Feeding ecology and food composition of the black carp Mylopharyngodon piceus and the grass carp Ctenopharyngodon idella inhabiting the fish pond of Al-Abbassa fish hatchery with emphasis given to vector snails.
Stomach contents of M. piceus and C. idella collected from earthen fish ponds at Al-Abbassa fish hatchery during different seasons were examined. Food items were analyzed by three methods; the numerical (N%) percentage of point assessment (P%) and frequency of occurrence (F%). A comparison of the different methods emphasized the importance of snails as the major food resources in the diet of M. piceus during all seasons. During winter, stomachs of the most fish samples collected from fish ponds were empty or had traces of food. The index of relative importance (I.R.I) indicated that snails were the major food category in the diet of M. piceus during summer, autumn and spring represented by 7331, 9696 and 11670 respectively. Plants were the main food item in the diet of C. idella during summer (4604), meanwhile they came 3rd in relative importance in the diet during autumn and spring. Artificial fish food came as the 2nd food item in the diet of M. piceus during summer (1398.9) and autumn (5896.3) but it completely absent in spring. It is considered the main food item in diet of C. idella during autumn (10384.3) and spring (6293.5) and being 3rd in summer (1395.5). The results showed that snails reached highest level in the diet of M. piceus during spring (about 80% of all diet, decreased during summer (about 70%) and reached lowest proportion in autumn (50%). Plants exhibited marked seasonal variation in abundance with maximum level during summer (about 41% of all diet decreased during spring (27%) and autumn (22%). Artificial fish food was the highest in the diet of M. piceus during autumn (39%), decreased in summer (22%) until disappeared during spring. It reached highest level in diet of C. idella during autumn (49%), decreased in spring (38%) and reached lowest proportion during summer (21 %).
Department of Environmental Research and Medical Malacology, Theodor Bilharz Research Institute, Imbaba, P.O. Box 30, Giza, Egypt.
Fatma A
FA
el-Deeb
Nahed M
NM
Ismail
D000818:Animals; D017756:Aquaculture; D001522:Behavior, Animal; D002347:Carps / Q000469:parasitology / Q000502:physiology*; D004534:Egypt; D005247:Feeding Behavior; D012621:Seasons; D012908:Snails