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Captive breeding: uses. Supplement existing populationsProvide insurance against extinction in wildPreserve species following extinction in wild25 animal species: black-footed ferret, Ca. condor11 Partula snail speciesseveral plants: Franklin tree (Frankham 2007). Captive breeding: critiques.
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1. Conservation geneticsand captive breeding Tim King, USGS
Meredith Bartron, USFWS
3. Captive breeding: critiques If used for population or species decline…
Population maintenance
Genetic diversity maintenance
Temporary fix
Doesn’t address cause for population decline
4. “Captive breeding should be viewed as a last resort in species recovery and not a prophylactic or long term solution because of the inexorable genetic and phenotypic changes that occur in captive environments. Captive breeding can play a crucial role in the recovery of some species for which effective alternatives are not available in the short term.”
-Snyder et al. Conservation Biology 1996
5. “Thus, our results suggest that the apparent short term demographic advantages of a supplementation program can be quite deceiving. Unless the selective pressures of the captive environment are closely managed to resemble those in the wild, long-term supplementation programs are expected to result in genetic transformations that can eventually lead to natural populations that are no longer capable of sustaining themselves.”
-Lynch and O’Hely, Con. Gen. 1991
6. “Many endangered species require captive breeding to save them from extinction, as they are incapable of surviving in inhospitable natural environments due to direct or indirect human impacts in the form of habitat loss, overexploitation, pollution, or introduced predators, competitors or diseases…”
-Frankham, Molecular Ecology 2007
7. Captive breeding ~2000-3000 terrestrial vertebrates
~2000 amphibians
245 vertebrate species being bred in captivity in zoos (1989)
Royal Botanic Gardens: 2700 sp. (of 25,000 threatened sp.)
US Center for Plant Conservation: >600 endangered US plants
Frankham 2007
8. Prerequisites and assumptions Phylogeographic and phylogenetic relationships within and among close relatives is known
Sufficient genetic diversity to realize unique multilocus genotypes
Preserving maximum levels of genetic diversity within and among populations will increase fitness
9. Captive breeding: genetic concerns Loss of genetic diversity
Inbreeding depression
Accumulation of deleterious mutation
Genetic adaptation to captivity
Reduced fitness in the wild
10. Captive breeding: genetic concerns
14. Captive breeding Program goals vs. genetic concerns
Restoration and recovery
Supplementation
Gene-banking
15. Interaction between captive and wild The program is run as an integrated hatchery program, however the number of wild fish in some populations is very low so the number of wild actually integrated might be very low. In these cases, the goal is to provide some “natural” experience and selection to the hatchery programThe program is run as an integrated hatchery program, however the number of wild fish in some populations is very low so the number of wild actually integrated might be very low. In these cases, the goal is to provide some “natural” experience and selection to the hatchery program
16. Captive breeding Founders
Size and diversity of source population
Selection pressure
Artificial selection: Changes to genetic and phenotypic diversity while in captivity
Gene flow
Interaction with wild population when returned to natural environment (Ryman and Laikre 1991)
Reproduction
Mating strategies
17. Captive breeding Mating strategies
Random
Use of pedigrees
Genetically-aided pairings
Single paired-matings vs. splitting of egg lots
Cryopreservation
Equalize reproductive contribution
Family size
Number times reproducing
18. Pairwise relatedness values Rxy
Females
Males 257C63CFE8 421B716624
257C63EF98 0.197 0.456
257C63D9CE -0.185 0.135
486850414D -0.084 -0.284
48512B7222 0.023 -0.566
4870464E2D -0.329 -0.078
422E5C432B -0.075 0.053
422E6E717E -0.013 -0.466
19. Captive breeding and effective population size Size of total population (wild + captive)
Size of captive population
Size of number individuals reproducing in captive
Fecundity/reproductive contribution
Contribution of captive reproduction to total population
20. Effective population size and stocking effects
22. Parentage assignment
23. Captive breeding: Atlantic salmon
24. Atlantic salmon : Maine adult returns Due to the declining stocks and endangered status, a conservation hatchery program was established, building on an existing program to aid in recovery and restoration.Due to the declining stocks and endangered status, a conservation hatchery program was established, building on an existing program to aid in recovery and restoration.
26. Some Maine populations listed as endangered-distinct population segment
Captive populations maintained at:
Craig Brook NFH
Green Lake NFH
Restoration programs also in southern range:
Merrimack River
Connecticut River
27. Atlantic salmon: CBNFH captive populations Parr collection Adult collection
Dennys Penobscot
East Machias
Machias
Narraguagus
Pleasant
Sheepscot Reason for different broodstock strategies is due to the differences in number of returning adults. DPS population returns are so low that a broodstock couldn’t be sustained & production goals couldn’t be achieved (along with many genetic concerns due to low numbers).Reason for different broodstock strategies is due to the differences in number of returning adults. DPS population returns are so low that a broodstock couldn’t be sustained & production goals couldn’t be achieved (along with many genetic concerns due to low numbers).
28. Program types: parr collection
29. Program types: adult collection Some parr are also stocked as grading by productSome parr are also stocked as grading by product
30. Data management
31. Maine Atlantic salmon broodstock program: broodstock screening
32. Genetic parentage assignment Evaluate % recapture as hatchery origin
Individual and family fitness
From stocking stage to recapture
Evaluate stocking practices
Segregated versus mixed
33. Genetic parentage analysis: parr Capture # # assigned %
Broodstock year screened parents assignment
Dennys 2001 101 25 24.8
2002 270 42 15.6
2003 142 32 22.5
2004 148 40 27.0
East Machias 2001 135 41 30.4
2002 168 78 46.4
2003 156 95 60.9
2004 154 71 46.1
Machias 2001 244 23 9.42
2002 336 133 39.6
2003 248 152 61.3
2004 247 100 40.5
Narraguagus 2001 248 52 21.0
2002 243 80 32.9
2003 252 145 57.5
2004 234 114 48.7
Sheepscot 2001 300 44 14.7
2002 157 98 62.4
2003 160 82 51.3
2004 149 82 55.0 Low % assignment could be due to:
incorporation of wild parr,
incorrect assignments,
errors during spawning,
not having all parental genotypesLow % assignment could be due to:
incorporation of wild parr,
incorrect assignments,
errors during spawning,
not having all parental genotypes
34. Genetic parentage assignment
36. Monitoring estimates of genetic diversity
Number
Sample alleles Heterozygosity
Broodstock size per locus (exp.) (obs.) mean rxy
Dennys 138.7 8.90 0.552 0.555 -0.021
East Machias 135.0 8.44 0.559 0.569 -0.005
Machias 229.9 8.68 0.564 0.563 -0.002
Narraguagus 261.3 9.23 0.568 0.567 -0.001
Penobscot 460.9 9.24 0.571 0.571 0.003
Pleasant 155.7 8.06 0.571 0.571 -0.007
Sheepscot 138.6 8.08 0.569 0.577 -0.005
DPS population averages between 1994 and 2004, except Pleasant River (1995-2004)
Estimates for Penobscot populations are averaged from 2002 to 2006
Rxy estimates from Queller and Goodnight (1989), 2000-2004
37. Spawning practices All fish PIT tagged & genotyped
Natural cycle of maturation followed
Multiple spawning dates throughout season based on maturation
Adults are spawned within river-specific broodstocks
Spawn “first time spawners”
All individuals have an opportunity to pass genes
2nd (and 3rd) - time spawners used when needed
1:1 spawning sex ratio Production drives effective population size
Tagging and genotyping all individuals allows for tracking
3 & 4. Natural maturation means no use of hormones or artificial means to speed up/slow down or change timing of spawning
5. Rivers are not crossed within the hatchery-natural straying and reproduction is allowed through incorporation of parr (and genetic screening processes allow for straying)Production drives effective population size
Tagging and genotyping all individuals allows for tracking
3 & 4. Natural maturation means no use of hormones or artificial means to speed up/slow down or change timing of spawning
5. Rivers are not crossed within the hatchery-natural straying and reproduction is allowed through incorporation of parr (and genetic screening processes allow for straying)
40. Other program components Improving parentage assignment
Aquaculture screening/mass marking
Continued evaluation for pedigree lines
Evaluation of specific traits to family and individuals for fitness
Quantitative trait monitoring
Evaluation of alternate rearing stocking practices
Continued evaluation to reduce artificial selection