Avaliação das necessidades em água doce do estuário do Guadiana (Portugal) com recurso aos desembarques da pesca profissional.

Abstract

The importance of the freshwater inflows to the estuarine and adjoining coastal waters fish communities are put in evidence and a relationship between the commercial fisheries landings and freshwater inflow is presented. For the period between 1988 and 2000, twenty-one different equations were obtained, relating fish catches landed at the Vila Real de Santo António harbor, and the freshwater flow of the River Guadiana. Spring and summer were the seasons of the year that showed a higher number of significant relationships between fresh water flow and commercial fisheries landings. Estimates indicated that a fish catch of 1220 t/ year would depend upon an annual freshwater inflow of 1280 hm3, distributed in the following way: 22.7 m3/ s during the wet season (December to March), 39.0 m3/ s during the spring (April and May), 18.3 m3/ s during the dry season (June to September) and 69.6 m3/ s during the autumn (October and November). A flushing flow of 280 hm3 (7.5 days/ year) should be added to the previous scenario, preferably during the spring.