Articulo
Influence of food quantity and temperature on development and growth of calanus chilensis from northern chile
MARINE BIOLOGY;
MAR BIOL
Registro en:
1432-1793
D91S1035
D91S1035
WOS:A1997XB56300013
0076-4442
Autor
Rodríguez-Villar, Luis
Escribano-V., Rubén
Irribarren, C.
Irribarren, C.
Institución
Resumen
An experiment under laboratory conditions was conducted to test the hypothesis that development and growth of copepodite stages in Calanus chilensis are temperature-dependent and not subject to food shortage in the upwelling area of the Humboldt Current, northern Chile. Field data obtained from June 1994 to May 1995 in Bahia Mejillones (23 degrees S) were used to define four combinations of temperature and food under which copepodites were reared from Stage CIII to adulthood. The high temperature was 18.1 degrees C and the low temperature 13.1 degrees C, whereas the high food level was in the range of 6.8 to 24.8 mu g 1(-1) chlorophyll a and the low level 1.0 to 6.8 mu g 1(-1) chlorophyll a. As food a mixture of three unknown species of phytoflagellates and the diatom Navicula cryptocephala was used. This phytoplankton was initially obtained from the same sampling sites as copepods and kept in f/2 media at stable levels and composition throughout the experiment. The development rate (1/t), estimated from the time (t) elapsing between Stage CIV and adult, was significantly affected by both temperature and food, although low-food effects were much more remarkable. Low-food conditions also significantly reduced body length and ''structural'' (lipid-discounted) body mass at adulthood, while temperature only affected body length. The weight-specific growth rate was also affected by food and temperature, but again food effects were much more drastic. The results indicate that C. chilensis is a highly sensitive species to lack of food, and is possibly subject to food shortage during its annual cycle in the coastal upwelling area of northern Chile. Food limitation may help explain the seasonal pattern of adult size reported by previous studies in the area and the lack of consistence between the number of generations predictable from a temperature-dependent model and that observed in the field during the annual cycle. 0 34 FONDEF 0 0 FONDEF 128