821 resultados para Rare birds.
Resumo:
Estimating rare events from zero-heavy data (data with many zero values) is a common challenge in fisheries science and ecology. For example, loggerhead sea turtles (Caretta caretta) and leatherback sea turtles (Dermochelys coriacea) account for less than 1% of total catch in the U.S. Atlantic pelagic longline fishery. Nevertheless, the Southeast Fisheries Science Center (SEFSC) of the National Marine Fisheries Service (NMFS) is charged with assessing the effect of this fishery on these federally protected species. Annual estimates of loggerhead and leatherback bycatch in a fishery can affect fishery management and species conservation decisions. However, current estimates have wide confidence intervals, and their accuracy is unknown. We evaluate 3 estimation methods, each at 2 spatiotemporal scales, in simulations of 5 spatial scenarios representing incidental capture of sea turtles by the U.S. Atlantic pelagic longline fishery. The delta-log normal method of estimating bycatch for calendar quarter and fishing area strata was the least biased estimation method in the spatial scenarios believed to be most realistic. This result supports the current estimation procedure used by the SEFSC.
Resumo:
Mats (biomasses) of macroalgae, i.e. Ulva spp., Enteromorpha spp., Graciolaria spp., and Cladophora spp., have increased markedly over the past 50 years, and they cover much larger areas than they once did in many estuaries of the world. The increases are due to large inputs of pollutants, mainly nitrates. During the warm months, the mats lie loosely on shallow sand and mud flats mostly along shorelines. Ulva lactuca overwinters as buds attached to shells and stones, and in the spring it grows as thalli (leaf fronds). Mats eventually form that are several thalli thick. Few macroinvertebrates grow on the upper surfaces of their thalli due to toxins they produce, and few can survive beneath them. The fish, crabs, and wading birds that once used the flats to feed on the macroinvertebrates are denied these feeding grounds. The mats also grow over and kill mollusks and eelgrass, Zostera marina. An experiment was undertaken which showed that two removals of U. lactuca in a summer from a shallow flat in an estuarine cove maintained the bottom almost free of it.
Resumo:
A região da Bacia de Campos está exposta a diversas atividades antrópicas, que interferem diretamente no funcionamento do ecossistêmico marinho. O estudo da fauna marinha na costa centro-norte fluminense mostra grande relevância, diversas aves marinhas residem ou passam grande parte de seu período migratório ao longo da Bacia de Campos, entre elas está Sula leucogaster (Boddaert, 1783). Embora essas aves sejam altamente móveis, suas populações apresentam uma estrutura populacional genética robusta. Com o intuito de verificar a estruturação e as relações evolutivas da população de Sula leucogaster na Bacia de Campos foram recolhidas 91 amostras de encalhe e os dados gerados para esta região foram comparados com dados já publicados de outras bacias oceânicas. A partir da região controle do DNA mitocondrial foram gerados 26 haplótipos, todos exclusivos da Bacia de Campos, muitos raros e apenas oito possuíram frequência comum. As análises mostraram que a população da Bacia de Campos é um estoque genético de Sula leucogaster. Tal fato pode ser atribuído ao comportamento filopátrico e ao hábito costeiro dessa espécie que impede o fluxo gênico entre populações. Além disso, a população da Bacia de Campos detém baixa variabilidade genética e possivelmente está sofrendo efeito gargalo ou seleção purificadora, corroborados por valores do teste Fu, o que é comum para espécies que se dividem em subpopulações. Os dados filogenéticos demonstram um contato recente entre as populações da Bacia de Campos e da ilha de Ascensão. As condições oceanográficas também têm influência na estruturação de populações de Sula leucogaster, visto que a ausência de barreiras e a proximidade geográfica poderiam favorecer contato secundário com o Mar do Caribe, fato não evidenciado nas análises. Sendo assim, a divergência de populações nessa espécie e a baixa variabilidade genética são fatores preocupantes para a manutenção da população de atobás marrons em uma área de grande impacto ambiental
Resumo:
1. Systematic list of birds (pp. 23-31) 2. Observations on the Galapagos fur seal, Arctocephalus australis galapagoensis Heller, 1904 (pp. 31-33) 3. Cetaceans observed (pp. 33-34)
Resumo:
NOAA’s National Centers for Coastal Ocean Science (NCCOS) conducts and supports research, monitoring, assessments, and technical assistance to meet NOAA’s coastal stewardship and management responsibilities. In 2001 the Biogeography Branch of NCCOS partnered with NOAA’s National Marine Sanctuary Program (NMSP) to conduct biogeographic assessments to support the management plan updates for the sanctuaries. The first biogeographic assessment conducted in this partnership focused on three sanctuaries off north/ central California: Cordell Bank, Gulf of the Farallones and Monterey Bay. Phase I of this assessment was conducted from 2001 to 2004, with the primary goal to identify and gather the best available data and information to characterize and identify important biological areas and time periods within the study area. The study area encompasses the three sanctuaries and extends along the coastal ocean off California from Pt. Arena to Pt. Sal (35°-39°N). This partnership project was lead by the NCCOS Biogeography Branch, but included over 90 contributors and 25 collaborating institutions. Phase I results include: 1) a report on the overall assessment that includes hundreds of maps, tables and analyses; 2) an ecological linkage report on the marine and estuarine ecosystems along the coast of north/central California, and 3) related geographic information system (GIS) data and other summary data files, which are available for viewing and download in several formats at the following website: http://ccma.nos.noaa.gov/products/biogeography/canms_cd/welcome.html Phase II (this report) was initiated in the Fall of 2004 to complete the analyses of marine mammals and update the marine bird colony information. Phase II resulted in significant updates to the bird and mammal chapters, as well as adding an environmental settings chapter, which contains new and existing data and maps on the study area. Specifically, the following Phase II topics and items were either revised or developed new for Phase II: •environmental, ecological settings – new maps on marine physiographic features, sea surface temperature and fronts, chlorophyll and productivity •all bird colony or roost maps, including a summary of marine bird colonies •updated at-sea data CDAS data set (1980-2003) •all mammal maps and descriptions •new overall density maps for eight mammal species •new summary pinniped rookery/haulout map •new maps on at-sea richness for cetaceans and pinnipeds •most text in the mammal chapter •new summary tables for mammals on population status and spatial and temporal patterns
Resumo:
The greatest concentration of Chinese Galliformes occurs in the Trans-Himalayas. We selected 4 northwestern Yunnan counties (Lijiang, Shangri-la, Deqin, and Weixi) in the Trans-Himalayas to assess the conservation status of 9 gallinaceous forest birds. We
Resumo:
Due to its specific characteristics, such as maternal inheritance and absence of recombination, each mtDNA belongs to certain monophyletic clade in the rooted mtDNA tree (haplogroup) according to the mutations it harbors. Rare mutation (excluding parallel mutation) occurring at multiple times in different haplogroups could thus be a potential reading error according to the mtDNA phylogeny. This experience has been widely used in double-checking the credibility of the rare mutations in human mtDNA sequences. However, no test has been performed so far for the feasibility of applying this strategy to the rare insertion/deletion (indel) events in mtDNA sequences. In this study, we attempted to relate the rare indels in mtDNAs to their haplogroup status in a total of 2352 individuals from 50 populations in China. Our results show that the insertion of A at position 16259 is restricted to a subclade of haplogroup C and can be verified. The other indel polymorphisms, which occur in the repeat of the deleted or inserted nucleotide(s), may not be distinguished from phantom mutations from a phylogenetic point of view. Independently and multiply sequencing the fragment with the indel is the best and the most reliable way for confirmation.