Relation between TMAOase activity and content of formaldehyde in fillet minces and bellyflap minces from gadoid fishes

Minced fish is a significant component of a number of frozen fishery products like fish fingers, cakes and patties. Predominately minced fish is produced from gadoid species (Alaska pollack, cod, saithe, hake and others) possessing the enzyme trimethylamine oxide demethylase (TMAOase, E.C. 4.1.2.32) (Rehbein and Schreiber 1984). TMAOase catalyses the degradation of trimethylamine oxide (TMAO) to formaldehyde (FA) and dimethylamine (DMA), preferentially during frozen storage of products (Hultin 1992). In most gadoid species light muscle contains only low activity of TMAOase, the activity of red muscle and bellyflaps being somewhat higher. In contrast, the TMAOase activity in blood, kidney and other tissues, residues of which may contaminate minced fish flesh, may be higher for several orders of magnitude (Rehbein and Schreiber 1984).

Social status and problems of fishing community at Allahabad

The paper highlights social status and socio-economic problems of fishermen living along the Ganga and the Yamuna at Allahabad. Since the problems of fishermen varied with respect to category (with owned boat and with hired boat) and location, significance of this variation was tested by x²-test. The paper further emphasises on an intensive study of fishermen community to have in depth analysis of their problems and to suggest remedial measures for their upliftment.

Social structure and underwater behavior of harbor seals in southern Monterey Bay, California

To understand harbor seal social and mating strategies, I examined site fidelity, seasonal abundance and distribution, herd integrity, and underwater behavior of individual harbor seals in southern Monterey Bay. Individual harbor seals (n = 444) were identified by natural markings and represented greater than 80% of an estimated 520 seals within this community. Year to year fidelity of individual harbor seals to southern Monterey Bay coastline was 84% (n = 388), and long-term associations (>2 yrs) among individuals were common (>40%). Consistent with these long-term associations, harbor seals were highly social underwater throughout the year. Underwater social behavior included three primary types: (1) visual and acoustic displays, such as vocalizing, surface splashing, and bubble-blowing; (2) playful or agonistic social behavior such as rolling, mounting, attending, and biting; and (3) signal gestures such as head-thrusting, fore-flipper scratch~ng, and growling. Frequency of these types of behavior was related to seal age, gender, season, and resource availability. Underwater behavior had a variety of functions, including promotion of learning and social development, reduction of aggression and preservation of social bonds by maintaining social hierarchy, and facilitation of mate selection during breeding season. Social behavior among adult males was significantly correlated with vocalization characteristics (r = 0.99, X2 = 37.7, p = 0.00087), indicating that seals may assess their competition based on underwater vocalization displays and adopt individual strategies for attracting females during breeding season based on social status. Individual mating strategies may include defending underwater territories, using scramble tactics, and developing social alliances. (PDF contains 105 pages)

Marketing of value-added products from silver carp and involvement of rural people in the production and marketing chain

Cost-profit analysis and market testing of some value-added products from silver carp such as fish mince block, fish sausage, fish ball, fish stick and fish burger were analyzed during April 2001 to March 2002. The study also explored the possibility to involve rural low-income people in the production and marketing of such products. The production of silver carp was higher in greater Jessore and Mymensingh districts but the price remained low during the peak-harvesting season in October to November. The price varied with size of the fish, season, market characteristics and effective demand of the buyers. Price of about 500 g size fish was found to be Tk. 20-25/kg in the rural markets. The average size of fish in the rural markets was 3S0-550 g while that in the urban markets it was 700-1,200 g. The cost of production of the value added products and profit margin were assessed on the basis of market price of the raw material as well as that of the finished products, transportation, storage and marketing costs. The profit margins of 34%, 39%, 81% and 31% of their sales price were obtained for fish sausage, fish ball, fish stick and fish burger, respectively. Actual production cost could be minimized if the fish is purchased directly from the farmers. Consumer's acceptance and marketability tests showed that both rural and urban people preferred fish ball than fish sausage. However, response towards the taste, flavor and color of fish ball and fish sausage was found to vary with occupations and age of the consumers. A correlation was observed between age group and acceptance of new products. Fish ball, fish stick and fish burger were found to be the most preferable items to the farmers because of easy formulation process with common utensils. Good marketing linkage and requirement of capital had been identified as the prerequisites for operating small-scale business on value-added fish products.

The fish stocks in Uganda aquatic systems: opportunities and challenges for transformation

The status of fish stocks in a water body at any one time is a function of several factors affecting the production of fish in that water body. These include: total number (abundance) and biomass(weight) present, growth (size and age), recruitment (the quantity of fish entering the fishery) including reproduction, mortality which is caused by fishing or natural causes, Other indirect factors of major importance to the status of the stocks include production factors (water quality and availability of natural food for fish), the life history parameters of the different species making up the stocks (e.g. sex ratios, condition of the fish, reproductive potential (i.e. fecundity) etc), Changes in fish stocks do occur when any of the above listed factors directly influence aspects of growth, reproduction and mortality and therefore, numbers and standing stock (biomass). In the exploited fisheries, major research concerns regarding stocks relate to the listed factors especially: estimates of stock abundance/biomass, the quantity of fish being caught,where the fish are caught, which species are caught (relative abundance)when the fish are caught, how the fish are caught. The balance between stock abundance and amount of fish caught provides the basis for intervention. Due to the diverse characteristics of the physical water environment, fishes are in general, not evenly distributed throughout a water body. Shallow and vegetated areas tend to support higher abundance and diversity of fish species. In addition, seasonal variations in fish abundance are so strong that fluctuations in catch have to be expected at fish landings.

Some problems and issues of sustainable management of mangrove ecosystems of Tamil Nadu, India

Mangrove, a tidal wetland, is a good example of complex land and water system whose resource attributes is neither fully understood from an ecological perspective nor valued comprehensively in economic terms. With increased ecological and social perception of the functions of wetlands, the utility and relative values will increase. The perception, however, varies from society to society. It must be recognized that mangrove forests differ greatly in local conditions and in their ability to produce a wide variety of economic products. What may be highly productive strategy for one country may have little meaning to its neighbor. Therefore, it becomes essential that from among diversity of potential uses of the mangrove environment, specific uses will have to be decided, and management plan developed on site, or area specific basis. It is therefore necessary to arrive at a balance between the views of the ecologists and economists on the management of mangroves. Biological conservation should encompass resource management in the sense that integrity of the biological and physical attributes of the resource base should be sustained and man-induced management practices should not alter an ecosystem to the extent that biological production is eliminated. Sustained yield management for food, fiber and fuel would serve to sustain local fisheries while generating new economic enterprises. This requires the recognition of mangrove environment as a resource with economic value, and managed according to local conditions and national priorities.