Why are UBC Researchers Studying Green Sea Turtles?

As recent media stories have noted, green sea turtles are an endangered species facing extreme predation from fishing industry bycatch as a result of climate change. Prof. Bill Milsom, Head of the Department of Zoology in the Faculty of Science, discusses research designed to better understand these animals and thereby reduce their mortality.

Why are UBC researchers studying green sea turtles?

The green sea turtles are a threatened/endangered species. The major causes of mortality for these turtles are natural predation on young, and human interference with adults. The latter arises from poaching, encroachment of human development on nesting beaches, and as bycatch in fishing nets. Clearly among the major problems to be addressed are the consequences of human population growth, habitat destruction, and fishing practices. These problems definitely need immediate redress but all will take time.

In the meantime, what can be done to mitigate the consequences of these problems? Are there short-term solutions that may help protect the species in the interim while these larger problems are being addressed?

UBC researchers have been studying a small group of sea turtles since 1998 to gain a better understanding of their foraging ecology and their range distribution. Equally importantly, other studies are being performed to better understand their physiology. The abilities of animals to exploit different habitats reflects their physiological capacities; the processes that determine what they can and can’t tolerate and how they will respond to environmental challenges. All studies are designed to gain information that will give scientists a better understanding of the biology and physiology of these animals and allow them to make more informed decisions about ways to conserve and manage wild populations. This information will also provide insights into ways to reduce the mortality arising from entrapment in fishing nets, something which is occurring more frequently as the range of this species increases due to global warming.

So little is known about the physiology of these animals and this information is essential if we are to more effectively and intelligently inform fishing policies and aid conservation management. The mortality rate for turtles entangled in nets is high: an estimated 85,000 deaths between 1990 and 2003.

How could researchers do terminal experiments on endangered animals?

In this instance, the researchers had the opportunity to obtain farmed turtles that were destined to die, for slaughter for meat. Rather than simply let them die, this study provided an opportunity to obtain valuable information that would help scientists to understand the biology and physiology of these animals. This information is critical to produce informed decisions about conservation management of the populations that are threatened and/orendangered in the wild.

Why can’t the study be done on animals in the wild using non-invasive techniques?

Many studies can and are being done in this way, including several by the UBC investigators. These studies use satellite tracking methods and data loggers to retrieve valuable information about the range distribution and diving behaviours of the animals.

So why then must laboratory experiments be done on captive animals?

For two reasons. The first is that validation experiments must be performed in the lab to enable scientists to interpret the data that are collected from the animals in the field. These experiments are relatively non-invasive and animals used in these experiments can be, and have been, retired to public aquaria afterwards.

The second reason is to obtain critical information about the physiological processes that underlie the unique lifestyle of these animals. This information will enable scientists to understand the causes of mortality and to effectively and intelligently inform fishing policy and conservation management.

Why must the animals be killed?

Some data can only be obtained from invasive studies that compromise the survival of the animal. These experiments are, of necessity and always regrettably, terminal. Also, after the experiments are complete, tissues will be harvested for a variety of associated studies. The researchers involved in these studies have gone to great lengths to involve the international community in this process to ensure that maximum benefit is obtained from the studies. As a result, however, these animals are not available to go to aquaria. The number required are the minimum number deemed necessary to collect valid data.

The turtles are not being killed once experiments on them are complete; they are being killed so that the experiments can be completed.

This research is necessary to help us understand the capacity of these animals to tolerate environmental challenges. All studies are designed to gain information that will give scientists a better understanding of the biology and physiology of these animals and allow them to make more informed decisions about ways to conserve and manage wild populations. This information will also provide insights into ways to reduce the mortality arising from entrapment in fishing nets, something which is occurring more frequently as the range of this species increases due to global warming.

The experiments are performed under anesthesia just as all major surgery is done on humans in hospital. At the end of the measurements, the dose of anesthesia will be increased until the animal is euthanized. The animals suffer no pain or discomfort.

Why can’t they be retired to aquaria where they can live out their lives?

These animals were obtained on CITES permits for research purposes. CITES does not allow us to transfer these animals to any facilitythat will use them for commercial purposes or financial gain. They can, with proper approval, be transferred to other research facilities. Some public aquaria do meet CITES requirements.

And so, this is exactly what has been done for half of the turtles that came to UBC already. The remaining animals are currently needed to obtain data that can only be obtained in invasive experiments that are usually terminal, and for tissue samples that can only be obtained after their death.

Why can’t they be released back into the wild?

Permission to export these animals to Canada was for scientific purposes only. Due to the unknown health impact of environmental release, the imported animals, all subsequent progeny and anytissues of these animals, other than those in final histological preparations, must not be removed from the premises of destination listed on this permit.

Hasn’t technology advanced to the point that these sorts of experiments are no longer necessary?

While modern imaging techniques and use of tissue culture and similar methods have contributed tremendously to the ability of scientists to obtain data without the need to sacrifice animals, they are not able to completely replace other forms of experimentation. They certainly reduce the need for invasive studies but do not completely replace them.

Who gave the researchers permission to do these experiments?

This study, like all research involving animals at UBC, has been reviewed and approved by the Animal Care Committee. To receive approval, studies must pass ethical review and demonstrate minimal use of animals as well as humane care, following national standards set by the Canadian Council on Animal Care.