A survey of the marine nematodes of Chesapeake Bay, Maryland

The study here reported is a survey of the most common non-parasitic nematode families of Chesapeake Bay, Maryland, with descriptions and figures, so that ecological workers and students of invertebrate zoology may be encouraged not to pass over this highly interesting and abundant invertebrate phylum. This survey is not a complete account of the free-living nematode population of the Bay, however, since only the middle section of the Bay was sampled and since the collections were not made systematically throughout the year. The physical and chemical factors of Chesapeake Bay may be found in several publications of the Chesapeake Biological Laboratory, Solomons Island, Maryland, and in the records of the Chesapeake Bay Institute, Annapolis, Maryland.

Limnological conditions of naturally turbid ponds and its effects on fish growth

An experiment was conducted on six naturally turbid ponds in the village of Salakandi situated to the south-west corner of Bangladesh Agricultural University, Mymensingh for a period of three months from July to September '96. The experiment was performed by studying the physicochemical factors of water and soil, the biological factors such as densities of phytoplankton and zooplankton, and the growth of fishes. During the experimental period water turbidity varied among ponds. The highest value of turbidity was found to be 679±183.6 FTU in pond 1 and the lowest was 158±23.31 FTU in pond 4. The maximum and the minimum water transparency were recorded in the month of July and September respectably. The lowest net weight of fishes was found 28.8 kg/ha/year in pond 1 due to high turbidity and the highest was 35.8 kg/ha/year in pond 4 due to low turbidity. Most of the correlations between turbidity and transparency, phytoplankton, and zooplankton were significant at 1% and 5% levels.

Illegal fishing of inland water bodies of Nigeria: Kainji experience

It is a common knowledge that illegal fishing which includes use of wrong gears, explosives, excessive exploitation of choice stocks, enhancement and stocking of water body and pollution has devastating effects on the critical biomass of fish biodiversity and livelihood activities associated with fishing. Efforts worldwide to arrest these menace are significant because it has been found that illegal fishing has made fishing non sustainable, resulted in poor fishermen catches, and exacerbated the use of illegal gears in an effort to a must catch. Conflict between fisher folk and policies has continued to generate different strategies in the control of illegal fishing. Some of these strategies at regional and National levels include creation and implementation of fisheries laws, fishing edicts, code of conduct for responsible fisheries, policing of inland water bodies, capacity building and capability through training of fishermen, creating necessary awareness, arrest and punishment of offenders. There are also other initiative on conservation and management of freshwater ecosystems which have interrelation with illegal fishing. This paper examines efforts in promoting and boosting the fisheries of Lake Kainji, through creating necessary awareness, campaign visits, radio programmes, gear control, reward systems, integration and diversification of livelihood activities, community based management and policing. It further analyses what is working, problems, and prospect of fisheries laws, the need to integrate factors of political policies, other global initiative on water management for people and nature. Recommendations on strategies including protection of fishing grounds, establishment of catch data base, integration of other intervention as alternative source of income to enhance livelihood, reduce fishing pressure, and capacity building of fisher folks, development of rules and regulations that is community based are highlighted.

Prevention of infestation by Dermestes maculatus Degeer in east African dried fish using pyrethrum and piperonyl butoxide

East African sun-dried fish dipped for 4 seconds in different solutions of pyrethrum and piperonyl butoxide were analysed for insecticide residue limits. All analyses showed residues above the FAO/WHO MRL; exceeding factors of between 7.6 (22.9 ppm) and 1.6 (5.3 ppm) were found for pyrethrum while exceeding factors between 5.1 (102 ppm) and 1.7 (33.1 ppm) were common for piperonyl butoxide after 6 months storage at ambient temperature. All insecticide treated fish, regardless of dip concentration, were observed to be less susceptible to infestation by Dermestes maculatus than samples of untreated fish. No dry weight losses due to insect infestation were recorded, however moisture evaporation caused weight losses between 6 and 8% during the period. Further investigations showed that careful handling and a dip concentration more in accordance with FAO/WHO MRL than the commercial practice will reduce the cost of insecticides from K.sh. 0.72 to K.sh. 0.23 per kg pyrethrum treated fish.

Diversity, abundance distribution and secondary production of intertidal and subtidal benthic macrofauna of Bushehr Province with emphasis on annelida groups

The present investigation was undertaken to establish a reference situation for future use, to identify temporal and spatial composition of macrofauna and estimate some ecological indices in the sub tidal waters along the Bushehr coastal waters in Persian Gulf. Six transects were selected including Genaveh, Farakeh, Shif, Bandargah, Rostami and Asalouyeh, at each transect 3 station were sampled in depths of zero, 5 and 10 metres. Sampling was seasonally carried out by a VAN VEEN grab 0.0225 m2, during summer 2008 until spring 2009. Samples were wet sieved immediately using 0.5 mm mesh size sieves and sediment retained in the sieve was preserved in 4% buffered formalin solution. Macrofauna specimen were separated from the sediments using decantation and elutriation methods, enumerated and identified up to the Genus level. Environmental factors such as temperature. pH, and salinity were recorded in field using sensitive probs and refractometer (for salinity) and also sediment samples were taken for TOM and grain size analysis in all the stations. 5611 specimens belonging to 66 genera were collected during the present study. Polychaetes were dominant both in terms of genus number (31) and relative abundance (74 % of total macrofaunal abundance). The other dominant groups were Artheropoda, (16.1%), Molusca (2.8%), Echinodermata (1.29%) and others including Nematoda, Nemertina, Echiura and Turbellaria (5.8%). Thirty one Genera belong of 27 families of polychaeta, one genus and family of Subphylum Chlicerata,19 genera belong to 14 families of Crustacea, 8 genera belong to 6 families of Molusca, were indentified in the studied region. 1 family (Polygordidae) and 3 genera (Flabeligera, Pilargis and Polygordius) of Polychaeta, 1 family (Nymphonidae) and genus (Nymphon) of Chelicerata, 1 Family (Nematoplanidae) and genus (Nematoplana) of Turbellaria, were identified for the first time in Persian Gulf area. The result indicated that macrofauna organism have strong relationship with the grain size characteristics of the sediments they inhabit. The most surface deposit feeder specimens such as Prionospio and Cossura were found in zero meters depth of Genaveh, Farakeh, Bandargah, Rostami and Asalouyeh stations with sandy substratum, however the most burrowing deposit feeder and scavenger specimens such as Capitella and Petaloproctus were collected in 5 and 10 meter depths of stations with silty–clay substratum. The annual mean abundance, Shanon- weiner diversity and evenness of macrofauna were estimated1152.73 N/ m² , 2.72 and 0.792 respectively .The annual average biomass and secondary production were computed 1.797 gDW m² and 3.594 gDW m² y-1 .The average of water temperature, salinity, pH and oxygen concentration were recorded between 16.37-36.05 °C, 38-42 g/l, 7.89-8.76 and 4.23-8.23 mg/l, respectively during this study in 6 studied region. Among of investigated stations Asalouyeh adjacent of effluent canal of Gas and petrochemical industry sewage and Farakeh regions adjacent the Helleh estuary had the lowets and the highest community indices. The average of diversity and density in 5 meters depth stations with moderate of sand, silt and clay were slightly more than 2 other depths stations, it seems that 5 meters stations are made a transition habitats between 2 sandy and clay habitats, that can be used by 2 groups of surface and borrowing deposit feeders. Based on the data provided in this survey, the temperature variation, sediment texture, TOM, type habitat and manmade factors of Gas and petrochemical industries have had the most effect on the macrofauna community structure in the studied region during sampling periods.

Identification of biodiversity and distribution pattern of benthic Foraminifera and Ostracoda in continental shelf sediments of the Oman Sea

Biodiversity and distribution of benthic Foraminifera and Ostracoda in the continental shelf sediments of the Omman Sea was studied in order to indicating of the composition of benthic foraminiferal and ostracodal communities and determining of their relationship with the environmental factors of the Omman Sea. Sediment samples were gathered in winter 2006 from twelve stations ranging in depth from 30 to 103 meters. Environmental factors including depth, temperature, salinity, dissolved Oxygen and pH were measured with a CTD system during sampling time and grain size and total organic matter were measured in laboratory. From the overall 57 benthic foram species, there were 52 identified species belong to 25 genera of 16 families. The cosmopolitan foraminifer, Ammonia beccarii, was common in all sampling stations. The composition of benthic foram communities had a highly positive correlation with depth, salinity and total organic matter. From the overall 30 ostracod species, there were 26 identified species belong to 22 genera of 13 families. Diversity and aboundance of ostracoda of the Oman Sea decreased from east to west and from south to north but increased slightly in the northwest (near the Strait of Hormoz). Ostracoda of the genus Propontocypris were common in all sampling stations but the genera Cyprideis, Paradoxostom and Hemicytheridea were rare in the Oman Sea. Diversity and aboundance of ostracoda in northern regions were less than southern and were less than foraminifera too. The composition of ostracodal communities had a highly positive correlation with dept, salinity and grain size. Biodiversity and distribution pattern of benthic foraminifera and ostracoda were being different in various sampling stations, especially between northern and southern regions. Water depth, salinity and structure of the sediments were the most important abiotic factors controlling the distribution pattern of benthic foraminifera and ostracoda in the Omman Sea. None existence or rare observation of structural abnormalities and oil polluted individuals in the vicinity of all sampling stations, resulted to the "clean" benthic environment of the Omman Sea.

Chemical ecology fatty acids of mollusks dominant species in intertidal zone of Chabahar Bay

Chemical ecology is the science of study and analysis of natural chemical products in result of biochemical processes in organisms and their reactions to variations of ecological and environmental parameters. In marine chemical ecology the existence of natural products in aquatic organisms and their ecological roles in marine animals and their reactions to environmental parameters variations will be studied. Among them, fatty acids are the most various and abundant ones in natural products which had been extracted from many marine organisms such as mollusks and algae. In this study selected animals were the dominant species of mollusks in intertidal zone of chabahar bay including gastropods, bivalves and polyplacophora classes. Nerita textilis and Turbo coronatus species are among gastropoda, Saccostrea cucullata is from bivalve, and Chiton lamyi is from polyplacophora. After seasonal sampling, separation and identification of natural products of these species, fatty acids had been isolated and identified by GC mass chromatography and their seasonal variations had been identified. In addition environmental factors of the location including pH, salinity temperature, dissolved oxygen, chlorophyll a and nutrients were measured monthly. Then the effect of seasonal variations of environmental factors on fatty acids had been studied by applying statistical analysis. GC/MS resulted thirteen fatty acids, which the most importants were myristic, stearic, oleic, palmitoleic, arachidonic and eicosapentaenoic acids. In majority of species palmitic acid was most abundant than the others and saturatedes had the most percentage levels than unsaturated ones. Although seasonal variations of identified fatty acids was not similar in species, but the majority of unsaturated ones had their maximum during winter, while saturated acids reached their maximum in summer. Statistical Analysis showed the strong correlations between Environmental factors and some fatty acids and temperature, nitrate, silicate and pH had strong correlations in all species. The species was studied from the point of lipid content and the results showed a good quality of lipid content in the selected species in the intertidal zone of Chabahar bay.

Physical and chemical characteristics of major aquatic ecosystems in the Victoria and Kyoga lake basins

The physical-chemical characteristics of any aquatic ecosystem include pH, conductivity, and temperature, water transparency, nutrient and the chlorophyll-a levels. Physical and chemical factors of any ecosystem determine the type and quality of flora present in it and these forms the basis on which the system operates. The elements required in largest amounts for plant productions are carbon, phosphorus, nitrogen, and silicon, which is important for diatoms as a major component of the cell wall. Nutrients may limit algal productivity in the tropics despite the high temperature there allowing rapid nutrient recycling. Nutrients most likely to be limiting African lakes are nitrogen (Talling & Talling 1965; Moss 1969; Lehman & Branstrator 1993, 1994) and phosphorus (Melack.et al l982; Kalff 1983) while silicon may limit diatom growth (Hecky & Kilham 1988). The objective of the study is to investigate the impact of physical-chemical characteristics on the distribution and abundance of organisms in the major aquatic ecosystems.