← Agri & Allied (CT)
Past Questions — 2024
Which are considered as “living carbon manuring machine” in integrated fish ponds?
A)
Pig
B)
Cow
C)
Chicken
D)
Duck
In integrated fish farming, ducks are referred to as 'living carbon manuring machines.' This is because ducks forage in the pond, and their excreta (rich in nitrogen and phosphorus) act as a direct organic fertilizer. This fertilization stimulates the growth of phytoplankton and zooplankton, which serve as the primary natural food source for fish. Additionally, ducks help in controlling aquatic weeds and insects. While pigs, cows, and chickens also provide manure in integrated systems, ducks are uniquely termed 'living manuring machines' because they live and excrete directly on the water surface, facilitating the immediate cycling of nutrients into the pond ecosystem.
Which type of respiration occurs in mollusks?
A)
Cutaneous
B)
Branchial
C)
Tracheal
D)
Pulmonary
Mollusks are a diverse phylum, but the primary and most characteristic mode of respiration across the group is branchial respiration.
1. **Branchial Respiration (Correct):** Most mollusks (such as clams, oysters, and cephalopods) possess gills, known as ctenidia, which are specialized organs for gas exchange from water. This is the defining respiratory characteristic of the phylum.
2. **Cutaneous Respiration (Incorrect):** While some small mollusks or those in moist environments may exchange some gases through their skin, it is not the primary or characteristic respiratory system for the phylum.
3. **Tracheal Respiration (Incorrect):** Tracheal systems (a network of tubes) are characteristic of insects and some other arthropods, not mollusks.
4. **Pulmonary Respiration (Incorrect):** While terrestrial gastropods (like land snails) have a modified mantle cavity that functions as a lung (pulmonary respiration), this is a specialized adaptation for land. The overarching, general answer for the phylum Mollusca, especially in a general science context, is branchial respiration.
Which vitamin is abundant in fish liver oil?
A)
Vitamin A
B)
Vitamin B12
C)
Vitamin C
D)
Vitamin D
Fish liver oils, particularly those from cod, are renowned for being rich sources of fat-soluble vitamins. While they contain both Vitamin A and Vitamin D, Vitamin A is typically found in significantly higher concentrations (abundant) compared to Vitamin D.
1. Vitamin A: Found in high concentrations in the liver of fish; it is essential for vision, immune function, and skin health.
2. Vitamin D: Also present in fish liver oil, but usually in smaller quantities than Vitamin A.
3. Vitamin B12: This is a water-soluble vitamin found in the muscle tissue (flesh) of fish, not concentrated in the liver oil.
4. Vitamin C: Fish liver oil does not contain Vitamin C, as it is a water-soluble vitamin and is generally absent in fish oils.
The main fish species of flood-plain capture fisheries are-
A)
Anchovies
B)
Carps
C)
Tunas
D)
Shrimps
Flood-plain capture fisheries refer to the harvesting of fish from inland water bodies that overflow during monsoon seasons, creating temporary wetlands and floodplains.
1. **Why Carps are correct**: Major and minor carps (such as Catla, Rohu, and Mrigal) are the dominant freshwater fish species in the riverine and flood-plain systems of South Asia. They are highly adapted to these environments, utilizing the nutrient-rich floodplains for feeding and spawning.
2. **Why other options are incorrect**:
- **Anchovies (a)**: These are primarily marine (saltwater) fish found in coastal waters.
- **Tunas (c)**: These are pelagic marine fish found in open oceans, not in freshwater floodplains.
- **Shrimps (d)**: While some species of prawns exist in freshwater, 'shrimps' as a general category are predominantly associated with marine or brackish water environments, and they are not the 'main fish species' (as shrimps are crustaceans, not fish).
Therefore, Carps are the primary fish species targeted in flood-plain capture fisheries.
To be designated as cold water fisheries minimum altitude should be-
A)
914 msl
B)
1500 msl
C)
887 msl
D)
1050 msl
In the context of fisheries and aquaculture, particularly in the Indian subcontinent and standard limnology, cold water fisheries are typically associated with high-altitude regions where water temperatures remain low throughout the year. The standard threshold used to designate cold water fisheries is an altitude of 3,000 feet above mean sea level (msl). Converting 3,000 feet to meters: 3,000 ft × 0.3048 m/ft = 914.4 meters. Therefore, 914 msl is the recognized minimum altitude for this designation. Options b, c, and d do not align with the standard 3,000-foot benchmark used in fisheries classification.
What structure in crustaceans is used for grinding food?
A)
Mandibles
B)
Maxillipeds
C)
Chelipeds
D)
Antennules
In crustaceans, the mandibles are the primary mouthparts used for the mechanical breakdown of food. They are heavily sclerotized (hardened) appendages that move transversely to crush, grind, or cut food particles before they enter the mouth.
Here is why the other options are incorrect:
- Maxillipeds: These are modified thoracic appendages that function as 'foot-jaws' to manipulate food and push it toward the mandibles, but they do not perform the primary grinding.
- Chelipeds: These are the first pair of walking legs, often modified into claws (pincers) used for capturing prey, defense, or mating, rather than grinding food inside the mouth.
- Antennules: These are sensory organs used for chemoreception (smelling/tasting) and touch, not for feeding.
Fish migration within river is known as:
A)
Diadromous
B)
Anadromous
C)
Potamodromous
D)
Catadromous
Fish migration is categorized based on the environment the fish moves between.
1. **Potamodromous (Correct):** This term refers to fish that migrate exclusively within freshwater systems (rivers and lakes) without ever entering the sea. Examples include certain species of trout and salmonids that stay in river systems.
2. **Diadromous (Incorrect):** This is a general umbrella term for all fish that migrate between freshwater and saltwater. It encompasses both anadromous and catadromous migrations.
3. **Anadromous (Incorrect):** These are fish that live in the ocean but migrate into freshwater rivers to spawn (e.g., Atlantic Salmon).
4. **Catadromous (Incorrect):** These are fish that live in freshwater but migrate to the ocean to spawn (e.g., Freshwater Eels).
Since the question specifically asks for migration 'within river' (freshwater to freshwater), the correct term is Potamodromous.
The most important mineral in fish bones is-
A)
Iron
B)
Calcium
C)
Phosphorus
D)
Magnesium
In fish, as in most vertebrates, the skeletal system is primarily composed of a mineralized matrix. The primary mineral responsible for the structural integrity, hardness, and density of fish bones is Calcium, typically stored in the form of hydroxyapatite [Ca10(PO4)6(OH)2]. While phosphorus is also essential as it forms the phosphate part of the bone mineral, calcium is the predominant and most critical mineral for bone formation and maintenance.
Analysis of other options:
- Iron (a): Primarily involved in oxygen transport (hemoglobin) and enzyme function, not a structural component of bone.
- Phosphorus (c): Important for bone mineralization, but it acts as a partner to calcium; calcium is the primary structural mineral.
- Magnesium (d): Plays a role in enzyme activation and some structural support, but is present in much smaller quantities compared to calcium in the skeletal system.
Which vitamin is particularly abundant in fatty fish?
A)
Vitamin C
B)
Vitamin B
C)
Vitamin A
D)
Vitamin D
Fatty fish (such as salmon, mackerel, sardines, and herring) are among the few natural dietary sources rich in Vitamin D. Vitamin D is a fat-soluble vitamin, meaning it is stored in the fatty tissues of the fish. While some fatty fish also contain Vitamin A, Vitamin D is the most characteristic and clinically significant vitamin associated with the consumption of oily fish for human nutrition.
Breakdown of options:
- Vitamin C: Primarily found in citrus fruits and vegetables; fish are not a significant source.
- Vitamin B: While fish contain B vitamins (like B12), they are not 'particularly abundant' in fatty fish specifically compared to lean fish or other animal proteins.
- Vitamin A: Present in fish liver oils, but Vitamin D is the primary hallmark of the flesh of fatty fish.
- Vitamin D: Highly concentrated in the fatty tissues of oily fish, making it the correct answer.
Which of the following is alive food organism used in aquaculture?
A)
Amoeba
B)
Cestoda
C)
Lernea
D)
Spirulina
In aquaculture, 'live food' refers to living organisms (microalgae, zooplankton, etc.) used to feed fish, shrimp, and other aquatic species, especially during their larval stages.
1. **Spirulina (Option d):** This is a multicellular, filamentous cyanobacterium (blue-green algae). It is widely used in aquaculture as a high-protein live feed supplement or as a base for formulated feeds because it is rich in proteins, vitamins, and essential fatty acids.
2. **Amoeba (Option a):** While a living organism, Amoeba are not cultivated or used as a standardized food source in aquaculture due to their size, nutritional profile, and lack of practical mass-culture methods for feeding fish.
3. **Cestoda (Option b):** These are parasitic flatworms (tapeworms). They are pathogens that cause disease in fish, not a food source.
4. **Lernea (Option c):** Specifically referring to *Lernaea* (anchor worm), this is a parasitic copepod that attaches to the skin and muscles of fish, causing tissue damage and secondary infections. It is a pest, not a feed organism.
Which type of vessel is used for deep-sea fishing?
A)
Canoe
B)
Trawler
C)
Gillnetter
D)
Coracle
Step-by-step reasoning:
1. Analysis of the requirement: The question asks for a vessel specifically designed for 'deep-sea fishing,' which implies the need for a large, motorized, and sturdy vessel capable of navigating open oceans and hauling heavy nets from the seabed.
2. Evaluating Option (a) Canoe: A canoe is a small, narrow boat typically used in shallow waters, rivers, or near-shore areas. It lacks the size and power for deep-sea operations.
3. Evaluating Option (b) Trawler: A trawler is a commercial fishing vessel designed to pull a large net (trawl) along the bottom of the ocean or in mid-water. They are equipped with powerful engines and refrigeration systems, making them the standard vessel for deep-sea industrial fishing.
4. Evaluating Option (c) Gillnetter: A gillnetter is a boat used to set gillnets. While some can be large, 'gillnetting' is a method of fishing rather than a specific vessel type designed for the deep sea; many gillnetters operate in coastal or brackish waters.
5. Evaluating Option (d) Coracle: A coracle is a small, rounded boat made of wickerwork and hide, used primarily in shallow rivers or lakes (traditional in Wales and India). It is entirely unsuitable for the open sea.
Conclusion: The Trawler is the only vessel listed specifically engineered for the rigors and techniques of deep-sea fishing.
What does the term “pond seepage” refer to?
A)
Evaporation loss
B)
Water infiltration into the soil
C)
Overflow discharge
D)
Silt deposition
Step-by-step reasoning: 1. Definition: In the context of pond construction and hydrology, 'seepage' refers to the slow movement of water through the pores of the soil or through cracks in the pond liner. 2. Mechanism: When a pond is filled, the hydrostatic pressure forces water to move from the pond basin into the surrounding soil (infiltration), leading to a loss of stored water. 3. Evaluating Options: (a) Evaporation loss is the conversion of liquid water to vapor due to heat and wind, not seepage. (c) Overflow discharge occurs when water exceeds the capacity of the pond and exits via a spillway. (d) Silt deposition is the accumulation of sediment at the bottom of the pond. Therefore, only option (b) describes the process of water leaking into the ground, which is the definition of seepage.
Which species is known to undergo catadromous migration?
A)
Salmon
B)
Eel
C)
Tilapia
D)
Tuna
Fish migration is categorized based on the direction of movement between freshwater and saltwater for spawning and growth.
1. **Catadromous Migration**: This occurs when fish spend most of their adult lives in freshwater and migrate to the ocean (saltwater) to spawn. The **European Eel (Anguilla anguilla)** is the classic example of a catadromous fish; it grows in rivers and lakes but travels to the Sargasso Sea in the Atlantic Ocean to breed.
2. **Anadromous Migration**: This is the opposite of catadromous. Fish spend most of their lives in the ocean and migrate to freshwater to spawn. **Salmon** (Option a) is the primary example of an anadromous fish.
3. **Other Options**:
- **Tilapia** (Option c) are generally non-migratory (sedentary) and are typically found in freshwater or brackish environments.
- **Tuna** (Option d) are oceanic (pelagic) fish that remain in saltwater throughout their life cycle and do not undergo catadromous or anadromous migration.
Therefore, the Eel is the correct species known for catadromous migration.
What is the term for spawning in controlled conditions?
A)
Induced breeding
B)
Natural spawning
C)
Gynogenesis
D)
Cryopreservation
Step-by-step reasoning: 1. Spawning refers to the process of releasing eggs and sperm by aquatic animals. 2. 'Controlled conditions' implies that the process is managed by humans to ensure higher survival rates or to breed species that do not spawn naturally in captivity. 3. Induced breeding (also known as artificial propagation) involves the use of synthetic or natural hormones (like pituitary extract or Ovaprim) to stimulate the maturation of gametes and trigger spawning in a controlled environment. 4. Analysis of other options: (b) Natural spawning occurs without human intervention in the wild. (c) Gynogenesis is a form of asexual reproduction where an embryo develops without the contribution of genetic material from the male. (d) Cryopreservation is the process of preserving biological materials (like sperm or embryos) at ultra-low temperatures, not the act of spawning itself.
What type of organism is Artemia commonly known as?
A)
Brine shrimp
B)
Rotifer
C)
Diatom
D)
Algae
Artemia is a genus of small crustaceans known as brine shrimp. They are highly valued in aquaculture as a live feed source for larval fish and invertebrates because they are rich in nutrients and their cysts can be stored for long periods and hatched on demand.
Analysis of other options:
- b. Rotifer: These are microscopic multicellular animals (plankton) used as first-feed for very small larvae, but they are biologically distinct from Artemia.
- c. Diatom: These are a major group of algae (single-celled eukaryotes) characterized by silica cell walls; they are primary producers, not crustaceans.
- d. Algae: This is a broad group of photosynthetic organisms (including diatoms) that form the base of the aquatic food chain, whereas Artemia is a consumer (crustacean).
In fish breeding, hybrid vigor is also known as-
A)
Dominance
B)
Heterosis
C)
Epistasis
D)
Polyploidy
Step-by-step reasoning: 1. Hybrid vigor refers to the phenomenon where the offspring (hybrid) of two genetically diverse parents exhibit superior qualities—such as faster growth rates, better disease resistance, or higher survival rates—compared to both parents. 2. In genetics and animal/fish breeding, the scientific term for this phenomenon is 'Heterosis'. 3. Analyzing other options: (a) Dominance occurs when one allele masks the effect of another; (c) Epistasis is the interaction between different genes where one gene masks or modifies the expression of another; (d) Polyploidy is a condition where an organism has more than two complete sets of chromosomes. Therefore, Heterosis is the only term synonymous with hybrid vigor.
Diffusion of innovations is studied in-
A)
Technology management
B)
Extension education
C)
Fisheries economics
D)
Statistical analysis
The 'Diffusion of Innovations' is a theory developed by Everett Rogers that explains how, why, and at what rate new ideas and technology spread through a social system. In the context of agriculture and fisheries, this is a core component of Extension Education. Extension education focuses on the non-formal education of rural populations (farmers, fishers) to help them adopt improved practices and technologies to increase productivity.
- Option (a) Technology management focuses on the operational and strategic side of managing tech, not the social process of adoption.
- Option (c) Fisheries economics deals with the financial and resource allocation aspects of the industry.
- Option (d) Statistical analysis is a tool used to measure diffusion, but it is not the field of study where the theory of diffusion originates or is primarily applied as a pedagogical framework.
Which of these is a live feed?
A)
Pellets
B)
Flakes
C)
Tubifex worms
D)
Dry shrimp
In fish nutrition, 'live feed' refers to living organisms used as food for fish, particularly for larvae and fry, to provide essential nutrients and stimulate natural hunting behavior.
1. Tubifex worms (Option c) are living oligochaete worms often used in aquaculture as a high-protein live food source.
2. Pellets (Option a) are processed, compressed artificial feeds.
3. Flakes (Option b) are dried, pressed artificial feeds.
4. Dry shrimp (Option d) are dehydrated/preserved animal matter, not living organisms.
Therefore, Tubifex worms are the only live feed among the given options.
What is the primary criterion for selecting a candidate species for aquaculture?
A)
High aesthetic value
B)
Fast growth rate
C)
Easy availability in the wild
D)
Loweconomic value
In aquaculture management, the primary goal is typically the efficient production of biomass for food or commercial purposes. A 'Fast growth rate' is a critical criterion because it ensures a shorter production cycle, allowing for quicker turnover of stock and higher profitability. While other factors like disease resistance and feed conversion ratio are also important, growth rate is a fundamental driver of economic viability.
Analysis of other options:
- (a) High aesthetic value: This is primary for ornamental fish farming, not general aquaculture (which focuses on food security and commerce).
- (c) Easy availability in the wild: While helpful for initial seed collection, it is not the primary criterion for long-term aquaculture success; many highly successful species are bred in hatcheries regardless of wild availability.
- (d) Low economic value: This is incorrect; species with high economic value are preferred to ensure the venture is financially sustainable.
Which fish is known as the “King of Aquariums”?
A)
Guppy
B)
Goldfish
C)
Discus
D)
Betta
In the field of ornamental fisheries, the Discus fish (Symphysodon spp.) is widely referred to as the 'King of the Aquarium'. This title is attributed to its majestic appearance, vibrant coloration, unique disc-like body shape, and the high level of care and expertise required to maintain them, making them a prized possession for serious aquarists.
Comparison with other options:
- Guppy (a): Known as the 'Million Fish' due to their prolific breeding and popularity as beginner fish.
- Goldfish (b): One of the most common and oldest ornamental fish, but not referred to as the 'King'.
- Betta (d): Known as the 'Siamese Fighting Fish', prized for its aggression and flowing fins, but not the 'King of the Aquarium'.
Green certificate for ornamental fish in India is provided by-
A)
FISHCOFED
B)
CMFRI
C)
NSDC
D)
MPEDA
The 'Green Certificate' for ornamental fish in India is a certification provided by the Marine Products Export Development Authority (MPEDA). This certification is designed to ensure that the ornamental fish being exported are bred in captivity (captive-bred) and are not illegally collected from the wild, thereby promoting sustainable trade and complying with CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) regulations.
Analysis of other options:
- FISHCOFED (Fish Co-operatives Federation) primarily focuses on the marketing and distribution of fish products through cooperatives.
- CMFRI (Central Marine Fisheries Research Institute) is a research body focused on marine fisheries management and conservation.
- NSDC (National Skill Development Corporation) is an organization focused on vocational training and skill development across various sectors, not fish certification.
In which year for the 1st time in history Global Aquaculture production surpassed capture fisheries?
A)
2018
B)
2024
C)
2022
D)
2020
According to the Food and Agriculture Organization (FAO) of the United Nations in its 'The State of World Fisheries and Aquaculture (SOFIA) 2024' report, a historic milestone was reached in 2022. For the first time in history, global aquaculture production surpassed capture fisheries. In 2022, aquaculture production reached 130.9 million tonnes, while capture fisheries production stood at 92.5 million tonnes (excluding aquatic plants). This shift highlights the increasing reliance on farmed fish to meet the growing global demand for aquatic protein as wild fish stocks have largely plateaued.
Which method is not an extension approach?
A)
Individual contact
B)
Social media outreach
C)
Group contact
D)
Mass contact
In the field of Agricultural and Fisheries Extension, extension methods are traditionally categorized based on the number of people reached and the nature of the interaction. The three fundamental 'Extension Approaches' or 'Contact Methods' are: 1. Individual Contact (e.g., farm visits, personal letters), 2. Group Contact (e.g., demonstrations, field trips, meetings), and 3. Mass Contact (e.g., radio, television, newspapers). While 'Social media outreach' is a modern tool used within these approaches (specifically as a tool for mass contact), it is categorized as a 'communication channel' or a 'tool' rather than a primary 'extension approach' in the classical pedagogical framework of extension education. Therefore, among the given options, it is the one that does not fit the standard classification of extension approaches.
Global Hub of ornamental fish trade.
A)
India
B)
Singapore
C)
US
D)
China
Singapore is globally recognized as the primary hub for the ornamental fish trade. While it has limited land area for large-scale breeding compared to other nations, it serves as the central redistribution and logistics center for the world. Most ornamental fish bred in Southeast Asia (such as in Thailand, Malaysia, and Indonesia) are shipped to Singapore, where they are sorted, graded, and re-exported to markets in Europe, North America, and East Asia. Its advanced logistics infrastructure, strategic geographical location, and specialized trade regulations make it the 'Global Hub' of the industry. In contrast, the US is primarily a major consumer market, and China and India are significant producers but do not function as the central global redistribution hub in the same capacity as Singapore.
Which factor does not affect fish production in reservoirs?
A)
Nutrient levels
B)
Fish species
C)
Water flow rate
D)
Color ofthe reservoir
Fish production in reservoirs is primarily driven by biological, chemical, and physical factors that influence the food chain (primary productivity) and the survival of fish species.
1. Nutrient levels (Option a): These are critical. Nitrogen and Phosphorus levels determine the growth of phytoplankton (primary producers), which forms the base of the aquatic food web. High nutrient levels (up to a point) generally increase fish production.
2. Fish species (Option b): Different species have different growth rates, feeding habits (herbivorous, carnivorous, omnivorous), and environmental tolerances. The composition of species directly affects the total biomass production.
3. Water flow rate (Option c): Flow rate affects oxygenation, nutrient distribution, temperature stability, and the ability of fish to spawn or migrate. Excessive flow can wash away larvae, while stagnant water may lead to hypoxia.
4. Color of the reservoir (Option d): While water color can be an indicator of other factors (e.g., green color indicates high chlorophyll/algae), the 'color' itself is a visual property and not a causal driver of fish production. The underlying cause (the nutrients or algae) is what affects production, not the resulting color of the water.