scholarly journals Trading off hatching success and cost in the captive breeding of Whooping Cranes

2021 ◽  
Author(s):  
H. A. Edwards ◽  
S. J. Converse ◽  
K. D. Swan ◽  
A. Moehrenschlager
2011 ◽  
Vol 23 (1) ◽  
pp. 214
Author(s):  
M. E. Brown ◽  
A. Crosier ◽  
W. Lynch ◽  
S. J. Converse ◽  
J. Chandler ◽  
...  

The whooping crane is one of the most critically endangered species in North America. The species underwent a severe genetic bottleneck with only 16 individuals remaining in the wild as of 1942. Captive breeding began in 1966 and continues to produce chicks for release in order to establish new wild populations. However, captive birds experience poor reproduction with approximately 40% of eggs being infertile. Males have been known to reach sexual maturity at 5 years of age and continue to reproduce almost as long as the duration of their adult life (i.e. 40 years). Understanding factors affecting seminal quality may assist in identifying and correcting causes of suboptimal reproduction. Our objectives were to determine the influence of age and reproductive seasonality on seminal quality. We hypothesised that seminal quality variations among whooping cranes and ejaculates within a given individual over time were due to bird age and stage of breeding season. In 2010, twenty-nine whooping cranes of 5 age groups housed at Patuxent Wildlife Research Center (Laurel, MD, USA) were studied: ≤5 years (n = 3); 6–10 years (n = 7); 11–15 years (n = 7); 16–20 years (n = 4); >20 years old (n = 8). Semen was collected using a manual manipulation technique at 3 stages of the breeding season: early (March, n = 29) mid (April, n = 24), and late (May, n = 14). Samples were evaluated for seminal volume and sperm concentration, motility, and morphology, with data evaluated by analysis of variance. Bird age had no influence on seminal quality, whereas stage of breeding season affected seminal volume and the proportion of sperm with normal morphology (95% confidence interval). Specifically, samples collected during Mid breeding season had the highest volume (mean ± SEM; early: 42.0 ± 8.0 μL; mid: 66.0 ± 15.2 μL; late: 39.7 ± 17.8 μL), but lowest proportions of structurally normal sperm (early: 78.4 ± 3.7%: mid: 61.5 ± 3.2%; late: 69.7 ± 3.4%). There was a significant difference (P = 0.06) in sperm concentration among stages of the breeding season (early: 66.3 ± 18.8 × 106 sperm mL–1; mid: 179.2 ± 46.2 × 106 sperm mL–1; late: 91.4 ± 47.8 × 106 sperm mL–1). Sperm motility was unaffected by season (early: 36.4 ± 3.5%; mid: 45.9 ± 4.1%; late: 48.0 ± 4.9%). In summary, there is a peak in seminal quality that corresponds with higher volume and more sperm during the mid stage of the season, although with higher instances of structural abnormalities. Despite the small founder base for this species, males in this population produce sperm with no variation in seminal quality across a wide variation in age.


2013 ◽  
Vol 31 ◽  
pp. 35-38
Author(s):  
Md. Sakhawat Hossain ◽  
M Firoj Jaman ◽  
Mushtaq Ahmed ◽  
Md Mokhlesur Rahman ◽  
Md Saidur Rahman

An extensive study was conducted from March 2007 to February 2012 on hatching success of saltwater crocodile (Crocodylus porosus) in the Reptiles Farm Ltd. (RFL) located at Hatiber village of Uthura union under Bhaluka upazila in Mymensingh. The study was mainly based on direct field observation and some previous data collected by farm’s technicians. A special type of incubator having 98-100% moisture and 31-330C temperature was maintained to improve the hatching success. Yearly hatching success in captivity was 95.8%, 95.15%, 97.44%, 96.03% and 94.53% in 2007 through 2011, respectively. The average rate of hatching success in RFL was 95.8 ± 1.09%. Hundred percent hatching success was found in 29 out of 56 clutches. Clutch size varied from 19 to 68 eggs. Unhatched eggs were 4.19%, of which most of the embryos died before hatching. The average time required for incubation was 79 ± 3, 79.5 ± 4.5, 80 ± 4, 80.5 ± 4.5 and 78.5 ± 3.5 days in the above mentioned period. Compared to the wild habitat, captive environment in controlled weather and predation might improve hatching rates. This study suggests that conservation of this endangered species is possible by captive breeding and reintroduction program.DOI: http://dx.doi.org/10.3329/ujzru.v31i0.15398Univ. j. zool. Rajshahi Univ. Vol. 31, 2012 pp. 35-38


2020 ◽  
Vol 27 (5) ◽  
pp. 245-256
Author(s):  
Cemil Aymak ◽  
Aşkın Hasan Uçar ◽  
Yusuf Katılmış ◽  
Eyup Başkale ◽  
Serap Ergene

In this study invertebrate infestation in green turtle (Chelonia mydas) nests were recorded for the first time for Kazanlı beach, Mersin, Turkey. For this aim, in 2006 nesting season, 294 natural intact green turtle nests were sampled to examine their contents and invertebrate infestation was found in 76 (25.85% of the total sampling green turtle nests). These infested nests were examined in terms of the invertebrate faunal composition. The specimens found in the green sea turtle nests were identified to order, family or genus levels and they were represented in 5 orders. These invertebrate groups are Elater sp. larvae (Elateridae; Coleoptera), Pimelia sp. larvae (Tenebrionidae; Coleoptera), Enchytraeidae (Oligochaeta), Cyrptostigmata (Acari), Oniscidae (Isopoda), Formicidae (Hymenoptera). Elater sp. was the most common invertebrate group in the green turtle nests. According to student t test, we found statistically significant differences between 7 independent variables and invertebrate species presence. Furthermore, logistic regression analysis explained that there is a negative relationship between hatching success rate and invertebrate species presence.


Author(s):  
Aaron T. Pearse ◽  
Mary J. Harner ◽  
David M. Baasch ◽  
Greg D. Wright ◽  
Andrew J. Caven ◽  
...  

2008 ◽  
Vol 2 (1) ◽  
pp. 63-75
Author(s):  
Augusto Fachín Terán ◽  
Eduardo Matheus Von Mülhen

In this study the nesting biology of Podocnem is unifilis was investigated from July to November 1998 at the Mamirauá Sustainable Development Reserve, located in the Solimões river, near Tefé, Amazonas, Brazil. Podocnemis unifilis nested in August and September, with the hatching event occurring in October and November. Nests were excavated in clay soils (67.5%), sand (25%), and leaf litter (7.5%). Hatching success was highest in the sand beach nests and lowest in the clay banks nests. Humans and the tegu lizard (Tupinambis) were the main egg predators. This turtle population can recover only by the protection of nesting beaches, educational programs for the in habitants of the Reserve, participation of the community in the conservation and management program , and permanent guarding of the nesting beaches by Instituto Brasileiro do Meio Ambiente e Dos Recursos Naturais Renováveis-IBAMA authorities.


Author(s):  
Dean E. Biggins ◽  
David A. Eads

Black-footed ferrets were reduced to a remnant population of 10 in 1985 due to diseases (plague, canine distemper), but successful captive breeding and releases have improved the prospects for ferret recovery. Comparisons between black-footed ferrets and Siberian polecats, close relatives that can interbreed and produce fertile offspring, allow the following evolutionary speculation. Predation on ferrets and polecats tends to narrow their niches and promote specialization due to requirements for escape habitats. In Asia, that influence is countered by the larger and more diverse area of steppe and alpine meadow habitats for polecats, and by plague which causes large variation in prey abundance. In North America, the selective pressure favoring specialization in ferrets on prairie dog prey and burrows had no strong counter-force before plague invaded. Plague is an immense challenge to black-footed ferret recovery, and several management tools including vaccines and vector control may be necessary to conserve the species.


2018 ◽  
Vol 5 (5) ◽  
pp. 172470 ◽  
Author(s):  
Stephanie K. Courtney Jones ◽  
Adam J. Munn ◽  
Phillip G. Byrne

Captive breeding programmes are increasingly relied upon for threatened species management. Changes in morphology can occur in captivity, often with unknown consequences for reintroductions. Few studies have examined the morphological changes that occur in captive animals compared with wild animals. Further, the effect of multiple generations being maintained in captivity, and the potential effects of captivity on sexual dimorphism remain poorly understood. We compared external and internal morphology of captive and wild animals using house mouse ( Mus musculus ) as a model species. In addition, we looked at morphology across two captive generations, and compared morphology between sexes. We found no statistically significant differences in external morphology, but after one generation in captivity there was evidence for a shift in the internal morphology of captive-reared mice; captive-reared mice (two generations bred) had lighter combined kidney and spleen masses compared with wild-caught mice. Sexual dimorphism was maintained in captivity. Our findings demonstrate that captive breeding can alter internal morphology. Given that these morphological changes may impact organismal functioning and viability following release, further investigation is warranted. If the morphological change is shown to be maladaptive, these changes would have significant implications for captive-source populations that are used for reintroduction, including reduced survivorship.


Animals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2191
Author(s):  
Pablo García-Salinas ◽  
Victor Gallego ◽  
Juan F. Asturiano

The chondrichthyan fishes, which comprise sharks, rays, and chimaeras, are one of the most threatened groups of vertebrates on the planet. Given this situation, an additional strategy for the protection of these species could be the ex situ conservation projects developed in public aquaria and research centers. Nevertheless, to increase sustainability and to develop properly in situ reintroduction strategies, captive breeding techniques, such as sperm extraction and artificial insemination, should be developed. These techniques are commonly used in other threatened species and could be also used in chondrichthyans. However, the different reproductive morphologies found in this group can complicate both processes. Therefore, a comparison of the reproductive anatomy of eight distinct chondrichthyans, with an emphasis on those important differences when performing sperm extraction or artificial insemination, is carried out herein. Sharks and chimaeras belonging to the Scyliorhinidae, Carcharhinidae, Centrophoridae, Etmopteridae, Hexanchidae, and Chimaeridae families were obtained from commercial fisheries, public aquaria, and stranding events. In addition, the process of obtaining viable sperm samples through cannulation, abdominal massage, and oviducal gland extraction is described in detail for both living and dead animals.


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