Qarun Lake is a closed salty basin located about 90km southern Cairo Egypt, cover an area of 230km 2 with annual production of about 3000 tonnes. The present study assessed the lake fishery for better management purpose. Data, information and samples were collected through 42 field trips and 311 fishermen interviews during fishing season (2010-2011). The lake was divided into three sub-areas, east, middle and west. It was found that the fishing gears used in the lake were; 1-Trammel nets with four types differed in their dimensions, mesh sizes and mainly targeting Mugil cephalus, Tilapia zillii, Solea spp. and Liza spp. 2-Seine nets with three types that were targeting M. cephalus, anchovy and shrimp. 3-Others fishing methods (Fishing aggregation system, traps and hooks) targeting mainly T. zillii. For each gear and methods used, the species composition (target and by-catch) and catch per unit effort were estimated according to sub-area and season. It is realized that middle area was more productive with higher species diversity. The present study recommends prohibiting traps in spring and all seine nets except Gahzl Zardina during summer in west and improving the fish catch and effort statistics for sustainable management of this valuable resource.

I n Egypt, four species of Tilapia have been described based on morphometric, meristic and cytotaxonomical characteristics. These species are Tilapia zillii, Oreochromis niloticus, Oreochromis aureus and Sarotherodon galilaeus. The accurate identification of these fishes is complicated by the high variation in these characters, similarity among species and in some cases by the size of the fish. In this paper, we examined the use of polymerase chain reaction (PCR) and restriction fragment length polymorphisms (RFLPs) analysis of the nuclear small subunit ribosomal RNA gene (srDNA) for molecular identification of Tilapia spp. in Egypt. The present study aims to evaluate such advanced molecular biological approach for identification of Tilapia spp. Genomic DNA was extracted from the four species of Tilapia. About 2000 bp 18S ribosomal DNA was amplified by PCR using specific primers. The technique of restriction fragment length polymorphisms was used to identify the specific 18S rDNA for each species. O. niloticus rDNA 'RFLPs species-specific pattern is proved by digestion with restriction endonucleases AIwNI and Aval, On the other hand, digestion of amplified 18S rDNA with endonuclease enzymes Smal, Xmal and Sstll produced speciesspecific patterns for T. zillii, O. aureus and S. galilaeus respectively. This indicates the efficiencies of these restriction endonuclease enzymes in species-specific identification of Tilapia spp. Restriction fragment length polymorphisms of the nuclear srDNA (RFLPs\PCR) proved to be a good tool for checking the relationships among species and their subspecies, even more than the morphological analysis. 466Sabry S. Ei-Serafr et ai.

Morphometric, meristic and DNA riboprinting analyses of Tilapia species and their hybrids inhabiting the River Nile were examined. Morphometric data showed striking similarities and overlapping among Tilapia species, making it impossible to differentiate these species. Meristic characteristics revealed that Tilapia species could be identified into four major groups (Oreochromis niloticus, O. aureus, Sarotherodon galilaeus and Tilapia zillii). The lateral line scales differed significantly between the four Tilapia species, while the number of fin rays in the dorsal and anal fins differed significantly, differentiating three species (but not between O. niloticus and O. aureus). Restriction fragment length polymorphisms (RFLPs) of nuclear small sub‐unit ribosomal RNA (18S srRNA) gene were used to differentiate the species. Polymerase chain reaction‐restriction fragment length polymorphisms data provided a unique pattern for each species with a specific restriction enzyme. Two hybrids of Tilapia designated H1 and H2 were detected. The endonucleases SacII and ApaI differentiated H1 and H2. This research revealed a monophylogenetic relationship among all the studied Tilapia species.

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The biology of the tub gurnard, Chelidonichthys lucerna (Linnaeus, 1758), has been studied based on data collected between August (2009) and July (2010) from the Egyptian Mediterranean water in front of Alexandria. A total of 873 specimens ranged between 10.6 and 28.2 cm TL and from 10.2 to 232.5 g total weight, were sampled. The age, growth, length-weight relationship, sex ratio, length and age at first sexual maturity and reproduction period were estimated. Total lengths of males ranged from 12.6 to 23.2 cm and of females from 11.8 to 28.2 cm. The maximum age observed was 4and 5 years for males and females respectively. Length-weight relationships for males and females were estimated as W = 0.0043*L 3.2644 and W = 0.0042*L 3.2651 , respectively indicating an allometric growth. Thevon Bertalanffy growth equations were L t = 29.77 (1-e -0.274(t+1.36) ) and L t =32.36(1-e -0.255(t+1.09) ) for males and females respectively. The growth performance index value (ΦL) was computed as 2.39 for males and 2.44 for females. Length at first sexual maturity was 15 cm (1.21 years) in males and 15.2 cm (1.40 years) in females. The male: femaleratio was 1:1.67. The Gonado-Somatic Index (GSI) values indicated that the spawning season starts from November to February with a peak in January for both sexes.