علوم زیستی دریا
Hooman Makvandi; Mahsa Haghi; Mohammad Zakeri
Abstract
The goal of the current study was to determine how feeding interactions among three species of tilapia affected growth and survival indices at various weights in the laboratory. In this study, four experimental groups were examined based on various weights at 60 days in the lab: control, the interaction ...
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The goal of the current study was to determine how feeding interactions among three species of tilapia affected growth and survival indices at various weights in the laboratory. In this study, four experimental groups were examined based on various weights at 60 days in the lab: control, the interaction of Blue-Nile, the interaction of Blue-Zilli, and the interaction of Nile-Zilli. The most of growth-related indices in the Nile control were more appropriate than in other control treatments. The increase in body weight was significantly different across various treatments, according to the results of the growth and survival indices of Blue and Zilli. Zilli had 100% survival in treatments 6-7 and minimal survival in treatment 5. Blue tilapia also had the maximum survival in treatment 4 and the lowest survival in treatment 7. The results of Nile and Blue's growth and survival indices similarly revealed significant differences in most growth and survival indicators. So, in treatment 11, Nile tilapia showed the highest growth in body weight. Furthermore, the 10th treatment for the Nile considerably reported the lowest FCR. In this experiment, the Nile's highest survival rate was 100%. In Blue, the survival rate was at least 73.3%. The results of growth and survival indices were significantly affected by the exposure of Nile and Zili, like the other two interactions. In the 12th and 13th treatments, the FCR was assessed to be the lowest in Zilli and Nile. Nile in treatment 13 achieved 100% survival in the feeding interaction of Nile and Zilli. Blue tilapia appears to have less food competition than Zili and Nile. It was discovered that Nile, Zilli, and, Blue tilapia of varying weights exhibit more intense food competition behavior in laboratory conditions.
علوم زیستی دریا
atefe soleimani; Mahsa Haghi; mohammad zakeri; majid shekari
Abstract
Feeding strategy of blue swimming crab (Portunus pelagicus) was investigated monthly in Khuzestan province water from April-2016 to march-2017. Samples were catch by trawl net. The content of P. pelagicus stomachs, percentage of occurrence frequency and Frequency percentage of feeding items was checked. ...
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Feeding strategy of blue swimming crab (Portunus pelagicus) was investigated monthly in Khuzestan province water from April-2016 to march-2017. Samples were catch by trawl net. The content of P. pelagicus stomachs, percentage of occurrence frequency and Frequency percentage of feeding items was checked. In crab stomachs different feeding items group such as crustacean, mollusks, sponges, phytoplanktons, corals, fish, sand particles and etc. Was observed. The highest frequency of occurrence belonging to sponges, crustaceans and mollusks, respectively. Furthermore, Frequency percentage of sponges (38.65%) was higher than other preys. Costello's graphical model analysis Results analysis of P. pelagicus stomach content by Costello's model showed that this crab is a predator with specific feeding nich and feeding specific prey include sponges, crustacean and mollusks during a year. Though, it's feeding pattern show few seasonally fluctuations. In this model, phytoplanktons, fish, polycheats, corals, nematode, protista, ctenophore, nematodes, cestod, sea insects and sand identified as accidental or rare prey. Probably, ingest by crab while feeding from specific prey.