[Feeding and growth of elvers of anguilla Anguilla L. (eel-like teleosten fish) experimentally reared at various temperatures in the laboratory].
In France, there are few researches carried out on the eel's elvers rearing. So, we have undertaken to do, in a first time, a study of their alimentation and growth, in relation to the temperature, at laboratory. The structure of european eels' elvers population, drawn in its natural environment, shows a polymodal frequency distribution of individual weights. The temperature has a direct effect on general metabolism of animals and consequently on their growth. For temperatures included between 10 degrees C and 25 degrees C, any increase of this factor induced an individual activity more important. The quantity of ingested food and its rapidity of utilization, the precocity of alimentary behaviour, are in relation with temperature. The best growth is obtained at 25 degrees C. It seems that this temperature permits to have a very low mortality. From 10 degrees C and below, growth is inhibited, the individual activity and the alimentary taking are very low or non-existent. However, if temperature is elevated, from 11,5 degrees C, growth can start off again, animals are very active and an alimentary behavious is observed. At least, rearing of the european eels' elvers is possible with a salt water (salinity : 32 p. 1000); this system permits suppress in totality fungi desease (saprolegnia).
[Feeding and growth of elvers of anguilla Anguilla L. (eel-like teleosten fish) experimentally reared at various temperatures in the laboratory]. In France, there are few researches carried out on the eel's elvers rearing. So, we have undertaken to do, in a first time, a study of their alimentation and growth, in relation to the temperature, at laboratory. The structure of european eels' elvers population, drawn in its natural environment, shows a polymodal frequency distribution of individual weights. The temperature has a direct effect on general metabolism of animals and consequently on their growth. For temperatures included between 10 degrees C and 25 degrees C, any increase of this factor induced an individual activity more important. The quantity of ingested food and its rapidity of utilization, the precocity of alimentary behaviour, are in relation with temperature. The best growth is obtained at 25 degrees C. It seems that this temperature permits to have a very low mortality. From 10 degrees C and below, growth is inhibited, the individual activity and the alimentary taking are very low or non-existent. However, if temperature is elevated, from 11,5 degrees C, growth can start off again, animals are very active and an alimentary behavious is observed. At least, rearing of the european eels' elvers is possible with a salt water (salinity : 32 p. 1000); this system permits suppress in totality fungi desease (saprolegnia).