Culture of Moina micrura on various organic waste products

Moina micrura, a cladoceran species, is considered to be one of the best live food organisms for rearing the young larval stages of fish and prawn. Considering the importance of this species in hatchery operations the present study was undertaken to record its fecundity and life span and to culture it using different locally available organic waste products. In indoor culture, a maximum production of 2600 ind/1 and a minimum of 1050 ind/1 were obtained when treated with gram + maize oilcake and "till" oilcake respectively. In outdoor culture, a highest production of 6000 ind/1 was achieved with "Alsi" and "till" oilcakes and a lowest density of 1050 ind/1 with coconut oilcake and raw cattle dung was obtained with an inoculation rate of 5 ind/1.

Fecundity of the snow-trout, Schizothorax plagiostomus (Heckel) from Garhwal Himalaya

Absolute fecundity of Schizothorax plagiostomus varied from 3474 in a fish measuring 345 mm (T.L.) and weighing 315 g to 13916 in a fish measuring 540 mm (T.L.) and weighing 1370 g. The weight of the fish ovaries accounted for 7.02 to 17.78% of the total weight of the fish. The average number of eggs per kg weight of fish and per gram of ovary weight was found to be 10820 and 81 respectively. The fecundity per kg of body weight was found to be 11539. The relationships between fecundity and other parameters (fish length/fish weight/ovary weight/ovary volume/ovary length) and fish length-ovary weight and fish weight-ovary weight were also determined.

Breeding, age and growth of the freshwater shark Wallago attu (Bloch and Schneider) from the Dhir Beel of the Brahmaputra Basin, Assam, India

The Dhir Beel, one of the major live beels of the Brahmaputra Basin, Assam, has an area of 689 ha and situated in Dhubri district of Assam. The dominance of freshwater shark, Wallago attu (8.10%) in the beel is a striking feature. Restricted breeding of W. attu once a year from June to September was observed. The mean observed length was 37.5, 65.0, 84.5 and 99.0 cm in the 6th, 12th, 18th and 24th months of age respectively. The length growth coefficient (K), the asymptotic length (L infinity ), and the arbitrary origin of the growth curve (t omicron ), for W. attu were estimated to be 0.054484 per month, 136.16 cm and 0.0355 month respectively. The calculated life span (T infinity ) of the fish is 123.86 months (about 10 years). The weight growth parameters were estimated where the monthly growth coefficient (K), the asymptotic weight (W infinity) and the arbitrary origin of the growth curve (t omicron) were found to be 0.0743 per month, 7636.92 gram and 0.431908 month respectively. The length-weight relationship follows the cube law.

Salt-tolerance in mangrove soil bacteria

A total of sixteen bacterial species were isolated from mangrove soils of Karachi, Pakistan. Twelve of the isolates were gram positive while four were gram negative. All sixteen species showed resistance to high concentration of streptomycin, however, resistance to chloramphenicol and tetracycline was variable. The isolates tolerated up to 110‰ salinity and accumulated sodium form the media.

A survey of the microbiological quality of commercial frozen prawn products

The paper presents the results of a bacteriological survey carried out on 2,917 samples of frozen prawn, 55 samples of raw material, 35 samples of water, 4 samples of ice and 42 samples of various equipment used for processing. The survey covered a period of three years (1960-63) and comprised of samples collected from five of the leading processing factories in Cochin. Frozen products tested consisted of headless (marine and fresh water), peeled and deveined and cooked frozen samples. Statistical analysis of the data shows that there is no significant variation between samples and between factories with respect to product quality. The standard plate count varied between 1.0x10(4 superscript) and 1.0x10(6 superscript) per gram for headless and between 1.0x10(4 superscript) and 1.0x10(7 superscript) for peeled and deveined and cooked frozen samples. Majority of the samples had bacterial load well within the limits prescribed for such products.

The bacterial flora and their possible association with spoilage in a variety of fresh-water fish: Cyprinus carpio. var. communis

The bacteria from a variety of fresh-water fish, Cyprinus carpio. var. communis, showed the presence of micrococci, Gram positive and Gram negative rods. These have been characterized as far as was possible. Of thirty-eight strains of bacteria used, only six strains were considered as causing spoilage of fish flesh in experiments where flesh was incubated with individual cultures of the bacteria. These six strains had been found on the surface and/or intestine of the fish and support the suggestions that, after death, invasion of flesh by bacteria from the surface and intestine could be the cause of bacterial spoilage of fish.

Utilisation of trash fish. Pt. 1. Preparation of fish flake

The paper deals with the investigations carried out on the preparation of odorless fish-starch flakes using partially deodorized trash fish meat and different sources of starch like corn, tapioca, maida and black gram. It has been found that the products using corn and tapioca are better compared to those prepared using other two starches, the product from corn being the best. The product has a protein content of about 20% and has been found to have a storage life of 4 months at 37°c.

Quantitative and qualitative studies on the bacterial flora of fresh sardines

Plate counts at R T and 8 C on the skin with muscle and the gut contents of absolutely fresh sardines (Sardinella longiceps) caught off Cochin showed a seasonal variation when sampling was done over a period of 12 months. The counts of the gut contents ran parallel with those of the skin with muscle, but at a higher level of magnitude. Qualitatively, the analysis of 360 strains of bacteria isolated from the skin with muscle and 100 strains from the guts during a year's study revealed a very high preponderance of Gram negative rods, mainly of Achromobacter, Vibrio, and Pseudomonas groups. The percentage of Gram positive organism was very low or nil at times in the ocean fresh sardines.

Common microflora involved in spoilage of canned prawns

An elaborate survey was carried out to ascertain the common types of micro-organisms responsible for spoilage in canned prawns. Among nearly 1.500 strains isolated from bacteriologically defective cans, 60% were Gram positive spore formers of the Bacillus type. Other types isolated belonged to Gram positive cocci, Gram negative rods, Gram positive non-spore forming rods, Gram negative cocci and coccoids. No anaerobe could be isolated. The predominant Gram positive spore formers were identified as Bacillus pantothenticus, B. firmus, B. brevis and B. Pumilus species.

Microbiological quality of some iced fishes of Imphal market, Manipur

Imphal is the main marketing centre of fish in Manipur. As fish production of the state is not sufficient to meet the demands, about 120 metric tons of iced fishes are annually brought from other states and sold in this market. Microbiological quality of iced Wallago attu, Labeo rohita, L. gonius and Aorichthy aor in respect of total fungal count (TFC), total plate count of bacteria (TPC), Most Probable Number (MPN) of coliforms, Streptococci, Staphylococcus, Salmonella and Escherichia coli in four tissues (skin, muscle, gill and intestine) were analysed. In all cases, the counts were highest in the gills and lowest in the muscles. The values of TFC, TPC, coliforms, Streptococci and Staphylococci were 0-10³/g 10(sup)6-10⁸/g, 2-α/g, 10-10⁵/g, 10-10⁵/g respectively. E. coli and Salmonella were not detected in any of the samples while the ice used in the preservation contained 10⁵-10⁷ of TPC per gram. The microbiological qualities of the iced fishes of Imphal market were adjudged poor. The extremely high counts of bacteria might be due to (1) poor quality and left over fishes being packed, (2) contact with contaminated ice and (3) repeated thawing and freezing during the process of marketing and transportation.

Antibacterial effect of the Indian squid, Loligo duvauceli (d'Orbigny), ink

The ink of the Indian squid Loligo duvauceli (d'Orbigny) was tested for antibacterial activity. The antibacterial effect of bacteria present in the ink gland was also tested. Only one type of bacteria was found to be present in the ink gland of squid and was identified as Photobacterium leiognathi. Among the various forms of ink extracts, the precipitated and freeze-dried ink showed more pronounced antibacterial effect against Gram-negative bacteria, Salmonella, spp. Escherichia coli, Vibrio cholerae, V. parahaemolyticus and Pseudoinonas spp., and a less pronounced effect against Gram-positive bacteria, Staphylococcus spp. and Micrococcus spp., P. leiognathi did not inhibit any of the above bacteria. The antibacterial activity was associated with the compounds of the ink.

Bacterial quality and depuration of the green mussel Perna viridis from natural beds

Green mussel (Perna viridis) and sea water from their natural beds on the coastal areas of Porto Novo were studied between April and August 1996 for their bacterial quality. Water samples from the beds were also analysed for their physico-chemical parameters. The total bacterial count of mussels from natural beds as well as bed waters ranged 10³ organisms per gram of mussel meat suspension and per milliliter of sea water. The faecal coliforms were found to be within the permissible limits. Pathogenic bacteria such as Salmonella spp., Streptococcus spp. and Staphylococcus spp. were absent. The variations in pH, temperature, salinity and dissolved oxygen of the seawater samples were insignificant. The mussels were subjected to depuration by different methods among which chlorination was found to be most effective.

A Comparison of the bacterial flora of surface and sub-surface water of the sea off Ceylon

Under stable conditions of stratification of the sea, evidence of generic differences of the associated bacterial flora of the water masses has been obtained, between surface and sub-surface water. Gram negative rods, especially pseudomonads and achromobacters were more frequent at the surface. The fermentative and oxidase negative flora was more frequent in sub-surface water. The surface water in general had a greater variety of bacterial types while the sub-surface water had a flora with a greater range of biochemical activity. These results are discussed in relation to the hydrological condition of the water masses and the bacterial flora of freshly caught fish.

The nature of the aerobic gastrointestinal bacteria of cichlid fish Sarotherodon mossambicus (Peters) and Tilapia nilotica (Linnaeus) grown under captivity

Bacteriological examination of the gastrointestinal microflora of 2 freshwater cichlid fish species (Sarotherodon mossambicus and Tilapia nilotica ) was performed, resulting in the bacteria enumeration of total viable counts of 1.06x10⁷/g and 7.75x10⁷/g of gastro-bacteria intestinal tract plus contents (wet weight) respectively, by aerobic incubation at 30+1°C. The majority (78%) of the total gut isolates from both fish species was Gram positive mesophilic which is characteristic of the higher ambient temperature in the tropics. These isolates were fastidious in their nutritional requirements and together with the rest are isogenous to bacteria autochthonous to soil and water. The occurrence of such organisms is attributed to the feeding habits of these fish. The gastrointestinal bacteria isolated in this study are transient residents but not "indigenous" in these cichlid fish.

Bacterial flora associated with diseased fish and their antibiogram

Bacterial flora associated with tail rot/fin rot of Carassius auratus, Xiphophorus helleri and hemorrhagic ulcers of Clarias spp were studied. Sensitivity pattern of 33 isolates comprising Aeromonas spp, Pseudomonas spp and Gram-positive rods from diseased C. auratus, X. helleri and Clarias spp were screened against six broad-spectrum antibiotics viz. ciprofloxacin, chloramphenicol, co-trimoxazole, gentamycin, nitro-furantoin and oxytetracycline. Ciprofloxacin was the most effective in inhibiting bacteria at 0.05-0.10 µg/ml level. About 44% of Pseudomonas spp. was resistant to nitrofurantoin. Resistance to oxytetracycline was seen in 27% of Aeromonas spp Gram-positive rods were comparatively more resistant to antibiotics. The multiple antibiotic resistances were seen in 21% of the bacterial isolates of diseased fish.