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IGNOU MZOE-003 Previous Year Solved Question Paper in Hindi

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Q1. (a) Discuss the trend of fish consumption in the context of India. 5 (b) How can you classify lakes based on their productivity ? 5

Ans. (a) Trend of Fish Consumption in India: In India, fish consumption has been on a steady upward trend, driven by rising incomes, urbanization, growing health awareness, and better availability. Traditionally, consumption was concentrated in coastal states like Kerala, West Bengal, Goa, and Odisha, as well as Northeast India. However, this trend is now expanding to inland states.

The key trends and drivers are:

• Increasing Per Capita Consumption: The current per capita fish consumption in India is around 12 kg per year, which is below the global average (~20 kg) but has been increasing consistently. The government aims to increase this further through initiatives like the Pradhan Mantri Matsya Sampada Yojana (PMMSY) .
• Growing Health Awareness: Fish is recognized as an excellent source of Omega-3 fatty acids , high-quality protein, and vitamins. Growing awareness of its benefits for cardiovascular health and brain development has boosted its demand.
• Economic Factors: Rising disposable incomes have allowed consumers to include higher-value protein sources like fish in their diets.
• Improved Supply Chain: The development of cold chains , processing facilities, and retail networks has improved the availability of fresh and processed fish in inland areas, thereby increasing consumption.
• Contribution of Aquaculture: The growing share of aquaculture in fish production has ensured a more stable supply of fish, helping to keep prices in check and making it accessible to a wider population.

In essence, fish consumption in India is on a positive trajectory with immense potential for future growth.

(b) Classification of Lakes based on Productivity: Lakes can be classified based on their biological productivity or Trophic State , which refers to the amount of nutrients, particularly nitrogen and phosphorus, present in them. This productivity determines the growth of algae and aquatic plants. The main categories are:

• Oligotrophic Lakes: These have a very low nutrient content. The water is very clear , and light penetrates to great depths. They have a low density of phytoplankton, leading to low biological productivity. Oxygen levels are high in the deeper layers. These lakes are often found in cold, mountainous regions. E.g., high-altitude Himalayan lakes.
• Mesotrophic Lakes: These have an intermediate level of nutrients. The water is less clear than in oligotrophic lakes, and they have moderate algal growth. They represent a transitional stage between oligotrophic and eutrophic states.
• Eutrophic Lakes: These are rich in nutrients, leading to excessive growth of algae (algal blooms) and aquatic plants. The water is turbid, and light penetration is limited. The deeper layers (hypolimnion) can suffer from oxygen depletion (anoxia) in summer as dead organic matter decomposes, consuming oxygen. They have very high biological productivity.
• Dystrophic Lakes: These lakes have a high concentration of dissolved organic matter, such as humic acids , which leach from surrounding peat or forests. The water is tea-coloured brown and is acidic (low pH) . Nutrient levels can be variable, but productivity is generally low due to the low pH and limited light availability.

Q2. (a) Write a brief account on the aquaculture practices in the mangrove regions of India. 5 (b) Discuss the distribution and biology of Macrobrachium rosenbergii or Channa punctatus. 5

Ans. (a) Aquaculture in Mangrove Regions of India: India’s mangrove regions, such as the Sundarbans in West Bengal, Bhitarkanika in Odisha, and Pichavaram in Tamil Nadu, are significant for both traditional and modern aquaculture practices. These brackishwater ecosystems are natural nurseries for various fish and shellfish species.

• Traditional Practices: The most prominent traditional system is the ‘Bheri’ of West Bengal or ‘Pokkali’ farming in Kerala. In these systems, large shallow impoundments are created within or adjacent to mangrove tidal flats. During high tide, brackish water is allowed to enter the ponds through sluice gates, bringing in wild seeds of fish and shrimp. The gates are then closed, and these species are grown extensively without any supplementary feed. This is a low-input, eco-friendly polyculture system, culturing species like tiger shrimp (Penaeus monodon), mullets, and pearl spot.
• Modern Practices: In recent decades, intensive shrimp farming has expanded in mangrove areas, focusing mainly on tiger shrimp (Penaeus monodon) and whiteleg shrimp (Litopenaeus vannamei) . These practices involve clearing mangroves for pond construction, high stocking densities, use of artificial feeds, and application of chemicals.
• Challenges and Sustainability: While intensive farming is economically lucrative, it has led to severe environmental problems like mangrove deforestation, water pollution, salinization of agricultural land, and loss of biodiversity. Sustainable practices like silvofisheries , which integrate mangrove conservation with aquaculture, are being promoted. This involves culturing fish or crabs in ponds or pens amidst mangrove trees.

(b) Distribution and Biology of Macrobrachium rosenbergii (Giant Freshwater Prawn):

Macrobrachium rosenbergii

, also known as the giant freshwater prawn or “scampi,” is a commercially important species in aquaculture.

Distribution: This species is native to the Indo-Pacific region , ranging from Pakistan to Vietnam and Northern Australia. Due to its fast growth rate and high market value, it has been widely introduced for aquaculture in tropical and subtropical regions across the world. In India, it is cultured mainly in states like Andhra Pradesh, West Bengal, Kerala, Tamil Nadu, and Odisha.

Biology:

• Habitat and Life Cycle: It is an amphidromous species. The adults live in freshwater rivers, lakes, and ponds. For reproduction, females spawn in freshwater, but the larvae, upon hatching, drift downstream to brackishwater estuaries. Larval development is only possible in brackish water. After metamorphosis, the post-larvae (juveniles) migrate back upstream to freshwater environments.
• Feeding: M. rosenbergii is an omnivorous and detritivorous feeder. In its natural environment, it feeds on algae, insects, molluscs, small crustaceans, and organic debris. In aquaculture, it can be easily reared on formulated supplementary feeds.
• Reproduction: Males exhibit three morphotypes: small-clawed males, orange-clawed males, and large blue-clawed males. Females carry a clutch of eggs attached to their pleopods (swimming legs) under their abdomen, a state known as ‘berried’. A single female can lay between 20,000 to 100,000 eggs, depending on her size.
• Importance: It has palatable flesh, grows rapidly, and commands a high market price, making it an attractive aquaculture species for farmers worldwide.

Q3. (a) Differentiate among series pond, parallel pond and racial pond with a neat schematic diagram. 6 (b) Discuss the different strategies adopted for treatment of sewage water to be used for aquaculture. 4

Ans. (a) Differentiation of Series, Parallel, and Radial Ponds: Ponds can be arranged in various layouts based on their water flow pattern. The three main configurations are series, parallel, and radial.

1. Series Ponds:
   • Configuration: Ponds are arranged sequentially, one after the other. Water enters the first pond from a single inlet, then flows from the first pond to the second, from the second to the third, and so on, before exiting from the last pond.
   • Schematic Diagram Description: A diagram would show ponds in a straight line: [Water Source] → [Pond 1] → [Pond 2] → [Pond 3] → [Outlet].
   • Advantages: Simple and cheap to construct as fewer channels are required.
   • Disadvantages: Water quality deteriorates in downstream ponds as nutrients and waste accumulate. Diseases can spread easily from one pond to the next. It is difficult to manage individual ponds.
2. Parallel Ponds:
   • Configuration: Each pond has its own separate inlet from a common supply channel and a separate outlet to a common drainage channel. The ponds are situated parallel to one another.
   • Schematic Diagram Description: A diagram would show a central supply channel feeding water into each pond individually, and a separate drainage channel collecting water from each pond.
   • Advantages: Each pond can be managed independently. All ponds receive water of the same quality. Transmission of diseases between ponds is prevented.
   • Disadvantages: More complex and expensive to construct due to the need for extra channels and water control structures.
3. Radial Ponds:
   • Configuration: These are typically circular or octagonal with a central drainage point. Water enters at the periphery of the pond and flows towards the center, creating a slow-moving vortex that concentrates solid waste at the central drain. This configuration is not common for traditional ponds and is a feature of more modern, intensive systems, but the question likely means “radial flow pond” design principles. A more accurate name for a pond layout type might be a ‘cluster’ or ‘module’ design, but interpreting the question as ‘radial flow’ is reasonable.
   • Schematic Diagram Description: A circular pond would be shown with multiple inlets along the outer wall and a single outlet drain in the center.
   • Advantages: Excellent waste removal efficiency (self-cleaning). Very suitable for high-density, intensive culture.
   • Disadvantages: High construction cost and requires specialized design expertise.

(b) Strategies for Sewage Water Treatment for Aquaculture: Sewage-fed aquaculture is a traditional and sustainable method of producing fish by utilizing the nutrients present in wastewater. However, to make it safe for fish and human consumption and to protect the ecosystem, treatment of the sewage is essential. The main strategies are:

1. Primary Treatment: This is a physical process. It involves the removal of large solids from sewage through screening and the settling of heavy particulate matter in sedimentation tanks.
2. Secondary Treatment: This is a biological process aimed at removing dissolved organic matter. The most common and cost-effective method for aquaculture is the use of Stabilization Ponds or Oxidation Ponds .
   • In these large, shallow ponds, a symbiotic relationship develops between algae and bacteria. Bacteria decompose the organic waste, releasing carbon dioxide and nutrients.
   • Algae use these compounds via photosynthesis, using sunlight and releasing oxygen. This oxygen, in turn, helps the bacteria to decompose more waste.
   • Through this process, the Biochemical Oxygen Demand (BOD) is significantly reduced, and pathogens are killed due to sunlight (UV radiation) and the long retention period.
3. Duckweed-based Treatment: Another strategy is the use of ponds covered with duckweed (e.g., Lemna ). Duckweed grows rapidly, absorbing nutrients from the water, and prevents algal growth below by covering the water surface. This also kills pathogens as sunlight cannot penetrate the water.

After treatment, the nutrient-rich water is channeled into fish ponds, where it promotes the growth of plankton, which serves as natural food for planktivorous fish like carps.

Q4. Enumerate the different methods of selection of species and desirable traits in aquaculture programme. 10

Ans. The success of aquaculture relies heavily on the selection of the right species and the improvement of their desirable traits. This involves two key stages: selecting a species to culture and then implementing genetic improvement within that chosen species.

Part 1: Criteria for Species Selection When choosing a species for aquaculture, several biological and economic factors are considered:

• Biological Criteria:
  • Fast Growth Rate and good FCR: The species should reach market size in the shortest possible time and convert feed into flesh efficiently (low Feed Conversion Ratio – FCR).
  • Disease Resistance: The species should be hardy and resistant to common diseases and parasites to minimize mortality.
  • Environmental Tolerance: The species must be able to tolerate fluctuations in water quality (e.g., low oxygen, high temperature).
  • Breeding in Captivity: The species should breed easily under controlled conditions to ensure a reliable supply of seed.
  • Feeding Habits: Herbivorous or omnivorous species are often more economical to culture than carnivorous ones.
• Economic Criteria:
  • Market Demand and Price: The species must have high consumer demand and fetch a good market price.
  • Consumer Preference: Factors like taste, texture, and bone content influence consumer choice.

Part 2: Methods of Selection for Desirable Traits Once a species is selected, its performance can be further improved using genetic selection programs. Desirable traits include faster growth, better body conformation, disease resistance, and stress tolerance. The main selection methods are:

• Mass Selection (Individual Selection): This is the simplest method. Here, phenotypically superior individuals (e.g., the largest or fastest-growing) from a population are selected as broodstock for the next generation. This method is effective for traits with high heritability, such as growth rate.
• Family Selection: In this method, selection is based on the average performance of entire families rather than on individual performance. Multiple families are reared separately, and all members of the best-performing families are selected as breeders. This is more effective for traits with low heritability, like disease resistance, as it minimizes environmental effects.
• Progeny Testing: This involves evaluating the quality of parents (sires and dams) based on the performance of their offspring (progeny). It is highly accurate but time-consuming and expensive. It is mainly used to assess the breeding value of valuable broodstock.
• Marker-Assisted Selection (MAS): This is a modern molecular technique. It involves identifying DNA markers that are linked to desirable traits. These markers are then used to select genetically superior individuals at an early age, even before the trait is expressed. It is particularly useful for traits that are difficult to measure, such as disease resistance.

By using these methods, significant improvements in aquaculture productivity and sustainability can be achieved.

Q5. State the biological functions of major amino acids and fatty acids present in fish. 10

Ans. Amino acids and fatty acids are crucial macronutrients in fish nutrition, essential for growth, energy, and overall health. Their biological functions are diverse and vital.

Biological Functions of Major Amino Acids: Amino acids are the building blocks of proteins. There are about 20 major amino acids, divided into two categories: essential and non-essential.

• Essential Amino Acids (EAAs): These are approximately 10 amino acids that fish cannot synthesize themselves and must obtain from their diet. They include lysine, methionine, arginine, and tryptophan .
• Non-essential Amino Acids: These can be synthesized by fish from other compounds.

Major Functions:

1. Protein Synthesis: The primary function of amino acids is to build and repair tissues. They are essential for the synthesis of muscle, enzymes, hormones, and antibodies. For example, lysine is critical for muscle growth.
2. Energy Source: When dietary carbohydrates or lipids are insufficient, amino acids can be catabolized to provide energy.
3. Metabolic Precursors: Certain amino acids serve as precursors for other important biological molecules. For example, tryptophan is required for the synthesis of the neurotransmitter serotonin and the hormone melatonin.
4. Osmoregulation: The pool of free amino acids in tissues helps maintain the balance of water inside and outside cells, particularly in species that migrate between saltwater and freshwater.

Biological Functions of Major Fatty Acids: Fatty acids are major components of lipids. They are classified as Saturated (SFA), Monounsaturated (MUFA), and Polyunsaturated (PUFA).

• Essential Fatty Acids (EFAs): These are PUFAs that fish cannot synthesize. The requirements differ: marine fish require omega-3 (n-3) fatty acids like Eicosapentaenoic acid (EPA) and Docosahexaenoic acid (DHA), while freshwater fish also require omega-6 (n-6) fatty acids like Linoleic acid.

Major Functions:

1. Energy Storage: Fatty acids are the most concentrated form of energy storage. They are stored as triglycerides in adipose tissue.
2. Cell Membrane Structure: PUFAs are vital structural components of cell membranes. They influence membrane fluidity and function, which is critical for temperature adaptation.
3. Hormone Precursors: EPA and other PUFAs are precursors to eicosanoids like prostaglandins, leukotrienes , and thromboxanes. These compounds regulate inflammation, immune response, blood clotting, and reproduction.
4. Nervous System and Vision Development: DHA is critically important for the development and function of the brain and retina, especially in the larval stage.
5. Buoyancy and Insulation: Lipids aid in buoyancy by reducing body density and provide thermal insulation to conserve body heat.

Q6. Name any three fungal diseases of fish. List out the symptoms of those diseases and mention the species affected. 10

Ans. Fungal diseases (or more accurately, oomycete diseases) in fish are a common problem in aquaculture, often affecting stressed or injured fish. Three major fungal-like diseases are:

1. Saprolegniasis (Water Mold Disease):

• Causative Agent: Caused by oomycetes (water molds) of the genus Saprolegnia .
• Symptoms: The most visible symptom is the appearance of cotton-like white to greyish-brown growths on the skin, fins, gills, or eyes. It often develops as a secondary infection on wounds or injuries. The disease can also infect eggs, causing them to become fuzzy and die.
• Affected Species: Affects almost all freshwater fish, particularly carp, trout, and salmonids , especially at low temperatures.

2. Branchiomycosis (Gill Rot):

• Causative Agent: Caused by fungi of the genus Branchiomyces .
• Symptoms: Fish show signs of respiratory distress (gasping at the surface). The gills exhibit a ‘marbled’ appearance with areas of necrotic (dead) tissue and hemorrhage. The affected gill tissue eventually rots and sloughs off, leading to mass mortality.
• Affected Species: Primarily affects cyprinids like carp and also eels , especially in eutrophic ponds with high organic matter and high temperatures.

3. Epizootic Ulcerative Syndrome (EUS):

• Causative Agent: Caused by the oomycete Aphanomyces invadans .
• Symptoms: Initially, small red spots appear on the body. These rapidly develop into large, deep, necrotic ulcers with a red center and a greyish-white rim. The infection can penetrate deep into the muscle, sometimes exposing the bone. Fish become lethargic, and mortality can be very high.
• Affected Species: Affects a very wide range of freshwater and brackishwater fish, including snakeheads (Channa), barbs (Puntius), catfish, and gouramis . It is a serious problem in Southeast Asia and India.

Q7. Write notes on any two of the following : 5+5 (a) Impact of intensive aquaculture on socio-economic resources (b) Role of Government of India in offering network of extension services in aquaculture (c) Major types of culture-based fisheries

Ans. (a) Impact of intensive aquaculture on socio-economic resources Intensive aquaculture, which involves high stocking densities and intensive inputs, has a profound impact, both positive and negative, on socio-economic resources.

Positive Impacts:

• Employment and Income Generation: It creates jobs in farming, feed production, processing, and marketing, leading to increased rural income.
• Food Security: It contributes to food and nutritional security for the population by providing an affordable and accessible source of protein.
• Foreign Exchange Earnings: Exports of high-value species like shrimp earn significant foreign exchange for countries like India.
• Livelihood Diversification: It offers an alternative livelihood to farmers and fishers, diversifying them from traditional agriculture or capture fisheries.

Negative Impacts:

• Conflict over Resources: Competition for limited resources like land and water increases between aquaculture and agriculture, leading to social conflicts.
• Social Inequity: Benefits often accrue to large-scale investors or corporations, marginalizing small-scale farmers and landless laborers, thus leading to inequitable distribution of wealth.
• Displacement: The conversion of agricultural land or mangroves into aquaculture ponds can displace local communities from their traditional livelihoods and lands.
• Market Volatility: Dependence on global markets makes farmers vulnerable to risks like price fluctuations and disease outbreaks, leading to economic instability.

(b) Role of Government of India in offering network of extension services in aquaculture The Government of India plays a pivotal role in the development and expansion of aquaculture by providing a network of extension services to transfer research and technology from the “lab to the land”.

• Institutional Framework:
  • National Fisheries Development Board (NFDB): This is the apex body for coordinating development activities in the fisheries sector, implementing schemes and programs.
  • Marine Products Export Development Authority (MPEDA): It focuses on promoting export-oriented aquaculture, particularly shrimp farming, and provides technical and financial assistance to farmers.
  • ICAR Institutes: Institutes like CIFA (freshwater), CIBA (brackishwater), and CIFE (education) conduct research and transfer technology through training programs.
• Key Schemes:
  • Pradhan Mantri Matsya Sampada Yojana (PMMSY): This is a flagship scheme for the sustainable and responsible development of the fisheries sector. It provides financial assistance to farmers for pond construction, seed, feed, and technology adoption.
  • Fish Farmers Development Agencies (FFDAs): At the district level, these agencies are crucial in providing technical guidance, training, and facilitating access to credit directly to the farmers.
• Services Provided: The extension services provided by these agencies include training on scientific farming methods, demonstration of new technologies, supply of quality seed and feed, advice on disease diagnosis and control, and help in establishing market linkages.

(c) Major types of culture-based fisheries (CBF) Culture-Based Fisheries (CBF) is a practice that enhances fish production in natural or man-made water bodies by artificially stocking them with fish. It represents a middle path between capture fisheries and aquaculture.

• Definition: In CBF, fish seed (fingerlings) are stocked into water bodies where natural recruitment is insufficient to sustain a fishery. The fish grow on natural food and are later harvested.
• Major Types:
  1. Reservoir Fisheries Enhancement: India has a vast network of large, medium, and small reservoirs. These are regularly stocked with fingerlings of fast-growing species, primarily Indian Major Carps (Catla, Rohu, Mrigal). This is an effective way to utilize the natural productivity of these vast water bodies.
  2. Floodplain Wetland (Beel) Fisheries: In states like Assam, West Bengal, and Bihar, CBF is practiced in floodplain wetlands (known as beels, mauns, or chaurs). These seasonal water bodies are stocked with fish seed during the monsoon, and fish are harvested in winter as the water recedes.
  3. Pen and Cage Culture: This is a more intensive form of CBF. It involves enclosing a portion of a lake or reservoir with netting to form a pen or installing floating cages in the water body. Fish are stocked at high densities and often provided with supplementary feed.
• Importance: CBF helps to increase fish production at a low cost, improve rural livelihoods, and utilize the potential of large, under-utilized water bodies.