摘要:

not available

ISSN:0706-652X    

DOI:10.1139/f54-011

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

The literature on hearing in fish is reviewed. Experiments withSemotilus a.atromaculatus(Mitchill) showed perception over a range from 1 to 5,750 c.p.s. Fish from which the ears had been removed seemed to perceive frequencies from 20 to 200 c.p.s. Fish without the lateralis nerve behaved as normal fish. Normal fish could distinguish one-fifth of an octave in the range of 50 c.p.s. Trained on 50 c.p.s. they had absolute pitch for 70 c.p.s. A threshold curve over the range of 20 to 5,750 c.p.s. was established for this species.Highest sensitivity was at 280 c.p.s.; lowest at 20 c.p.s. and above 2,000 c.p.s. The movements of the fish in response to vibration stimuli were studied by means of motion pictures. The fish were able to locate the source of vibration, most likely oriented by fields of higher intensity in the experimental tank. In approaching the source the fish followed curved pathways. The relationships between length of pathway, direct distance from source of vibrations, and speed of locomotion were analysed. Measurements of sound intensity in the experimental rank indicated that intensity gradients existed along the pathways followed by the fish. Further measurements of low frequency vibrations in the water are in progress.

ISSN:0706-652X    

DOI:10.1139/f54-012

出版商:NRC Research Press    

年代:1954

数据来源: NRC

摘要:

Conditioned-response experiments show that both bony fishes and selachians have surface thermal receptors. Electrophysiological studies have demonstrated in selachians two mechanisms which could provide continuous information about constant temperature conditions—the ampullae of Lorenzini and the lateral-line system. In other fishes only one such mechanism has been demonstrated, namely the trunk lateral-line system. Impulses from the ampullae and the lateral-line organs are, apparently, always being poured into the central nervous system at a rate which is characteristic of the temperature of the environment. The change in frequency of these action potentials with a given change in temperature is not great and there is no sign of adaptation. These sensory receptor mechanisms could operate in such a way as to give fish an absolute sense of temperature. In addition to this non-adaptive effect of temperature on these two kinds of receptors, there occurs, in the ampullae of Lorenzini only, another spectacular change in frequency of the nerve impulses with change in temperature, and this response is adaptive. This effect disappears with continued exposure to the new temperature, and the spontaneous impulses gradually assume the stable frequency which is characteristic of the temperature.The principal effects of temperature on the activities of fish are as follows: Fish moving in a temperature gradient select a particular temperature because of an effect of the gradient temperatures on their movements. When fish move through the temperatures of a gradient, the frequency of their movements is least in the selected region. Moderately rapid changes of temperature do not elicit locomotor responses from resting fish until very high temperatures are reached, but do affect the frequency of movements of active fish. The frequency of spontaneous movements is related to the equilibration temperature, being greatest at the temperature ordinarily selected by the same fish if placed in a temperature gradient. Maximum cruising speed, as measured at different equilibration temperatures, is greatest at the selected temperature, as is also the distance moved in response to an electric shock. The maximum cruising speed that can be maintained by fish increases, with acclimation temperature, to a peak at the final preferendum.Temperature selection by fish in a gradient is a function of surface thermal receptors not in the trunk lateral line, and of the forebrain. The relation between frequency of spontaneous movements and equilibration temperature depends in some way upon the integrity of the cerebellum.There are a few instances where a correlation has been demonstrated between temperature conditions and behaviour of fish in nature because of the effect of temperature on activity. There are other instances in which distribution of fish in nature appears to be correlated with temperature as a result of selection responses to temperature gradients.

ISSN:0706-652X    

DOI:10.1139/f54-013

出版商:NRC Research Press    

年代:1954

数据来源: NRC