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1.
J Fish Biol ; 74(10): 2279-98, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20735553

RESUMO

Estimated pike Esox lucius recruitment varied by a factor of 16 for females from 1944 to 1991 and by a factor of 27 for males from 1943 to 1990 in Windermere, a temperate, mesotrophic U.K. lake. No significant stock-recruitment relationships were found, but analysis with general additive models (GAMs) revealed that early autumnal water temperature, strength and direction of the North Atlantic Oscillation displacement (corresponding to different climatic conditions in winter) and zooplankton abundance but above all, late summer water temperature were important explanatory variables over the entire time series. Female recruitment was also influenced by young-of-the-year winter temperature. There was no evidence that perch Perca fluviatilis year-class strength, lake level or the summer position of the Gulf Stream influenced recruitment. The fitted models explained up to c. 65% of the overall observed variation between years.


Assuntos
Meio Ambiente , Esocidae/fisiologia , Água Doce , Animais , Feminino , Masculino , Modelos Biológicos , Densidade Demográfica , Dinâmica Populacional , Estações do Ano , Temperatura , Fatores de Tempo , Reino Unido , Zooplâncton/fisiologia
2.
Biometrics ; 62(2): 372-8, 2006 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-16918901

RESUMO

Mark-recapture models applied to double-observer distance sampling data neglect the information on relative detectability of objects contained in the distribution of observed distances. A difference between the observed distribution and that predicted by the mark-recapture model is symptomatic of a failure of the assumption of zero correlation between detection probabilities implicit in the mark-recapture model. We develop a mark-recapture-based model that uses the observed distribution to relax this assumption to zero correlation at only one distance. We demonstrate its usefulness in coping with unmodeled heterogeneity using data from an aerial survey of crabeater seals in the Antarctic.


Assuntos
Biometria , Animais , Animais Selvagens , Regiões Antárticas , Coleta de Dados , Funções Verossimilhança , Modelos Estatísticos , Densidade Demográfica , Estudos de Amostragem , Focas Verdadeiras
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