Trade of live brooders of the black tiger shrimp, Penaeus Monodon Fabricius 1978, at Visakhapatnam, Andhra Pradesh

The demand for brooders of Penaeus monodon by the hatcheries, which are solely dependant on wild brooders for their seed production, has resulted in a vigorous fishery and trade for this species, especially along the Visakhapatnam coast. More than three hundred brooders are brought in per day for trading during the peak landing season from December to March every year. The price of gravid brooders has been declining over the years but on an average is about Rs. 30,000 per brooder. The total length of male brooders ranged from 190 to 246 mm during the three years under study and for females it varied between 210 and 330 mm. A specialized methodology for transportation, storage and trade of P. monodon brooders has been evolved over the years at Visakhapatnam Fishing Harbour. Concentrated exploitation of brooders from the wild and presence of pathogens in them makes a strong case for development of specific pathogen free brooders and conservation of wild stock.

Substitution of live feed by formulated diet: effect on the growth and survival of Betta splendens (Regan) fry

The present work evaluates the effectiveness of partial or total replacement of live feed (LF) (Tubifex) together with formulated diet (FD) for Betta splendens. Three hundred Betta splendens fry of uniform size (mean weight 0.19±0.01g) were equally distributed in five treatment groups with three replicates in glass aquaria of 351itre capacity. Fishes were given diets at different ratio of LF and FD viz. T1(C) 100% LF; T2 75% LF, 25% FD; T3 50% LF, 50% FD; T4 25% LF, 75% FD and T5 100% FD and the experiment continued for 105 days. T2 group registered highest (P<0.05) % body weight gain (125.61±0.26) and specific growth rate (2.34±0.02), which was similar to T1 and T3 groups. Lowest FCR was recorded in T2 (2.40±0.11) group, which was similar to Tl, T3 and T4 groups. Highest (P<0.05) PER was observed in T4 (1.00±0.03) group, which was similar to T3 and T5 groups. At the end of experiment, highest % survival was recoded in T1, T2 and T3 groups (96.67±1.67), which was similar to T4 group. From the study, it is concluded that LF can be successfully replaced up to 75% by FD without any adverse effect on the growth and survival of Betta splendens.

Studies on depuration of live clams (Villorita sp.)

Live clams collected from their natural beds were depurated by starving them in water. Water from their natural environment, potable water from municipal water supply and sodium chloride solution made up to the strength of natural brackish water as well as all these chlorinated at 5 p.p.m. level were used. The acid insoluble ash could be brought down to insignificant level by depuration in natural water for a period of 16-18 h. Bacterial quality of the meat also could be improved by this method. Chlorination of the system at the end of depuration further improves the bacterial quality of the meat.

Studies on the transportation of live clams

Live clams (Villorita cyprinoides) collected from their natural beds were packed in different ways like dry pack, tray pack, in oxygenated water (wet pack) and depurated samples in wet pack. It was found that the packaging in l kg lots in 200 gauge polythene bags with oxygen at a temperature of 20°C could keep them live for 4 days. In tray pack without oxygen and water they can be kept alive for 3 days at 20°C. Temperature seems to be the critical factor in the transportation of live clams. At room temperature both dry and wet pack can be kept for 24 h only. Depuration technique does not appear to be useful in prolonging the storage life of clams in live condition as percentage mortality is more at 48 h both at 20°C and room temperature compared to the non-depurated samples.

Preliminary studies on the holding of live mussels after harvest

Green mussel (Perna viridis) were harvested to study the applicability of chilling to keep the mussels alive for a longer period of time and to review existing methods of packaging and transport. Data obtained from preliminary studies indicated the effectiveness of keeping mussels alive as long as 4 days with minimal mortality rates.

Study on the growth and survival of Channa striatus (Bloch) postlarvae using live feed

Feeding experiments were conducted on the postlarvae of Channa striatus with two different live feeds - a copepod (Thermocyclops decipiens) and cladocerans (Moina micrura and Ceriodaphnia comuta) individually and in mixture. Food was provided at the rate of (500±50 Ind/L) and the experiments were carried out in 100 litre capacity tanks for 30 days. Results indicated better weight gain (951.85±28.77%) and survival (92.00<%) of postlarvae fed with mixed live food than individual live feed organisms.

Effect of feeding bioencapsulated Lactobacillus sp. in live Tubifex sp. on the growth performance of gold fish Carassius auratus (Linnaeus, 1758)

An attempt was made to feed bioencapsulate Lactobacillus sp. in live fish food organism Tubifex for use in the culture of gold fish Carassius auratus. The C. auratus fries when fed with bioencapsulated Lactobacillus sp. in Tubifex showed significant improvement in total wet weight gain (p<0.007) and FCR (p<0.01) compared to control. The specific growth rale and mean survival were slightly higher, although insignificantly (p>0.05) in bioencapsulated Tubifex fed group. None of the bacteriological parameters of the fish gut between the experimental and control groups differed significantly (p>0.05). Lactobacillus sp. was recorded at a level of log 5.11/g on the 90th day of experimentation. When the experimental C. auratus fries were infected with Pseudomonas fluorescents, the bioencapsulated Tubifex fed group resisted the infection. The survival was significantly higher (p<0.05) in bioencapsulated Tubifex fed group (44%) than in control (22%). The C. auratus fed with bioencapsulated Tubifex showed less (55%) signs of tail/fin rot. Likewise, a significant improvement in total wet weight gain (p<0.009), FCR (p<0.01) and SGR (p<0.04) of C. auratus brooder fed with bioencapsulated Tubifex was seen compared to control group fed with depurated Tubifex.

A microelectrode drive for long term recording of neurons in freely moving and chaired monkeys

An electrode drive is described for recordings of neurons in freely moving and chaired monkeys during the performance of behavioural tasks. The electrode drives are implanted for periods of up to 6 months, and can advance up to 42 electrodes using 14 independent drive mechanisms. The drive samples 288 points within a 12 mm x 12 min region, with 15 min of electrode travel. Major advantages are that recordings are made in freely moving monkeys, and these recordings can be compared with those in chaired experiments; waveforms of single neurons are stable, enabling prolonged recordings of the same neurons across periods of days; recordings can be made throughout the brain, including the dorsolateral prefrontal cortex and hippocampus; the drive accommodates both sharp microelectrodes and fine wire assemblies such as tetrodes. (C) 2003 Elsevier Science B.V; All rights reserved.

Supply of Astaxanthin and its combinations through live feed (Moina micrura) enrichment affects the growth, survival and fatty acid profile of Macrobrachium rosenbergii larvae

A study was carried out with three replicates to determine the effects of feeding Moina micrura enriched with astaxanthin alone (M1) or astaxanthin in combination with either vitamin E (M2), vitamin D (M3) or Cod Liver oil (M4) on the growth, survival and fatty acid composition of giant fresh water prawn Macrobrachium rosenbergii (de Man) larvae. Growth rate was expressed as the time taken to the settlement of 95% post larvae. Maximum growth, the lowest time taken to the 95% PL settlement (38.5±0.50 days), was observed in larvae fed with M3 Moina. The highest survival rate (66.0±1.00%) was observed in those fed with M4 Moina and the second highest survival (61.0±1.00%) and growth rates (40.0±0.00 days) were shown with M2 Moina. The minimum values for both growth (42.5±0.50 days) and survival (33.0±1.50%) were observed in the group fed un-enriched Moina. Results also showed that the survival of prawn larvae increased as the quantities of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) increased in the dietary Moina. The highest levels of EPA (5.57±0.21%), DHA (3.50±0.21%) and highest total Highly Unsaturated Fatty Acids (HUFA) (13.87±0.68%) were seen in the Moina fed on astaxanthin and Cod Liver Oil (CLO). The results of the study showed that the nutritive quality of Moina, with respect to important fatty acids, can be increased by enrichment and will influence the growth, survival and the fatty acid composition of fresh water prawn larvae fed on them.

Survey of food supplementary (Pseudomonas fluorescence) and live food (Algae and brine shrimp) on Penaeus indicus larval stages

In this study ,the effects of Pseudomonas fluorescence obtained from generator pond water of Kolahi as supplementary and four algae consisting of : Chaetoceros sp, Chlorella and Skeletonema sp and Tetraselmis sp, three types of artemia as live food larval states from zoa to postlarvae (PL4 ) Penaeus indicus were investigated. The results indicate that Pseudomonas fluorescence has positive effect on Penaeus indicits larvae growth and their living food. Effective ranges at minimum and maximum were estimated. In most cases optimum dosage was approximately determined. Optimum dosage is between 50 -150 milligrams per liter for living food and Penaeus larval More than 200 milligram per liter resulted in a negative effect on the growth and survival. Also the results indicate Uromiana artemia. Requires a higher concentration of the bacteria the imported artemia. As a conclusion it is recommended to introduce Pseudonionas fluorescence as a new medium for the growth of some mentioned algae .

Strengthening the log book recording system for fishing vessels: Sri Lanka

Activities of the project included: preparation of awareness materials on data reporting; organizing stakeholder awareness programmes; setting and maintaining an electronic database; inputs from participants and recommendations

Live food: a lesser known essential

This article is a short discussion of the requirements for live food production in aquaculture and a brief presentation of the processes involved.

Agiis: a bivalve cultivated as live shrimp feed

Live 'agiis' have been proven to be a good feed for shrimp for the past ten years by polyculture fish farmers in the province of Capiz, in the island of Panay, west central Philippines. A brief account is given of culture and feeding operations. Its cultivation period is short and seeds are readily available. It can reduce dependence on trash fish which is now getting to be scarce; it also seems much cheaper. Perhaps this fast-growing tiny bivalve can be scientifically investigated by students of aquaculture as feed for other commercial aquaculture species. Its scientific identification can be a good start.

Manual for production of live feed (Moina) for African catfish fry

The African catfish (Clarias gariepinus) is a commercially farmed fish in Uganda, second in importance after the Nile tilapia (Oreochromis niloticus). This catfish has gained rapid popularity in aquaculture because of its faster growth and higher pond yields attaining average weight of over one kg with pond yields as high as 3.0 kg/m2 in six months compared to an average weight of 500g and pond yields of 1.2 kg.m2 for the Nile tilapia