No abstract

Berried females of Macrobrachium nipponense were incubated under four different temperatures (20,23,26 and 28 ºC) and two types of tanks with different background coloration (dark and transparent tanks) to determine the best larval release and the post larvae survival were observed. The results show best larval release were 124 ind./L achieved at 26 ºC at dark color tanks, while 68 ind. / L larvae were released at the transparent color tank at the same temperature, while only 16 ind./L were released from berried females incubated at 20 ºC at dark color tanks and 6 ind./L at the transparent tanks. The best survival of larvae was 80 % at 23 ºC at dark color tanks and 75 % at transparent color tanks. Four stages for eggs development were discriminated based on color, size and eyes.

This study was conducted during the period from November 2009 to March 2010 when the river of Shatt Al-Arab was subjected to abnormal rising in water salinity. The diversity of rotifers was studied in three different stations included two branches of Shatt Al-Arab River: Station 1 (Al-Asafia), Station 2 (Abu Al-Khaseeb-Jecor) and Station 3 (Shatt Al-Basrah canal). The highest values of water salinity (8.6, 16.7 and 22.5‰) were found during November 2009 in St. 1, St. 2 and St. 3 respectively and the lowest values (1.5, 1.9 and 2.8‰) were recorded in March 2010 in the three stations respectively. About 26 species of rotifers were diagnosed belongs to 16 genera, about 25 species recorded in St. 1 whereas, 13 and 12 species were recorded in St. 2 and St. 3 respectively. Jaccard's index showed presence of similarity of rotifers species between St. 2 and St. 3 compared to St. 1.

This study showed that the natural food could be used successfully in the rearing of Al- Gattan larvae (Barbus xanthopterus). Some types of life food were collected by by different nets, the collection site was a fish pond manure by liquid cow manure. The life food was used for the feeding of Gattan larvae and compared with artificial food coming to these pond liquid manures of cows. At the end of experiment (28 days), the results showed the average weight and length of larvae when fed on rotifer were 25.6 mg / larvae and 29.3 mm / larvae respectively. While the lowest average weight and length were for the larvae which fed on artificial food, 12.4 mg / larvae and 18.5 mm / larvae respectively. The survival rate for larvae fed on rotifer; phytoplankton and artificial food were 85, 79 and 65 % respectively.

The present study suggested a medium hatchery design for production of about 8,000,000 larvae / year in Basrah region. All the requirements, such as, water treatment shrimp culture ponds and all tools and equipment are given and discussed