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Captive breeding programs Peter de Sève. Saving species Assuming a decline is already well under way: what to do? - remove threats (harvest regulation,

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Presentation on theme: "Captive breeding programs Peter de Sève. Saving species Assuming a decline is already well under way: what to do? - remove threats (harvest regulation,"— Presentation transcript:

1 Captive breeding programs Peter de Sève

2 Saving species Assuming a decline is already well under way: what to do? - remove threats (harvest regulation, development, etc.) (what if threat is exotic species?) - enhance natural reproduction; improve habitat (conspecific attraction; food supplementation, etc.) - translocate individuals to increase variation, N - captive breed for short term to produce stock for translocation - captive breed for long term to have stock ready for periodic use - captive breed indefinitely

3 Purposes of captive breeding programs: conservation of threatened species – objective to restore wild popns (no wild individuals left) – objective to supplement wild populations that have declined or are threatened

4 Purposes of captive breeding programs: captive maintenance of threatened species –habitat is completely lost –threats to extinction cannot be overcome –duration of captivity has irrevocably altered species

5 consequences of genetic mismanagement minor major maintain in permanent captivity re-establish wild population supplement wild population

6 Stages in a captive breeding program decline of wild population, genetic consequences choice of founder population growing captive population maintaining captive population reintroducing individuals managing reintroduced population in captivity

7 Issues for captive propagation source of founder population(s) space requirements in captivity/space availability in zoos courtship/mating behaviors intrinsic rate of increase isolation of sub-populations availability of wild populations as sources of new variation

8 Rules for captive propagation Founding the population - minimize genetic and phenotypic change –collect random sample of founders –collect data on locality, habitat of origin –collect genetic data from founders –keep sub-populations isolated

9 Rules for captive propagation Maintaining the population maximize N and Ne (maximize sex ratio) maintain equal family sizes

10 Rules for captive propagation Maintaining the population maximize N and Ne (maximize sex ratio) maintain equal family sizes Lion: average family size 1.65 variance in family size 32.7 reduces effective popn. size to 8%

11 Rules for captive propagation Maintaining the population maximize N and Ne (maximize sex ratio) maintain equal family sizes golden lion tamarin - founder population 242 individuals - 48 contributed to subsequent gene pool - most of offspring (2/3) from single pair

12 Rules for captive propagation minimize loss of genetic variation –maximize N and Ne (maximize sex ratio) –maintain equal family sizes –periodically check variability, compare with wild populations minimize behavioral changes –minimize duration of captivity (maximize generation time) minimize inbreeding –conduct pedigree analysis/management –outcross population with new individuals

13 Rules for captive propagation manage demographics –determine reasonable carrying capacity (note effect on other taxa) –achieve carrying capacity rapidly –stabilize population at carrying capacity maintain representation of age classes what to do with excess animals?

14 Rules for captive propagation Species Survival Plans (SSPs) for zoo species goal: preserve genetic variation – 90% of H over 100 years

15 Rules for captive propagation Species Survival Plans (SSPs) for zoo species goal: preserve genetic variation – 90% of H over 100 years –list each individual in a studbook – sex, sire and dam, likely alternatives if uncertain parentage –acquire data: age-specific fecundity, mortality, lifetime reproductive success, inbreeding –equalize reproductive contributions of each individual –pair individuals of lowest mean kinship –work with other zoos to share genetic material Limits to zoo taxa….

16 Problems with captive propagation African wildlife in Texas ranches

17 Problems with captive propagation Deliberate (artificial) selection for increased productivity – fecundity, growth, or both for ‘better’ type or traits (color, size) for tractability (handling, breeding season) –problems with linkage of undesirable traits

18 Problems with captive propagation Problems with linkage of undesirable traits (white tiger): strabismus (crossed eyes) weakened immune system shortened tendons of the forelegs, club foot, kidney problems, arched or crooked backbone and twisted neck, reduced fertility and miscarriages unwanted (normal) kittens discarded… Ron Kimball

19 Problems with captive propagation Accidental selection for increased productivity – fecundity, growth, or both domestication – select for fitness under captive conditions –tends to homogenize differences among sub-populations

20 Problems with captive propagation Absence of selection…

21 General post-release problems lower fitness in wild –domestication – genetic and/or behavioral –loss of variation increased fitness in wild –loss of wild populations through competition for mates, habitat – captive-bred may be healthier –different development stages

22 General post-release problems lower fitness in wild –domestication – genetic and/or behavioral –loss of variation increased fitness in wild –loss of wild populations through competition for mates, habitat – captive-bred may be healthier –different development stages lake trout (Foster 1984) rapid early growth in hatchery young age at sexual maturity premature reproductive senescence

23 General post-release problems captive individuals may hybridize with wild indivs. –pollution of wild genome –loss of variation if lowered variance in captive stock

24 Additional methods: Cross-fostering “head-start” programs – minimize duration of captivity Artificial insemination Embryo transfer

25 Association of Zoos and Aquariums Guidelines for Reintroduction of Animals Born or Held in Captivity


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