Protocol For Releasing Captive Dolphins

Ric O'Barry's Dolphin Project History

Protocol for the Rehabilitation and Release of Captive Atlantic Bottlenose Dolphins (Tursiops truncatus)

By Richard O’Barry Founder/Director, Dolphin Project

Why Call it Science?

There are general criteria for the rehabilitation and release of captive dolphins back into the wild. But not a complete guide or cookbook. That’s impossible because each captive dolphin is unique, requiring its own cookbook.

Dolphins react differently to captivity. Some have experienced more abuse than others. I have worked with dolphins who, when reunited with the sea, very quickly remembered who and what they were before their capture. Others needed more help, more time. So the most important part of my job is patience. I must simply sit back and observe the dolphins with a clear and open mind, allowing them to show me how best to help them regain their identity as opportunistic foragers, wild and free.

When every captive dolphin is different from every other one in a thousand different ways, returning one to the wild, his or her natural habitat, is therefore more art than science.


Over the past sixty years, I have been involved in the rehabilitation and release of more than two dozen dolphins.

This is not to say that all captive dolphins can or should be returned to their natural homes. But all captive dolphins may be re-adapted to a more natural environment, to a fenced off natural sea lagoon, for example. This would provide the dolphin with the natural rhythms of the sea, the tides, the currents and exposure to live fish. All of this is therapeutic and improves the dolphin’s quality of life. Reuniting the dolphin with his natural sea environment is an essential part of the rehabilitation process, and at this point the dolphin may be a candidate for release depending on several factors:

  1. Health and physical condition
  2. Use of sonar
  3. Ability to catch live fish
  4. Defensive skills against predators
rehabilitation and release case for dolphins in Brazil

Many captive dolphins born in what we call ‘the wild’ are candidates for release. But not all of them. Some dolphins have received too many human imprints and have forgotten or lost the skills needed to survive in what was once their home. Habitat dictates behavior. Captivity has destroyed something vital in their lives, something that, were they human, we would call ‘spirit.’ For them, it is too late.

Some years ago, for instance, I had occasion to study a dolphin in Nassau, Bahamas, who had been in captivity for a long time and was now quite mad. They called him ‘Big Boy’ and he spent much of his time ramming his head against the wooden entrance to his sea pen. On one side of the wooden gate was the area where he was protected, admired and watched with fascination, sometimes by hundreds of people. He was fed all he wanted to eat and was clearly master of his world. On the other side was the sea, his natural home. And as I watched him banging his head against the gate one day, I wondered if it would be possible to re-adapt him to the wild again.

What would happen if we simply let him go?
In the old days at the Miami Seaquarium when we no longer needed a particular dolphin, we put him in a sling, carried him out to the seawall and simply dumped him into Biscayne Bay. In the captivity industry this is called a ‘Dump and Run.’ This happened to Pedro, for instance, a huge male dolphin who became too hard to handle. How he fared in the waters off Miami, nobody knows.

But Big Boy was quite another problem dolphin. Captivity had turned him into a mental cripple. If we could re-adapt him, I thought, we could re-adapt any dolphin. But the longer I watched, the more I realized that we were too late. He’d had too much of it. I don’t mean mistreatment. I never saw anybody deliberately mistreat Big Boy. In fact, I saw the reverse of that. What I saw was an excess of ‘love.’ Everybody wanted to be with him, to touch him and talk to him; in short, everybody wanted to ‘help’ this big old dolphin. But nobody knew how. And so, day after day, always smiling but full of rage, the big dolphin banged his head as if to get free again; a stressed out dolphin who was so uncooperative, unpredictable, suspicious and dangerous, a dolphin filled with so much hate that I knew I could never reach him.

What caused this to happen? Human intervention and stress. This always plays a leading part in the death of captive dolphins. Stress is a result of not enough space, too many people and having to play the fool too long. It is also the result of having to live in an artificial world, a world without tides, without the tastes and sounds of the ocean, and without anything that normally makes life worth living. When we try to turn dolphins into pets or ‘companion animals,’ it never works. This is hard to realize when it’s happening. The dolphin seems to want to be a pet. He’s always smiling — seems to be laughing. He seeks us out to be petted and played with. All of this just like a real pet. But this is an illusion. Dolphins are forever wild, created by nature to play a role in nature, not to play silly games in a tiny pool for our amusement.

Apparent exceptions to this are dolphins born in captivity. There is no ‘returning’ them to their natural habitat. They have none. A few of these so-called ‘battery dolphins’ have been ‘trained’ to act like wild ones and they’ve been released into the sea. But until this procedure has been carefully monitored over time, we should consider each case on its own merits.

Dolphin Rehabilitation Sanctuary - Dolphin Project

Knowing Dolphins in Nature

The key to rehabilitating and returning captive dolphins to the wild is to know what a dolphin is like in his natural habitat. If you know that, then you can recognize the dolphin’s learned behavior in captivity.

What are some of these? Watch a dolphin show for five minutes and you’ll see virtually all of it. When the trainer comes out with a bucket of dead fish, the dolphin gets excited and swims in circles. He leaps out of the water with excitement, comes down and lies on his back, paddling around with his flukes and flapping his pectoral fins as if clapping. When the trainer squats down to get a fish, the dolphin swims up and begs for food, making squeaky sounds and bobbing his head up and down, showing no fear even if there are hundreds of people watching.

All of this behavior is learned. The wild dolphin never does these things in nature because they would be irrelevant and without purpose. Now, though, when we are re-adapting the captive dolphin, these learned behaviors are quite significant. Indeed, we should make note of them because in preparing the dolphin to live once more in his natural environment, we can keep track as we extinguish these behaviors one by one.

When we talk about ‘extinguishing’ behaviors learned in captivity, it sounds like we’re throwing water on a fire. Actually we’re simply no longer paying the dolphin to do them. He learned to do these behaviors in the first place because we paid him to do them. When the dolphin swims up to the feeding station, sticks his head up and bobs it up and down while making a squeaking noise, we paid him to do each of those behaviors by tossing him a fish. That’s how you reinforce behavior in a dolphin. So now, if we want to stop that behavior, we stop paying him. And very soon he stops doing it. Because we no longer pay him, it is irrelevant behavior, irrelevant both here and in the world we want him to live in. Again, habitat dictates behavior. At the same time, behavior that has survival value in the wild is reinforced and the dolphin, over time, is ready to return to his natural habitat.

When I put a Team together to help me rehabilitate a dolphin, I tell them that our basic job is to ‘empower’ the dolphin. When the dolphin is captured, I tell them, he loses his power. He is like a prisoner. And now it is for us to return his power to him. I tell the Team that in restoring the dolphin to his rightful place there are three things they should keep in mind:

Assume that you know nothing, meaning that one should not assume that the candidate dolphin can or cannot be successfully released back into the wild. In other words, keep an open mind.

Maintain sustained observation.

Consider the obvious.

These are subtle and very difficult instructions to follow, especially the first one and especially for dolphin trainers. Before trainers can step into the arena, they must strip away their own learned behavior. This is difficult for them because their whole experience with dolphins has been putting on a show, and now this, to them, is the ‘re-adaptation show.’ They want to be part of the act, and at times it seems as if they expect applause. This is just the reverse of how we prepare a dolphin for living in his natural world. We are not putting on a show. We’re putting on a non-show, and the less we do the better.

There is no shortcut to the sustained observation phase. This is not research; this is a technique. One must eat with the dolphins, sleep with them, and be with them constantly. We call this ‘dolphin time.’ How do you learn it? Not merely by reading about it. You have to experience it.

Like anything else, whether science or art, you learn how to do it from someone who already knows. Then you know when you are in tune with them. You can feel it. If they gain ten pounds or lose ten pounds, you know it. We need to see exactly what is happening with the dolphins, not what we say is happening. This is not easy for most people.

Like an exercise in Zen, it’s non-verbal. We lose ourselves and become one with the dolphin. When I’m doing it, I live in a tent next to the dolphins and I can feel myself become part of the scenery, like one of the trees, a leaf floating on the water, or a heron that simply comes and goes. When I don’t respond to the dolphins’ learned behavior, eventually they give it up. And everything I do is without words. I have to make reports, of course; that and the few directions I sometimes give are the only exceptions. But living with the dolphins on the silent level gives you an insight into dolphins that I think is necessary to understanding them and helping them become who and what they are. We think we already know who these dolphins are, for example, because we have their names, we know where they came from, what they eat and how much they weigh. But none of this tells us who they really are. In order to know them on that level, we must go beyond words. Beyond descriptions.

All of this is to eliminate false words and false theories about what we are doing. When we strip away our previous thinking, throw out our theories and substitute them with what we know for sure from our sustained observation, we can begin to see the dolphins as they really are and can better assess their survivability back in nature.

Before anything can be done, the entire Release System must be in place. The Release System is in three parts:

The Right People

The Re-adaptation and Release Process, and

Post-Release Tracking

Joe and Rosie release
Image of dolphin rehabilitation team at the umah lumba center

The Right People

The Director of Rehabilitation and Release, a recognized authority, knows dolphins both in captivity and in their natural habitat. He or she needs to be an authority because much of the job is dealing with local and federal authorities and the public through the media. He or she must also have hands-on experience in marine mammal husbandry, the care, feeding and transporting of captive dolphins.

The Project Manager manages the Staff and daily affairs, which include record keeping and documentation of the project as well as dealing with the required permitting processes. He or she also identifies an appropriate release site and organizes the population study of the resident dolphins near the site.

Helpers and Volunteers will be hands-on in the population studies and the post-release tracking of the dolphins. They are responsible for gathering suitable live fish for the dolphins.

The Veterinarian of Record, a qualified marine mammal veterinarian, should assess the health and fitness of the dolphins, be present during the transport, and available in case of emergency.

Rehab & Release

Is it necessary to return dolphins to the very place they were captured? It is often desirable, but not always necessary. For example If a male dolphin is captured at a very young age and removed from his family pod, he cannot be expected to rejoin this pod several years later. Even if he had not been captured, he most likely would not remain with his original pod, because male dolphins at maturity normally join a new pod or form their own pod, sometimes a bachelor pod, with groups of females and their offspring, or both males and females traveling together. We also sometimes find singular dolphins who have either chosen to be alone or were ostracized from their pod.

So it is a mistake to think that we must return dolphins to the very place they were first captured. In fact, if the water in which they were captured had become polluted or poisoned during their absence or if fish they normally ate were no longer plentiful, we would not want to return them there. Their original home-range might have changed. Deadly monofilament nets could now be stretched out all over the area. A search of the literature indicates that there is no empirical scientific documentation to substantiate the claim that dolphins must be returned to exact spot of capture.

Dolphins are quite adaptable and can readily accommodate themselves to a new home range if it is similar to the site where they were captured, similar in terms of tides, currents, extremes of water temperature, food supply and potential predators.

Our team will arrange for capturing enough local live fish for the dolphins to practice catching and eating. Water quality tests of the region have also been conducted and are available.


One of the most important functions in rehabilitating captive dolphins is to maintain a proper feeding regimen. The main objective is for them to maintain proper body weight by foraging and eating only live fish. This is a gradual process that may be viewed in four phases:

  1. Encouraging the dolphins to eat with their heads underwater.
  2. Eliminating interaction with the feeder by varying feeding times and locations.
  3. Dolphins eating only live fish.
  4. And once again becoming opportunistic foragers.
underwater image of live fish feedings for ex-performing dolphins

In Phase 1, all activities are done from a regular feeding station, both live and dead fish to be offered only when the dolphins’ heads are underwater. We continue feeding them dead fish but include live ones just to acquaint them, tossing the fish randomly at short distances, gradually increasing the distance and discouraging the dolphins from feeding with their heads out of water.

In Phase 2, we gradually wean the dolphins from their usual feeding regimen by tossing both dead and live fish from different locations and at different times. By now we are behind a blind to keep the dolphins from seeing us. We don’t want them to associate feeding with the feeder.

We always toss live fish toward the center of the pen so the dolphins have a better chance to catch the fish before it escapes through the fence.

Sometimes it is necessary, initially, to immerse the fish in ice water to slow them down, giving the dolphins a better chance of a successful chase.

Feeding becomes more random and uncertain. We now toss dead and live fish from behind a blind at all hours, including early morning and after dark. In the water we have a hydrophone so that we can monitor the dolphins’ use of sonar in finding fish, especially live fish. We can compare audio recordings of confirmed catches during the day with night feedings.

We increase the number of feeding sessions, decreasing the quantity of fish per session. Short, quick feeding sessions from varied locations and at all hours will discourage the dolphins from searching for the feeder.

In Phase 3 (eating only live fish) we must first make sure we can provide enough live fish for the dolphins. We need a good source of fish indigenous to the release site. We analyze these for nutritional value and, in figuring the dolphins’ total diet, allow for the energy used in chasing live fish.

While continuing to feed the dolphins at various times and from various places, we now increase the proportion of live fish. When the dolphins are eating mostly live fish, we introduce them in groups of 10 or 15, creating a ‘school’ of fish, which adds realism and forces the dolphins to select the prey they will chase down.

Finally, in Phase 4, we eliminate the human element from feeding and encourage the dolphins to forage on their own. We constantly introduce live fish into the pen and keep track of the dolphins’ rate of consumption, finally replacing dead fish in their diet with live indigenous fish such as mullet. When the dolphins are ready to venture out of the pen, they make it very clear to those who can read their body language.

In Indonesia, we added a new component to our process with the creation of our beloved “foraging pen”. It’s built inside the primary floating seapen. This is a small, shallow pen 10m x 10m x 3m deep. Hundreds of live fish are dumped in throughout the night by local fishermen. The gate is opened in the morning and our three rescued dolphins spend a few hours cooperatively foraging. The foraging pen becomes an “all you can eat“ dolphin diner. This new addition to the rehabilitation and release process has been extremely helpful.

Post-Release Tracking

In past releases, dolphins have been freeze-branded during the re-adaptation stage to aid in visual identification. Radio-tracking devices had been invasive and provided sites for future infection. However, transmitters have come a long way since my original protocol was published. Post-release tracking in future releases should include Satellite Transmitter tags for each dolphin. Details regarding this tags can be found at this link.

dolphin release Ric and team
Satellite tag for post-release tracking

When you release a dolphin, you want everything to be as natural as possible. All along we’re setting up a tracking team made up of people who live on the water, fishermen and boat operators. We talk to them in person. The fishermen and boat operators are not part of the dolphin’s captive world, they’re part of the sea. If you tell the fishermen what’s going on, they become part of it. It’s not like they’re joining something. They’re already part of it. They know the dolphins they see every day like they know their own children. Later when we finally release the captive dolphin, when they spot him swimming, they report it to us and we record it, we record who spotted the dolphin, where and when, what direction he was going and with what or how many companions. Most especially we’re interested in any unusual behavior.

If the dolphin is begging for food, for example, that doesn’t mean failure. That means we have to keep people away. When the dolphin is first released, this is a very crucial time. He goes through a period of adjustment. He might even miss a meal. Up till now we’ve been feeding him regularly, all he wants. He’s fat and sassy. Now he’s having to feed himself. That’s the main adjustment for the dolphin. And we must get out of his way and let it happen.

That’s the whole point of rehabilitation and release, to let this crucial moment happen. At first we get reports of his whereabouts every day. Sometimes several reports. We put it on a chart, trace his movements. He’s here on the chart one day, there another. We see patterns. That means the dolphin is developing a life of his own. And after a while — if we let him alone — he’ll establish a new home range, a natural life in the wild again.


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