Evaluation of transferred fisheries technology in Kainji Lake basin

Fisheries is important to Nigeria agricultural economy because it provides employment for fisherfolks (men and women fishers, fishmongers (fish traders), fish processors and fish farmers. It also supplies protein to the diet of Nigerians and it is equally a viable source of foreign exchange earning to the government.The estimated Nigeria population of 120 million consumes about 1.2million metric tones of fish and fish products annual. This justified the important role fisheries could play in nigerian diet considering that Nigeria has vast inland waters that cover an estimated total surface area of 199,580km super(2) and equally vast sea area of 25,000km super(2). In these waters the author claimed that there are diverse fish resources that are of economic importance in both inland and seawaters. FDF (2000) also estimated that the current annual yield of both inland and seawater put together is about 418,069,3 metric tones from artisanal fisheries and 23,720 metric tones from aquaculture. The shortage between the annual consumption level of 1.2million metric tones and annual yield of 418,069,3 metric tones is made available through importation. It is therefore of concern that given the level of current fish yield from the various fisheries resources the demand still exceeds supply. One wonders whether the production inadequacy is due to poor management of available fisheries resources or that improved fisheries technology that could aid increased production was not efficiently transferred to fish farmers. To answer these questions one need to examine the past and present extension policy in Nigeria as they affect dissemination of fisheries technologies

Imagen corporal en estudiantes universitarios: comportamientos dietéticos y actitudes nutricionales

[ES] En el presente estudio se evalúa la relación entre el estado nutricional, las actitudes y comportamientos dietéticos, y la percepción de la imagen corporal en universitarios. Se registraron más casos de sobrepeso en hombres que en mujeres. Sin embargo, la tendencia a “hacer dietas” fue mayor en las mujeres, lo que podría deberse a la presión social por mantener una imagen estilizada.

Simetria ala simetria eza? Hitzordenaz hausnarrean

Iñigo Arteatx, Xabier Artiagoitia, Arantzazu Elordieta (arg.)

Hypertrophic phytoplankton: an overview

An overview is provided of studies on hypertrophic phytoplankton in order to explore the subject and to suggest uncovered areas of research in this increasingly important theme. The authors restrict themselves to stagnant environments, using a community criterion to define hypertrophic environments. They are defined as those whose yearly average of phytoplankton chlorophyll is equal to or higher than 100 mg per cubic metre of water. The paper deals with species composition, diversity, biomass, primary production, losses and seasonal succession of hypertrophic phytoplankton. Other topics, such as population dynamics and ecophysiological issues, either lack enough information to be considered or are well known, e.g. Microcystis and Oscillatoria ecophysiology.

Taking a systems-oriented view of phosphorous enrichment in fresh waters

Eutrophication of fresh waters through anthropogenic enrichment by phosphorus is a global problem. The role of phosphorus enrichment in the formation of blooms of toxic blue-green algae (Cyanobacteria) in fresh waters is well established and of considerable concern in terms of human and animal health, loss of water resources and amenities, threats to fish stocks, and aesthetic considerations. Cultural eutrophication also poses threats to the ecosystem balance in fresh waters, with implications for wildlife. This article examines phosphorus enrichment in fresh waters from a systems perspective, and explores systems solutions that may be helpful in the development of more sustainable policies.

Ultranarrow absorptive spectral line induced by microwave field

This paper investigates the absorptive spectral lines of four-level atomic system driven by a coupling, probe and microwave fields. Due to the perturbation of the microwave field, the original electromagnetically induced transparency is changed to electromagnetically induced absorption and the absorptive spectral line can be very narrow. This ultranarrow spectral line has potential applications to the microwave atomic frequency standard and the measurement of very weak magnetic field.

Species composition and relative abundance of zooplanktivorous haplochromines in the northern portion of Lake Victoria (Uganda)

Recent surveys have indicated an increase in haplochromine biomass recorded from the bottom trawl and in the beam trawl. The haplochromines recovering in the offshore waters belong to three species in the zooplanktivorous trophic group: Yssichromis laparogramma (Greenwood and Gee), Yssichromis fusiformis (Greenwood and Gee) and Astatotilapia lacrimosa (Boulenger). In this paper, the species composition and relative abundance of the zooplanktivorous haplochromines recorded from the bottom and frame trawl surveys in the various parts of the Ugandan waters of Lake Victoria are discussed.