Estimating the mortality rate of humpback whale calves in the central North Pacific Ocean

摘要: Sighting histories of individually identified female humpback whales (Megaptera novaeangliae) in their win- ter and summer ranges were used to investigate mortality North Pacific whale calves. We compiled re- cords collected between 1979 1995 by eight independent research groups, which yielded 29 cases where 25 different mothers sighted Hawaii later the same year Alaska. In 7 cases, a calf with its mother was missing from mother's Alaska sighting(s). After investigating many factors, we deter - mined that largest potential bias would occur late-autumn observations, when absences might indicate wean- ing or temporary mother-calf separation rather than mortality. Our minimal most robust estimate excluded all mortalities survivals based on sightings after October 31; 3 20 0.150 (95% confidence intervals (CI) = 0.032, 0.378). The maximal rate, derived available data, 0.241 CI 0.103, 0.434). An intermediate single omitted late-season (2 11 0.182; 95% 0.023, 0.518) is perhaps closest actual first- rate for calves, although it compromised small sample size. results dem- onstrate both value limitations using longitudinal data determine life-history parameters are essential documenting recovery endangered populations. 600 Resume : L'observation suivie de Baleines bosse femelles identifiees individuellement dans leurs aires d'hiver et d'ete permis d'etudier la mortalite des petits population du Pacifique Nord. Nous avons compile donnees obtenues par huit groupes independants chercheurs l'operation revele cas ou meres differentes apercues les eaux hawaiennes ont ete observees nouveau en plus tard meme annee. Dans cas, une mere apercue avec son petit revue sans petit. Apres avoir examine plusieurs facteurs, nous que cause probable d'erreur potentielle etait reliee aux observations fin d'automne, alors l'absence pourrait s'expliquer le sevrage temporaire d'avec sa mere, plutot mortalite. Notre estimation minimale robuste ne tient pas compte taux survie bases sur apres 31 octobre; 0,150 (95 % IC 0,032, 0,378). Le petits, base toutes donnees, 0,241 0,103, 0,434). Une moyenne excluant tous d'observations uniques saison 0,182; 95 0,023, 0,518) est peut etre pres reelle au cours premiere annee, bien resultats soient compromis taille