Captive Stock Research Articles

Captive stock management of the critically endangered Mekong giant catfish, Pangasianodon gigas in Thailand

Captive stock management of the critically endangered Mekong giant catfish, Pangasianodon gigas in Thailand

Mitochondrial DNA Variation in the Endangered Colorado Pikeminnow: A Comparison among Hatchery Stocks and Historic Specimens

AbstractThe Colorado pikeminnow Ptychocheilus lucius is a federally endangered species restricted to the Colorado River. Dexter National Fish Hatchery and Technology Center, Dexter, New Mexico, maintains three separate captive stocks of the Colorado pikeminnow: 1974YC (Yampa River), 1981YC (Green–Colorado rivers), and 1991YC (Colorado River). We surveyed mitochondrial DNA diversity in these three stocks (879 base pairs [bp]; ND‐4L and ND‐4 genes; N = 30) and in museum specimens collected from 1890 to 1976 (450 bp; ND‐4; N = 11). All individuals had the same haplotype except for a 1‐bp variant detected in 2 of the 12 fish from 1981YC. The low variation is postulated to be the result of a post‐Pleistocene bottleneck in the wild and small sizes of the hatchery founder populations.

Using historical captive stocks in conservation. The case of␣the␣lesser white-fronted goose

Many captive stocks of economically or otherwise valuable species were established before the decline of the wild population. These stocks are potentially valuable sources of genetic variability, but their taxonomic identity and actual value is often uncertain. We studied the genetics of captive stocks of the threatened lesser white-fronted goose Anser erythropus maintained in Sweden and elsewhere in Europe. Analyses of mtDNA and nuclear microsatellite markers revealed that 36% of the individuals had a hybrid ancestry. Because the parental species are closely related it is unlikely that our analyses detected all hybrid individuals in the material. Because no ancestral polymorphism or introgression was observed in samples of wild populations, it is likely that the observed hybridisation has occurred in captivity. As a consequence of founder effect, drift and hybridisation, captive stocks were genetically differentiated from the wild populations of the lesser white-fronted goose. The high level of genetic diversity in the captive stocks is explained at least partially by hybridisation. The present captive stocks of the lesser white-fronted goose are considered unsuitable for further reintroduction, or supplementation: hybridisation has involved three species, the number of hybrids is high, and all the investigated captive stocks are similarly affected. The results highlight the potential shortcomings of using captive-bred individuals in supplementation and reintroduction projects, when the captive stocks have not been pedigreed and bred according to conservation principles.

EFFECTS OF SEASON, TEMPERATURE CONTROL, BROODSTOCK CONDITIONING PERIOD AND HANDLING ON INCIDENCE OF CONTROLLED AND UNCONTROLLED SPAWNING OF GREENLIP ABALONE (HALIOTIS LAEVIGATA DONOVAN) IN WESTERN AUSTRALIA

Abstract Managing the broodstock conditioning process is important to the successful establishment of an abalone industry that can reliably produce juveniles from captive stock and pursue selective breeding. Four conditioning periods of 6, 8, 10 and 12 wk intervals were tested with captive greenlip abalone (Haliotis laevigata), using a constant conditioning temperature and ambient temperature as a control. The conditioning periods of 6, 8, 10 and 12 wks are equivalent to ~420, 560, 700 and 840 EAT (effective accumulative temperature), based on a biological zero point (BZP) of 6.9°C for gonad development. Greenlip abalone broodstock collected from the wild (87.5–142.1 mm in shell length and 108.2–482.8 g in whole weight) were spawned in all seasons including numerous induced spawnings outside of the normal breeding period with conditioned stock. Over the whole trial period, greater egg production from prescheduled spawnings occurred in the conditioned group with an average of 1.70 × 106 eggs per tub of 5 f...

Ecology of the Rio Grande Silvery Minnow (Cyprinidae: Hybognathus amarus) Inferred from Specimens Collected in 1874

The Rio Grande silvery minnow (Hybognathus amarus) was historically an abundant and widespread species in the Rio Grande Basin. Its decline to endangered status had many probable causes and has spanned more than a century. Specimens of H. amarus collected in July 1874 at San Ildefonso, near Santa Fe, New Mexico, allowed a retrospective assessment of the ecology and morphology of the species and the environmental conditions of the Rio Grande in areas foraged by these minnows. Analysis of diatoms from the gut showed that H. amarus foraged mainly in nutrient-enriched areas on mud substrates in 1874 and to lesser extents on periphyton associated with plant, sand, and rock substrates. Gut contents included a considerable amount of fine-grained sediment and a wide variety of organic materials including detritus, pine pollen, cyanobacteria, algae, and diatoms. Scale annuli showed that H. amarus was once a relatively long-lived minnow; all age classes from 1 to 5 were present in 1874. The presence of multiple individuals of several ages suggested that annual survival rates were high historically and that the species may be iteroparous, rather than short-lived and semelparous as widely held. The morphology of H. amarus from a captive stock in 2003 was consistent with the morphology of the 1874 specimens.

Urgent call for further breeding of the relic zoo population of the critically endangered Barbary lion (Panthera leo leo Linnaeus 1758)

The Barbary lion became extinct in the wild around 1942. Since the end of the 19th century, a last purebred captive breeding stock existed at the court of Morocco. The rest of these animals became the core exhibition of the new Rabat Zoo after passing through repeated bottlenecks and possibly some introgression events by foreign lions. This study uses mitochondrial DNA sequencing data to clarify the relationship among these lions and their sub-Saharan and Asian relatives. We analysed mitochondrial cytochrome b sequences obtained from a sample from a Barbary lion descended from a young female of the Barbary lion breeding group at the Rabat Zoo and various other members of the genus Panthera. In our cytochrome-b-based phylogenetic tree, the North African Barbary lion, represented by a biopsy sample from the Neuwied Zoo, joins the Asian lion clade, although it is slightly different from its Asian sister group. However, it is clearly distinct from sub-Saharan lions and can be considered as a genetically defined phylogeographic group of its own. Molecular dating of the extant sub-Saharan and Asian lion groups shows that the split between North African Barbary lions and Asian lions must be considerably more recent than 74–203 kilo years ago.

Microsatellite-based genetic variability and differentiation of domesticated, wild and feral common carp ( Cyprinus carpio L.) populations

In the past, the genetics of common carp populations has mainly been studied on regional levels using traditional protein markers. We analysed four microsatellite loci of 577 individuals from 22 domesticated, wild and feral populations spanning a geographical area as wide as from Europe through Central Asia to East and South-East Asia. The variability of these loci was much higher than that of the allozyme loci examined in our previous studies. A total number of 143 alleles were recorded across loci ranging from 27 at MFW28 to 47 at MFW7. However, the mean number of alleles per locus was remarkably lower: from 2.50 in a captive stock of River Amur wild carp to 14.25 in a wild population from Lake Arnasaiskie, Uzbekistan, and domesticated Chinese carp from Wuhan. The variability of populations did not show a clear geographical pattern but a highly significant difference was found in allelic richness between the 13 domesticated/captive stocks (average A r = 4.436) and the nine wild−caught populations (average A r = 8.221). The prevalence of different alleles in different populations resulted in a high degree of population differentiation: the F ST values for all but four pairwise comparisons of Central Asian wild populations were significant. Within geographical regions the D A distances between populations were smallest in Central Asia (average D A = 0.139), intermediate in Europe (average D A = 0.434) and largest in East/South-East Asia (average D A = 0.833). Between geographical regions the European and Central Asian populations showed the smallest distances (average D A = 0.484) whereas the distances of these two regions and East/South-East Asia were almost identical but substantially larger (Europe vs. East/South-East Asia: average D A = 0.801, and Central Asia vs. East/South-East Asia: average D A = 0.806). All populations clustered into only two highly divergent major groups with 91% bootstrap support: Europe/Central Asia and East/South-East Asia. Thus, the microsatellite data also suggest an ancient separation of European/Central Asian from East/South-East Asian carp and a single origin of European carp in Central Asia as already inferred from our previous allozyme and mtDNA RFLP studies. The taxonomic status of subspecies assigned to European ( C. c. carpio) and East Asian carp ( C. c. haematopterus) is supported. However, because of their close relationship to European carp the Central Asian carp do not deserve a separate subspecies status ( C. c. aralensis).

Monitoring the genetic diversity of three Asian arowana ( Scleropages formosus) captive stocks using AFLP and microsatellites

Asian arowana ( Scleropages formosus) is listed by CITES as a highly endangered fish species. The genetic diversity and population structure of three Asian arowana captive stocks was analyzed using microsatellites and AFLP markers on 32 randomly collected individuals from each stock. Six AFLP primer pairs amplified a total of 324 bands across the three sample sets. The green stock showed the highest percentage of polymorphic bands (15.6%) and expected heterozygosity (0.26), followed by the red (13.0% and 0.24), then the golden one (12.7% and 0.22). Microsatellite analysis showed high allelic and gene diversity in all three varieties. The green stock showed higher allele number (100) and higher gene diversity (0.75) than the red (98 and 0.74) and golden ones (85 and 0.71), respectively. The estimates of long-term effective population size by two different methods ranged from 4741 to 7288 and from 25,056 to 64,641, respectively. Tests of heterozygosity and allele frequency distribution indicate that a recent bottleneck in any of the three captive populations is highly unlikely. Altogether, the data suggest that the captive breeding program for conservation and sustainable use of the endangered Asian arowana will be successful. In addition, we found that the differentiation among populations was intermediate ( F ST=0.047, R ST=0.103) and the genetic distance was the smallest between the green and red, whereas the largest between the red and golden varieties.

Genetic monitoring of the Amazonian fish matrincha (Brycon cephalus) using RAPD markers: insights into supportive breeding and conservation programmes

Summary The importance of genetic evaluations in aquaculture programmes has been increased significantly not only to improve effectiveness of hatchery production but also to maintain genetic diversity. In the present study, wild and captive populations of a commercially important neotropical freshwater fish, Brycon cephalus (Amazonian matrincha), were analyzed in order to evaluate the levels of genetic diversity in a breeding programme at a Brazilian research institute of tropical fish. Random Amplified Polymorphic DNA fingerprinting was used to access the genetic variability of a wild stock from the Amazon River and of three captive stocks that correspond to consecutive generations from the fishery culture. Although farmed stocks showed considerably lower genetic variation than the wild population, a significantly higher level of polymorphism was detected in the third hatchery generation. The results seem to reflect a common breeding practice on several hatchery fish programmes that use a small number of parents as broodstocks, obtaining reproductive success with few non-identified mating couples. The obtained data were useful for discussing suitable strategies for the genetic management and biodiversity conservation of this species.

New observations of the ‘extinct’ Barbary sheep Ammotragus lervia ornata in Egypt

The Barbary sheep or aoudad Ammotragus lervia is widely distributed in the mountains of the Sahara and North Africa. The 2000 IUCN Red List assessment of the Egyptian subspecies A. l. ornata categorized this taxon as Extinct in the Wild. We present new evidence, collected during 1997–2000, that this subspecies is extant in both the extreme south-east and south-west of Egypt, and reassess the status of captive aoudad in Egypt. We recommend that the category of A. l. ornata on the IUCN Red List be changed to Critically Endangered, that conservation of wild aoudad in Egypt be prioritized, and that the subspecific status of both the wild and captive stocks in Egypt be reassessed.

The histology of mature gonads of Oreochromis (Nyasalapia) karongae (Trewavas)

AbstractHistology of gonads of Oreochromis karongae was undertaken to study internal cell characteristics during maturation. This study was necessitated by low spawning output of the fish species. Several oocyte stages, ranging from primary forms to vitellogenesis, suggest that the maturation was generally succesfully attained in the fish ponds. Pre‐vitellogenesis oocytes (oogonia to perinuclear stage) and more advanced vitellogenesis (primary vesicle to tertiary yolk vesicle) oocyte stages were all found in the same gonads. However, there were some discontinuities observed during stages 3 and 4, suggesting selective maturation. Failure of gonads to mature normally is attributed to an ecological crunch that was in a previous study associated with environmental factors. Atretic oocytes were also recorded in the same gonads, a sign that some oocytes failed to mature normally. This indicates insufficient stimuli for normal gonad development. Several stages of spermatogenesis (spermatocytes, spermatid and spermatozoa) were also found in the same gonads. Selective recrudescence was more pronounced in O. karongae because generally less oocytes attained final maturation stages compared to Oreochromis niloticus and other tilapias. This could be the main reason for low natural breeding that has been observed in both wild and captive stocks, and led to the abandonment of its use in aquaculture. This study corroborates findings of previous studies that depended solely on external gonad characteristics. Histology provides conclusive evidence from internal cell characteristics that other techniques are unable to show.

An analytical investigation of the dynamics of inbreeding in multi-generation supportive breeding

Supportive breeding is being increasingly usedas a measure to reduce the short-termprobability of extinction of populations withhighly reduced abundance relative to historicallevels. In this paper, we provide a conceptualframework and analytical tools to computechanges in inbreeding coefficient (F) in thecase of supportive breeding over any number ofgenerations. The dynamics of inbreedingcoefficients were investigated by means of asystem of recurrence equations. We focussed onquantifying the dynamics of F for specificcombinations of parameter values in terms ofthe effects of captive population census size,refreshment rate of breeders in captivity,scale of supplementation program, and migrationrate. We observed that supplementation did notalways result in substantial inbreedingincrement and several conditions loweredoverall inbreeding relative to controlsituations without supplementation. The censussize of captive populations was the single mostimportant controllable parameter determiningthe genetic consequences of supportivebreeding. While the proportion of captivebreeders brought into captivity from the wildbore a complex relationship to inbreedingcoefficient dynamics, the results indicatedthat managers should generally aim at highrefreshment rates (that is, large proportionsof their captive stock originating from thewild). This is especially important when asmall captive population is expected tocontribute large numbers of breeders to thesupplemented population. The analysis alsoshowed how supplemented populations connectedto a large metapopulation through gene flowrecover from the genetic risks of inbreedingdue to supportive breeding program more quicklythan isolated populations. The results of thisstudy join those of an increasing number ofinvestigations showing that supportive breedingdoes not always increase inbreeding, and mayeven decrease it in several circumstances.However, supportive breeding systems arecomplex, and results such as presented hereshould not be used in isolation, but inconsideration of other issues such as theconsequences on long-term fitness of wildindividuals.

Breeding of captive python at Kota Zoo, Rajasthan

496 Among snakes, the Indian python (Python molurus) appears to have bred for the first time at Jaipur Zoo as reported in 1965. Since then many zoos have bred this species (Acharjyo, 1998). The first attempt was made in 1974 at Nandankanan Biological Park, Orissa by Dr. L.N. Acharjyo to record the reproduction and growth rate of Indian Python in captivity. The study was further extended up to 1978 and duly reported by him (Acharjyo, 1980). Successful breeding of captive stock depends on the age, health, living conditions and adequacy of food supply.

Molecular characterization of native (Italy) and introduced (USA) Podarcis sicula populations (Reptilia, Lacertidae)

The wall lizard Podarcis sicula has been introduced in many locations outside its native range. Partial sequences from the 12S rDNA, that had proved diagnostic for the three main subspecies, were used to test specimens from marginal native and from intro duced American populations. The mitochondrial haplotype of a specimen from Apulia, traditionally ascribed to P. s. campestris, belongs to the P. s. sicula gene‐pool. Specimens from a P. s. sicu la ‐ P. s. campestris boundary area (southern Latium), with transi tional morphology but P. s. sicula‐like ecology, show mitochondrial haplotypes clearly of the campestris type. The mitochondrial hap‐lotypes of the American specimens (from Kansas and New York), that originated from captive stocks, were included in a P. s. campestris clade. A definitive assessment of the status of both na tive and introduced populations will require the use of nuclear markers.

Mitochondrial DNA Variation in Pupfishes Assigned to the SpeciesCyprinodon macularius(Atherinomorpha: Cyprinodontidae): Taxonomic Implications and Conservation Genetics

Abstract Variation in mitochondrial DNA (mtDNA) was assessed in a captive stock and 11 wild populations (n = 259) from throughout the native range of Desert Pupfish Cyprinodon macularius as traditionally understood. Using PCR-SSCP, 18 composite haplotypes were identified from a 333-bp segment of the mitochondrial D-loop and two segments of the ND2 gene (333 and 325 bp). Representatives of each haplotype were sequenced for the entire ND2 gene and the 337-bp segment of the D-loop. Phylogenetic analyses revealed that haplotypes form two monophyletic groups, one in the Rio Sonoyta/Quitobaquito Springs area and one in the Salton Sea/Colorado River Delta. This, with previous observations on morphology, color pattern, and geological history, supports recognition of the Rio Sonoyta/Quitobaquito populations as a separate species, the Quitobaquito Pupfish C. eremus Miller and Fuiman, from the more widespread desert pupfish C. macularius Baird and Girard. More than 70% of mtDNA diversity across all populations was a...

Breeding biology of captive, reintroduced and wild greater bilbies, Macrotis lagotis (Marsupialia : Peramelidae)

The breeding biology and growth of Macrotis lagotis was investigated using captive stock in Alice Springs and Dubbo and a reintroduced population at Watarrka National Park. Individuals of M. lagotis reached sexual maturity at about six months of age and continued growing until about 18 months old. Pouch life and weaning took approximately 90 days and females produced up to four litters per year. Litters comprised 1–3 young. Average litter size at pouch exit ranged from 1.0 to 1.88, depending on whether animals were studied in captivity or under reintroduced free-range conditions. Females commonly continued breeding past the age of four years and longevity extended to 10 years in captivity. In comparison, the most animals caught in the wild were estimated to be less than 12 months old. Animals in the reintroduced population exhibited a greater reproductive output than the captive populations examined. However, survivorship was far greater for animals in captivity. An intensively managed captive population may achieve a three-fold increase in size in a 12-month period.

Genetic improvement of marronCherax tenuimanusSmith and yabbiesCheraxspp. in Western Australia

Marron and yabbies are farmed commercially in Western Australia and are native and introduced species respectively. Genetic improvement of farmed stock for aquaculture can be achieved by choosing particular strains, by selective breeding or by producing hybrids of different strains. Studies into the taxonomy and growth of both marron and yabbies have shown variation between geographically isolated populations. This variation may offer potential for selecting strains that demonstrate desirable traits for aquaculture, such as improved growth rates. In addition to selection of wild strains that demonstrate desirable traits for aquaculture, further advances in production may be achieved by selection of characteristics in captive stock that are heritable. In marron, moderate proportions of the phenotypic variation in growth rate, tail and chelae size have been shown to be heritable (h2 = 0.3–0.6). Recent research into yabby genetics involved assessing growth and reproductive characteristics of geographically isolated populations of yabbies inhabiting a range of ecotypes throughout Australia. Growth rates and size at sexual maturity varied among populations. However, there was no significant difference in the sex ratio between these geographically isolated groups. The main focus of the yabby genetics research has been to develop a method to prevent or reduce reproduction of yabbies. Uncontrolled reproduction in this species results in high densities and smaller animals because growth is density dependent. Preventing reproduction and thereby controlling densities in yabby ponds or dams can be achieved by stocking monosex populations. The stocking of monosex populations results in an estimated 70% increase in gross income. Hybidization of yabby populations was investigated as a method of controlling reproduction. Sterile hybrids were produced by crossing yabbies from geographically isolated populations. These experiments have also revealed a hybrid cross that consistently produces only male progeny. If this all-male hybrid strain performs as well as all-male monosex pond stock, achieved by manual sexing, the production of large, and therefore higher value, yabbies will be increased in the commercial aquaculture industry.

Goose hybrids, captive breeding and restocking of the Fennoscandian populations of the Lesser White-fronted goose (Anser erythropus)

The lesser white-fronted goose (Anser erythropus) isthe most threatened of the Palearctic goose species with a decliningpopulation trend throughout its distributional range. The currentestimate of the Fennoscandian subpopulation size is 30–50 breedingpairs, whereas it still numbered more than 10000 individuals at thebeginning of the last century. Reintroduction and restocking have beencarried out in Sweden and Finland using captive lesser white-frontedgoose stock with unknown origins. We have carried out a study of thegenetic composition of captive-bred stock by sequencing a 221 bphypervariable fragment of the mitochondrial DNA (mtDNA) control regionfrom 15 individuals from the Hailuoto farm, Finland. Two out of thethree maternal lineages detected in the captive stock are also presentin wild populations. The third maternal lineage among the captive lesserwhite-fronted geese originates from the closely related greaterwhite-fronted goose (Anser albifrons). None of the investigatedwild lesser white-fronted goose individuals carried the mtDNA of thegreater white-fronted goose. The presence of greater white-fronted goosemtDNA in the lesser white-fronted goose captive stock suggests thathybridization has occurred during captive propagation.

Reintroduction of guans of the genus Penelope (Cracidae, Aves) in reforested areas in Brazil: assessment by DNA fingerprinting

We used DNA fingerprinting in order to assess `a posteriori' the outcome of a captive breeding and reintroduction program of guans Penelope obscura bronzina and P. superciliaris jacupemba. The reintroductions started after the reforestation of part of the area that was damaged during the construction of a hydroelectric power dam in São Paulo, Brazil, in a region belonging to the Atlantic Forest. Our results showed that the free-living populations that became established in the reforested areas were related to the birds of the captive breeding and reintroduction programs. The segregation pattern of paternal and maternal DNA fragments of a captive family show that at least nine independent loci were detected by each of the human minisatellite multilocus probes used in the present work (33.6 and 33.15). Even though we detected a reduction in the genetic variability of these free-living populations compared to that of the captive stocks as a consequence of their small number of founders, the birds of both species have been breeding adequately in the reforested areas.

Genetic diversity, phylogenetic relationships and conservation of Edwards's Pheasant Lophura edwardsi

SummaryAn historical study shows that the present day ex situ population of Edwards's Pheasant Lophura edwardsi, now numbering over 1,000 living specimens, originated in the 1920s from at least six different sources and c. 30 potential founders, including more males than females. Partial sequences, 820 nucleotides long, of the mitochondrial DNA (mtDNA) control-region were obtained in representatives of about half of 21 captive-reared bloodlines, identified from data in the revised International Studbook. All captive-reared birds had identical sequences. Sequences of mtDNA obtained from museum skins and samples of birds collected in the wild were slightly different from that representing the captivereared birds. The lack of mtDNA variability in the captive stock is probably due to the small number of founding females and genetic drift during c. 30 generations of captive breeding. Estimation of true extent of mtDNA sequence variability in historical and living wild Edwards's Pheasants awaits the procurement and analysis of more specimens. At least one bloodline of captive Edwards's Pheasant is polluted with exogenous genes resulting from past hybridization with Swinhoe's Pheasant L. sivinhoii. Edwards's Pheasant is more closely related to Vietnamese Pheasant L. hatinhensis and Imperial Pheasant L. imperialis than to several other taxa regarded as full species in the genus Lophura. However it is not yet possible to determine the extent of their evolutionary divergence and of their proper taxonomic rank. The initial results of this genetic research suggest that there should be efforts to (1) expand field sampling and genetic analyses of wild populations of Lophura species, (2) purge the captive stock of Edwards' Pheasant of all hybrids, (3) apply microsatellite analyses to estimate the level of genetic diversity in nuclear DNA.