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Captive Breeding (captive + breeding)
Selected AbstractsManagement and Recovery Options for Ural River Beluga SturgeonCONSERVATION BIOLOGY, Issue 3 2010PHAEDRA DOUKAKIS caviar; CITES; criadero; Mar Caspio; puntos de referencia; sobrepesca Abstract:,Management of declining fisheries of anadromous species sometimes relies heavily on supplementation of populations with captive breeding, despite evidence that captive breeding can have negative consequences and may not address the root cause of decline. The beluga sturgeon (Huso huso), a species threatened by the market for black caviar and reductions in habitat quality, is managed through harvest control and hatchery supplementation, with an emphasis on the latter. We used yield per recruit and elasticity analyses to evaluate the population status and current levels of fishing and to identify the life-history stages that are the best targets for conservation of beluga of the Ural River. Harvest rates in recent years were four to five times higher than rates that would sustain population abundance. Sustainable rates of fishing mortality are similar to those for other long-lived marine species such as sharks and mammals. Yield per recruit, which is maximized if fish are first harvested at age 31 years, would be greatly enhanced by raising minimum size limits or reducing illegal take of subadults. Improving the survival of subadult and adult females would increase population productivity by 10 times that achieved by improving fecundity and survival from egg to age 1 year (i.e., hatchery supplementation). These results suggest that reducing mortality of subadults and adult wild fish is a more effective conservation strategy than hatchery supplementation. Because genetics is not factored into hatchery management practices, supplementation may even reduce the viability of the beluga sturgeon. Resumen:,El manejo de pesquerías de peces anádromos en declinación a veces depende estrechamente de la suplementación de poblaciones mediante la reproducción en cautiverio, no obstante la evidencia de que la reproducción en cautiverio puede tener consecuencias negativas y no abordar la causa principal de la declinación. El esturión beluga (Huso huso), una especie amenazada por el mercado de caviar negro y por reducciones en la calidad del hábitat, es manejado mediante el control de la cosecha y suplementación de poblaciones, con énfasis en esta. Utilizamos análisis de producción por recluta y de elasticidad para evaluar el estatus de la población y los niveles de pesca actuales y para identificar las etapas de la historia de vida que son los mejores blancos para la conservación del beluga en el Río Ural. Las tasas de cosecha en años recientes fueron cuatro a cinco veces mayores que las tasas que sustentarían la abundancia de la población. Las tasas sustentables de mortalidad por pesca son similares a las de otras especies marinas longevas como tiburones y mamíferos. La producción por recluta, que es maximizada si los peces son cosechados a la edad de 31 años, podría incrementar significativamente elevando los límites de talla mínima o reduciendo la captura ilegal de subadultos. La mejora de la supervivencia de hembras subadultas y adultas incrementaría la productividad de la población 10 veces más que la mejora obtenida incrementando la fecundidad y supervivencia de huevo a 1 año de edad (i. e., suplementación de poblaciones mediante reproducción en cautiverio). Estos resultados sugieren que la reducción de la mortalidad de peces silvestres subadultos y adultos es una mejor estrategia de conservación que la suplementación. Debido a que la genética no es considerada en las prácticas de manejo en los criaderos, la suplementación incluso puede reducir la viabilidad del esturión beluga. [source] Phylogenetic Reanalysis of the Saudi Gazelle and Its Implications for ConservationCONSERVATION BIOLOGY, Issue 4 2001Robert L. Hammond The Saudi gazelle ( Gazella saudiya) was endemic to the Arabian peninsula but is now considered extinct in the wild and is potentially a candidate for captive breeding and reintroduction. Using 375 base pairs of mitochondrial DNA (mtDNA) cytochrome b gene derived from museum samples collected from the wild prior to the presumed extinction of this species, we show that G. saudiya is the sister taxon of the African dorcas gazelle ( G. dorcas). Reciprocal monophyly of G. saudiya mtDNA haplotypes with G. dorcas, coupled with morphological distinctiveness, suggests that it is an evolutionarily significant unit. These data indicate that captive populations identified previously as potential sources of G. saudiya for captive breeding appear incorrectly designated and are irrelevant to the conservation of G. saudiya. The polymerase chain reaction,restriction fragment length polymorphism ( PCR-RFLP) analysis of several private collections of living gazelles in Saudi Arabia provides no evidence for the survival of G. saudiya. We recommend that field surveys be undertaken to establish whether G. saudiya is indeed extinct in the wild and that other private collections within the Arabian peninsula be screened genetically. We urge caution when captive animals of unknown provenance are used to investigate the phylogenetics of cryptic species groups. Resumen: La identificación de poblaciones taxonómicamente apropiadas de especies en peligro para programas de reproducción en cautiverio y de reintroducción es fundamental para su éxito. La Gacela Saudi (Gazella saudiya) fue endémica a la península de Arabia pero ahora está considerada como extinta en su medio y es un candidato potencial para reproducción en cautiverio y reintroducción. Utilizando 375 pares de bases de ADN mitocondrial (ADNmt) del gene citocromo b derivados de muestras de museos colectadas en el medio silvestre antes de la extinción de la especie, mostramos que G. saudiya es el taxón hermano de la gacela dorcas africana (G. dorcas). La monofilia recíproca de haplotipos de ADNmt de G. saudiya con G. dorcas, aunado a diferencias morfológicas, sugiere que es una unidad evolutiva significativa. Estos datos indican que las poblaciones cautivas identificadas previamente como fuente potencial de G. saudiya para reproducción en cautiverio están incorrectamente identificadas y son irrelevantes para la conservación de G. saudiya. El análisis PCR-RFLP de varias colecciones privadas de gacelas vivas en Arabia Saudita no proporcionan evidencia para la supervivencia de G. saudiya. Recomendamos que se realicen muestreos en el campo para establecer si en efecto G. saudiya está extinta en su hábitat y que se examinen genéticamente las otras colecciones privadas en la península Arábiga. Recomendamos precaución cuando animales cautivos de origen desconocido son utilizados para investigar la filogenia de grupos de especies crípticas. [source] Demography of the California Condor: Implications for ReestablishmentCONSERVATION BIOLOGY, Issue 4 2000Vicky J. Meretsky The most prominent mortality factor was lead poisoning resulting from ingestion of bullet fragments in carcasses. Successful captive breeding has allowed many birds to be released to the wild since 1992, based originally on an assumption that exposure to lead could be prevented by food subsidy. The mortality of released birds, however, has generally exceeded levels needed for population stability calculated from simple population models. Collision with overhead wires was the most frequent cause of death in releases before 1994. Lead poisoning again surfaced as a problem starting in 1997 as older birds began feeding on carcasses outside the subsidy program. Although poisonings have been treated successfully by chelation therapy in recaptured birds, food subsidy is proving an ineffective solution to lead exposure. The best long-term solution appears to be either the creation of large reserves where hunting is prohibited or the restriction of hunting to nontoxic ammunition in release areas. Until sources of lead contamination are effectively countered, releases cannot be expected to result in viable populations. In addition, problems involving human-oriented behavior have resulted in the permanent removal of many released birds from the wild. The most promising reduction in human-oriented behavior has been achieved in one release of aversively conditioned, parent-reared birds. Rigorous evaluation of the factors reducing attraction to humans and human structures has been hampered by confounding of techniques in releases. Behavioral problems could be more quickly overcome by adoption of a comprehensive experimental approach. Resumen: Las poblaciones silvestres remanentes del cóndor de California (Gymnogyps californianus) de los anõs 80 exhibieron una disminución poblacional rápida debido a altas tasas de mortalidad de individuos adultos e inmaduros. El factor de mortalidad más prominente fue el envenenamiento por plomo ocasionado por la ingestión de fragmentos de municiones en cadáveres. La reproducción exitosa en cautiverio ha permitido muchas liberaciones en ambientes silvestres desde 1992, bajo el argumento de que la exposición al plomo puede ser prevenida mediante el subsidio de alimento. Sin embargo, la mortalidad de aves liberadas ha excedido generalmente los niveles necesarios para alcanzar una estabilidad poblacional calculada a partir de modelos poblacionales simples. Las colisiones con alambres en lo alto fueron la causa más frecuente de las muertes en liberaciones anteriores a 1994. A partir de 1997, el envenenamiento con plomo surgió una vez más como un problema, puesto que las aves de edad avanzada comenzaron a alimentarse de cadáveres fuera del programa de subsidio. A pesar de que el envenenamiento ha sido tratado exitosamente mediante terapia de quelación de las aves recapturadas, el subsidio de alimento ha probado ser una solución ineficaz contra la exposición al plomo. Las mejores soluciones de largo plazo aparentan ser la creación de reservas grandes donde la caza sea prohibida o se restrinja la caza a municiones no tóxicas en las áreas de liberación. Solo una vez que la contaminación por plomo sea contrarrestada efectivamente, no se podrá esperar que las liberaciones resulten en poblaciones viables. Además, los problemas de conductas orientadas hacia humanos ha resultado en la remoción permanente de muchas aves liberadas de zonas silvestres. La reducción más prometedora de conductas orientadas hacia humanos ha sido obtenida en una liberación de aves criadas por sus padres y condicionadas adversamente. La evaluación rigurosa de los factores que reducen la atracción hacia humanos y estructuras de humanos ha sido obstaculizada por la confusión de técnicas en las liberaciones. Los problemas de conducta podrían ser superados más rápidamente mediante la adopción de una estrategia experimental comprensiva. [source] Growth of the tufted-tailed ratINTEGRATIVE ZOOLOGY (ELECTRONIC), Issue 4 2007Vololomboahangy R. RANDRIANJAFY Abstract Eliurus myoxinus (Rodentia: Nesomyidae, Nesomyinae) is one of the four species of endemic Malagasy rodents known to exist in the Ankarafantsika National Park, northwestern Madagascar. In order to study growth parameters and to determine at which age E. myoxinus commences breeding, we used two different techniques: captive breeding and a capture-mark-release field program in the species' natural habitat. The data collected on the breeding of E. myoxinus in captivity demonstrated that females can give birth to a litter of up to four pups, with up to four litters per calendar year. Reproduction of E. myoxinus was more likely to be continuous in captivity than under natural habitat conditions. If parturition failed, then post-partum mating occurred. Pups had a rapid linear growth phase from birth until 1 month of age. Between 1.5 and 2 months of age, the growth rate continued to increase, but then decreased at around the time of weaning, which occurred by 3.5 months of age. The successive maximum method of age determination showed that individuals at the "young" stage had an average body length of 90 mm and a weight of 30 g and were between 1.5 and 2 months old. The greatest variation in measurements of juveniles occurred at the age of 3.5 months. At this stage, sub-adults resembled adults but their external genitalia were not well developed. Individuals were classified as adults if they had reached a body length of 110 mm and a body weight of 40 g. This occurred at more than 4.5 months of age when the animals were generally reproductively active. The Vo n Bertalanffy method indicated that individuals reach the adult stage by 6 to 7 months. Males grew more rapidly than females, reaching adulthood by 5.5 months of age, whereas females only reached adulthood several weeks later. This species is polygamous. The sex ratio of pups at birth favored females by approximately 3:1. The higher proportion of female pups at birth may represent a survival strategy of this species, possibly associated with ecological conditions. [source] Sexual reproduction of scleractinian corals in public aquariums: current status and future perspectivesINTERNATIONAL ZOO YEARBOOK, Issue 1 2007D. PETERSEN A multiple-choice questionnaire was distributed, mainly via the list servers of the EUAC (European Union of Aquarium Curators) Coral ASP (Animal Sustainability Program) and AquaticInfo, to evaluate the potential of today's aquariums for the captive breeding of scleractinian corals. Sixteen (including the temperate coral Astroides calycularis) of, in total, 24 species (nine families) were recorded as showing reproductive behaviour that could establish an F1 generation. Broadcast spawners (13 species) reproduced mainly in open systems under natural light conditions (in all cases natural moonlight exposure), whereas brooders (11 species) showed less sensitivity towards certain environmental factors known to trigger reproduction in field populations (here moonlight and temperature fluctuations). Except for a few recruits of Galaxea fascicularis and Echinopora lamellosa maintained in a 750 000 litre system, recruits of broadcast spawners could be exclusively obtained by manipulating fertilization and settlement. Brooding corals established generally less than 100 recruits if settlement was not enhanced experimentally. When reproduction was manipulated, it enhanced reproductive success, in most cases to above 100 recruits. We assume that more species, especially brooders, might reproduce in public aquariums without being noticed by the staff owing to the lack of recruitment and of experimental design (larval collection). This study illustrates the great potential for public aquariums to reproduce corals sexually. However, more investigation is necessary to optimize reproductive success and possibly to broaden the spectrum of species reproduced in public aquariums. [source] The captive breeding and educational display of the Medicinal leech Hirudo medicinalis (Linnaeus 1758) at Bristol Zoo GardensINTERNATIONAL ZOO YEARBOOK, Issue 1 2007W. SPENCER This paper provides information on the culture of the Medicinal leech Hirudo medicinalis, including housing and environmental requirements, husbandry protocols and captive breeding. The conservation status of the Medicinal leech and issues surrounding its preservation, and also uses for this species in medicine and as an educational-display subject, are discussed. This species has been maintained at Bristol Zoo Gardens, UK, from May 1996 to the present and has been bred successfully since 2001. The Medicinal leeches that are used in both the husbandry trials and educational display at Bristol Zoo Gardens originated from Turkish stock and were obtained from Biopharm UK Ltd, Dyfed, UK. [source] Domestication, comparative biology and interactions of wild and cultured fish: convenor's synthesisJOURNAL OF FISH BIOLOGY, Issue 2004K. Lorenzen Aquaculture is expanding rapidly and many fish species are brought into cultivation, entering a process of domestication with consequences for their morphology, physiology, ecology and evolution. In some species the abundance of cultured populations matches or exceeds that of wild stocks, and interactions between cultured and wild fish can pose significant conservation challenges. At the same time, captive breeding and re-introduction play an important role in the conservation of some of the world's most endangered fishes. Drawing on contributions from the FSBI Symposium and the wider literature, we synthesize current knowledge of the process and extend of fish domestication, interactions between cultured and wild fish, and the use of cultured fish in fisheries enhancement and restoration. We provide a perspective on the role of biological issues within the wider context of aquaculture development and aquatic conservation biology, and conclude with a discussion of promising avenues for further research. [source] Survival of very small macropod pouch young followingshort-term isolation from the pouch at various environmental temperaturesANIMAL CONSERVATION, Issue 4 2002David A. Taggart There is considerable interest in the use of assisted breeding techniques as a component of conservation programmes for a variety of macropods threatened with extinction. While cross-fostering is being conducted in some programmes in captivity, little is known about the best techniques for carrying this procedure out from wild populations. In this study we compare the success of various procedures for isolating small tammar wallaby (Macropus eugenii) and brush-tailed rock wallaby (Petrogale penicillata) pouch young (0.4 g,410 g) for short periods (6 hours) as a first step towards establishing a methodology for recruiting endangered macropod pouch young directly from the wild for foster-rearing in captivity. Pouch temperature and humidity were determined. Pouch young from females in experimental groups were weighed, measured and then isolated, at 30°C, 27°C or 23°C, and 100% humidity. After isolation the weight of pouch young maintained at 30°C and 27°C had declined significantly (2,17% of body weight), whereas those held at 23°C and 100% humidity lost less than 0.5% of body weight. All young were reattached to the active teat of their mother following pouch isolation and their survival and growth monitored. Pouch young from the control group and those isolated at 23°C and 100% humidity survived and grew at normal rates. Only the largest pouch young maintained in isolation at either 30°C or 27°C survived to day 7 following reattachment. Data indicated that the proportion of weight lost by pouch young as a result of isolation decreased with increasing size and age of the pouch young. These trials indicate that it would be possible to harvest very small macropod pouch young from a species in the wild with a very high probability that they would survive short-term isolation from the pouch and reattachment to the teat. The use of this procedure in combination with cross-fostering techniques will allow small pouch young from threatened macropod species to be recruited directly from the wild into captivity, for captive breeding or to improve genetic diversity in captive colonies. It should also act to reactivate diapause embryos in these animals and hence may accelerate breeding in wild-based mothers. [source] | ||||||||||||||||||||||