East African Fisheries Research Organization Annual Report 1954/1955

This Report covers the period 1st January, 1954, to 30th June, 1955. Scientific work of the organization carried out during the reporting period included the following: Hydrology, Mollusca, Arthropoda , Tilapia, Haplochromis , The Fishes of Uganda , species of fish occurring in Lake Victoria, Analysis of commercial catches, Experimental fishing, The Relative fecundity of Tilapia species, The breeding behaviour of Tilapia, The rings on Tilapia Scales, The Growth of very young fish, The reproductive cycle of non-cichild fishes, The food of fish, some notes on the food of crocodiles, Varanus Lizards and Otters and List of Publications

Hydrographical conditions and benthic assemblages in the Suez Gulf, Egypt

The coastal development and human activities along the Suez Gulf leading to sedimentation, degrade the quality of water, disturbing the natural structure and functions of aquatic communities. The Suez Gulf is a large semi-closed area with a 346 km long coastline on the western beach side. The prevailing physicochemical parameters in shallow intertidal waters were measured seasonally over the year. Benthic faunas in the sampling sites were studied indicating their regional distribution in relation to the impact of different environmental parameters in the intertidal region. The concentration of copper in seawater reached high level at St. IV (4.57 ug/1), which is exposed to sewage and petroleum hydrocarbons. The grain size of the sediment is a determining factor for the organic carbon concentration and the sandy substrate enhances organic matter degradation processes. A large number of oil fields are present along the western coast of the Suez Gulf, therefore, cadmium and organic matter appeared to be high. The values of pH did not vary greatly among the different sampling sites. It was high at EI-Ein, El-Sukhna and Ras-Shukeir due to the disposal of mainly acidic sewage and industrial effluents of the two stations Adabiya and Ras-Gharib respectively. The macrobenthos included 71 species embraced mainly from Mollusca (53.5% Gastropoda and 12.7% Bivalvia) and the other invertebrates included 7 groups namely, Rhizostoma, Polychaeta, Cirripedia, Amphipoda, Isopoda, Decapoda and Echinodermata. The distribution of benthos is affected by the temperature and salinity of seawater. The concentration of organic matter in seawater and in sediments in shallow waters shows high values in the central part of the Gulf of Suez.

Biological characteristics and determination of population dynamics parameters of Nemipterus japonicus in the coastal waters of Province Bushehr, Persian Gulf

This study was conducted to determine biological characteristics and population dynamics parameters of threadfin bream (Nemipterus japonicus) in Persian Gulf (Bushehr Province), during November 2006 and October 2007. The minimum and maximum specimens were 75-273 mm FL and their weight was 7.6 - 351.9 g. Based on the exponential relationship between fork length and weight, slope (b) for individuals, males and females was 2.987321, 2.992546 and 3.007314, respectively. The emptiness value (V) was 45.6% and it shows that N. japonicus is a moderate feeder. The results of Fp indicates that crustacean with 78.2% are main foods, mollusca (27.7%), fishes (20.7%), polychaeta (19.2%) and Foraminifera (11.7%) were identified as minor foods and phytoplanktons (9.9%), nematoda(8.0%), echinodermata (2.3%) and sea weeds (0.3%) were random foods. The reproduction studies showed the spawning season extended within 2 peaks, from April- May and September and main spawning occurs in spring season.The mean absolute and relative fecundities were 472388±42633 and 3817±293 (X±SE), respectively. The maximum, minimum and mean of oocyte diameter were 0.448, 0.022 and 0.221mm (SE=0.071), respectively.The fork length at 50% maturity estimated to be 20.25 cm for females. The growth coefficient (K) , length infinity (L∞ ) and ɸ' was estimated 0.42/yr , 34.17 cm and 2.69, respectively. The coefficient of total mortality, fishing mortality, natural mortality and E was 1.37, 0.43, 0.94 and 0.31, respectively.

Benthic fauna and water quality in Gorganrood River, Iran

This present work study on water quality and benthic Macro invertebrate in Gorganrood, river. The research was carried out at 6 sampling site and the abundance and diversity of benthos were monitored along the length of river between 2007_2008_14 families were recorded in phyla, namely Annelidae, Mollusca,.... The greatest number of species was at 1 st station and the least number was at 6th station. The upper section supported more diverse community then the lower section. A low macro invertebrate abundance was observed during spring as a result of heavy rainfall and flood, and generally in all lowest section because of high valve of nitrogen and other nutrients. Water physiochemical parameters such as Phosphate, Nitrate,TPS and others were measured and water quality were studied through different indices such as saprobic system, Helsinhoff (FBI), BMWP and the results were compared and evaluated by physical chemical and parameters. The result indicated that the water quality in the up stream and the middle were good to fair, but the down stream qualities were pour at all sites.

Study of distribution, growth and reproduction polychaetes Nereidae in intertidal zone of Bandar Abbas and effect dominant species on white Indian shrimp brood stocks (Fenneropenaeus indicus)

Distribution of polychaetes worms Nereidae in intertidal zone of Bandar Abbass indicated that distribution rate of worms from the west to east for the reason status of seabed type, habitat and feeding substrate used to worms increased. Also investigation description that last-mentioned worms are belong to Nereididae family, Perinereis genus and species of Perinereis nuntia. By viewpoint seabed soil types experiments implement indicated Nereididae worms have higher survival with sandy clay loam soil texture. Statistical analysis showed positive relation coefficient correlation of Pearson between substrate type to frequency of worms and too substrate type with soil organic matter value (P<0.05). By viewpoint feeding also experiments with different feed treatment indicated that Nereid worms is Omnivore but in natural condition more utilized algae substrate special Entermorpha and survival rate had the worms last-mentioned in dietary treatments on this algae 93/3% different significant with other treatments (P<0.05). In this project pond-reared white Indian shrimp (Fenneropenaeus indicus) were used in four maturation and spawning trials lasting 60 days. one group of shrimps was fed a formulated pelleted special of broodstock diet only, a second group was fed squid meat diet; a third group of shrimps with mollusca (Solen vagina) meat diet and fourth group was fed polychaete worms Nereidae family, collected in intertidal zone of Bandar Abbass. Four types of dietary treatments (M1, M4) were given to separate batches that were run in three duplicate. Results of experiments demonstrate that more grew rate and maturation and spawning rate and we found that shrimps fed with polychaete worms have the best condition and then shrimps fed with solen. This is demonstrate furthermore environmental circumstance, endocrine hormone, types of feed important of maturation and spawning of shrimps and in polychaete worms used HUFA help to maturation ovarian in shrimp.

Benthic community survey of Gwadar (east bay) Balochistan, Pakistan

Benthic communities of the Gwadar east bay (Balochistan) was surveyed during the onset of S.W. monsoon. A total 1030 specimens were collected which represented Phyla of Arthropoda, Mollusca, Annelida, Echinodermata. The most abundant class observed was that of Bivalvia. Seawater parameters such as dissolved oxygen, temperature, pH, salinity together with sediment characteristics were measured. Analysis of variance between observed stations and fauna do not show any significant difference (P<0.05). The present observation forms a baseline study in the area.

Check list of plankton of the northern Red Sea

Qualitative estimation of phytoplankton and zooplankton of the northern Red Sea and Gulf of Aqaba were carried out from four sites: Sharm El-Sheikh, Taba, Hurghada and Safaga. A total of 106 species and varieties of phytoplankton were identified including 41 diatoms, 53 dinoflagellates, 10 cyanophytes and 2 chlorophytes. The highest number of species was recorded at Sharm El-Sheikh (46 spp), followed by Safaga (40 spp), Taba (30 spp), and Hurghada (23 spp). About 95 of the recorded species were previously mentioned by different authors in the Red Sea and Gulf of Suez. Eleven species are considered new to the Red Sea. About 115 species of zooplankton were recorded from the different sites. They were dominated by four main phyla namely: Arthropoda, Protozoa, Mollusca, and Urochordata. Sharm El-Sheikh contributed the highest number of species (91) followed by Safaga (47) and Taba (34). Hurghada contributed the least (26). Copepoda dominated the other groups at the four sites. The appearances of Spirulina platensis, Pediastrum simplex, and Oscillatoria spp. of phytoplankton in addition to the rotifer species and the protozoan Difflugia oblongata of zooplankton impart a characteristic feature of inland freshwater discharge due to wastewater dumping at sea in these regions resulting from the expansion of cities and hotels along the coast.

Ecological health analysis of Caspian marine environment based on the diversity and distribution pattern of meiofauna in the Mazandaran Province, Caspian Sea

Biodiversity and distribution of benthic meiofauna in the sediments of the Southern Caspian Sea (Mazandaran) was studied in order to introducing and determining of their relationship with the environmental factors. From 12 stations (ranging in depths 5, 10, 20 and 50 meters), sediment samples were gathered in 6 months (2012). Environmental factors of water near the bottom including temperature, salinity, dissolved oxygen and pH were measured during sampling with CTD and grain size and total organic matter percentage and calcium carbonate were measured in laboratory. In different months, the average water temperature (9.52-23.93), dissolved oxygen (7.71-10.53 mg/L), salinity (10.57±0/07 and 10.75±0/04 ppt), pH (7.44±0/29 and 7.41±0/22), EC (17.97±0/12 and 18.30±0/04μs/cm2), TDS (8.92±0/04 and 9.14±0/02 mg/L), total organic matter (5.83±1/43 and 6.25±0/97%) and calcium carbonate (2.36±0/36 and 1.68±0/19%) were measured respectively. Structure of the sediment samples mostly consisted of fine sand; very fine sand, silt and clay. From the 4 group animals (Foraminifera, Crustacea, Worms and Mollusca), there were identified 40species belong to 29 genera of 25 families. The cosmopolitan foraminifer, Ammonia beccarii caspica, was common in all sampling stations. Result showed that depth was important factor on distribution of meiofauna. Most density of foraminifera and crustacean was observed in depth of 20m and for mollusca and worms observed in 5m. Shannon diversity index decreased with depth that showed in shallow water diversity was higher than deep water. Mean of maximum and minimum Shannon index was obsorvers in depth of 5m and 50 m that was measured in order 0.93 and 0.43. Account of Shannon index showed that this area is under pressure. Account of peioleo index showed distribution in this area was not steady.

Fisheries ecology in the interface zone of Lake Nabugabo

This study was carried out in the interface zone of Lake Nabugabo, which is situated to the west of Lake Victoria. Four study sites were chosen from the south-western to the eastern ends of the euhydrophyte-dominated interface zone, which was about 10 km long, 10 to 50 m wide, 2 m deep and characterized by a thick layer of peat at the bottom. Nymphaea caerulea was the most dominant and widespread euhydrophyte species except in the eastern tip of the lake where it was replaced by Nymphaea lotus. Interspersed among these lilies was Ceratophyllum demersum in certain bays which were thought to be either water inlets or out-flows; Utricularia and Nymphoides indica were associated with monospecific stand of N. caerulea in the south- western end of the zone. The microinvertebrates were dominated by Copepoda (represented mainly by Cyclopoida), and Rotifera, with Cladocera occurring sporadically, while the macroinvertebrates were represented by Mollusca, Acarina, and seven insect orders of which Diptera (represented by Chironomidae) was the most dominant and widespread. Snails were found to have increased in abundance and distribution since the early 1960's. Nymphaea-Ceratophyllum mixed habitats had far more larval fishes and macroinvertebrates than monospecific stands of N. caerulea. Generally, the eastern end of the interface zone had more macroinvertebrates and larval fishes than the south-western end. Food habits of larval fishes were dominated by chironomid larvae; others consumed included detritus, aufwuchs and, periodically, cladocerans.

An investigation on benthic macro-invertebrates species diversity as bio-indicators of environmental health in Bahrekan Bay

The purpose of this study was to evaluate benthic macro-invertebrates species diversity as bio-indicators of environmental health in Bahrekan bay (in the Northwest of Persian gulf). Seasonal sediments sampling along 5 transects, 15 stations at 4 replicates (3 replicates for macrobenthos and 1 replicate for sediment analysis) was done from November 2008 to August 2009 by 0.025 m2 Van Veen grab sampler. Physical and chemical parameters of water, grain size analysis, %TOM and Ni and Va concentrations of sediments were assessed through four seasons. Macrobenthic communities after staining and sorting, using stereomicroscope have been identified. Their density in every station and every season calculated. For using of AMBI index, identified macrobenthos according to their sensitivity to stressors and pollutants, categorized into 5 ecological groups and for using of Bentix index categorized into 3 ecological groups. The diversity indices and indicators that showing ecological status were calculated. Also, the differences between physiochemical parameters of sea water, sediments TOM% and grain size, diversity indices in stations and seasons were recorded (P=0.05). The correlation coefficient determined for all parameters. According to the results of grain size analysis, bottom grain size categorized as clay. Highest percent of TOM was belong to autumn (36.39±.075) and lowest was belong to summer (19.01±0.51). Also there was positive correlation (p=0.01) between %TOM and %Clay that showing sediments with lowest size containing highest amounts of organic matters. Ni concentrations in sediments (87.80±21.25)mg/kg showed the amounts over than standards levels but Va concentrations in sediments (53.54±17.60)mg/kg showed the amounts lower than standards level. The highest density of macrobenthos was recorded for summer (8254±485) N/m2 and the lowest density was recorded for spring (3775±172)N/m2. The highest annual density was belong to mollusca (81%) and then polycheates (13%), Others (4%) and crustaceae (2%). The highest diversity was recorded for winter (Simpson index: 0.13±0.01, H':3.47±0.06) and the lowest diversity recorded for autumn (Simpson index: 0.16±0.01, H':3.17±0.06). in all stations, the highest amount of Shanon index was belong to T2S3 station in summer (4.11± 0.32) and the lowest amount was belong to T1S1 station in autumn (2.42± 0.41). The annual mean of Simpson diversity index: (0.15 ±0.04) and Shanon diversity index (3.36±0.03), illustrated that macrobenthos in Bahrekan bay have a good variation. The results of Brilluin and N1 (Number of equally common species) indices confirm the results of Simpson index. For study on the regions that diversity has a little difference between stations, with use of Ni index, the degree of differences could be better ono recognizable. According to the results of AMBI index in all seasons (autumn: 0.46±0.03; summer: 0.22±0.01; annual mean:0.31±0.01) and standards (0.0