Estimating breeding population size of the red-crested pochard (Netta rufina) in the Camargue (southern France) taking into account detection probability: implications for conservation

AbstractThe present study was undertaken to assist conservation and improvement schemes in the Sahiwal breed of cattle in Pakistan. A data set, consisting of records of 244 pure Sahiwal breeding bulls and 5247 cows, the latter representing about 80% of all recorded Sahiwal cows in Pakistan born during a period covering about 20 years, was analysed with regard to inbreeding, additive relationships, effective population size and generation intervals. Average inbreeding coefficients of 1224 cows and 49 bulls, for which at least the grandparents and great-grandsires were known, were 0·043 and 0·046, respectively. About two-thirds of the inbreeding was due to matings between animals with parents or grandparents in common. The mean additive relationship among the cows was 0·062, with within-herd averages ranging from 0·087 to 0·358. The average population size in a subdata set of recorded Sahiwal cattle from 1980 to 1984 was 1612, whereas the most likely estimate of the effective population size was about 30 animals for the same active breeding population. The study indicated the immediate need for an active conservation programme whereby the Sahiwal subpopulations of India and Kenya also should be involved.

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Distribution and abundance of Chubut Steamerducks: an endemic species to Central Patagonia, Argentina

Bird Conservation International ◽

10.1017/s0959270911000244 ◽

2011 ◽

Vol 22 (3) ◽

pp. 307-315 ◽

Cited By ~ 3

Author(s):

MARÍA LAURA AGÜERO ◽

PABLO GARCÍA BORBOROGLU ◽

DANIEL ESLER

Keyword(s):

Invasive Species ◽

Population Size ◽

Endemic Species ◽

Oil Pollution ◽

Anthropogenic Activities ◽

Breeding Population ◽

Habitat Destruction ◽

Small Section ◽

Marine Park ◽

Breeding Distribution

SummaryWe documented the breeding distribution and estimated abundance of Chubut SteamerducksTachyres leucocephalus,a flightless waterbird endemic to a relatively small section of coastline in Patagonia, Argentina. The distribution of Chubut Steamerducks is restricted to approximately 700 km of coast. We counted 1,703 adult steamerducks at a subset of shorelines within their range and estimated 1,841 adults after correcting for visibility for shore-based surveys. To estimate adult densities in unsurveyed areas, we used two different methods of extrapolation, resulting in estimates of 1,587 and 1,832 adults. Combined with numbers from surveyed shorelines, the total breeding population size is estimated to be between 3,428 and 3,673 adults. In addition, we counted 1,899 juvenile steamerducks, which occur in irregular aggregations. The Interjurisdictional Marine Park in San Jorge Gulf contains about 46% of the entire population, which may provide some protection from disturbance and habitat destruction. However, oil pollution, other anthropogenic activities, and invasive species still pose potential threats to the population.

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Use of the superpopulation approach to estimate breeding population size: an example in asynchronously breeding birds

Ecology ◽

10.1890/10-0137.1 ◽

2011 ◽

Vol 92 (4) ◽

pp. 821-828 ◽

Cited By ~ 15

Author(s):

Kathryn A. Williams ◽

Peter C. Frederick ◽

James D. Nichols

Keyword(s):

Population Size ◽

Breeding Population ◽

Breeding Birds

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Whole genome linkage disequilibrium and effective population size in a coho salmon (Oncorhynchus kisutch) breeding population

10.1101/335018 ◽

2018 ◽

Cited By ~ 5

Author(s):

Agustín Barría ◽

Kris A. Christensen ◽

Grazyella Yoshida ◽

Ana Jedlicki ◽

Jean P. Lhorente ◽

...

Keyword(s):

Linkage Disequilibrium ◽

Population Size ◽

Effective Population Size ◽

Coho Salmon ◽

Association Studies ◽

Breeding Population ◽

Physical Distance ◽

Average Density ◽

Whole Genome ◽

Effective Population

AbstractThe estimation of linkage disequilibrium between molecular markers within a population is critical when establishing the minimum number of markers required for association studies, genomic selection and for inferring historical events influencing different populations. This work aimed to evaluate the extent and decay of linkage disequilibrium in a coho salmon breeding population using ddRAD genomic markers.Linkage disequilibrium was estimated between a total of 7,505 SNPs found in 62 individuals (33 dams and 29 sires) from the breeding population. The makers encompass all 30 coho salmon chromosomes and comprise 1,655.19 Mb of the genome. The average density of markers per chromosome ranged from 3.45 to 6.11 per 1 Mbp. The minor allele frequency averaged 0.20 (with a range from 0.08 to 0.50). The overall average linkage disequilibrium among SNPs pairs measured as r2 was 0.054. The Average r2 value decreased with increasing physical distance, with values ranging from 0.37 to 0.054 at distances lower than 1 kb and up to 10 Mb, respectively. An r2 threshold of 0.1 was reached at distance of approximately 1.3 Mb. Chromosomes Okis05, Okis15 and Okis28 showed high levels of linkage disequilibrium (> 0.20 at distances lower than 1 Mb). Average r2 values were lower than 0.1 for all chromosomes at distances greater than 4 Mb. Linkage disequilibrium values suggest that whole genome association and selection studies could be performed using about 75,000 SNPs in aquaculture populations (depending on the trait under investigation). From the identified SNPs, an effective population size of 100 was estimated for the population 10 generation ago, and 1,000, for 139 generations ago.Based on the extent of r2 decay, we suggest that at least 75,000 SNPs would be necessary for an association mapping study. Over 100,000 SNPs would be necessary for a high power study, in the current coho salmon population.

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