On the distinction between Penaeus indicus H. Milne Edwards and Penaeus merguiensis De Man (Crustacea : Penaeidae) with special reference to juveniles

Clear-cut differences between the juveniles of Penaeus indicus and Penaeus merguiensis are pointed out in this paper. On the basis of the colour pattern of the antennal flagella, antennular flagella and the pleopods, and the disposition of the rostral teeth it is now possible to identify the juveniles of P. indicus and P. merglliensis with certainty

Effect of temperature and salinity on the hatching of eggs and larval development of sugpo, Penaeus monodon

Abstract only.Incubation of Penaeus monodon eggs and rearing of different larval stages were undertaken at nine temperature-salinity combinations. The eggs, nauplii, zoea and mysis from one spawner kept as stock culture at ambient temperatures of 26-30°C and salinity of 32-33 ppt were exposed to temperature levels of 23, 28 and 33°C and salinity levels of 23, 28 and 33 ppt. Eggs and nauplii survived the sudden change of temperature and salinity (from ambient to experimental) but the zoea and mysis did not. However, salinities of 23 and 28 ppt in combination with any of the temperature levels produced weak larvae. Highest mean hatching rate was obtained at the temperature-salinity combination of 23°C-33 ppt, followed by 28°C-33 ppt and 33°C-33 ppt. Incubation periods for these treatments were 22, 16 and 14 hr, respectively. Survival rate of nauplius (taken from stock cultures) to first zoeal stage was highest at 28°C-33 ppt, followed by 33°C-33 ppt and 23°C-33 ppt with molting time of 50, 45 and 75 hr, respectively. The nauplii exposed to 33°C-33 ppt molted to zoea stage within 38 to 40 hr but later died. Those exposed to 23°C-33 ppt and 28°C-33 ppt reached zoea stage within 57 to 60 hr and 48 to 50 hr, respectively. Similarly, the nauplii taken from the stock cultures and reared until postlarval stage (P1) under experimental conditions completed the zoea and mysis stages in 9 to 11 days at 28°C C-33 ppt, 7 to 9 days at 33°C-33 ppt, and 13 to 15 days at 23°C-33 ppt. Statistical analysis showed that salinity had highly significant effect on rates of hatching of eggs and survival from nauplius to first zoeal stage but not temperature although the latter had an apparent effect. However, both factors affected time of hatching of eggs and time of molting from nauplius to zoea. Interaction effect was significant only on rate and time of hatching. Different sources (spawners) of eggs and nauplii did not have significant effect on time of hatching and molting from nauplius to zoea, but significantly affected the hatching rate of eggs and survival rate of nauplii to zoea stage

Recruitment of postlarval penaeid prawns in the Vellar estuary, South India

Abstract only.The northern bank of Vellar estuary (Parangipettai, India) is ideal for postlarval penaeid prawn recruitment. The annual recruitment, distribution and the substratum preference of postlarval immigrants at three different stations in the estuary were studied in detail. Among the postlarvae of Penaeus, P. (Fenneropenaeus) indicus was dominant followed by P. (Penaeus) monodon, P. (P.) semisulcatus, P. (F.) merguiensis and P. (Melicertus) latisulcatus. In Metapenaeus, postlarvae of M. monoceros were abundant followed by M. dobsoni, M. affinis, M. bre-vicornis and M. lysianassa. Two peaks were observed in the postlarval penaeid prawn population. In P (F.) indicus and P. (P.) monodon, the primary peak occurred from January to April and the secondary peak from July to September. In M. monoceros and M. dobsoni, the primary peak was from March to May and the secondary peak from August to September. The postlarvae of P. (F.) indicus, P. (P.) monodon, M. monoceros and M. dobsoni were available throughout the year while the others were seasonal. The distribution of postlarvae in the estuary is related to the type of substratum, salinity and temperature. The postlarval population declined during the northeast monsoon (November-December) and in peak summer (May-June). Their abundance decreased in the lower salinity areas of the upper reaches of the estuary

Cholesterol requirements of juvenile Indian white prawn Penaeus indicus H. Milne Edwards

Cholesterol is an essential nutrient in the diet of juvenile P. indicus. Survival, growth FeR (Feed conversion ratio), PER (Protein efficiency ratio) and protein retention of juveniles were greally affected by cholesterol deficiency. The growth, FCR, PER and protein retention in the body were significantly improved on inclusion 01 0.5% cholesterol in the diet of prawn which resulted in more protein deposition in the body. Cholesterol requirement tor juvenile prawn seems to be 0.5% of the diet. No harmful effect was observed in the prawn on addi.tion of higher level (4%) cholesterol in its diet

Dietary lipid requirements of the juveniles of Indian white prawn Penaeus indicus H. Milne Edwards

Lipids are indispensable nutrients for growth and survival of shrimps and prawns (Kanazawa, 1985). However, information regarding quantitative lipid requirement of prawns is limited, though most researchers included lipid in th eir dietary formulations for prawns. Lipids derived from plant products, animal products and mixture of plant and animal products have been used in the diets of prawns according to their availability (Kanazawa, 1985). The level of lipid used in the diets also varied according to their convenience, without considering the dietary requirement of the animal concerned

Factors determining spawning success in Penaeus monodon Fabricius

Spawning success in relation to the size of spawner, clumping of eggs, percentage of spawning and frequency of spawning was studied in Penaeus monodon collected off Tamil Nadu, India. The results indicated positive correlation between the size of spawner and the fecundity and hatching percentage, but not the start of hatching. Hatching characteristics were influenced by clumping of eggs or abortive spawning; the greater the clumping, the longer the time taken for hatching, resulting in a lower hatching percentage. The start of hatching time increased when the frequency of spawning increased. Lower hatching rate was observed as the frequency of spawning increased

Seed production and hatchery management of Penaeus indicus

CMFRI has developed an economically viable and ecofriendly hatchery technology suited to Indian conditions, for the seed production of Penaeus indicus. The technology consists of a number of package of practices such as broodstock management, spawning, larval rearing, diatom culture and preparation of particulate feed for the postlarvae. The various package of practices are compartmentalised in separate units so as to maintain proper hygiene and prevent/reduce the incidence of outbreak of diseases. The larvae from protozoea through mysis 2/3 are fed exclusively on diatom. From mysis 2/3 stage to postlarvae 2 to 5 are fed with prawn custard along with diatom. The postlarvae 2 to 5 are transferred to the nursery and reared using egg prawn custard. Details on the maintenance of live feed culture and preparation of egg prawn custard are given. Mention is also made on the hatchery management and economics of two types of hatcheries. The main emphasis of the technology is to make the best use of the available resources and to harness the natural solar radiation and light to the maximum thereby providing an ecofriendly technology which is cost effective

Performance of Penaeusindicus, Cultured Under Three Salinities with Diet Containing Varying Energy Levels and Kilka, Clupeonella Delicatula, Oil Supplementation in the North of Persian Gulf, I.R. Iran

The effects of varying energy and kilka oil levels on the performances of Indian prawn Penaeus indicus were evaluated in a 35 day experimental period in three water salinities (25, 35 and 45 ppt). For each salinity, four experimental diets with energy levels of 3500, 3800,4 1 00 and 4400kcallkg, each containing three kilka (C/upeonel/a de/icatu/a) oil levels of 2, 4, 6% (totaling 1 2 experimental diets) were fonnulated using Lindo softwear program. All diets were isonitrogenous (40% protein) and fed at 8 percent of body weight to 3 6 groups of 200 juvenile shrimps (P. indicus) in each level of salinity. The results showed that under 25 ppt salinity, the diet containing 4 100 kcaV kg with 4% kilka oil showed the best results. For 35 ppt, 3800 kcaV kg with kilka oil level of 6 % was the suitable energy level. At 45 ppt, the best result was observed for the shrimp fed with 3500 kcall kg at 6% kilka oil level. It thus appeared that energy requirement vary with salinity. It also revealed that the energy to protein ratio of 1 1 0-1 1 8 kcaU g proteins was the most suitable ratio for the growth of the shrimp under different salinities. The incorporation of kilka oil in the diet as a source of energy and essential fatty acids showed a satisfactory growth performance of the prawn. The n-3 fatty acid of shrimp body tissue increased with the increasing the dietary n-3 fatty acid levels