Discriminative Density-ratio Estimation

The covariate shift is a challenging problem in supervised learning that results from the discrepancy between the training and test distributions. An effective approach which recently drew a considerable attention in the research community is to reweight the training samples to minimize that discrepancy. In specific, many methods are based on developing Density-ratio (DR) estimation techniques that apply to both regression and classification problems. Although these methods work well for regression problems, their performance on classification problems is not satisfactory. This is due to a key observation that these methods focus on matching the sample marginal distributions without paying attention to preserving the separation between classes in the reweighted space. In this paper, we propose a novel method for Discriminative Density-ratio (DDR) estimation that addresses the aforementioned problem and aims at estimating the density-ratio of joint distributions in a class-wise manner. The proposed algorithm is an iterative procedure that alternates between estimating the class information for the test data and estimating new density ratio for each class. To incorporate the estimated class information of the test data, a soft matching technique is proposed. In addition, we employ an effective criterion which adopts mutual information as an indicator to stop the iterative procedure while resulting in a decision boundary that lies in a sparse region. Experiments on synthetic and benchmark datasets demonstrate the superiority of the proposed method in terms of both accuracy and robustness

Heterotrophic marine bacteria as supplementary feed for larval Penaeus monodon

Conventionally, penaeid shrimp larvae are reared by feeding microalgae (Chaeloceros; Tetraselmis, etc) at the protozoea stage and Artemia nauplii during the mysis stage

Probiotics and its application in mariculture

Aquaculture is a multidisciplinary activity, more complex than agriculture due to the multidimensional aquatic medium. The aquaculture boom and increased sodo-economic benefits together with increase in extent and intensity of aquaculture are alleged to have created several problems, particularly those of deteriorating water and soil quality and outbreak of diseases (Kutty, 1999). For example, the global production of farmed shrimp has doubled in the past 15 years

Indian Cephalopod Resources: Distribution, Commercial Exploitation, Utilization and Trade

Cephalopods are purely marine in habitat, and there are about 600 living species. They are considered as the fastest marine invertebrates. The cuttlefishes come under the order Sepioidea and are characterized by the presence of a shell (chitinous or calcareous), 10 circum oral appendages and the tentacles are retractile into pockets. Suckers have chitinous rings. Posterior fin lobes are free and not connected at midline. The cuttlebone is internal and located dorsally underneath the skin

Spawning congregations of Indian squid Loligo duvauceli (Cephalopoda Loliginidae) in the Arabian Sea off Mangalore and Malpe

Two successive spawning congregations of Loligo duvauceli occurred along the southern Karnataka coast during 1990 and 1991. The congregations took place during the post monsoon months (Sept.-Oct) and resulted in steep increase in catch rales of squids in trawlers and purse seiners operating from Mangalore and Malpe. Occurrence of such notable quantities of large sized mature squids during Septembcr-October of 1990 and 1991 is attributed to the increase in seawater tcmperatures along the inshore areas during the period. Further new evidences like low gonadosomatic index and tangible growth arter reaching sexual maturity are presented to highlight a non-scmelparous reproduction in this tropical inshore squi

Conservtion of Marine Fishery Resources Through Eco-labelling in India

Severe habitat loss and population declines of species have occurred in the oceans, leading to concerns that fished populations may be at risk of extinction over large spatial scales. Three quarters of 62 depleted stocks worldwid

Probiotics in aquaculture - a review - Winter school on recent advances in diagnosis and management of diseases in mariculture, 7th to 27th November 2002, Course Manual

Aquaculture is a nuiltidisciplinary activity, more complex, than agriculture due to | the multidimensional aquatic medium. The aquaculture boom and increased socioeconomic benefits together with increase in extent and intensity of aquaculture are alleged to have created several problems, particularly those of deteriorating water and soil quality and outbreak of diseases (Kutty, 1999). For example, the global production of farmed shrimp has doubled in the past 15 years. India has also witnessed such spectacular growth in shrimp farming until the mid nineties, after which it became beset with disease and environmental problems. Overstocking, overfeeding and excessive use of antibiotics during farming are some of the reasons attributed to the outbreak of shrimp diseases. Even by the year 2001, a total solution to the problem has evaded the scientists and policy makers. But what has been recognised now by scientists and policy makers is that aquaculture must be environmentally friendly so that it can sustain itself without seriously affecting the coastal ecosystem. In other words, the ecological footprint of aquaculture must be sufficiently small so as to ensure sustainability

Trophic modelling of marine ecosystems and ecosystem based fisheries management

Fish populations are an integral part of marine ecosystems. Historically, fish population dynamics have been studied as single species, for example as mackerel, shrimp or sardine, and almost always in isolation from the system in which they exist. In recent years, however, there has been growing awareness that traditional approaches to managing fisheries are incomplete and partially unsuccessful. Sustainable use of living marine resources must consider both the impacts of the ecosystem on the living marine resources, and the impacts of fishery on the ecosystem. This holistic approach to fisheries management has been termed as ‘ecosystem based fisheries management’. The Principles of Ecosystem-Based Fisheries Management are: 1. Maintaining the natural structure and function of ecosystems, including the biodiversity and productivity of natural systems and identified important species, is the focus for management. 2. Human use and values of ecosystems are central to establishing objectives for use and management of natural resources. 3. Ecosystems are dynamic; their attributes and boundaries are constantly changing and consequently, interactions with human uses also are dynamic. 4. Natural resources are best managed within a management system that is based on a shared vision and a set of objectives developed amongst stakeholders. 5. Successful management is adaptive and based on scientific knowledge, continual learning and embedded monitoring processes

Prospects of molluscan mariculture in India- Winter School on Recent Advances in Breeding and Larviculture of Marine Finfish and Shellfish

The global aquaculture production is estimated as 54.8 million tonnes (FAO, 2003) of which molluscs contributes for more than 20% (11.1 million t). The rate of increase in production is presented in Fig.1. The major species farmed globally are the Pacific Cupped oyster, clams, mussels, scallops, abalones, etc. (Fig.2). In the recent past, India has made a small beginning (annual production of nearly 10,000 t) in molluscan farming (mussels and oysters) in the state of Kerala, but it is yet to pick up in other maritime states, inspite of its immense potential. The nation has been able to develop full fledged mariculture technologies for edible oysters, mussels, marine pearl production in fucata oysters, and also developed hatchery technologies for pearl oysters, mussels, clams and some species of cephalopods and gastropods

Molluscan fisheries of India -Winter School on Impact of Climate Change on Indian Marine Fisheries held at CMFRI, Cochin 18.1.2008 to 7.2.2008

In India, the molluscs contribute to important fisheries, providing nutritious food, and are also foreign exchange earners to the country. The shell has many industrial uses and is the object in making eyecatching articles by deft craftsmen. Men, women and children participate in fishing molluscs, which provide employment and income in coastal rural areas