Breeding and larviculture of the sapphire devil damselfish Chrysiptera cyanea

Abstract

The sapphire devil damselfish, Chrysiptera cyanea is one among the top ten species of marine ornamental fishes in the international trade. For the first time, broodstock development, breeding and larviculture techniques of C. cyanea were developed and standardised and the details are presented. Broodstock (length of fish:5 to 6.5 cm) was developed in two tonne capacity FRP tanks with biological filter and by feeding with natural feeds ad libitum. The number of eggs per spawning ranged from 2000 - 2500. The interval between successive spawnings ranged from 5 to 20 days. The eggs were oval - shaped and measured around 1.3mm in length and 0.6mm in width. Parental care by the male was noticed. Hatching occurred on the night of the third day of incubation. The larvae were altritial type but with mouth opening at the time of hatching. The length of newly hatched larvae averaged to 2.5mm and the mouth gape around 150μ. Larviculture was done in five tonne capacity FRP tanks by employing greenwater produced by the microalga Nannochloropsis sp. Different larviculture systems were experimented by varying the cell counts of greenwater and live feeds. The cell counts of greenwater employed for the experiments were in three ranges - 1 x 104 to 9 x 104 ml-1, 1 x 105 to 9 x 105 ml-1 and 1 x 106 to 9 x 106 ml-1. Four sets of experiments were conducted by feeding with different live feeds – one set with enriched rotifer (Brachionus rotundiformis) alone, the second set by employing mixed culture of two copepods species viz. Euterpina acutifrons and Pseudodiaptomus serricaudatus, the third set by employing copepods and rotifers together as live feed and the fourth set with copepods as starter feed for the first six days followed by enriched rotifers from 7 to 15 days post-hatch (dph). The larval survival was recorded on 15th dph . Feeding experiments with B. rotundiformis alone and those with B.rotundiformis and copepods together as live feeds were not successful. Coculturing of the two selected species of copepods in optimum range of cell count of greenwater gave the best survival. In this set, survival rate of larvae on 15 dph ranged from 5 to 8%. The maximum survival rate was 5-6% in the group fed with copepods as starter feed upto 6 dph followed by enriched rotifers from 7 to15 dph. It was noted that a cell count range of 1 x 105 cells ml-1 was the optimum, which yielded the maximum larval survival in both these sets of experiments. After 15 dph, the larvae were fed with freshly hatched Artemia nauplii and no further mortality was noted. Metamorphosis of larvae started from 24th day and all the larvae metamorphosed by 30th day. The technique developed has the potential to scale up to commercial level production