Captive-born Individuals Research Articles

Effective size of a wild salmonid population is greatly reduced by hatchery supplementation

Many declining and commercially important populations are supplemented with captive-born individuals that are intentionally released into the wild. These supplementation programs often create large numbers of offspring from relatively few breeding adults, which can have substantial population-level effects. We examined the genetic effects of supplementation on a wild population of steelhead (Oncorhynchus mykiss) from the Hood River, Oregon, by matching 12 run-years of hatchery steelhead back to their broodstock parents. We show that the effective number of breeders producing the hatchery fish (broodstock parents; N(b)) was quite small (harmonic mean N(b)=25 fish per brood-year vs 373 for wild fish), and was exacerbated by a high variance in broodstock reproductive success among individuals within years. The low N(b) caused hatchery fish to have decreased allelic richness, increased average relatedness, more loci in linkage disequilibrium and substantial levels of genetic drift in comparison with their wild-born counterparts. We also documented a substantial Ryman-Laikre effect whereby the additional hatchery fish doubled the total number of adult fish on the spawning grounds each year, but cut the effective population size of the total population (wild and hatchery fish combined) by nearly two-thirds. We further demonstrate that the Ryman-Laikre effect is most severe in this population when (1) >10% of fish allowed onto spawning grounds are from hatcheries and (2) the hatchery fish have high reproductive success in the wild. These results emphasize the trade-offs that arise when supplementation programs attempt to balance disparate goals (increasing production while maintaining genetic diversity and fitness).

Genetic adaptation to captivity can occur in a single generation

Captive breeding programs are widely used for the conservation and restoration of threatened and endangered species. Nevertheless, captive-born individuals frequently have reduced fitness when reintroduced into the wild. The mechanism for these fitness declines has remained elusive, but hypotheses include environmental effects of captive rearing, inbreeding among close relatives, relaxed natural selection, and unintentional domestication selection (adaptation to captivity). We used a multigenerational pedigree analysis to demonstrate that domestication selection can explain the precipitous decline in fitness observed in hatchery steelhead released into the Hood River in Oregon. After returning from the ocean, wild-born and first-generation hatchery fish were used as broodstock in the hatchery, and their offspring were released into the wild as smolts. First-generation hatchery fish had nearly double the lifetime reproductive success (measured as the number of returning adult offspring) when spawned in captivity compared with wild fish spawned under identical conditions, which is a clear demonstration of adaptation to captivity. We also documented a tradeoff among the wild-born broodstock: Those with the greatest fitness in a captive environment produced offspring that performed the worst in the wild. Specifically, captive-born individuals with five (the median) or more returning siblings (i.e., offspring of successful broodstock) averaged 0.62 returning offspring in the wild, whereas captive-born individuals with less than five siblings averaged 2.05 returning offspring in the wild. These results demonstrate that a single generation in captivity can result in a substantial response to selection on traits that are beneficial in captivity but severely maladaptive in the wild.

Maximizing re-introduction success: Assessing the immediate cost of release in a threatened waterfowl

Translocations have become one of the most commonly used tools for biodiversity restoration worldwide, however one out of three re-introduction plans fails to create a viable population or to successfully reinforce the existing one. We used results from the analysis of individual-based information on the re-introduction of a threatened waterfowl species, the crested coots Fulica cristata, to provide guidelines to maximise re-introduction success. We found that about a third of the post-release mortality took place within the first month after release. This immediate ‘cost of release’ in terms of local survival or ‘release risk factor’ seems to be a common feature of re-introduction projects, and it is likely due to the inexperience of captive-born individuals to face the new environment. This hypothesis was supported by the positive association between survival and time spent in the wild Results suggested that coots released between February and May have a slightly higher survival. A joint measure of survival and breeding probabilities indicated that birds released in late winter (February-March) had a higher chance to survive and reproduce compared to birds released later in the year. From an applied perspective our results can be used within an adaptive management framework to determine the optimum period of release, providing substantial support for future decision-making in the management of waterfowl, and other long-term projects of re-introduction of threatened vertebrate species.

Genetic Variation and Structure in Eurycea nana, a Federally Threatened Salamander Endemic to the San Marcos Springs

The San Marcos salamander (Eurycea nana), endemic to the headwaters of the San Marcos River, is federally threatened because of its restricted range and threats to its habitat. Captive propagation efforts for E. nana were initiated in 1996 to maintain a captive population for restocking in the event that E. nana becomes extinct. We surveyed DNA sequence data for a mitochondrial and a nuclear gene region (ND4 and rag1) and 281 AFLP markers to obtain baseline data on the level of genetic diversity across the known range of E. nana and to test for population subdivision within its restricted range. Next, we compared levels of genetic variation between E. nana in the wild and captive-born individuals from the captive population to assess the efficacy of the captive breeding program. We investigated inbreeding in the captive population by testing for deviations from Hardy-Weinberg equilibrium at the rag1 locus for captive-born individuals. The level of genetic diversity detected in wild E. nana was similar to that of other Eurycea populations in central Texas, and we found no evidence of population structure across the range of E. nana. The surveyed captive-born E. nana contained reduced genetic diversity at some loci, but similar genetic diversity at others relative to the wild, and there was no evidence of inbreeding within the wild-caught individuals that sired these captive-born individuals. The data we have obtained regarding the level of genetic variation in wild E. nana and in the captive population will provide baseline information for this species.

A Visual Health Assessment of Captive Asian Elephants (Elephas maximus) Housed in India

A visual health assessment and survey questionnaire was conducted on 81 Asian elephants (Elephas maximus) housed in 10 animal facilities throughout India between November 2004 and February 2005. The survey questionnaire consisted of 10 questions that evaluated the health of the elephants, and they were completed after visually assessing each individual elephant. The information collected was ranked on a scale that was used to statistically compare the health among the study subjects. This study documented that 43.21% of the captive elephants surveyed exhibited hyperkeratosis. A significant proportion of the elephants owned by tourist camps had poor skin condition when compared with elephants from zoos and at a forest camp. Similarly, captive-born individuals were found to have better skin condition than animals that were caught from the wild. Sixty (74.1%) of the captive elephants that were observed during this study had fissures in their footpads, 20% of which were severe. The prevalence of foot fissures was significantly higher in females. A greater proportion of elephants owned by tourist camps displayed vertical and horizontal toenail cracks in comparison with the forest camp and zoo elephants. It was noted that 76.9% of the wounded animals and 80% of those having abscesses were housed at temples and tourist camps. Also, approximately 8.5% of the captive elephant population observed during this study had eye-related problems, and they were all housed at temples and tourist camps. In conclusion, it was evident that elephants housed at temples or tourist camps exhibited poor skin condition with wounds and abscesses. These findings suggest that the overall condition of the elephants housed at tourist camps was poor compared with elephants housed at zoos and at the forest camp.

Captive Breeding and a Threatened Gecko

In their letter “Scientific description can imperil species” (26 May, p. [1137][1]), B. L. Stuart et al. warn that scientific description can draw attention to newly described species attractive for hobbyists, which could lead to their overexploitation or even extinction. Although this scenario sounds plausible, and taxonomists should keep in mind the conservation impacts of their work, at least one of the three examples given is incorrect. The gecko Goniurosaurus luii from southeastern China was heavily threatened by hunting for pet trade and local medicine purposes and was probably extirpated from its type locality before it was scientifically described. The specimens of G. luii obtained from pet dealers and listed as Goniurosaurus sp. were studied by Japanese molecular phylogenetics before the official description ([1][2]). Lui, the collector of the holotype of G. luii , himself “became aware of the existence of Goniurosaurus luii and G. araneus” from “individuals who specialise in gecko collecting for commercial purposes” ([2][3]). Stuart et al. also claim that immediately after being described in 1999, G. luii reached a breathtaking price of $1500 to $2000 per individual in importing countries. During the last few years, hobbyists perfectly mastered the keeping and breeding of G. luii and closely related G. araneus and established numerous breeding colonies of both species. Recently, hundreds of captive-born juveniles have been available on the world pet market every year for about $40 each, which has two important conservation consequences. First, there is no further demand on the imported, wild-caught animals. Second, as G. luii is a species with limited range still hunted for local medicine trade ([3][4]) and endangered by habitat damage ([2][3]), the captive population will soon outnumber the wild one and can serve as a guarantee that this species will survive at least in captivity with a potential chance for re-introduction. ![Figure][5] A G. luii gecko CREDIT: TONY GAMBLE/UNIVERSITY OF MINNESOTA 1. 1.[↵][6] 1. H. Ota, 2. M. Honda, 3. M. Kobayashi, 4. S. Sengoku, 5. T. Hikida , Zool. Sci. 16, 659 (1999). [OpenUrl][7][CrossRef][8] 2. 2.[↵][9] 1. L. L. Grismer, 2. B. E. Viets, 3. L. J. Boyle , J. Herpetol. 33, 382 (1999). [OpenUrl][10] 3. 3.[↵][11] 1. K. S. Lee, 2. M. W. N. Lau, 3. B. P. L. Chan , “Wild Animal Trade Monitoring in Selected Markets in Guangzhou and Shenzhen, South China 2000–2003” (Kadoorie Farm and Botanic Garden Corporation, Tai Po, Hong Kong SAR, 2004). # Response {#article-title-2} Our letter used three Asian herpetological examples to illustrate the point that publishing scientific descriptions of new species may inadvertently facilitate their overexploitation by advertising “novelties” to hobbyists and providing detailed locality information to commercial collectors. Kratochvil correctly notes that one of our examples, the gecko Goniurosaurus luii , was already being heavily harvested in China for sale in the international pet trade ([1][12], [2][13]) prior to its description as a new species ([1][12]). However, immediately after being described, its value in the U.S. pet trade jumped from approximately $500 under an older name to approximately $1500 under its new name as a result of increased demand from hobbyists seeking a unique addition to their collections (the $2000 quote in our Letter referred to a second reptile example, Chelodina mccordi , provided in the same sentence). Thus, we feel that G. luii remains an appropriate example of how scientifically describing a new species can unintentionally fuel its commercial exploitation ([3][14]). It is fortunate for G. luii that demand for wild-caught individuals has now diminished, owing to the availability of inexpensive, captive-born individuals produced by hobbyists. The conservation merits of unregulated, private, captive breeding programs are beyond the scope of our Letter, but it does seem that G. luii paid a high cost for the end result of inexpensive, captive-born substitutes in the pet trade. 1. 1.[↵][15] 1. L. L. Grismer, 2. B. E. Viets, 3. L. J. Boyle , J. Herpetol. 33, 382 (1999). [OpenUrl][10] 2. 2.[↵][16] 1. H. Ota, 2. M. Honda, 3. M. Kobayashi, 4. S. Sengoku, 5. T. Hikida , Zool. Sci. 16, 659 (1999). [OpenUrl][7][CrossRef][8] 3. 3.[↵][17] 1. L. Guterman , Chron. Higher Educ. 52, A12 For additional plant and animal examples, see (21 July 2006). [1]: /lookup/doi/10.1126/science.312.5777.1137b [2]: #ref-1 [3]: #ref-2 [4]: #ref-3 [5]: pending:yes [6]: #xref-ref-1-1 View reference 1. in text [7]: {openurl}?query=rft.jtitle%253DZool.%2BSci.%26rft.volume%253D16%26rft.spage%253D659%26rft.atitle%253DZOOL%2BSCI%26rft_id%253Dinfo%253Adoi%252F10.2108%252Fzsj.16.659%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [8]: /lookup/external-ref?access_num=10.2108/zsj.16.659&link_type=DOI [9]: #xref-ref-2-1 View reference 2. in text [10]: {openurl}?query=rft.jtitle%253DJ.%2BHerpetol.%26rft.volume%253D33%26rft.spage%253D382%26rft.atitle%253DJ%2BHERPETOL%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [11]: #xref-ref-3-1 View reference 3. in text [12]: #ref-4 [13]: #ref-5 [14]: #ref-6 [15]: #xref-ref-4-1 View reference 1. in text [16]: #xref-ref-5-1 View reference 2. in text [17]: #xref-ref-6-1 View reference 3. in text

A behavioral comparison of captive-born, reintroduced golden lion tamarins and their wild-born offspring

[The behavioral development of reintroduced, captive-born animals and their wild-born offspring is understudied, limiting the scientific understanding and, therefore, utility of reintroduction as a conservation tool. Several reintroduction programs have shown that survival rates of captive-born animals are lower than those of their wild-born offspring. However, whether these differences are because of increased behavioral competency of wild-born animals or age-related factors is unknown. This study compared behavior of captive-born golden lion tamarins to that of their age-matched first- and second-generation descendents. Subjects included 134 golden lion tamarins living in and around the Poco das Antas Biological Reserve in Brazil. Overall, captive-born animals were deficient in locomotor and foraging skills as compared with their wild-born offspring, and some of these deficiencies persisted after two years in the wild. Locomotor and foraging differences were also observed between generations of wild-born animals, suggesting that behavioral change continued past the first generation. Recommendations for future reintroductions with this and other species include: (1) increased exposure to complex environments prior to release; (2) intensive post-release support; (3) introduction of naive animals with experienced conspecifics when possible; (4) comparisons of reintroduced and wild populations when possible; and (5) short-term management plans aimed at the survival of captive-born individuals combined with long-term plans focused on maximizing natural adaptive processes., The behavioral development of reintroduced, captive-born animals and their wild-born offspring is understudied, limiting the scientific understanding and, therefore, utility of reintroduction as a conservation tool. Several reintroduction programs have shown that survival rates of captive-born animals are lower than those of their wild-born offspring. However, whether these differences are because of increased behavioral competency of wild-born animals or age-related factors is unknown. This study compared behavior of captive-born golden lion tamarins to that of their age-matched first- and second-generation descendents. Subjects included 134 golden lion tamarins living in and around the Poco das Antas Biological Reserve in Brazil. Overall, captive-born animals were deficient in locomotor and foraging skills as compared with their wild-born offspring, and some of these deficiencies persisted after two years in the wild. Locomotor and foraging differences were also observed between generations of wild-born animals, suggesting that behavioral change continued past the first generation. Recommendations for future reintroductions with this and other species include: (1) increased exposure to complex environments prior to release; (2) intensive post-release support; (3) introduction of naive animals with experienced conspecifics when possible; (4) comparisons of reintroduced and wild populations when possible; and (5) short-term management plans aimed at the survival of captive-born individuals combined with long-term plans focused on maximizing natural adaptive processes.]

Saving the gorillas (Gorilla g. gorilla) and chimpanzees (Pan t. troglodytes) of the Congo Basin.

The forests of the Congo Basin in equatorial Africa are home to significant populations of gorillas and chimpanzees. However, numbers are declining owing to hunting and to alteration of their habitat. Gorillas and chimpanzees are particularly vulnerable for biological reasons: slow reproduction, prolonged developmental periods and complex social behaviour. In addition, their capacity to recover from disturbance is limited and the reinforcement of wild populations with captive-born individuals is rarely an option. Compared with the critically endangered mountain gorillas and the beleaguered chimpanzees in forest fragments in West Africa, there are some reasons for optimism about the future of the Congo Basin apes: levels of threat remain relatively low; and conservation of tropical rainforests has become a priority of the international community. At the same time, knowledge of the ecological needs of wild apes has increased and non-invasive techniques now exist to monitor population health. Sadly, no animals remain truly 'wild', as their survival depends to a greater or lesser extent on management. Protected areas and laws that forbid hunting of vulnerable species are classic tools of management, but broader landscape visions are now emerging that may allow the Congo Basin to avoid the fragile scenario of larger animals persisting only in 'island' parks.

Responses of Cotton-Top Tamarins (Saguinus Oedipus) to Faecal Scents of Predators and Non-Predators

AbstractThe responses of 56 cotton-top tamarin monkeys (Saguinus oedipus) to the faecal scent of predators and non-predators were recorded to determine if there was a differential response. Methylene chloride extracts were prepared from the faeces of suspected predators (margay and tayra) and non-predators (capybara and paca) known to co-exist with the tamarins in the wild The faecal extracts were presented to the tamarins on wooden dowels in their enclosures. Untreated dowel and dowel treated with methylene chloride served as controls. The tamarins exhibited high anxiety responses to predator scent compared to non-predator scent which produced low anxiety responses. No sex differences were found but an age difference was apparent: younger individuals were more curious than their elders. The response pattern was observed in captive-born individuals and was not affected by whether or not their parents were wild-caught or captive-born. This indicates that the discrimination of predator and non-predator scents is innate. However, this should not be taken to mean that captive cotton-top tamarins should be re-introduced to the wild without prior predator avoidance training. The implication of this study for animal welfare is that in captive environments where both predator and prey species are kept, it is important that predators, and their faeces, are not situated where prey species can detect their presence through olfaction, because prey species may suffer continual levels of heightened anxiety with possible detrimental effects.

Responses by Red-Bellied Tamarins (Saguinus labiatus) to Fecal Scents of Predatory and Non-predatory Neotropical Mammals

Adult and subadult red-bellied tamarins (Saguinus labiatus) were tested for responses to the odors of predatory and non-predatory neotropical mammals. Methylene chloride extracts of the feces of the jaguar (Panthera onca), margay (Fel/s wiedi), jaguarundi (Herpailurus yagouaroundi), tapir (Tapirus terrestris), paca (Cuniculus paca), and agouti (Dasyprocta fuliginosa) were presented to tamarins on wooden dowels in their enclosures. Untreated dowels and dowels treated with methylene chloride served as controls. Chemicals from predators elicited more sniffing and avoidance than did those of the non-predators or controls. The tamarins gave alarm calls to margay scent, a response not observed with the other extracts. The responses to predator chemicals were exhibited by captive-born individuals, suggesting that experience with a predator is not necessary for tamarins to distinguish between the fecal scents of predatory and non-predatory species. TAMARINS AND MARMOSETS (PRIMATES: CALLITRICHIDAE) are preyed upon by neotropical birds, snakes, and mammals (e.g., Moynihan 1976, Terborgh 1983, Goldizen 1986, Emmons 1987). These primates display a number of behavior patterns thought to have antipredator functions. For example, at least three different alarm calls, given in response to stuffed owls, unfamiliar humans, and objects moved overhead, have been identified in captive saddleback tamarins (Saguinus fuscicollis) (Moody & Menzel 1976). Similarly, the cotton-top tamarin (S. oedipus) emits different alarm calls to aerial and terrestrial predators (Neyman 1977). The Panamanian tamarin (S. oedipusgeoffroyi) becomes quiet and vigilant prior to retirement each evening (Dawson 1979), a response that may, in part, reduce vulnerability to nocturnal and crepuscular predators. The golden lion tamarin (Leontopithecus rosalia) may sleep in tree holes to avoid predators (Coimbra-Filho 1977). Responses to predators by captive red-bellied tamarins (S. labiatus) include alarm calls, mobbing, and visual watchfulness (Coates & Poole 1983; Caine 1984, 1986, 1987). This arboreal species lives in the forests of Brazil, Peru, and Bolivia and eats primarily fruit, insects, and some vegetable matter (Hershkovitz 1977). Red-bellied tamarins, like all tamarins, live in groups consisting of two or more breeding adults (300-575 g) and one or more generations of offspring. Monogamy probably is not obligatory (cf. Garber et al. 1984), but cooperation among group members in infant care, territory maintenance, and predator defense suggests long-term relationships and kin selected behavior. We report here responses by red-bellied tamarins to chemicals from South American mammals. Our tests indicate that S. labiatus distinguishes between the odors of some predatory and non-predatory mammals, and the data suggest that this callitrichid exhibits chemically elicited defenses to such odors. To our knowledge, this is the first demonstration of reactions to predator chemicals by a nonhuman primate.

Dental eruption in captive-bornCebus apella: From birth to 30 months old

This work reports on the ages of gingival eruption of deciduous and permanent teeth observed from the time of birth until 30 months old, captive-born individuals. All of the animals were born with the protrusive di1 already through the gingival border. The dmp4 were the last teeth of the deciduous series which emerged at 24.5±3.11 weeks in the males and 27.8±2.95 weeks in the females. Significant sexual differences were found between the eruption period of the dpm2, dmp4 (p<0.05), and dpm4 (p<0.01), with the males being more precocious than the females. The first permanent tooth that emerged, usually, was the M1 at 13.50±2.12 months in the males, and 14.00±0.82 months in the females. At 30 months of age, not one individual had replaced his deciduous canine or premolar teeth with the permanent ones, and, moreover, the M 3 3 had not yet emerged.