9.1 Background
There is widespread interest in the culture of shrimps and prawns in many countries of Latin America. Experimental work on shrimp culture has been carried out in Honduras, Brazil, Colombia and Argentina, and pilot farms are now in operation in Costa Rica and Panama, both on the Pacific Coast. In the shrimp culture project sponsored by the Banco de Desenvolvimento do Rio Grande no Norte in Natal (Brazil), considerable advances are reported to have been made in the hatchery production of shrimp (Penaeus brasiliensis) larvae, using the techniques adopted in the Galveston Laboratory of the United States National Marine Fisheries Service. Experimental rearing of P. brasiliensis and P. paulensis is also being carried out at Guritiba and Cabo Frío, State of Rio de Janeiro. Commercial shrimp farming on a fairly large scale has developed on the coast of Ecuador and is now spreading to the north coast of Peru (Tumbes area) as well. Local species of shrimps, mainly Penaeus vannamei and P. stylorostris are cultured in earthen ponds built in mangrove areas following the traditional techniques adopted in Southeast Asia (Cobo, 1977), yielding 500-600 kg/ha in nine months. Juveniles are collected from mangrove swamps for stocking the ponds.
Several species of penaeid shrimps contribute to commercial fisheries in Latin America and a screening of species is necessary to determine the more important species to be investigated by the Centre. A major problem faced in the culture of shrimps is the production of larvae or juveniles. Even in Ecuador, where wild juveniles are collected from the mangrove swamps for culture, one of the difficulties in the expansion of the industry is the insufficiency of seed. To add to that, commercial fishermen claim that their catches are adversely affected by the large-scale collection of juveniles by shrimp culturists. There is, therefore, some urgency in establishing viable hatcheries for local species. The production of larval food, which is of considerable importance in the rearing of shrimp larvae, may probably not present major difficulties as there are a number of known sources of Artemia in the region which are not utilized at present. Another high-priority item of research will be the formulation and production of suitable compounded feed for juvenile and adult shrimps in ponds. The possibility of combining pond fertilization and supplementary feeding to obtain satisfactory production needs to be investigated through appropriately designed yield trials.
In view of the facilities required for the above investigations, the resources currently available and the overall workload of the Centre, the Task Force was of the view that any detailed investigations on shrimp culture should be attempted only at a later stage. The Centre could, however, cooperate as far as possible in the on-going studies on shrimp culture in Natal and undertake some of the preliminary work required, which may include the following:
(i) selection of most suitable species for pond culture;(ii) development of simple breeding techniques (induced gonad maturation and ovarian re-maturation of spent females) aimed at reducing dependency on natural stocks of shrimps, by establishing and caring for suitable brood Stocks kept under artificially-controlled conditions;
(iii) development of simple hatchery techniques based on locally available material and designed for easy transportation;
(iv) evaluation of Artemia resources and possibilities for their commercial utilization;
(v) evaluation of other planktonic or benthic foods (Brachionus, Moina, chironomid larvae, etc.) for larval and post-larval stages;
(vi) formulation and preparation of shrimp feeds using locally available ingredients.
Some of the engineering studies proposed to be carried out in connexion with the culture of Mugil spp. will be applied in shrimp culture investigations as well.
A suitable shrimp hatchery and a series of brackishwater ponds should be built in the Cananeia Sub-Centre in the course of the next two years to enable further investigations on shrimp culture.
Although the culture of Macrobrachium has received some attention in a few countries of the region, the Task Force does not consider it necessary for the Centre to undertake any investigation on Macrobrachium culture for the present.
