The main objective of this study is to measure empirically the level of use of accounting and accounting documents in the informal sector (food stores, shops and stores). To record economic phenomena within an administration and their results, identify management principles, establish forecasts and monitor them, you need an instrument. Among the instruments linked to its organization, accounting, beyond its real mission, currently appears as the regulatory instrument of the company. Climatic contrasts have a notable influence on the soils and, as we will see, on the vegetation of the city. 'Uvira. Accounting, considered as a basic cell and key institution of the economy of a country, The use of accounting documents explains positively and significantly the use of accounting to the extent that accounting is kept on the basis of the information contained in various accounting documents used to record current operations within the company.

Our overall objective was to know the ecological and food relations between Tilapia niloticus and Clarias gariepinus in Lake Kivu, precisely in the Kalengera site. The statistical method helped us to compile tables of data from our surveys in our field of study; the analytical method allowed us to analyze all the data and to interpret them, the techniques of the interview by the questionnaire and the documentation allowed us to collect the data of this study, the tools used are the questionnaire, the notepad , pencil and pen. The random sample was determined by Lynch's formula, which for us was more scientific in nature. 25 questionnaires were administered to fishermen and other individuals working in the Kalengera site and 25 others to provincial inspection agents of Agriculture, Fisheries and Livestock with a size of 152 surveyed. The feeding of Tilapia niloticus and Clarias gariepinus must be done taking into account the species but also the stages, among others the fry between them, the juveniles between them and the marsh fish each other according to size, weight and feeding rate to avoid prey and predators in natural selection and protected species umbrellas by several methods in their ecology by the The method of occurrence, number, volume and weight allowed us to study the food ecology of fish (Tilapia niloticus and Clarias gariepinus) which allows to know the number of fish in which each type of food appears to be expressed as a percentage of the total number of fish examined with the total number of individuals of each type of food given as dominant or recessive and to express the volume or weight of each type of food in each stomach with the beneficial percentage of its contents because 99% of Tilapia niloticus species reproduce in pelagic zones by storing their nests in benthic bottom rocks and only 1% can do so at littoral level with the risk of predators while 100% of Clarias gariepinus species bottom their nests. nesting in spawning grounds precisely in coastal macrophytes.