Abstract: Individual difference in vulnerability to angling is a common phenomenon within natural fish population, which is affected by various environmental factors (e.g., food availability). To examine the effect of starvation on the vulnerability to angling of Cyprinidae fish and its ecological consequences, we used juvenile grass carp as the experimental model. Fish from two food treatments (starvation and control) were angled at day 0 and day 14 at 25±0.5 ℃. There were three replicates for each treatment with 40 individuals in each replicate. After angling 20 individuals in each replicate, the angling activity was ceased. During the angling process, the time and serial number of each individual which was successfully angled were recorded. The total angling time for each replicate and coefficient of variation (CV) of the time spending in angling for each individual was calculated. Our results showed the morphological characters (body mass, body length and condition factor) were higher at day 0 than at day 14 in the starvation treatment. The morphological characters of the control treatment did not change during the experiment, but the morphological characters of the control treatment were larger than those of the starvation treatment at day 14. The body mass and body length of individuals with higher vulnerability to angling were greater than those of individuals with lower vulnerability to angling at day 14 in both treatments. The total angling time of the control treatment was longer than that of the starvation treatment at day 14, whereas no difference was found in the CV of the time spending in angling in those treatments. The specific growth rate (SGR) of the starvation treatment was negative during the experiment. The SGR of individuals with lower vulnerability to angling was higher than that of individuals with higher vulnerability to angling in the starvation treatment. However, no difference in SGR was found between the two phenotypes of vulnerability to angling in the control treatment. Our results suggest that grass carp increased their vulnerability to angling in the face of starvation. Differences in ecological consequences (i.e., growth performance) existed between two phenotypes of vulnerability to angling in grass carp under the condition of severe food shortage. This fish species has morphological basis for phenotypes of vulnerability to angling.

Key words: Cadmium uptake, Zinc efficiency, Genotype, Barley, Zn-Cd interaction