A CONTRIBUTION TO THE UNDERSTANDING OF HOW TO CULTURE THE NATIVE PRAWN Macrobrachium carcinus THAT HABITS THE RIVERS OF THE CARIBBEAN COAST OF COSTA RICA
Juvenile prawns Macrobrachium carcinus were collected with tramps used by
the fishermen in the estuary of the river Colorado in the Caribbean coast of Costa Rica.
Their average weight was 10 grams and a 50-50% males and females was assumed.
They were transported in tanks with oxygen to the aquaculture station of INCOPESCA
in Pococí, Limón, where they were acclimated and stocked in earthen ponds with cement walls.
After 3 months, an average growth rate of 6.78 grams/month, 100% survival
and one of the females with a mass of orange eggs were obtained. Since then, it was
possible to find berried females in that pond during every month in a year. This observation is very important to predict that always are berried females ready in a potential brood stock pond to spawn at any moment in tanks for larval culture. In fact, 6 berried females with brown eggs were capture in this pond and transported to the Parque Marino in Puntarenas where the culture of larvae was implemented.
A larval culture system without any control in environmental conditions was
implemented using the same commercial system applied for the introduced specie Macrobrachium rosenbergii. They were alive 22 days and during this period were observed at microscope. The most visible morphological changes were recorded in order to show the different larval stages. Seven larval stages were found, but last stages before post larvae were not obtained.
In conclusion, there is still a lot of technical details to solve in the larval culture
of this native prawn of the Caribbean coast of Costa Rica. First at all, the kind of food
and the feeding practices must be adjusted to its small size and slow growth rate although morphological development can be observed. Secondly, more research about the role of salinity should be made because it seems to be that should not be fixed but flexible. As in the natural environment of the river estuaries, salinity could fluctuate according to the larval development.