our hands. Their food was a special mix of fish, vitamin-enriched invertebrates and fish oil. Feeding was carried out with tweezers three times a day and we recorded each feeding on a special table so we could identify problems early on and treat them. We were also able to monitor the turtles’ eating habits and growth.
At 4 months old, the young turtles were transferred to common pools. Individual monitoring continued thanks to the markings. The turtles were now being weighed once a week and their diet changed to pieces of fish, jellyfish and invertebrates served on the pool surface. This way, the turtles learned to dive and use their claws to cut food. The turtles lived in this common pools for a year before being released at sea.
Recent years have seen a drastic drop in the number of turtles in the Gulf of Eilat. In cooperation with the Israel Nature and Parks Authority, the Underwater Observatory Marine Park initiated a project for the raising and release of Hawksbill turtles in the Gulf.
When preparations for the release of the turtles began, the team was filled with excitement, anticipation, trepidation and a feeling of satisfaction. A microchip was injected into the hind leg of each turtle which will remain there throughout the turtle’s life and will enable it to be identified in the future with a chip reader. The turtles were thoroughly examined before release. Only the healthy ones would be released into the open sea. The markings on the shell were highlighted to enable remote identification. Spring is usually jellyfish season and young turtles usually feed on jellyfish, so releasing them in the spring promises the young turtles a rich food environment during their initial adjustment to the sea.
The big moment arrived. We collected the turtles in special baths and loaded them onto a boat named “Pearl of the Corals” The release was entitled, “I have a turtle in the sea.” The turtles were releases at three locations in the Gulf of Eilat: the coral reserve adjacent to the Underwater Observatory Marine Park, the Trans-Israel pipeline area, and the shores of Jordan.
A team of divers from the Underwater Observatory Marine Park entered the water and observed each turtle in the sea. At the last release in Jordan, a team from the Aqaba Green Initiative joined us because we share the Aqaba-Eilat gulf.
A total of 90 turtles were released into the sea.
Turtle “5 red” was released on the shore adjacent to the Underwater Observatory weighing 3.150 kg.
7 months later our paths crossed – following an observation of the coral beach reserve, turtle “5 red” was caught and brought to the observatory for examination. It weighed 4.250 kg and was in good health. After the examination, “5 red” was released back into the sea. This was followed by four subsequent meetings, the last of which took place in May 2004, when “5 red” weighed 7.5 kg. At every meeting we found “5 red” in the coral reserve and therefore nicknamed it “Turtle Reserve”. When I dive in the Gulf, I find myself looking for “5 red”, even for a fleeting moment.
Hawksbill turtles are endangered worldwide. Fishing, pollution and vulnerability in the nesting areas as well as a decline in the quality of sea water are key factors in their disappearance. Mistaking them for jellyfish, turtles accidently eat plastic bags which block their digestive system and can cause death. Working together to maintain nature’s values will ensure the continued existence of turtles in the Gulf for future generations.
The Raise and Release Project of Hawksbill turtles was carried out in collaboration with the Israel Nature and Parks Authority.
Author: Aviv Levy – Scientific Director of the Underwater Observatory Marine Park