Impacts of environmental conditions on macrobenthic distribution along the Suez Gulf, Egypt

Increases in coastal development and human activities leading to sedimentation degrade the quality of water; disturb the natural structure and functions of aquatic communities. The Suez Gulf is a large semi-closed area (~625 km long coastline).The assemblages of bottom fauna were studied qualitatively and quantitatively in the shallow intertidal waters along the western coast of the Suez Gulf. The quality of seawater and sediment structures were analyzed. The distribution of macro-benthos included a total of 38 species of Gastropoda and 9 Bivalvia; and 25 species from the other invertebrates included 7 groups namely, Rhizostoma, Polychaeta, Cirripedia, Amphipoda, Isopoda, Decapoda and Echinodermata. The most dominant group among invertebrate groups was the Polychaeta which included 4 species: Hydroides elegans, Perinereis cultilifera, Perinereis nuntia and Ophelina acuminata. The Cirripedia were represented by 3 species namely, Balanus amphitrite, Chithamalus challengeri and Tetraclita squamosa. The variations in the numerical abundance and biomass of bottom fauna studied between the observation periods and at sampling sites. There was a marked increase in benthos biomass at St. IV (Ras Gharib) yielding an average of 318.8 g/m² in which the gastropod community represented the dominant species in collected samples reaching 270.28 g/m² (84.4% of the total biomass) and numerically numbered 116 ind./m². Veliger larvae of bivalves and gastropods appeared to be present in the plankton for long periods and their production seems to be continuous throughout the year. In the intertidal zone of the Suez Gulf, the values of pH varied within narrow limits. Water temperature and salinity seemed to be important in the distribution and abundance of the macro-benthos communities in the study areas. The organic content in shallow intertidal waters and sediments indicated high values in the central part of the Gulf of Suez.

Ecological impacts of coastal aquaculture developments

The study presents the type and scale of any ecological change associated with coastal aquaculture development. These are enrichment, interaction with the food web, oxygen consumption, disturbance of wildlife and habitat destruction, interaction between escaped farmed stock and wild species, introduction and transfers, bioactive compounds (including pesticides and antibiotics), chemicals introduced via construction materials, and hormones and growth promoters.

Impacts of fishing gears, fishing methods and fishing effort in the fisheries of Lake Victoria and proposals for management

The initial subsistence fisheries of Lake Victoria were dominated by two indigenous tilapiines, Oreochromis esculentus (Graham 1929) and Oreochromis variabilis Boulenger 1906, exploited with simple fishing crafts and gears that had little impact on the fish stocks (Jackson 1971). Commercial fisheries, targeting the tilapia fishery, started at the beginning of the 20th Centurywhen cotton flax gillnets were first introduced in 1905 into the Nyanza Gulf in Kenya. Gillnets were quickly adopted around the whole lake and consequently, the native methods of fishing soon died out (Jackson 1971). Following the introduction of gillnets, fishing boats and their propulsion methods were also improved. These improvements in fishing capacity coincided with development of urban centres and increasing human population around the lake, which increased the demand for fishery products. To satisfy the increasing demand, fishing effort increased greatly during the 20th century, despite the decline of catch per unit of effort (CPUE) (Jackson 1971; Ogutu-Ohwayo 1990). The initial catch rates of 127mm (5 inch) mesh size gill nets in the tilapia-based fishery, in 1905, was in the range of 50 to 100 fish per gillnet of approximately 50 m in length. However, twenty years later, the catch rates of gillnets of the same mesh size had declined to about six fish per net and gillnets of smaller mesh sizes, which had better catch rates, had been introduced suggesting overfishing (Worthington and Worthington, 1933).

Monitoring of adoption and socio-economic impacts of fisheries management measures on Lake Victoria, Uganda

The overall objective of the study was to develop a better understanding of how people perceived and responded to the fisheries management measures on Lake Victoria and were affected by them.

Economic impacts of globalisation at the district, landing site and sub-sector enterprise levels on Lakes Kyoga, Albert and Victoria

The Globalisation and fish utilisation and marketing study is a collaboration between the Fisheries Resources Research Institute (FIRRI) and the Mike Dillon Associates Limited , with funding from the Department for International Development (DFID) of the Government of the United Kingdom. The study is designed to examine the impact of the development of the export fishery on the fish producers, processors, traders and consumers in the artisanal fishery in Uganda. FIRRI 's role is to collect field data relating to the livelihoods of artisanal fish producers, processors, traders and consumers. in particular data relating to income and revenue flow. The initial focus is on the eccnomic structure of fish landing sites. The purpose of this paper is to review the progress in implementation of the project and present the interim findings for discussion. During the first quarter, namely April to June, 2002, work was carried out on Lakes Kyoga and Albert and a report produced. During the second quarter, July to September, 2002, Lake Victoria was covered. In both phases, the focus has been on the economic structure of fish landings.

Perspectives of impacts of international fish trade in Kenya

There has been tremendous growth in international trade on fish and fisheries products in the last four decades. In 1970 the value of internationally traded fish was estimated at 3 billion; this increased to US$ 15 billion in 1980, US$ 36 billion in 1990 and US$ 55 billion in 2000 (Ahmed, 2003). Recent statistics show that fish trade has surpassed other agricultural commodities that have traditionally been traded internationally such as coffee, tea, cocoa, sugar, cereals, meat, oils and milk. In 2000, fish contributed 22% of the value of all agricultural exports, making it the highest internationally traded food product (Ahmed, 2003). In another perspective, nearly 40% of the world's fish is now sold in the international market. The flow of fish in the international market is highly lopsided. About 50% of fish exportscomefromthedevelopingworld ,ofwhich 20%arefrom low-incomefood deficient countries. Most of this fish, however, is consumed by the developed countries, which account for nearly 80% of all imported fish. The EU, USA and Japan are the major importers, accounting for over 77% of global fish imports. Thus, while developing countries playa big role in fish production , they consume very little of it, instead preferring to sell for the hard currency. In some fish exporting countries, especially those in Asia, there is some link between fish exports and imports of substitute and complementary foods. Much of the increased earning from fish exports in those countries is explained by a corresponding rise in expenditure on imported foods. This is not the case in many of the fish exporter nations in Africa. In their case, fish exports generate foreign exchange that they use to meet other socio-political objectives; hardly is it aimed at solving the wider food needs. Therefore, one of the most immediate concerns of international fish trade is its impact on food security in the poor exporter nations.