Sub-communities within this community

Recent Submissions

  • Growth, mortalities and yield per recruit of the shrimp fish scad Alepes djedaba (Forskal) (F. Carangidae), from Abu Qir Bay, Eastern Alexandria, Egypt

    El-Sayed, H.Kh.A. (2005)
    Egyptian Journal of Aquatic Biologgy and Fisheries
    Growth and population dynamics parameters of Alepes djedaba as an exotic carangid fish species from Red Sea into the Levant Basin of the Mediterranean Sea, were investigated. Fish samples were obtained from purse-seiners operating during the day time from Jan. to Dec. 2003 in Abu Qir Bay, Eastern Alexandria. The results obtained show that back-calculated lengths (based upon otolith readings) for the first; second and third age groups were 10.38; 15.4 and 19.32 cm TL respectively, the estimated Bertalanffy growth parameters were L∞=33.29 cm, K=0.2473 and t0= -0.51. The Length-weight relationship was represented by the formula: Log W=-1.9245+2.9762 Log L. Total mortality (Z), natural mortality (M) and fishing mortality (F) were 1.85; 0.62 and 1.23 respectively. The exploitation rate (E) was found to be 56%. A Beverton and Holt yield per recruit model indicated that the maximium sustainable yield could 20.20 g at fishing mortality F= 1.6, while the current yield per recruit was 20.10 g at fishing mortality 1.23. The results proved that the purse-seine fishery of A. diedaba is over exploited in Abu-Qir Bay and requires to be managed.
  • Cell culture from two red sea benthic invertebrates: a case study on the soft octocorals dendronephthya klunzingeri and anthelia glauca

    Ammar, M.S.A.; Emara, A.M.; Perovic, S.; Wiens, M.; Billinghurst, Z.; Müller, I.M.; Müller, W.E.G. (National Institute of Oceanography and Fisheries (NIOF), Egypt, 2007)
    Egyptian journal of aquatic research
    Primmorphs were obtained from single cells of both coral species Dendronephthya klunzingeri and Anthelia glauca following incubation for three or four days during 2001. Both ultraviolet light (UVB; peak of emission of 320 nm) and visible light (wavelength between 400 and 520 nm with a maximum at 480 nm) were applied to the primmorphs as stressors. The following incubation probes have been isolated from D. klunzingeri and were used to monitor the expression of the respective genes in the homologous cell system; the heat-shock protein HSP90 (to monitor general stress responses), the histone H4cDNA (to monitor the cell cycle/proliferation) and the UVS-related protein (response to ultraviolet light) from D. klunzingeri. The data show that the steady state level of HSP90 expression is only upregulated at low level of exposure to UVB (30 J/cm2), while at stronger irradiation the expression level decreases. The expression of the histone H4 gene is blocked following exposure to UVS. Interestingly, in the absence of UVB no transcripts of UVS-related protein can be visualized. However, after exposure of the primmorphs with 30 to 300 J/cm2 a strong upregulation of the expression of the UVS-related gene is seen. The response of the primmorphs to visible light is distinct to that following exposure to UVB. The expression of the gene for histone H4 is significantly upregulated following exposure to UVB, while no expression of the gene UVS-related protein can be detected. It is concluded that, the primmorph system is useful to assess potential nature and anthropogenic disturbances on coral cells.
  • Influence of salinity variations on zooplankton community in el-mex bay, alexandria, egypt

    Zakaria, H.Y.; Radwan, A.A.; Said, M.A. (National Institute of Oceanography and Fisheries (NIOF), Egypt, 2007)
    Egyptian journal of aquatic research
    El-Mex Bay receives a heavy load of waste waters (7×109 m3/year) both directly from industrial outfalls and indirectly from Lake Maryuit via El-Mex Pumping Station. Zooplankton samples were collected bimonthly from seven stations during the period March 2005 to January 2006 to illustrate the influence of salinity variations on the abundance and community structure of zooplankton in El-Mex Bay waters. Based on the salinity values, four water types are identified: the mixed land drainage (L) of salinity < 10ppt, mixed water (M) of salinity range 10 to 30ppt, diluted sea water (D) of salinity range 30 to 38.5 ppt and Mediterranean Sea water (S) of salinity > 38.5. The highest zooplankton standing crop (106.6×103 ind/m3) was recorded in the mixed land drainage water type (L); while the lowest counts (5.9×103 ind/m3) was found in the Mediterranean Sea water type (S). Rotifera were the most dominant zooplankton groups in water type (L) constituting about 86% to the total zooplankton and represented by 19 species belonging to 10 genera. Brachionus urceolaris and Filinia longiseta dominate Rotifera population. Protozoa was the second important group in this water type contributing 9.23% to the total zooplankton crop. In water type (M), Rotifera, Protozoa and Copepoda were the most dominant groups constituting 57.87%, 21.32% and 13.45% to the total zooplankton counts respectively. In water type (D), Copepoda and their larval stages were the most dominant zooplankton groups constituting about 51% to the total zooplankton. Protozoa was the second important group constituting 37.20%, while Rotifera represented only 4.20%. In the Mediterranean water type (S), Copepoda and their larvae were the most dominant zooplankton group, forming 49.46% of the total zooplankton. Oithona nana, Acartia clausi and Paracalanus parvus dominated copepod population. Cirriped larvae occupied the second order of abundance at this water type with a percentage frequency of 19.17% to the total zooplankton crop.
  • Influence of barley straw and submerged macrophytes on fishpond wastewater quality

    Ghobrial, M.G.; Okbah, M.A.; Gharib, S.M.; Soliman, A.M. (National Institute of Oceanography and Fisheries (NIOF), Egypt, 2007)
    Egyptian journal of aquatic research
    Barley straw has received, recently, considerable attention as an algicide, which could be used to control algal growth in fishponds. It is regarded as cost-effective, user friendly and environmentally sounds. On the other hand, the submerged wetland macrophytes are crucial for the stabilization of clear water state in shallow lakes, by their active production of anti-algal compounds (allelochemicals) through allelopathy. Microcosm experiments using barley straw and the submerged macrophytes: Najas marina L., Potamogeton pectinatus L. and Ceratophyllum demersum L. in culture media with fishpond water were carried out outdoors to simulate the situation as natural as possible. Nutrients concentrations were measured beside the analysis of phytoplankton and zooplankton communities were analyzed during nineteen days incubation period. Nitrogen and phosphorus elements were determined in the tissues of used aquatic macrophytes at the beginning and by the end of the experiment. Multivariate statistical assessment using matrix correlation and principal components analysis was applied for interpretation of the experimental data. Principal component PC1 in barley straw medium accounted for about 47% of the total variance with strong correlation between selected parameters and a positive coefficient (r = 0.94 and 0.84) for diatoms – PO4 and diatoms – SiO4 respectively. On the other hand, PC1 in the status of N. marina and C. demersum contributed to 46% and 58% of the total variance, respectively with high positive loading between diatoms and green algae, while in case of P. pectinatus PC1 accounted for 62% of the variance with positive loading for chlorophyll – a, green algae and rotifers. Thus, rotted barley straw stimulated the growth and dominance of diatoms, rather than the green algae, throughout the incubation period. In the mean time, the macrophytes had allelopathic impact on the diatoms community, particularly Najas, while stimulated growth of the green algae. Zooplankton community was dominated by rotifers in all macrophytes media, while protozoan dominated barley straw medium. Complete depletion of nutrients was detected after few days in all media, while oxygen sustained acceptable levels. Phytoplankton assemblages shifting from green algae dominance to diatoms in barley straw medium is recommended as an invention to provide an integrated bioremediative product with readyto-use. Active biological compounds (algicides) derived from barley straw were more reliable than allelochemicals from aquatic macrophytes. Through their beneficial effects they would render aquatic environments such as, ponds, lagoons, aquaria, aquaculture systems, wastewater treatment, holding or conveying systems more aesthetically pleasing, efficient in aquatic animal production, and less susceptible to algae and other undesirable aquatic plants. They would thus require less maintenance. It is a tentative suggestion to use barley straw for field manipulation experiments.
  • Surface characteristics and coverage pattern of the new damietta port area, as mapped by high resolution remote sensing

    Moufaddal, W.M. (National Institute of Oceanography and Fisheries (NIOF), Egypt, 2007)
    Egyptian journal of aquatic research
    The New Damietta port area has been subjected to large landscape changes and reformations since construction of the port in early 1980s. The area still under development and is expected to experience some more changes during the next few years. This reveals the urgent need for assessment of the present coverage pattern and land-uses of the port area. The present study attempts to determine details of land cover and land use information of the New Damietta port and surrounding area using high resolution remote sensing in conjunction with results of the ground survey and field observations. A recent image from QuickBird has been used for this purpose. Land cover types and surface characteristics were described and their areas estimated and mapped using the standard remote sensing methods. Results of this study show that the landscape of the New Damietta port area is dominated by man-made cover types and infrastructures, rather than natural land cover types. The most prominent surface features of the study area include: port area, bare land, water bodies, road and rail network, built-up area, and sand dunes. The area includes also various types of land use e.g. commercial and industrial, agriculture and mixed crops, residential fabrics and dump sites.
  • Comparative study on octopus vulgaris (cuvier, 1797) from the mediterranean and red sea coasts of egypt

    Riad, R.; Gabr, H.R. (National Institute of Oceanography and Fisheries (NIOF), Egypt, 2007)
    Egyptian Journal of Aquatic Research
    Specimens from common octopus, Octopus vulgaris captured from the Red Sea and Mediterranean Sea showed significant differences in four of seven morphometric measurements .These differences are sufficient to recognize the populations of this species in the two habitats. The computed length-Wight relationship and condition factor for common octopus in both areas showed that representatives of this species from the Red Sea are heavier than those captured from the Mediterranean Sea for the same length group. Moreover, the natural mortality coefficient of Mediterranean representatives was comparatively higher than for the Red Sea octopus. This shows that the environmental conditions in the Red Sea are more suitable for O. vulgaris than in the Mediterranean Sea.
  • Molecular genetic monitoring of bacterial communities in manzala lake, egypt, based on 16S rRNA gene analysis

    El Saied, H.E. (National Institute of Oceanography and Fisheries (NIOF), Egypt, 2007)
    Egyptian journal of aquatic research
    A first molecular genetic study on the diversity of bacterial communities at Manzala Lake, Egypt, was determined by culture-independent 16S rRNA gene analysis. Bulk DNAs were extracted from water and sediment at two different sampling sites namely; Bashtir and Genka, in the lake. The 16S rRNA gene was positively amplified by polymerase chain reaction (PCR) from bulk DNA of each sample, cloned and sequenced. The sequence analysis of one hundred clones from each clone library obtained number of phylotypes ranged from 8 phylotypes, in Genka water, to 20 phylotypes in each of the sediment samples. The 16S rRNA gene showed diversity in sediment samples higher than in water samples. Based on Libshuff pairwise clone library comparisons, the 16S rRNA gene phylotypes from Bashtir water encompassed the phylotypes of Genka water, while the phylotypes of Genka water account only a portion of those of Bashtir water. Both water and sediment samples were dominated by phylotypes closely related to different classes of the phylum Proteobacteria. Most of the recovered water phylotypes from the two sites were localized in the branches of Cyanobacteria, Proteobacteria and Bacteroidetes. Genka water was differentiated from Bashtir by harbouring a phylotype related to the phylum Firmicutes. Several phylotypes from Bashtir and Genka sediments were affiliated to species from the phyla Proteobacteria, Chloroflexi, Bacteroidetes, and Planctomycetes. Genka sediment sample had two phylotypes affiliated to Fusobacteria, a character differentiated this sample from that of Bashtir, which characterized by a phylotype belonging to Actinobacteria. Other sediment phylotypes constituted unique phylogenetic lineages, suggesting new bacterial phyla. The obtained results clearly demonstrated that each studied site has unique bacterial phylotypes that can be used as site-characterizing biomarkers. The successes of this study were the determination of the actual composition of bacterial populations in the studied samples and the discovery of novel bacterial phylotypes, never recorded by traditional techniques.
  • Nutritive and antimicrobial profiles of some seagrasses from bardawil lake, egypt

    Daboor, S.M.; Abd El-Hady, H.H.; Ghoniemy, A.E. (National Institute of Oceanography and Fisheries (NIOF), Egypt, 2007)
    Egyptian journal of aquatic research
    Seagrasses species in Bardawil Lake have been defined through broad quantitative sampling. From the biochemical constituent's point of view, two species namely; Cymodocea nodosa and Ruppia cirrhosa were evaluated as feed additives and antimicrobial active compounds. The obtained results showed an obvious increase in chlorophyll "a", carbohydrate and lipid contents in the C. nodosa than R. cirrhosa while protein contents was higher in R. cirrhosa than in C. nodosa. Whole plant tissues powder substance (10.0%w/v) and ethanolic extracts (200μg/ml) of C. nodosa and R. cirrhosa were evaluated against some microorganisms using pour plate technique. Powdered substance of C. nodosa was exhibited the highest antifungal activity than that of R. cirrhosa, also its ethanolic extract inhibited all of the tested bacterial isolates except E. coli. R.cirrhosa whole plant tissues powder showed antibacterial effect on all the used bacterial isolates in addition to its reduction the radial growth of Alternaria alternatium. The inhibitory effects of the whole powder and ethanolic extracts varied considerably between the assays microorganisms.
  • Steroid hormone in serum of male mugil cephalus from lake quaron in relation to ultrastructure of steroidogenic secreting tissue

    Fahmy, A.F.; El-Gharabawy, M.M.; Assem, S.S. (National Institute of Oceanography and Fisheries (NIOF), Egypt, 2007)
    Egyptian journal of aquatic research
    The grey mullet (Mugil cephalus) is one of the most common fish species in the Mediterranean Sea. Morphological and histological studies on testes of this species indicate six successive maturity stages. The specific changes in serum sex hormone levels were found to occur during the different phases of gonadal development. Concentration of serum steroid hormone in male Mugil cephalus revealed a marked drop in serum steroid (estradiol and testosterone) hormone levels in nearly ripe stage when compared with ripe stage, while the concentration of estradiol, testosterone and progesterone at late stage (ripe stage) of sexual maturity was increased. Histological examination and cyclic change in the testes were revealed of active spermatogenesis with all generations in the early stages of testicular development. Nearly ripe testes showed more active spermatogenesis, nests of spermatocytes and small number of spermatids. While at ripe stage, the seminiferous lobules contained a fair quantity of spermatozoa with little spermatids. Ultra-structural examination showed well differentiated interlobular connective tissues which noticed at early stages. In nearly ripe stage, the fine structure revealed that early spermatids have round shaped vacuolized cells, a spherical nucleus with diffuse chromatin and without mitochondria. At this stage the interlobular connective tissue were hypertrophied, increase in thickness and filled with abnormal fibers. The abnormal shape of interlobular tissue was observed. Ultra-structurally, all the spermatozoa cells were deformed in shape, characterized by small ovoid or spherical nucleus with highly compact chromatin, surrounded by thick tissue appeared with two deformed mitochondria. In the present result, the concentration of steroid hormone in Mugil cephalus in Lake Quaron was highly correlated with the dysfunction of gonadal hormone, maturation of gametes and considered as good sign of infertility and shortage in secretion function of these tissues may be due to unsuitable environmental condition in Lake Quaron needed for spawning of male.
  • Biodegradation kinetics of bromoxynil as a pollution control technology

    Askar, A.I.; Ibrahim, G.H.; Osman, K.A. (National Institute of Oceanography and Fisheries (NIOF), Egypt, 2007)
    Egyptian journal of aquatic research
    Nonpoint source (NPS) pollution from agriculture is the leading source of impairment to Survey Rivers and lakes. Pesticides are one of the major NPS pollutants that result from agricultural activities. Among those pesticides, is Bromoxynil (BRMX) which is a widely used herbicide. The present study was carried out to determine the capability of selected biological control agents to degrade BRMX at different incubation periods. Microbial degradation of BRMX at the rate of 100 ppm in pure liquid culture media of either seven isolates of bacteria; Azotobacter chroococcum, Azospirillium barasilense, Klebsilense pneumoneae, Pseudomonas cepacia, Pseudomonas fluoresences, Bacillus subtilis, and Bacillus polymyxa or two isolates of fungi; Trichoderma viride and Trichoderma harzianum has been determined at different time intervals using high performance liquid chromatography (HPLC) with UV detection, and solid phase extraction (SPE) technique. A biphasic model was assumed in order to carry out the statistical study of the loss of BRMX from the media enriched with either bacteria or fungi. The results showed that, the percentages of residual amount of BRMX from media enriched with bacteria ranged from 29.51 -71.94, 18.89-43.88, 9.82-35.07, 3.47-31.90 and 1.80-19.24% after 3, 7, 14, 21 and 28 days of incubation, respectively. On the other hand, the residual amount of BRMX from media enriched with fungi ranged from 45.61-60.26, 21.25-30.56, 6.48-20.63, 1.25-10.49 and 0.63-1.56% after 3, 7, 14, 21 and 28 days of incubation, respectively. The data indicate that there was a faster rate of BRMX loss in the first phase than the second one. This is clearly reflected in the t1/2 values. Therefore, it is recommended to use these microorganisms as biological control agents for the integrated pest management (IPM) programs to reduce agricultural non point source (NPS) pollution to prevent pesticides from reaching ground and surface water.
  • environmental assessment on the aqaba gulf coastal waters, egypt

    Abdel-Halim, A.M.; Aboel-Khair, E.M.; Fahmy, M.A.; Shridah, M.A. (National Institute of Oceanography and Fisheries, Egypt, 2007)
    Egyptian journal of aquatic research
    Environmental Information and Monitoring Programme (EIMP) for the Egyptian coastal waters of Aqaba Gulf was established to initial monitoring and data base system by applying quality control assessments in order to evaluate, protect and sustainable use of coastal regions. Within the framework of this programme six bimonthly field campaigns were carried out annually during 1998 – 2004. A total of 11 coastal stations were selected to cover different locations of the Gulf. The surface distribution patterns of hydrographical parameters (water temperature, salinity, dissolved oxygen and pH) as well as chlorophyll-a, total suspended matter, transparency, nitrogen and phosphorus forms and reactive silicate were investigated. The obtained data of seven years work deduced that no thermocline or thermal pollution, variations in the pH and salinity values were insignificant and the water was well-oxygenated. The concentrations of nitrogen and phosphorus in the dissolved and total forms as well as reactive silicate were found quite low. The abundance of inorganic nitrogen forms were found in the order NH4-N > NO3-N≥ NO2-N reflecting the increasing rate of NH4-N production than its uptake rate as compared with the other inorganic nitrogen forms. The study showed that, nitrogen and phosphorus were found in Aqaba Gulf coastal waters, principally, in organic forms. The low levels of obtained during the present away for each of Chl-a, TSM, NH4-N, NO3-N, TN, PO4-P and TP signified that Aqaba Gulf Coastal waters can be classified between oligotrophes to mesotrophic state. Accordingly, it is safe to conclude that the area of study is not yet seriously threatened, in spite of the rapid recreational and human developments taken place on its coast during the last ten years.
  • Kinetic and isotherm studies of copper (II) removal from wastewater using various adsorbents

    Abdel Wahab, O. (National Institute of Oceanography and Fisheries, Egypt, 2007)
    Egyptian journal of aquatic research
    The present investigation deals with the utilization of marine green algae (GA), Ulva lactuca, and an activated carbon prepared from green algae (CGA) as adsorbents for the removal of copper from wastewater. A series of experiments were conducted in a batch system to evaluate the effect of system variables. The effect of pH, initial copper concentration, dose of adsorbents were considered. The optimal pH value of copper (II) adsorption onto GA and CGA was found to be pH 5.0. The maximum uptake capacities were 24.5 and 32.3 mg copper (II) per gram of GA and CGA, respectively. The efficiency of removal was slightly changed by replacing an aqueous solution by saline water or wastewater containing the same copper concentration. Adsorption kinetic data were tested using pseudo-first order, pseudo-second order, Bangham's equation and intra-particle diffusion models. Kinetic studies showed that the adsorption followed a pseudo-second order reaction. Studies revealed that intra-particle diffusion played an important role in the mechanism of copper (II) adsorption. The equilibrium data were analyzed using Langmuir, Freundlich, Tempkin, Dubinin-Radushkevich, Redlich-Peterson and Koble-Corrigan isotherm models at different doses of GA and CGA. The equilibrium data were analysed using different error analysis equations. The Freundlich and Redlich-Peterson models were found to be describing the data of GA, while Freundlich model describes the data of CGA.
  • Status of coral reef affected by different impacts in some sites of the red sea

    Ammar, M.S.A.; Ghobashi, A.A.; Omran, M.A.; Shaaban, A.M. (National Institute of Oceanography and Fisheries, Egypt, 2007)
    Egyptian journal of aquatic research
    Using Using SCUBA diving, surveying the coral reef communities at four sites, Red Sea Egypt was done. These sites are: Ras El Behar (polluted by petroleum oil), El-Hamraween (impacted by phosphate shipping), Shabrour Umm Gam’ar (harmed by recreational activities and has been suffering from the outbreak of Acanthaster planci during 1998) and Kalawy (a control site). The skeletal growth of the coral Stylophora pistillata was promoted greatly at the expense of other corals, in presence of chronic oil pollution (Ras El-Behar). In contrast, this species was completely suppressed in presence of phosphate and sulphur enrichment. Petroleum oil led to coral scarcity, space monopolization by one coral and increased sea urchins and algae. Coral reefs enriched with phosphate in the field, surprisingly was accompanied by extraordinary well flourishing corals. El-Hamraween was the only site having as higher number and abundance of Acropora as the control site. The abundance of Porites and Pocillopora was higher than the control site. Shabrour Umm Gam’ar, the site suffering from Acanthaster planci outbreak during 1998, was characterized by soft corals which were more abundant than stony corals, indicating that soft corals have higher rate of growth and recovery than stony corals after Acanthaster planci attack. Hydrocorals were abundant in the control site (kalawy).
  • Induce spawning and larval reading of gilthead sea bream (sparus aurata)collected from fish farms, egypt

    Aziz, F.K.; Zaki, M.I.; El-Absawy, M. El-G. (National Institute of Oceanography and Fisheries, Egypt, 2007)
    Egyptian journal of aquatic research
    Sparus aurata females in captivity were injected with human chorionic gonadotropin hormone (HCG), pituitary extraction and both them during the spawning season. First hormonal treatment was applied as cumulative doses required for successful ovulation ranged from 4500 to 7500 IU\fish, the maximum fertilization percent was 71. The ovulation period under the influence of this treatment extended up to 14 days. In the second experiment, the total dose requirement for successful ovulation ranged from 2 to 4 pituitary extractions. Fish and the maximum fertilization percent recorded was 81, while the longest ovulation period obtained was 15 days. In the third experiment the total doses required for successful ovulation ranged from 2 pituitary extractions and 4500 IU to 3 pituitary extraction and 7500 IU/fish. The maximum fertilization percent recorded was 88, while the ovulation period was extended up to 23 days. The combined treatment gave the highest value of fertilization percent and the longest ovulation period. Moreover, the results from the combined treatment showed the highest value of hatching percent of 83.5 when compared to those of HCG was 70.5 % or pituitary extraction was 80%. The maximum ovulation and fertilization percent was recorded at temperature ranging between 10 and 16°C. The survival percent of Sparus auratus larvae up to 10 days old after hatching were greatly affected by both temperature and photoperiod. The proper temperature ranged between 17 – 22 °C recording the highest survival percent 29 at natural photoperiod (8 h. light), while it increased to35% under continues illumination. The larvae starts feeding with rotifer at third day old were measured 0.2 mm. At 11th day old the post larvae measure 3.1 mm. and being reared to accept next feeding regime represented by Artemia nauplii.
  • Qualitative and quantitative study of copepods in damietta harbor, egypt

    Ghobashi, A.E.; Abdel-Aziz, N.E.; Dorgham, M.M.; El-Tohami, W.S. (National Institute of Oceanography and Fisheries, Egypt, 2007)
    Egyptian journal of aquatic research
    The qualitative and quantitative dynamics of the copepod community in Damietta Harbor was studied through zooplankton samples collected monthly from May 2003 to April 2004. The copepods community was represented by 21 species, belonging to calanoids (9 species), cyclopoids (5 species) and harpacticoids (7 species). A few species appeared to be persistent, while the majority of copepods were recorded either intermittently or rarely. The abundance of copepods showed wide range of variations (7x103 - 175 x103 organisms/ m3), and the annual cycle of the standing stock displayed bimodal peaks in June and August-September. The nauplii and copepodides constituted the bulk of copepods count (71.6% and 12.3% respectively). Of the adult forms, Oithona nana was the most abundant species, forming 8.1% of the total copepods, followed by Euterpina acutifrons (3.8%) and Paracalanus parvus (2.5%). Most of copepod species displayed distinct seasonal occurrence relative to environmental conditions. The stepwise regression analysis based on the annual average revealed that temperature was the most important factor controlling the size of standing stock of copepods in Damietta Harbor, while on seasonal bases, Chlorophyll a, pH and salinity seem to play a role in the copepods abundance. The cluster analysis demonstrated different types of association between copepods species, while Shannon-Weaver Diversity Index reflects relatively pronounced changes in biodiversity of the copepods community.
  • Impact of drainage water inflow on the environmental conditions and fishery resources of lake borollus

    Al Sayes, A.; Radwan, A.; Shakweer, L. (National Institute of Oceanography and Fisheries, Egypt, 2007)
    Egyptian Journal of Aquatic Research
    The brackish water lake Borollus occupies a central position at the north between the two branches of the Nile delta. This lake has a particular importance in the fish economy of Egypt. Therefore environmental and fisheries investigation was carried out at the lake during 2000–2002, where 15 stations covering the whole area of the lake were sampled. The present study points out that: 1. The water transparency of the lake is low where the average Secchi disc depth ranged between 21.14 cm and 43.89 cm. 2. The average water temperature attained its minimum in winter and ranged between 16.20 °C and 17.80 °C. The highest temperature was in summer where it ranged between 28.33 °C and 28.52 °C. 3. The recorded pH values indicate that the lake water was generally in the slightly alkaline side and optimum for fish to live in. 4. The eastern part of the lake exhibited higher chlorosity values comparing with the middle or western areas as a result of mixing with the penetrated sea water. 5. The whole water body of the lake is well oxygenated where the average values of dissolved oxygen ranged between 6.6 mg/L and 11.1 mg/L. 6. The most abundant species among the inorganic nitrogen compounds was the nitrates. The average concentrations of nitrates in the water of the lake ranged between 1.23 μ gat/L and 7.165 μ gat/L. 7. The isolines distribution of phosphates concentrations indicate that such concentrations were high at the south decreasing northwards. 8. The drainage water contributes in increasing silicates concentrations in the lake water. 9. The sharp decrease in chlorosity of the lake water during the last 30 years greatly contributed in changing the species composition of fish population in the lake. 10. The percentage weight of marine fish species in the experimental catch decreased from 15.99% in 1973 to 1.81% in 2002, where the most of marine fish species did not exist in the catch. 11. The percentage weight of Oreochromis niloticus increased from 19.70% in 1973 to 39.43% in 2002.
  • Reproductive biology and histological studies of the grey mullet, liza ramada, (risso, 1826) in lake timsah, suez canal

    Ramadan, A.M.; El-Halfawy, M.M.; Mahmoud, W.F. (National Institute of Oceanography and Fisheries, Egypt, 2007)
    Egyptian journal of aquatic research
    Reproductive characteristics of Liza ramada in Timsah Lake showed that the male reaches first sexual maturity smaller than the female at a total body length of 14 cm. and 16 cm., respectively. Overall sex ratio is 1: 1.7 for males to females. The gonado-somatic index of males was lower than that of females. Where, the maximum GSI values were recorded in November 5.03 % and 12.4 % for males and females, respectively. The maturity stages of male and female Liza ramada are morphologically separated according to the changes in shape, size and colour of the gonad in different successive stages. These stages are virgin, maturing virgin, developing, developed, gravid and spent stages. Histologically, the oocyte maturation showed the following phases; first growth phase which includes chromatin stage, early and late perinucleolus stages. Second growth phase includes vacuolization stage, yolk stages (primary, secondary and tertiary), mature stage and ripe stage. The testes maturation classified into spermatogonia, primary spermatocytes, secondary spermatocytes, spermatids and spermatozoa. Different points of view which take place in this work show that of the spawning season of Liza ramada in Timsah lake which may be extending from November to January.
  • Sidementological and environmental impacts of development projects along the coast of hurghada, red sea, egypt

    Mansour, A.M.; Mohamed, A.W.; El Dien, G.K.; Sayed, S.M. (National Institute of Oceanography and Fisheries, Egypt, 2007)
    Egyptian journal of aquatic research
    The studies areas lay in Hurghada region include different aspects of coastal development. It represents different environmental problems and threats to the Red Sea ecosystem and geosystem. They include two tourist projects, a central marina for yachts and fishermen and a site for oil exploration and production. All sits have implemented Environmental Impact Assessment studies (EIA). Unfortunately, dredging and landfilling caused severe coast destruction and shoreline change in these areas. All sites have accurately surveyed and environmental problems cited, oceanographic parameters were measured, and 109 samples were collected from the beach and the tidal flat of four sits forming the study area. Grain size, carbonates and organic matter contents, major and trace elements were determined. Cluster analysis and correlations were carried out. The results reflect the impact of coast destruction and shoreline change. Grain size analysis indicated the predominance of coarse grained sediments close to the landfilled areas. Mixtures of terrigenous and biogenic fragments are the main components of these sediments. The distribution of carbonates supports this result where carbonates content is low in the beach area and gradually increases seaward. Fine sands and mud dominate the dredging areas and cover the nearby corals and bottom facies. Results of major and trace elements, total organic matter (TOM), organic carbon (OC), and carbonate contents were used to discuss the sediment characteristics and interpret the abundance of some parameters in the impacted areas. The findings of this study help decision makers to identify anthropogenic impacts and better assess of the needs for remediation.
  • Ozone treatment of textile wastewater relevant to toxic effect elimination in marine environment

    Guendy, H.R. (National Institute of Oceanography and Fisheries, Egypt, 2007)
    Egyptian journal of aquatic research
    Ozone is a powerful oxidizing agent. The reaction of ozone with organic compounds in aqueous media has achieved a variety of treatment goals. The advantage of ozonation over the other oxidants is that the degradable products of ozonation are generally non-toxic, its final products are CO2 and H2O, and also the residual O3 in the system changes in few minutes to O2 .Convential treatment of textile wastewater includes various combinations of biological (activated sludge), physical and chemical processes. The dyestuffs existed in these wastewater are highly structured organic molecules which are hardly break down biologically. Decolorization of two types of dyes, Direct Pink 3B and Reactive Violet SH- 2R, by ozonation in aqueous medium was studied in presence of some effective variables.These variables were: the rate of ozone generation, ozone dose, current, pH and the initial concentration of the wastewater. The total quantity of ozone generated is determined from the calibration curve of the ozoniser performance, while the unused ozone is determined from the titration of iodine liberated; the difference being the amount of ozone actually used in the reaction. It was found that 98% decolorization occur in few minutes. Data on time of ozonation, temperature and other chemical variables were discussed. This research proved its success as a method for treatment of wide concentration range from the dye wastewater (100-1000 ppm), so it overcomes the problems of textile wastewater treatment.
  • Phytoplankton community in abu-qir bay as a hot spot on the southeastern mediterranean coast

    Shams El-Din, N.G.; Dorgham, M.M. (National Institute of Oceanography and Fisheries, Egypt, 2007)
    Egyptian journal of aquatic research
    The phytoplankton community in the stressed part of Abu Qir Bay was studied monthly relative to the prevailing ecological conditions from April 1998 to March 1999 at eight stations. The study recorded a total of 182 species of both fresh and marine origins, belonging to diatoms (89 species), chlorophytes (34 species), dinoflagellates (26 species), cyanophytes (18 species), euglenophytes (12 species), silicoflagellates (2 species), and cryptophyte (one species). Most of the recorded species occurred either seasonally or rarely, while small number of them appeared as persistent. The diversity of the phytoplankton community experienced wide variations on both monthly and spatial scales, accompanied by analogous variations in the diversity index, richness and evenness. The phytoplankton count was low (0.01 x 103 - 12.5 x 103 unit/L) all the year round, except high density in September (55.6 x 103 units/L). In contrast, chlorophyll-a attained markedly high values over the year (2.06 – 52.64 _g/L). The diatoms Nitzschia pungens and Asterionella japonica were the predominant, in addition to Chaetoceros affinis, Thalassionema nitzschioïdes and the dinoflagellate Prorocentrum micans. The phytoplankton count showed insignificant correlation with the nutrient salts, may be due to the water deterioration, resulting from the acute eutrophication and the increase of pollution stress in the bay. The present study revealed a marked drop in phytoplankton abundance as compared to the earlier records.

View more