PLoS ONE :科学家在南极海域发现冬眠鱼

据国外媒体报道，科学家在南极发现一条为了在漫长的冬季保存能量而冬眠的鱼。英国科学家5日表示，这条革首南极鱼进入了和刺猬等陆地动物的冬眠类似的静止状态。

研究人员已经知道南极鱼的血液中有防冻化学物质，并且它们在冰中冻不死的能力是另外一个适应极端环境的非凡能力。英国南极调查局的凯伦·弗拉瑟尔说：“显然它们利用短暂的南极夏季获得充足能量，借此度过漫长的冬季。它们在冬季之所以进入类似冬眠的状态，大概是因为体内的机制为了将能量需要量将至最小化的缘故。”

弗拉瑟尔和同事们将他们的研究结果发表在科学公共图书馆的在线杂志《公共科学图书馆·综合》上。

生物谷推荐原始出处：

PLoS ONE 3(3): e1743. doi:10.1371/journal.pone.0001743

Hibernation in an Antarctic Fish: On Ice for Winter

Hamish A. Campbell, Keiron P. P. Fraser, Charles M. Bishop, Lloyd S. Peck, Stuart Egginton

Abstract

Active metabolic suppression in anticipation of winter conditions has been demonstrated in species of mammals, birds, reptiles and amphibians, but not fish. This is because the reduction in metabolic rate in fish is directly proportional to the decrease in water temperature and they appear to be incapable of further suppressing their metabolic rate independently of temperature. However, the Antarctic fish (Notothenia coriiceps) is unusual because it undergoes winter metabolic suppression irrespective of water temperature. We assessed the seasonal ecological strategy by monitoring swimming activity, growth, feeding and heart rate (fH) in N. coriiceps as they free-ranged within sub-zero waters. The metabolic rate of wild fish was extrapolated from fH recordings, from oxygen consumption calibrations established in the laboratory prior to fish release. Throughout the summer months N. coriiceps spent a considerable proportion of its time foraging, resulting in a growth rate (Gw) of 0.18±0.2% day?1. In contrast, during winter much of the time was spent sedentary within a refuge and fish showed a net loss in Gw (?0.05±0.05% day?1). Whilst inactive during winter, N. coriiceps displayed a very low fH, reduced sensory and motor capabilities, and standard metabolic rate was one third lower than in summer. In a similar manner to other hibernating species, dormancy was interrupted with periodic arousals. These arousals, which lasted a few hours, occurred every 4–12 days. During arousal activity, fH and metabolism increased to summer levels. This endogenous suppression and activation of metabolic processes, independent of body temperature, demonstrates that N. coriiceps were effectively ‘putting themselves on ice’ during winter months until food resources improved. This study demonstrates that at least some fish species can enter a dormant state similar to hibernation that is not temperature driven and presumably provides seasonal energetic benefits.