By Kirsten Burg and Casey Candy

The issue of captivity is a very controversial one. Some of the major concerns of researchers and anti-captivists and workers in the captive industry are conditions, treatments, and the survival of the animals. Marine mammals in particular have experienced a public outcry against their captivity.

The positive or "pro" viewpoint of captivity focuses on four main benefits of keeping marine mammals captive. These benefits are entertainment, conservation, research, and education. Advocates feel that displaying these animals in a show provides entertainment, which generates interest and awareness about these animals. During performances, trainers often talk about the animals and give information about what they eat and how they are trained. Aquariums also have exhibits to educate the public about the behaviors and habitats of the mammals in the wild. The captive industry feels that by maintaining a population of marine mammals in captivity, they are helping to sustain that species in the wild through breeding programs. The rehabilitation of stranded and injured animals is another way captivity helps conserve marine mammals because it reduces the need for wild catch. Researchers can easily gather data that would be much more difficult to obtain from wild animals in the field. Most of the information acquired about marine mammals has been obtained from captive species (Comm. Nat’l. Envir. 1997, Fine 1982).

The negative point of view argues that these benefits do not justify keeping animals captive. Researchers who study captive animals are not observing the true and natural behaviors that they would normally see in the wild. They are instead studying their behavior that has been altered by the stresses of an unnatural captive environment. Jacques Cousteau once said "There is about as much educational benefit to be gained in studying dolphins in captivity as there would be studying mankind by observing prisoners held in solitary confinement" (Bluedolphins 1999). A big concern of anti-captivists is that animals become tame and then cannot be returned to the wild with out extensive rehabilitation. An example of this problem is the Sugarloaf release on May 23, 1999. Two bottlenose dolphins were released without rehabilitation and were found days and weeks later severely injured and starving. These animals had to be readmitted into captivity for recovery and rehabilitation. The good intentions of the releasers ended only in injury and extended captivity for the two animals (NOAA Press Release 1999).

Some other concerns are that few animals are maintained in the most natural conditions possible. Training and performing can not replace the exercise and mental stimulation of maintaining a wild existence. Tanks do not offer a natural habitat with their cement walls and manufactured seawater. Species that are most often held captive are not endangered or threatened and many that are endangered are never captive. These less famous species do not enjoy the public affection of the more popular species usually found in captivity. This seems to give less credence to the captive conservation argument because the species that could benefit from captive breeding are not the best performers or most marketable and striking specimens (Comm. Nat’l. Envir. 1997).

Data for captive survival rates are largely obtained from the Marine Mammals Inventory Report (MMIR). The MMIR records mortalities from capture to captive births and deaths (Small 11.2 1995). A study conducted by Small and DeMaster in 1995 concluded that there was a need to categorize data by age, sex and captive versus wild born. They calculated survival as:

1- (# of deaths / # of total days studied)

This equation produces a daily survival rate, which is then converted to an annual survival rate.

For age specific survival, the study defined two focus groups by age; calf and non-calf. Survival was 0.666 for bottlenose dolphins in their first year in captivity. Rates increased during their second year to 0.917. The study also highlighted another popular captive pinniped specie, the California sea lion. Their rates increased throughout their first through third years from 0.858 to 0.970. During the fourth year, the researchers found that the rate stabilized and by the fifth year there were no mortalities (Small 11.2 1995, Williamson 1995, DeMaster 1988).

The study noted that sex specific differences were significantly less than age specific data. In general, it was found that females tend to survive longer than males. California sea lions showed the same trend with a slightly larger difference between males and the longer lived females (Small 11.2 1995).

The rates of captive born survival versus wild born showed no distinct differences in dolphins. However, captive born California sea lion non-pups survived much better than their wild born counterparts. For the second year of captivity the numbers dramatically changed. Wild born non-pups survived much better than captive born. This finding was again indicative of the need for further age specific studies (Small Oct 1995).

Another major aspect impacting marine mammal life spans in captivity is the many problems aquariums encounter when maintaining very large social marine animals. The major problems include the water quality and social behavior. Water quality maintenance is a very large task. Some water concerns are the presence of pathogens, levels of chemicals, temperature, clarity and treatment of the water. Some pathogens that are problematic to captive animals are not so in the wild. Very little is known about the affects of many chemicals on marine mammals. Many zoos and aquariums often neglect to monitor the levels of ammonia, nitrate, and nitrite in tanks and water supplies of animals. One of the greatest chemical concerns is that many aquariums house marine mammals in freshwater because it is cheaper and easier to maintain than seawater. A largely aesthetic need for aquariums is clear water. Very clear water is not necessarily clean water. The amount of suspended matter determines how clear or murky water appears. The angle of the viewer along with available light ultimately determines visual levels (Kleiman 1996).

The aspect of maintenance that can most influence an animal's health is temperature. Most marine mammals are kept at higher temperatures than they normally experience in the wild. This leads to skin problems and hair loss in many species. Warmer water is less expensive than having to continually cool the water (Kleiman 1996).

Aquariums have several options when deciding how to treat the water in their enclosures. There are three main types of treatment systems. The first, a complete flow through system, allows the entire volume of water to be continuously replaced. No water is reused. The second, a partial flow through system, is a system in which a portion of the water in the tank is treated and reused while the rest of the water is discarded and replaced. Finally, the third type of system is a closed loop. This type recycles the entire amount of water for a given amount of time and then is replaced (Kleiman 1996).

Many marine mammals have complex social structures. These relationships are based on age, sex, and relatedness. Physical contact is important in forming and maintaining their relationships. Maternal bonds are critical to becoming a functioning member of society, especially for cetaceans. Animals that are housed with "strangers" with whom they have no social bonds often become aggressive toward each other because there is no dominance hierarchy. The majority of animals in captivity have had all social relationships severed. For many animals, their relationship to trainers often helps fulfill this social need (Wells 1989).

The Marine Mammal Protection Act (MMPA) of 1972 attempts to control the how and how many of marine mammals captures. The MMPA requires a permit for the capture of wild marine mammals, releasing a captive animal back into the wild, and importing and transferring marine mammals. There is also a permit required to handle and care for beached or stranded animals. It appears that the numbers of captures for public display are decreasing. There has not been such a permit issued since 1989 (Comm. Nat’l. Envir. 1997, MMPA 1972).

There have been several proposed alternatives to keeping live captive animals. Members of both sides of the captivity issue agree that much can be learned about cetaceans without the need to keep the animals captive. Exhibits featuring anatomical models with a hands-on approach would enable people and especially children to be intimately introduced to many marine mammals. Film footage of wild behavior and virtual reality interaction would help present animals realistically, as one would encounter them in their natural surroundings. Virtual reality could be combined with sound and echolocation recordings to make the experience authentic. Finally, many species in need of conservation could gain awareness through rare and endangered species exhibits. These exhibits could feature beaked whales, river dolphins, elephant seals and other lesser known cetaceans and pinnipeds.

In summary, females tend to survive slightly better in captivity rather than males. Also, the older an animal is when it is captured the more likely it is to survive capture and live longer in captivity.

In conclusion, it appears that marine mammal life spans are, in fact, shortened in captivity. However, a lack of data on the natural life spans of marine mammals makes a definitive answer difficult. The many problems encountered with keeping marine mammals in captivity combined with inadequate efforts by many captive establishments makes it very likely that marine mammals do not, as a whole, live as long in captivity as in the wild.

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