CULTURE EXPERIMENT AND RELEVANT BIOLOGICAL STUDIES ON PLAGIOGNATHOPS MICROLEPIS

Plagiognathops microlepis Bleeker,an economic freshwater fish (Xenocyprininae,Cyprinidae) widely distributed in China,is a favorite with our broad masses,but itsnatural population is not large and the yield of this fish is low in many waters.As a result of our experimentation and research,now we can successfully conductartificial propagation and culture of this fish on a large scale.We have already stoc-ked a reservoir with a large number of its sizable fingerlings,in anticipation of inc-reasing yield in the coming years.For pond-farming,it has been demonstrated that the participation of Plagiog-nathops in polyculture with the team of“domestic”carps does not interfere with thenormal growth of the latter,and the total yield of a pond is actually increased byabout 10%.The fish is easy to catch (by seining);this makes it a desirable objectfor the practice of recurrent stocking and“skimming”within a year in ponds in-tended for bumper yield.The juveniles as well as the adults of Plagiognathops feed on humus,bottomdetritus and benthic algae,which are not much utilized by the traditional“domestic”fishes.Growth rate of Plagiognathops is rather high during the first two years of life:young fish 6 months of age weigh about 100—150 g,those of 18 months old,above250 g (450 g for the largest specimen);the average weight of 2-year-old individuals is500 g,a size ready for the market.Owing to its tastiness and relatively more edibleparts,fish even of the grade of 100—150 g are readily acceptable to customers.The principal results of our experiments on the rearing of this fish,togetherwith the relevant biological data obtained,are given in this paper.