We can see that the misuse inbreeding in limited captive population or on purpose can cause many problems which start a chain reaction on the animals and surroundings around it.
Genetic Drift is when by random chance some alleles do not get passed on to the offspring, this reduced the variation in a population, In large populations this does not have as much effect as a smaller population as each generation tends to even out to the process, But it have a greater effect on small populations and progresses much faster. This is important when genetic uniformity comes into place.
If all the males in a population were genetically similar, and Inbreeding depression had already started to affect the health of the male population, a disease could set in and wipe out the males if there was a weakness in resistance to that disease, the females would be left and no males to reproduce, therefore leaving that population to extinction.
The Bottleneck effect is linked to genetic drift and is a catalyst of genetic drift, for example, inbreeding was occurring in a small population and an event like an ice age killed off a certain offspring with the same alleles because those offspring had been affected by inbreeding depression, they were smaller and had little-to-none cold resistance. Mean while the rest of the population has more genetic variation and have less deleterious and recessive alleles and can cope better with the environmental chance. Without management of breeding in Zoo’s, all of these problems can occur in a limited captive population.
“ScienceDaily (Dec. 25, 2008) — Human impacts on the environment have reduced populations of wild species to dangerously low levels. Nowhere is this more apparent than in worldwide fisheries, where thanks to overfishing and habitat destruction, countless species and populations of fish are on the brink of disappearing forever”. – 2,
Due to human interference populations of species are being wiped out due to over farming, one example is the basking shark which is now an endangered species and under the protection of international Trade species, traditionally hunted for the liver in Japan and the high demand of shark fin soup.
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A growing problem we face today is that captive breeding programs may not always be the best solution for endangered animals, the problem of mass farming of fish causes a huge unbalancing in the food chain, as fish is globally consumed a number of factors could cause the populations to rapidly decease i.e., Ocean temperature change. On the other hand, Humboldt Squid lay 30 million eggs and is rapidly increasing in population size could take over the dinner plate, A shift in the food chain like this could cause other species of fish to decrease/increase, This has a huge implication in economics as the fisheries business would have to change the way they operate completely. The Humboldt squid is a dominate predator as to the shark, species below it are common fish & once those have a significantly smaller population, fishing for Humboldt squid could be a main priority, meaning not only do the common fish population decrease but the Humboldt squid will have less to feed on.
-6. This Chart shows the difference between the most inbreeded group and the least inbreeded group, the results show that on average, the least inbreeded group will live 4 years longer then the most inbreeded group of poodles
“Unfortunately, without captive breeding to bolster their numbers, we may soon have too few individuals from which to repopulate disappearing fish populations, leaving us essentially in a fisheries catch-22..” –3
In the same article Fraser et al discusses that without captive breeding helping to keep numbers of species up from the ever growing consumers, it is necessary for captive breeding to be used, however deleterious effects on species go hand in hand.
However, Inbreeding in Limited captive populations can bring some benefits.
Conversation programs like the GRB can offer the chance of current/future technologies in re-populating animals, sometimes inbreeding in limited captive populations can’t be avoided when the populations are so small.
For example, there are only around 250 Sumatran tiger’s left, due to humans causing deforestation, these animals are being put under conservation programs, Inbreeding in captive populations could be there only chance to maintain the population, Cryopreservation is a method used by zoos and scientists to hold DNA and tissue from animals over a long period of time, like plants, animals can hold materials for new medicines and balancing bio diversity.
Solutions on how to avoid Limited Captive Populations Inbreeding;
“Managers of Zoos often try to organize a population of animals large enough, so that only 10% of the population becomes inbred over 100 years”. –5,
This is a tactic used by many Zoos’ across the world, Studbook keepers make sure that they pick the best partner as possible for mating and preserving the bio-diversity.
In some zoos when choosing animals to breed, managers use pedigrees to make sure that all of the genes are kept safe, this allows genetics in a population to stay healthy and recessive free whenever possible, They also try to make sure that the male and the female are the most unrelated as possible to stop the problems that inbreeding causes.
There are a number of cooperative breeding programs that involved a chain of zoos in multiple countries, for example
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Zoos and Aquariums in North America form the ‘Species Survival Program’.
- Australian regional association of Zoological parks and the Australian Aquariums species management program.
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EAZA - European Association of Zoos and Aquaria's European Endangered species program.
London Zoo is a part of EAZA, which has 2 different projects, The first project is the EEP (European endangered species program), often requirements for a cooperative program like this are to form Studbooks and have a Coordinator and their team who manage the studbook and make analysis’s on which animals will be mating, where they will be mating, the coordinators also analysis’s problems before and after breeding, lack of reproductively & crowed population control, demographical and genetic analysis The problems that occur are recorded into the studbook for other zoo’s as information on that animal.
The ESB(European Studbook) which is based on the same principles of the EEP but one person is in charge of the a specific studbook in which they have to collect all of the data for the on births, birth rates, deaths and causes and transfers to other zoos for breeding. This is all vital when it comes to choosing which animals mate in order to stop inbreeding as much as possible and keeping animal populations healthy, which is the zoo’s primary role.
Another solution zoos across the world have come up with is ‘Genome Resource Banking’ (GRB) which is a conservation program for endangered species.
Using tissue samples, sperm, embryos and DNA. The GRB plays an important role in the development of new technologies for re-populating endangered animals, Cryopreservation allows samples to be transported between Zoos easily, and it is also a safe way of maintaining bio diversity and safe conversation.
Ethical Issues;
One issue that can be argued is whether Humans are correct in interfering with nature and stopping inbreeding when it has been happening for millions of years. Even though captive breeding may help regenerate a population, animals have been on the planet longer than humans and the effects of nature has tested the survivability of animals to its limits, surely nature should be left to run its course without human interference as it has been for so many millions of years.
Taking animals out of their natural environmental could cause mental and physical disadvantages such as the lack of ability to hunt as well as wild animals of the same species, this could cause them to be endangered altogether because of human inference.
Another issue is if the Zoo’s are based on making money or actually protecting endangered species and rehabilitating them into the wild.
London Zoo has funds from tourists, visitors, charities, government funding for research and breeding, Customs of Excise in Britain has said that the zoological society of London is not a completely run on a charitable basis.
Several films and Television shows have been filmed in London zoo as a film set. It also as many employee’s and to be sustainable it has to generate more income than outcome in its expenditures, some can argue that the disability of animals to survive in the wild is being taken advantage of, as species become endangered and extinct as has happened before, it can be argued that human interference is causing problems like weeding out the weaker species ‘survival of the fittest’. One way this can be determined is to weigh up the successful breeding that zoo’s have caused and compare it to the costs and the amount of species being born into the wild, it could be the case that Zoo’s across the world know that the captive population of maybe 20 panda’s will only be for publicity and tourism, the chance that they would be introduced into the wild is small due to the number of them.
With the over farming and destruction of animal’s habitats, does captive breeding really make any productivity with so much counter-productivity?
Animals in Captivity is probably for the best and to ensure the survival of the species that faces problems natural and man-made, therefore we should try our best to fix our problems and/or offer other ways to making up for it.
Another Issue is the point some have made about Zoo’s playing the role of ‘God’.
Some might argue that Zoo’s are disrupting the nature and taking the role of god and using that to breed animals for commercial, economical and environmental reasons, the ‘pick & mate’ strategy, delivering of offspring and feeding by human hand do not seem right to some people.
It is also argued that the Zoo’s pick and mate tactic is to promote rarer breeds and to make it more exclusion to pull in visitors, to me this is almost the same as pure breeding to breed desired characteristics in an animal, as well as breeding new animals, they also have to sustain captivity for the other animals in the Zoo’s and ones that are becoming more and more endangered each day due to the ever changing conditions.
An Economical Issue is that Zoological Societies provide many jobs for people across the world in Researching, Conservation Projects, Supplies and Delivery, Media and Advertisement, Maintenance, Utilities and Construction, Education and Government Monitors and more. Without Zoo’s and Societies people educated in the field of zoology and veterinary would be unemployed to struggle to find jobs, the industry is vital in our modern economy and this is why it is important for captive programs to exist and succeed.
Conclusion;
In conclusion I think the problem of inbreeding is now recognized unlike the early 1900’s when it was ignore and little was known about it.
Scientists and researchers have found good solutions to help limit and stop inbreeding and they work efficiently in Zoo’s across the world, However they are constantly against nature and human interference in other parts of the world. I think that avoiding inbreeding in a limited captive population is workable and should continue. The bio-diversity of organisms is crucial to the environment including humans, one change can have a chain of effects would can lead to a change in the way we live and deter future research and technology.
Maintaining animals in captivity is costly, but the cost is worth helping to preserve the world’s different species,
Bibliography
1- The University of California Museum of Palaeontology, Berkeley, and the Regents of the University of California. (2006), Bottlenecks & Founder Effects, [Internet], Available: ,Accessed [17/12/2008]
2 – DailyScience. (2008), Fisheries Catch-22: Captive Breeding Aims To Conserve Biodiversity But Plunders Genetic Diversity, [Online], Available: ,Accessed [05/01/2008]
3 – (Journal) Fraser et al. How well can captive breeding programs conserve biodiversity? A review of salmonids. Evolutionary Applications, [Book], 2008; 080602014503553 DOI: ,Accessed [19/12/2008]
4 – DogHobbyist.com, The Downside of Inbreeding: It’s Time For a New Approach, [Internet], Available: ,Accessed [05/01/2008]
5 - Smithsonian Institution. (2008), Managing Small Populations, [Internet], Available: ,Accessed [17/12/2008].
6- Effects of Inbreeding in Poodles. (2007), Paris Poodles, [Internet], Available: ,Accessed [29/12/2008]
