Size and long-term growth trends of Endangered fish-eating killer whales
نویسندگان
چکیده
منابع مشابه
the effects of keyword and context methods on pronunciation and receptive/ productive vocabulary of low-intermediate iranian efl learners: short-term and long-term memory in focus
از گذشته تا کنون، تحقیقات بسیاری صورت گرفته است که همگی به گونه ای بر مثمر ثمر بودن استفاده از استراتژی های یادگیری لغت در یک زبان بیگانه اذعان داشته اند. این تحقیق به بررسی تاثیر دو روش مختلف آموزش واژگان انگلیسی (کلیدی و بافتی) بر تلفظ و دانش لغوی فراگیران ایرانی زیر متوسط زبان انگلیسی و بر ماندگاری آن در حافظه می پردازد. به این منظور، تعداد شصت نفر از زبان آموزان ایرانی هشت تا چهارده ساله با...
15 صفحه اولThe mixed blessing of echolocation: differences in sonar use by fish-eating and mammal-eating killer whales
Despite well-documented experimental evidence of echolocation in toothed whales, virtually nothing is known about the use and functional significance of cetacean sonar in the wild. Here, the patterns of echolocation sounds produced by killer whales, Orcinus orca, off British Columbia and Alaska are described. Two sympatric populations with divergent food habits differed markedly in sonar sound ...
متن کاملIcelandic herring-eating killer whales feed at night
Herring-eating killer whales debilitate herring with underwater tail slaps and likely herd herring into tighter schools using a feeding-specific low-frequency pulsed call ('herding' call). Feeding on herring may be dependent upon daylight, as the whales use their white underside to help herd herring; however, feeding at night has not been investigated. The production of feeding-specific sounds ...
متن کاملFactors influencing the diving behaviour of fish- eating killer whales: sex differences and diel and interannual variation in diving rates
Diving behaviour of air-breathing vertebrates may be influenced by a variety of factors including age, body size, and changes in prey behaviour and (or) abundance over both short and long timescales. We studied the diving behaviour of a highly sexually dimorphic odontocete cetacean, the killer whale, Orcinus orca (L., 1758), using suctioncup-attached time-depth recorders (TDRs). We tested the h...
متن کاملPopulation Trends of Southern Resident Killer Whales from 1960-1999
In the mid 1960’s, prior to live-capture collections for oceanariums, it is believed that about 100 individuals comprised the Southern Resident community of killer whales. A decline in population levels occurred as a result of collections for public display through the early 1970’s (Hoyt 1990), decreasing the number of whales to about 70 individuals. Beginning in 1974, the Southern Resident com...
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ژورنال
عنوان ژورنال: Endangered Species Research
سال: 2011
ISSN: 1863-5407,1613-4796
DOI: 10.3354/esr00330