Effects of temperature on growth, survival and body composition in larvae of barbel, Barbus barbus (L.)

Barbel larvae were reared for 21 days at 21.0, 24.1, 27.2 or 30.0 °C and fed ad libitum live Artemia nauplii for 16 h a day. The final survival rates exceeded 99 %. The highest mean daily growth rates, amounting to 0.97 mm total length (TL) and 17.3 % body weight (BW), were found at 27.2 °C. The optimum temperature calculated for the growth of larvae was 26.9 °C for TL and 26.5 °C for BW. An increase in water temperature accelerated the development rate to a larger degree than the growth rate. Temperature significantly influenced the final fish body chemical composition. The lowest dry matter content (19.1 %) was found at 24.1 °C. The highest values of ash content were determined for 27.2 and 30.0 °C and were 11.3 and 11.0 % of dry matter, respectively. The fish body caloric value was the highest at 30.0 °C (30.0 J mg^?1). The analysis of changes in the fish body chemical features against the effective day-degrees age scale did not reveal significant influence of temperature. Therefore, the effects of temperature on larval body composition seem to be related mainly to differences in barbel developmental progress at particular temperatures.