Blackening of canned prawn and its prevention

The paper gives an account of the types of blackening associated with canned prawn in brine and their control. It was found that blackening caused by iron sulphide could be controlled by maintaining proper titratable acidity of fill brine in cans. The paper also elaborates on the factors responsible for or governing this critical titratable acidity. In regard to copper sulphide blackening, control was found to be difficult by maintaining the acidity or by additives such as EDTA when the copper content in the material went above the critical level

Studies on blackening of canned prawns. Pt. 1. Influence of copper and iron on product blackening

A linear relationship was observed between the copper content and intensity of blackening in commercially canned prawn meat. Average copper and iron contents of non-blackened canned prawn meat were 9.6 and 32.5 ppm on dry weight basis respectively. In the blackened product copper content ranged from 15.8 to 63.9 ppm and iron content between 43.7 and 71.45 ppm depending on the intensity of blackening. But incorporation of copper in the above range to experimental cans produced blackening while iron up to 250 ppm did not impart any blackening under standard conditions of canning

Marked Blacktip shark landed at Calicut

A marked 'Blacktip shark' Carcharhinus limbatus measuring 200 cm was landed at Elathur, about 14 km north of Calicut. The shark was caught by long lines with large hooks

Present status of exploitation of fish and shellfish resources: Flatfishes and flatheads

The present paper deals with the fishery of flatfishes and flatheads along the west coast of India. Among flatfishes, the malabar role Cynoglossus macrostomus contributes significantly to the catch; Psettodes erumei also forms a fishery along Maharashtra and Gujarat Coasts. Among flatheads Platycephalus macuUpinna contributes to the fishery. These two resources are mainly exploited by trawl. It is found that both the species are continuous spawners, with peak sf>awning taking place during September - November period. In both the groups the one year old fish contributes to the fishery. The major peaks of fishing are either immediately after the onset of monsoon or postmonsoon months

Catch, abundance and some aspects of biology of deep sea fish in the southeastern Arabian Sea

The bottom trawls operated by FORV Sagar Sampada in the southeastern Arabian Sea revealed the existence of grounds with potentially rich unexploited deep sea finfish resources. Chlorophthalmus sp. formed the most dominant species with catch rates of 4.6 tonne/hr at lat. 8°56' N long. 73° 35' E and 4.2 tonne/hr at lat. 8°55' N, long. 73°35'E. Cubiceps rmtalensis with catch rates of 2.8 t forms the next important species. Maximum catch rate of deep sea fish was observed at depths ranging from 300 to 350 m. The other major exploitable species include Neopinnula orientalis, Pseneopsis cyanea, Chascanopsetta lugubris, Priacanthus hamrur and Chlorophthalmus bicomis. Information on some aspects of biology of fishes landed in fairly good quantity are also dealt with. Concentrations of deep sea fish resources are found in comparatively shallower depths in the northern latitudes whereas a wider distribution is seen in the southern latitudes

EXPERIMENTAL FIELD CULTURE OF WHITE PRAWN, PENAEUS INDICUS, IN THE POLYETHYLENE FILM - LINED PONDS USING PELLETISED FEED

The results of two experiments on the culture of Penaeus indicus conducted during the year 1982 are given. A high survival rate of 99.2% was obtained for the prawns which were stocked at a mean size of 15.8mm. Maximum production rates obtained per hectare within a period of 83 days mono-culture under stocking densities 4, 5, 7 and 10/m2 were respectively 355, 253, 431 and 398 kg. The size of prawns at harvest ranged from 90.8 to 119.3 mm mean length and from 4.4 to 12.3 g mean weight. The instantaneous growth rate varied from 0.0211 to 0.0251 for length and from 0.0591 to 0.0720 for weight in the different ponds. The pelletised feed used in these experiments gave a good feed conversion ratio of 2.62 in one of the ponds

Experiments on the culture of Penaeus indicus in polyethylene film-lined ponds at Calicut

The possibilities of converting extensive areas of sandy shores into productive aquaculture ponds by providing polyethylene film-lining have been reported based on the experiments conducted at Calicut by the Central Marine Fisheries Research Institut

Homogenized dynamics of stochastic partial differential equations with dynamical boundary conditions

A microscopic heterogeneous system under random influence is considered. The randomness enters the system at physical boundary of small scale obstacles as well as at the interior of the physical medium. This system is modeled by a stochastic partial differential equation defined on a domain perforated with small holes (obstacles or heterogeneities), together with random dynamical boundary conditions on the boundaries of these small holes. A homogenized macroscopic model for this microscopic heterogeneous stochastic system is derived. This homogenized effective model is a new stochastic partial differential equation defined on a unified domain without small holes, with static boundary condition only. In fact, the random dynamical boundary conditions are homogenized out, but the impact of random forces on the small holes' boundaries is quantified as an extra stochastic term in the homogenized stochastic partial differential equation. Moreover, the validity of the homogenized model is justified by showing that the solutions of the microscopic model converge to those of the effective macroscopic model in probability distribution, as the size of small holes diminishes to zero.Comment: Communications in Mathematical Physics, to appear, 200

Exploratory trawl fishing and ground fish resources along the Kerala coast and adjacent waters

The paper deals with exploratory fishing operations mainly trawling, conducted along Kerj^a Coast and adjacent waters since 1908. Early operations prior to 1950 demonstrated tlie occurrence of rich grounds for percoid fishes in the Cape Comorin area and good hand-line fkhiiig grounds off South Kerala Coast. Bull trawling in the Cannanore-Cape Comorin region by the vessels of the Deep Sea Fishing, Station of the Government of India showed that elasmobranchs and miscellaneous fish comprising small sciaenids, lizard fishes, flatheads, etc., were common for the area with a dominant catfish element in the Cannanoi«- Calicut sector, perch element south of AUeppey including Cape Comorin grounds and a transitional middle sector having a few catfishes and perches. Inshore otter trawl operations with medium-sized boats were increasingly carried out by the lndo>.Norwegian Project, Deep Sea Fishing Station and private agencies mainly centred around Coehin during; the last decade. Deep Sea Fishing Station operations in the region revealed a composition of about SO % miscellaaeous fish, 20-35% prawns, 8-14% Nemipterus japonicus, 6-14% elasmobranchs and 1-3% Laeiarius faciariiu. These operations showed the area between Calicut and Alleppey to be more productive, those off river and bar mouths yielding good quantity of prawns. The catch rate of prawns and fish increased steadily around Cochin from 1957 to 1961 and since then showed a slight decline. The picture is indicative of excessive fishing pressure over a limited area. This points to the necessity for even dispersal of fishing effort. Indo-Norwegian Project hand-line fishing operations provided considerable information regarding the 'Kalava' (Epinephelus spp.) resources of the rocky grounds on the continental shelf usually lying in 70-110 m depth zone off Kerala Coast. The occurrence of a variety of deep sea prawns, densely shoaling bathypelagic fishes like Cubiceps uatalensis, Chlorophthatmus spp., Antigonia spp., mid-water concentrations of balistids etc. have been found out along the Kerala Coast mainly by the fishing operations of the Indo-Norwegian Project. These as well as the "Kalava" resources could be better exploited with increased effort