समुद्री संवर्धन: एक कदम मछली की मांग और आपूर्ति के संतुलन की और

Mariculture : A step towards balance on demand and supply of fis

Virtual population analysis

Virtual population analysis (VPA) is a modeling technique commonly used in fisheries science for reconstructing the historical population structure of a fish stock using information on the deaths of individuals in each time step. The time steps are typically annual (though not necessarily) and the deaths are usually partitioned into mortality due to fishing and natural mortality. VPA therefore looks at a population in an historic perspective. The advantage of doing a VPA is that once the history is known it becomes easier to predict the future catches, which is usually one of the most important tasks of fishery scientists. Virtual population analysis calculates the number of fish alive in each cohort for each past year. It is also called cohort analysis because each cohort is analysed separately. VPA relies on a very simple relationship for each cohort. VPA or Cohort analysis was first developed as age-based methods in temperate regions further developed as length-based methods for tropical regions

Multispecies virtual population analysis

Fisheries are the major driver for the changing in properties of both fished and unfished species, through direct and indirect effects. Direct effects can include reductions in population abundance, age and size structure, biodiversity, community composition and habitat destruction. Indirect effects, including incidental mortality, are transmitted through the ecosystem by trophic interactions and competition, and may result in increased or decreased abundance of prey or predator species, altering community composition. In recognition of the complex, interconnected nature of marine ecosystems, ecosystem approaches have been promoted as a way to improve fisheries assessment and management. There is a widerange of multi-species and ecosystem modelling approaches. They range from extended single species models to multi-species minimum realistic models, food web models to whole ecosystem models with age and spatial structure. All models have their strengths and weaknesses: simplicity may entail missing key processes, whereas complexity requires more data, time and resources

Basic Finfish Features

Taxonomy is the practice of identifying different organisms, classifying them into categories and naming them. The whole life (living or extinct) of the world are classified into distinct groups with other similar organisms and given a scientific name. The classification of organisms has various hierarchical categories. Categories gradually shift from being very broad and includes many different organisms to very specific and identifying single species

Fish Stock Assessment Method: Virtual Population Analysis

Basic purpose of fish stock assessment is to provide advice on the optimum exploitation of aquatic living resources such as fish and shrimp. In fisheries, optimum exploitation is called Maximum Sustainable yield (MSY). Fishing effort level which gives the Maximum Sustainable yield is indicated by Maximum Sustainable effort. The understanding of concept about stock is very essential in fisheries before applying the fish stock assessment method. Stock can be defined as sub-set of one species having the same growth and mortality parameters, and inhabiting a particular geographical area. Growth parameters are numerical values in an equation by which we can predict the body size of a fish when it reaches a certain age and mortality parameters reflect the rate at which the animals die i.e. the number of deaths per time unit

Life cycle of anchovy and climate driven changes in its distribution on the southwest coast of India

Large scale fluctuations of anchovy catch are observed across Indian coast and an understanding of the complex interactions of climato-oceanic and biological factors of fishes is essential to realize the cause of such catch variations. Therefore, the trend of sea surface temperature anomaly in the context of the spatial and temporal aspects of anchovy (Stolephorus spp.) fisheries along southwest coast of India were investigated. The coast was classified into three strata; first (ST_1, 8° to 10.2° N), second (ST_2, 10.2° to 13° N) and third (ST_3, 13° to 16° N) to study the spatial variation. Similarly, seasonality was studied by considering three seasons in a year as pre-monsoon (February-May, PRM), monsoon (June-September, MON) and post-monsoon (October-January, POM). The catch (kg) per unit effort (hour) for the all gears operated was also analyzed to observe the distribution of Stolephorus spp. The impact of climate change on Stolephorus fisheries was evident in both vertical and horizontal shifting of the catch

Mud banks fishery estimates

Most of the natural processes are common to all coastlines and their physico-chemical characteristics are quite well known. But, there are some localised and seasonal process, have significant role in socio-economic benefit of coastal habitant and require continuous study to understand for sustainable exploration. Mud banks are such an inquisitive coastal phenomenon which occurs only at a few locations in the nearshore waters of the world ocean. Muddy shores and adjacent shore faces are found along several open coasts of the world including south west coast of India. They are generally associated with the dispersal pathways of rivers that discharge large quantities of fine-grained sediment. The high mud supply also has considerable coastal ecological and economic impacts on several coastal countries

मत्स्य पालन: बिहारवासियों की सामाजिक-आर्थिक स्थिति में सुदृढ़ता का विकल्प

भौगोलिक क्षेत्रफल की दृष्टि से बिह ार भारत का 13वाँ सबसे बड़ा राज्य है और यह भारत के क्षेत्रफल का केवल 2.86% है। बिह ार को भौतिक और संरचनात्मक स्थितियों के आधार पर तीन भागों में वि भाजि त कि या जा सकता है अर्था त् शि वालिक क्षेत्र (रामनगर दनू , सोमेश्वर की पहाड़ी और हरहा घाटी); मैदानी क्षेत्र (उत्तरी पर्वत और दक्षि णी पठार के मध्य का भाग) और दक्षि णी पठारी क्षेत्र (पश्चिम में कैमूर जिल ा से पूर्व में बाँका जिल ा का स्थल )

Basic Shellfish Features

The shellfish includes two highly diversified phyla i.e. phylum Arthropoda and phylum Mollusca. These two groups are named as shellfishes because of the presence of exoskeleton made of chitin in arthropods and shells made of calcium in molluscs. These two major phyla are invertebrates. Phylum Arthropoda includes spiders, scorpions, ticks, mites, crustaceans, millipedes, centipedes and insects. The economically important groups of two phyla include lobsters, shrimps, crabs, clam, mussel, oysters, chank, squid and cuttlefish

तेरा दीवाना

तेरा दीवान