Fish culture in marine farm at Mandapam

The large-scale monoculture and polyculture of the milkfish, Chanos chanos were reported earlier form Southeast Asian countries.This article highlights some interesting and encouraging results obtained during the experiments of milkfish monoculture and polyculture of milkfish with mullet in Mandapam ponds. In the monoculture of milkfish the average size of the fish as well as the production rate could be substantially stepped up by resorting to supplementary feeding. In the polyculture of milkfish, the average growth rate was found to be more or less similar in both the fertilized and unfertilized ponds but the survival and production rates were higher in unfertilized pond. The yield of milkfish under monoculture in the present study is comparable to that of Ceylon, where selective harvesting followed by replenishment gave a production of 799 to 1159 kg/ha/annum. A production rate of 1405 kg/ha/10 months obtained in the present experimental polyculture of milkfish

Further observations on polyculture of finfishes and Prawns in saltwater ponds and in a net-pen at Mandapam

The paper deals with the results of polyculture experiments with milkfish. mullets, Sillago and prawns in salt water ponds and in a netpen in the coastal waters of Palk Bay at Mandapam, during the period 1979-82. The growth of mullet and Sillago was better in the netpen than in the pond, whereas milkfish showed better growth in the pond. Significant differences in production from fertilized and unfertilized ponds have not been noticed, the result of which is attributed to poor soil conditions of the farm. Mullets sharply reacted to low levels of oxygen in ponds. During 1979-80 period, in experiment I, the production per hectare was 671.1 kg for Chanos chanos, 68.9 kg for Valamugil seheli, 593. 3 kg for Liza macrolepis and 31.1 kg for Penaeus indicus, thereby recorded the total of 1364.4 kg. In experiment II, the production was 1286. 7 kg for C. chanos, 551.1 kg for V. seheli md 26.7 kg for Sillago sihama with the total of 1864.5 kg. In 1980-81 experiment, the total production was 1600 kg with the combination of 1266.7 kg C. chanos and 333.3 kg V. seheli in the fertilized pond and 1422.2 kg with the combination of 1205.5 kg of C. chanos and 216.7 kg of V. seheli in the unfertilized pond. During 1981-82 period, the total production was 1377.8 kg in which C. chanos showed 1288.9 kg and V. seheli 88.9 kg in the fertilized pond, and in the unfertilized pond it was 1469.9 kg with 1405.5 kg of C. chanos and 64.4 kg of V. seheli

Culture of the sea bass Lates calcarifer

Studies on the growth of Lates calcarifer cultured in coastal ponds and net cages in the three different places at Tuticorin showed an increase of 16.2-23.2 mm/ 18.6- 53.2 g/ month at Karapad, 21.1-29.8mm/19.3- 36.3 g / month at Veppalodai in coastal ponds and 21.6-32.4 mm/ 31.4-55.0 g / month in a net cage in the Tuticorin Bay. The growth in Karapad pond, where supplementary feed was provided was better than in Veppalodai pond. The highest growth rate was obtained in net cage culture at Tuticorin Bay. Length-frequency analysis of samples from commercial catch reveal a faster growth in the wild than in the culture systems. The better growth in the brackishwater culture and in the wild is attributed to the lower salinity and better live feed availability in brackishwater. In the pond system, the growth can be improved by maintaining proper water exchange so as to maintain the salinity equivalent to open sea/bay/ brackishwaters and by providing supplementary feed

Further observations on the suitability of the marine fish farm at Mandapam for the culture of milkfish and grey mullets

The paper gives an account on the culture of milkflsh Chanos chanos and the grey mullet Valamugil seheli under mono and polyculture systems in the saltwater ponds at Mandapam during the period 1982- 1983. Ponds of 2,400 mS (two ponds), 450 m2 (2 ponds) and 200m2 (3 ponds) were used for conducting the culture experiments. The stocks were fed with a supplementary feed. The growth of fish was better in polyculture experiments. The rate of production of Chanos chanos was 354-443 kg/ha with a survival of 73.2-79.9% in monoculture and 422-872 kg/ha with 56.7-70.0% survival in polyculture experiments. V. seheli indicated a production of 200-290 kg/ha and 67-89 kg/ha with the survival rates of 22-91 % and 13.3-20.7% in mono and polyculture experiments respectively

Status and new operation modes of the versatile VLT/NACO

This paper aims at giving an update on the most versatile adaptive optics fed instrument to date, the well known and successful NACO . Although NACO is only scheduled for about two more years at the Very Large Telescope (VLT), it keeps on evolving with additional operation modes bringing original astronomical results. The high contrast imaging community uses it creatively as a test-bench for SPHERE and other second generation planet imagers. A new visible wavefront sensor (WFS) optimized for Laser Guide Star (LGS) operations has been installed and tested, the cube mode is more and more requested for frame selection on bright sources, a seeing enhancer mode (no tip/tilt correction) is now offered to provide full sky coverage and welcome all kind of extragalactic applications, etc. The Instrument Operations Team (IOT) and Paranal engineers are currently working hard at maintaining the instrument overall performances but also at improving them and offering new capabilities, providing the community with a well tuned and original instrument for the remaining time it is being used. The present contribution delivers a non-exhaustive overview of the new modes and experiments that have been carried out in the past months.Comment: 10 pages, 7 figures, SPIE 2010 Astronomical Instrumentation Proceedin

Fish mortality due to pollution by industrial effluents in inshore waters of Kayalpatnam

Mortality of fishes and aquatic organisms due to pollution was observed in inshore waters of Kayalpatnam and adjacent area. A brief account of this incident with results of analysis of relevant parameters is described in this paper

Abundance of milkfish fry in relation to lunar periodicity in the nearshore waters around Manoli Island, Gulf of Mannar

Observations on the occurrence of fry of milkfish Chanos chanos carried out at ManoIi Island from April 1983 to June 1984 in relation to the lunar periodicity are presented in this paper. During this period 137, I75 fry were obtained, with a peak occurrence in May. Large quantities of fry were collected during day time of new moon period. The study also indicated the peak occurrence of fry in the initial flow of water during h i b ti&. The possibilities of large scale collection from the adjoining areas appear to be bright

Induced spawning and larval rearing of the grey Mullet Liza macrolepis (Smith)

The paper deals with the results of experiments on induced spawning and larval rearing of Liza mecrolepis (Smith) during the years 1981 and 1982 at Mandapam. Major carp pituitary glands and chorionic gonadotropin were used for hypophysation. The effective dosages varied between 600 and 1200 mg and 110000 and 340000 I.U. per kg body weight of the fish in the case of major carp pituitary gland and chorionic gonadotropin, respectively.' In the combination of both, the dose required was 1200 mg and 12000 to 15000 I.U. The size of fully mature egg ranged from 0.70 to 0.74 mm and that of fertilized egg from 0.74 to 0.78 mm. The newly hatched larva measured 1.43 mm. Mouth formation was observed at 42 h after hatching when the larvae were 2.36 mm. High mortality occurred on the third day. The larvae could be reared for seven days, when they attained a size of 2.47 mm. The larval development is described in detail

Preliminary experiments on the culture of grey mullets at Mandapam

The paper deals with experiments on the culture of grey mullets Valamugil seheli, Liza vaigiensis and Liza macrolepis in monoculture and polyculture systems in seawater ponds and a pen erected in coastal waters at Mandapam

Threadfin breams and lizard fish resources in the shelf waters of the Indian EEZ

The regional and seasonal distribution and abundance of threadfin breams and lizard fish are presented as revealed by the bottom trawling operations of FORV Sagar Sampada during cruises 56-91 (1989 and 1992). The threadfin breams occurred in 49 and lizard fish in 25% of the total number of bottom trawhng stations surveyed. The most productive grounds for threadfin breams were located in the southwest coast between 8° and 15° N latitudinal zones, with the area 11775° yielding the highest average catch rate of 1794 kg/hr. Very high congregation and concentration of threadfin breams, composed mainly of Nemipterus mesoprion and N. japonicus, was observed in the southwest in 41- 80 m depth zones during southwest monsoon period. Lizard fish resources, composed mainly of Saurida tumbil and S. undosquamis were also relatively more dominant in the southwest coast than along the east coast and in the EEZ of Andaman-Nicobar islands. The size distribution of N. japonicus and A', mesoprion showed that smaller modal groups were dominant in shallower depth zones. The potential yield of threadfin breams in the southwest zone was estimated to be 2.05 x 10