52 resultados para 19
Resumo:
Taxonomic observations on the larval forms of Cyclops leuckarti are being discussed and compared with Cyclops oithonoides var. hyalina. Observations include Nauplius and Metanauplius stages. The author concludes that specific differences are recognisable even in the nauplius stages.
Resumo:
Recent histochemical and histophysiological research on the skin of fish has posed interesting problems both with regard to the presence of specialized types of cell and with regard to the function of this organ. The present paper intends to study the development and the functional differentiation of the trout's skin, both from the histomorphological and the histochemical point of view. The skin of Salmonids is devoid of specialized cells; the granular cells of Petromyzonti, the serous cells of Selacii and the clavate cells described in many other teleosts and it lacks keratin. As such it can be considered a good working model which can be used to show the eventual histomorphological and histochemical changes occurring both in the transformation from the endovular to the aqueous environment. Histomorphological observations were carried out demonstrate the great structural simplicity of the trout's skin at all stages. The article concludes that glycogen increases greatly when the epidermis thickens and therefore when it becomes necessary to guarantee resistance, amongst which is a support mechanism.
Resumo:
In the Ukraine there are several thousand large, medium and small lakes and lake-like reservoirs, distinguished by origin, salinity, regional position, productivity and by construction a significant number of large and small water bodies, ponds and industrial reservoirs of variable designation. The problem of national systems necessitates the creation of specific schemes and classifications. Classifying into specific types of reservoir by means of suitable specifications is required for planning national measures with the objective of the rational utilisation of natural resources. It is now necessary to consider the present-day characteristics of Ukranian lakes. In the case of the Ukraine it is possible to use two approaches - genetical and ecological. This paper uses the genetical system to classify the lake-like water bodies of the Ukraine.
Resumo:
The present work is concerned with the processes of sand movement in the region of the Elbe estuary. In the first part the results of various investigations which have given indications of the regional transport directions are collected together. The interpretation of the results of a large number of continuous current recordings gives a picture of the resulting transport to be expected under the influence of the tides with those current conditions. This partial translation of the original paper provides the summary of this paper the regional distribution of the flood and ebb flow zones.
Resumo:
This publication gives the results of the bottom trawlings made during the cruise TOGO 7 by the oceanographic research vessel Andre Nizery on the continental shelf of Togo during the estimation program of halieutic resources.
Resumo:
This publication gives the results of bottom trawlings made during the cruises Chalci 83.01 and Chalci 83.02 by the oceanographic research vessel "André Nizery", on the ivorian continental shelf. The publication content is: - an introduction explaining the form of results; the trawl recording cards with the characteristics of trawl and the detail of catches by species; the length frequency distributions of the measured samples.
Resumo:
The workshop and symposium titled Sustainable Small-scale Fisheries: Towards FAO Guidelines on Marine and Inland Small-scale Fisheries was jointly organized by the National Fishworkers’ Forum (NFF) and the Society for Direct Initiative for Social and Health Action (DISHA), in collaboration with the International Collective in Support of Fishworkers (ICSF). The workshop was the first in a series of consultations around the world organized to discuss the Voluntary Guidelines on Small-scale Fisheries (VGSSF) and propose measures, keeping in mind the interests and concerns of small-scale fisheries and fishing communities. The workshop was also a forum to make the role of small-scale fisheries and fishworkers more visible in the context of food security, poverty alleviation and sustainable use of fishery resources. The workshop had 62 participants from both the marine and inland sectors, representing 10 States of India. The participants included fishworkers, representatives of fishworker organizations, policymakers and representatives of multilateral organizations. The workshop was structured to facilitate active interaction and discussion among participants, taking into account linguistic diversity and the contextual differences of the marine and inland sectors. This publication will be useful for fishworkers, fishworker organizations, researchers, policymakers, fish farmers, members of civil society and anyone interested in small-scale fisheries and livelihoods.