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In preparation for eventual release, the turtles were kept in a 2000 gallon aquarium which was 5 meters long to allow them to swim as much as possible in captivity. The tank was populated with fish and invertebrates and made to resemble the wild environment as much as possible. The turtles could forage, eat invertebrates and catch fish. They caught and ate lobsters and fish and ate colonial sea squirts and sea anemones on a regular basis. This diet was supplemented with fish, lettuce and turtle pellets. When the turtles reached 24-26 cm CCL, between 16 and 18 months old, they were taken for swims to slowly acclimate them to the wild and prepare them for eventual release. This size was chosen because it is the size of the smallest hawksbills seen nearshore.

A harness was made of neoprene (wherever it touched skin) and adjustable nylon straps, buckled at the widest part of the turtle and connected to a retractable dog leash (Fig. 1). There were no straps between the turtles’ back flippers. Several days before their first swims they were introduced to the harness. Every day we would put the harness on the turtle. After awhile they would wear it for a short time in the tank. When they did not avoid being handled when the harness was put on them they were taken out to the sea. Once in the water the turtles were not restricted or guided in any way until it was time to get them back to shore. On their first forays into the sea all three turtles exhibited signs of stress, as described below, including hyperventilation and disorientation. None of them behaved the way they did in the aquarium where they were accustomed to their environment. All of them at one time or another tried to crawl up onto the beach at least once.

Turtle 1, observed on its first swim in the sea in 2002, began by swimming slowly but kept changing directions after a few yards, then eventually swam to shore and tried to climb onto the beach. Turtle 2, studied in 2004, on its first swim initially floated at the surface for several minutes and hyperventilated. After approximately 4 minutes it swam to the bottom and sat there for another 2-3 minutes. Suddenly, it swam purposely and at a constant moderate speed in one direction. It stopped under the drain pipe where the water from its aquarium emptied into the sea. It did not move until I picked it up about one minute later and returned it to the aquarium. Turtle 3, studied in 2006, started its first acclimation swim by swimming full speed the moment it touched the water. The water was slightly murky. After 30 seconds of swimming away from shore under water it slowed and for the next 2-3 minutes swam in different directions approximately every 30 seconds. Then it came to the surface, took two deep breaths and swam to the bottom (1 meter deep) at a moderate pace. It swam in different directions and had no consistent course. This behavior was repeated until the turtle, appearing to be tired, floated at the surface and made no effort to avoid me when I picked it up. Time elapsed was ten minutes. When returned to its tank it sat on the bottom, face down in the corner and did not move for several hours. Fish was offered but only one small piece was taken. The next day it barely moved around the tank. My guess was that its muscles were sore. On Turtle 3’s second swim we were filming and we took it to another location where the water was clear and calm. When placed in the water it swam to the bottom, approximately 7 meters down, and slowly cruised over the turtle grass. It looked at conch shells and sandy areas but did not explore them. It could have swum longer but after a half an hour we had to leave. Behavior was normal on return to the aquarium. The next time Turtle 3 was in the water was nine days later back at its home bay. The water was clear. It floated at the surface for awhile then swam to the bottom. It had some buoyancy issues and was struggling to reach the bottom. It took five big mouthfuls of sand and swallowed them. It stayed in the shallows and often swam to shore in just centimeters of water. It checked out the algae, especially the Mermaid’s Shaving Brush, also the first thing investigated by Turtles 1 and 2, tasted a little and then swam on, zigzagging parallel to the shore, in about a meter of water. It swam slowly and examined its surroundings, coming to the surface only to take a breath. After 20 minutes it would take two breaths at the surface. By 30 minutes, it swam to shore and just floated on the surface. Upon return to the aquarium, it acted normally and ate a regular amount of fish.

Figure 1. A headstarted hawksbill turtle, fitted with a neoprene harness, being acclimatized to feeding in the wild.

Eight days later, Turtle 3 appeared at ease when placed in the clear water. It immediately swam to the bottom and gulped a mouthful of sand. At first Turtle 3 stayed in the shallows, investigating the dead turtle grass that had washed in. It interacted briefly with a juvenile jack that circled and swam with it. After approximately 5 minutes it swam out to water 3 meters deep, staying at the bottom cruising over the turtle grass. When we had been in the water for a half an hour, this turtle swam to shore and remained still until picked up. Turtle 3’s next swim was three weeks later. The water in the bay was cloudy close to shore. When this turtle first got in the water its breathing was fast and it swam quickly in no particular direction. Its behavior was similar to that on its first time in the sea when the water was also cloudy. I led it to deeper, clearer water where its breathing slowed and it appeared to calm down. Eventually it swam to the bottom and began cruising slowly. The next behaviour Turtle 3 displayed was a new one for me. It would cruise slowly along the bottom then sprint forward at top speed for about 15 seconds. This behavior seemed like an evasion technique. For the next 20 minutes it would cruise for a minute or two then dart forward for several seconds, then slow to a cruise and repeat. After 20 minutes it appeared tired, swam to shore and tried to crawl up onto the beach.

Turtle 3’s next trip was two weeks later in clear, calm water. I had learned that when placed in the shallows, it would swim to shore. When I put it in water over 2 meters deep it would begin exploring. Turtle 3 always headed to the bottom after taking a breath and would stay there and average of three minutes. Often it would eat a mouthful of sand. On this particular trip Turtle 3 swam along the bottom over the turtle grass looking at everything it passed. There were various spots with soft corals and this dive was the first time it had ever seen a soft coral. It swam over to it and brushed against it as it swam past but displayed no negative or positive reaction. It saw its first sea cucumber and mouthed it but did not take a bite out of it. The swim lasted an hour and a half. The turtle cruised slowly for more than an hour over turtle grass and areas of sand and soft coral sea plumes. It checked out everything including a sea egg urchin and poisonous spiny black urchin slowing and looking closely but not biting, then moving on. The only time it had a startle reaction was when we were approximately 7 meters from a 1.5 meter sand covered square cement block mooring without a chain or rope attached. It saw it out of the corner of its eye and immediately darted away at about a 45% angle from its swim path. Nothing else seemed to bother it. Turtle 3 and I ended up out in 10 meters of water in the channel about 75 meters from shore. After one and a half hours swimming I had to take the turtle and swim him back to shore. Behavior in the tank was normal. It swam around the aquarium and ate a great deal of fish, appearing hungry after all the exercise. I thought its physical endurance had increased since the first foray into the ocean.

Turtle 3 was taken for swims every two weeks or less depending upon time available. It would swim for up to two hours – my limit in the sea. It spent all this time cruising and investigating the environment. Plastic cups and bags always attracted its attention and it would swim off its route to check them out. It mouthed them but did not try to eat them. When we went to rocky shore areas it would stop and nibble at things on or under the rocks. Sometimes it would scrape its beak under the rock ingesting whatever had been there. On some of the swims it would spend a few minutes cruising then sprinting for short distances as if exercising its muscles or practicing escape maneuvers. In December 2007 Turtle 3 was released near the shore and immediately swam out to sea. I have seen Turtle 3 four times since then, twice in 2008 and twice in 2009. It has very distinctive markings on its head and its shell was deformed in a unique way when it had been ill during captivity, making identification easy. Turtle 3 was most recently spotted on February 16, 2009, across the channel from Nevis in one of the bays.

Watching these three turtles has led me to believe that although other studies have reported captive-raised turtles surviving in the wild without special acclimatization (e.g. Nichols et al. 2000, Bell et al. 2005), a period of acclimation before releasing turtles raised in captivity will reduce stress at the final release and boost their chances of survival in the wild. During the acclimation period they can increase their muscle strength and adapt to a world without walls, predators or a ready supply of food. To assess the importance of such variables, the migratory movements and wellbeing of turtles acclimated to the marine environment should be compared to those of turtles released without acclimation.

BELL , C., J. PARSONS, T.J. AUSTIN, A.C. BRODERICK, G. EBEAN-PETRIE & B.J. GODLEY. 2005. Some of them came home: the Cayman Turtle Farm headstarting project for the green turtle Chelonia mydas. Oryx 39: 137-148.

MROSOVSKY, N. 2007. Translocating turtles: trials, tribulations and triumphs. In: López-Jurado, L.F. & A.L. Loza (Eds.). Marine Turtles:Recovery of Extinct Populations. Monographía del Instituto Canario de Ciencias Marinas. No.5, pp. 199-229.

NICHOLS, W.J., A. RESENDIZ, J.A. SEMINOFF & B. RESENDIZ. 2000. Transpacific migration of a loggerhead turtle monitored by satellite telemetry. Bulletin of Marine Science 67: 937-947.