Age and growth of the Mesopotamian barb, Capoeta damascina, in central Iran

Age and growth of Mesopotamian barb, Capoeta damascina, were studied in the Zayandehrud River, in central Iran, from March 2007 to April 2008. Among the 689 specimens studied, age groups in males ranged from 1+ to 9+ and that in females ranged from 1+ to 10+. The sex ratio (1 M: 1.6 F) was not significantly different from 1:1 ratio. Maximum fork length and weight was 39 cm and 1.115 g for males and 54.2 cm and 2.340 g for females. In all age classes, females were larger than males. The most frequent age groups were 3+ in males and 4+ in females. The highest value for condition factor was observed in June. The growth of C. damascina was described by von Bertalanffy growth curve as k=0.01, L_∞=56.2 cm, t_0=-0.63 for males and k = 0.05, L_∞=117.1 cm and t_0= -0.43 years for females. The length-weigh relationship was described as W=0.0169L^2.95 (r^2 =0.98) for males and as W=0.0155L2.99 (r^2 =0.99) for females, indicating an isometric growth pattern in both sexes. Growth performance index φ` was estimated as 5.73 for males and 6.53 for females, indicating a faster growth rate in females

Effect of different diets on fecundity, development time and body size of freshwater copepod Eucyclops serrulatus

The effect of five different diets consisting of green algae Scenedesmus quadricauda, cereal plant meal (wheat+white+canola+barley), fish food meal, mixed manure powder (chicken manure+cattle manure), and baker's yeast (Saccharomyces cerevisiae) were investigated on fecundity rate, larval development time and body length in freshwater copepod Eucyclops serrulatus. A complete randomized design was employed using an individual gravid female in 50ml vials at 26ºC water temperature. The maximum fecundity was obtained in copepods fed on fish diet (18.6±1.08, eggs /female; mean±SD) followed in order by baker's yeast (17.3±3.19), cereal plant meal (13±2.45), Scenedesmus (9.3±0.41), and mixed manure powder (8.6±0.82). The larval developmental time of copepod E. serrulatus was significantly different in copepods fed on examined diets. The mean shortest naupliar time (8.3±0.81 days) and copepodit time (1.0±0.70 days) were observed in copepods fed on fish food meal with a significant difference compared to other examined treatments. In addition, length and width of naupliar, copepodit, and adult of copepod E. serrulatus increased when copepods fed on fish diet and baker's yeast

Gut contents study of white leg (Litopenaeus vannamei) shrimp during a culture period from earthen ponds in Delvar of Bushehr

In this research, gut contents of white leg shrimp Litopenaeus vannamei were investigated for 113 days culture period at earthen ponds in Delvar of Bushehr, by sampling every 15 days. Results showed that artificial food had highest weight percentage in gut contents (foregut, midgut, and hindgut) following in order by detritus, zooplankton, phytoplankton, and macrobenthic. In the beginning of culture period, macro-bentic were observed in larval gut contents while other food items were throughout culture period. The maximum occurrence of detritus in gut contents was at 26 and 40 days-old larvae while highest phytoplankton was obtained at 86-days-old larvae in end of culture period. The zooplankton had approximately similar amounts throughout culture period in different parts of gut, while macro-benthic only observed at 26-old-days larvae with maximum amount at foregut and midgut. The mean highest gut fullness attained at foregut (0.95 %) and lowest at hindgut (0.20 %). The dominant color of gut content was green-brown in all parts of gut that could be due to consumption of natural pond products. This study illustrated that most consumed food items in L. vannamei was prepared by natural pond foods. In addition, detritus and plankton have most important in L. vannamei during culture period