Parámetros poblacionales del Ostión de Roca Striostrea prismatica (gray, 1825) en Punta Gorda, Manabí, Ecuador

Abstract

The priority for sustainable use of ecosystems and their biological diversity has been increasing for years, while at the same time allowing the conservation of natural resources and the social and economic welfare of the population. The objective of the present study was to determine the population parameters in the rock oyster S. prismatica in Punta Gorda-Manabí, Ecuador: population structure, define its growth in weight, growth rate, total mortality, by fishing, natural and index of exploitation. Samples were collected monthly for a period of one year (September 2016 - August 2017), obtaining a total of 830 oysters. The average total length was 83,84 ± 1,96 mm, with a length range of 28,80 mm to 215,00 mm. The growth was of negative allometric character, the rate of increase in total weight was slightly less than 3. An L∞ = 225,75 mm was obtained; K = 0.53; t0 = 0,176 and a growth index Φ '= 4,432. The total mortality rate Z = 1,77 ± 0,32 / year, the natural mortality rate M = 0,514 and the fishing mortality F = 1.256,0 The exploitation rate was E = 0,709 and according to the population structure the stock is being exploited mainly in its first years of life. The rate of growth of the S. prismatica rock oyster shows a relatively slow growth, and it would acquire a size of 215 mm in around 6 years. The sizes with greater frequency of capture (65 mm to 100 mm of total length) are organisms of ages of around 2 years, larger sizes although they are available, they are not accessible, considering the fishing gear and the conditions of the site, that make extraction difficult. In general terms, it can be concluded that the rock oyster could be a species to be cultivated, considering that around two years of life are tradable, promote its reproduction in the laboratory for its cultivation under different methodologies and, if necessary, repopulate the natural banks.