Fish and Fisheries 2019
a) Give a scientific name of accessory respiratory organ containing fish.
Ans→ Heteropneustes fossilis (Singi Fish)- Pneumatic sac
b) Write two features of subclass-Actinopterygii.
Ans→ (i) Presence of bony endoskeleton.
(ii) They possess cycloid or ctenoid scales.
c) What is the scientific name of silver carp?
Ans→ Hypophthalmichthys molitrix
d) What is ductus pneumaticus?
Ans→ Ductus pneumaticus is a duct that connects the swim bladder with the alimentary canal (oesophagus) in physostomous fish.
e) What are dermotrichia and somactids?
Ans→ Dermotrichia: Dermotrichia are elongated, flexible fin rays providing additional support to the fins associated with adipose din found in species of class Actinopterygii.
f) What is gill raker?
Ans→ Gill raker is a bony or cartilaginous structure of gills of fish that is used to filter food particles from water.
g) What are Weberian ossicles?
Ans→ Weberian ossicles are small bones of some fishes connecting the air bladder with the inner ear to enhance hearing and aid in balance.
h) Mention two salient features of cycloid scale.
Ans→ (i) Circular scales with smooth edges.
(ii) Thin, flexible scales overlapping to each other.
i) What is fishing craft?
Ans→ The floating and movable platforms used in fishing operations on which fishers operate the fishing gears are called fishing craft.
Example: Catamaran, Dugout canoe
j) Name two fishing harbours in West Bengal.
Ans→ Two fishing harbours in West Bengal are – Frasergunj Fishing Harbour & Digha Fishing Harbour
k) What is the function of electric organ?
Ans→ Electric organs in fish produce an electric field that helps in navigation, communication, self-defence and for predation.
l) What does capture fishery mean?
Ans→ Capture fishery is the catching of fish directly from natural water bodies like ocean, sea, rivers, lakes and harvesting for consumption or commercial use.
m) Write scientific name of an ornamental fish.
Ans→ Carassius auratus (Gold fish)
n) What is the causative agent of fish parasitic disease?
Ans→ Pseudomonas punctata (Bacterial Parasite causes Dropsy disease)
o) Name two commercial fish by-products.
Ans→ Fish meal, Fish-oil
- Answer any five from the following:
a) Distinguish between elasmobranchii and holocephali.
Ans→
| Elasmobranchii | Holocephali | |
| 1) Caudal Fin | Heterocercal | Diphycercal |
| 2) Gill Openings | Uncovered | Covered by a gill flap |
| 3) Jaws | Movable upper jaw | Upper jaw fused to the skull |
| 4) Body Shape | Streamlined or flattened | Rounded body with a whip-like tail |
| 5) Example: | Sharks, Rays | Chimaeras |
b) What is labyrinthine organ? In which fish will you find it?
Ans→ The labyrinthine organ is a sensory structure found in fish, primarily in species like labyrinth fish. It allows them to breathe air by extracting oxygen from the atmosphere.
Bettas and gouramis, labyrinthine organ found.
c) Differentiate between holobranch and hemibranch.
Ans→
| Holobranch | Hemibranch | |
| 1) Definition | A gill with filaments on both sides of the gill arch. | A gill with filaments on only one side of the gill arch. |
| 2) Structure | Complete gill with lamellae on both sides. | Partial gill with lamellae on one side. |
| 3) Functionality | Fully functional for respiration | Partially functional for respiration |
| 4) Example | Found in most bony fishes. | Found in certain cartilaginous fishes like sharks. |
d) Name two fishes which show bioluminescence.
Ans→Anglerfish (Lasiognathus species) and Lanternfish (Myctophidae family)
e) What does semi-intensive culture mean? Which fishes are cultured over here?
Ans→ Semi-intensive culture refers to a type of aquaculture where fish are grown in controlled environments, but with a combination of supplementary feeding and natural productivity.
Tilapia (Oreochromis spp.), Catfish (Clarias spp.), Carp (Cyprinus carpio) are cultured over here.
f) Mention application of remote sensing and GIS in fisheries.
Ans→ (i) Monitoring fish habitats: Identifying and mapping aquatic ecosystems to assess suitable habitats for fish species.
(ii) Tracking fish migration: Using satellite imagery to study migration patterns and distribution of fish stocks.
(iii) Water quality assessment: Monitoring environmental factors like temperature, salinity, and chlorophyll levels for sustainable fish farming.
g) What do you mean by sex-reversal in fish?
Ans→ Sex-reversal in fish refers to the process where a fish changes its sex, either naturally or artificially. This can occur due to environmental factors, genetic influence, or hormonal treatments, and is often used in aquaculture.
h) Give example of two transgenic fish.
Ans→ GloFish (Danio rerio) and AquaBounty salmon (Salmo salar)
Fish and Fisheries 2020
1.) a) Name two alternative protein sources of fish feed except fish meal.
Ans→ Soybean meal, Insect meal, Algae and Seaweeds.
b) What are the different types of cages used in cage culture?
Ans→ 4 types – (i) Fixed (ii) Floating (iii) Submerged (iv) Submersible cages
c) How swim bladder act as resonator?
Ans→ Swim bladder intensifies the vibrations of sound and transmits these into the inner ear through weberian ossicles and by this act as resonator.
d) Name two synthetic hormones used in induced breeding in carps.
Ans→ Ova prim, Ova tide, WOVA-FH
e) What is oviparity?
Ans→ oviparity is a reproductive mode where organisms lay eggs rather than live youngs is called oviparity.
f) Name two carp species used in polyculture.
Ans→ Surface feeder – Catla (Catla catla)
Column feeder – Rohu (Labeo rohita)
Bottom feeder – Mrigal (Cirrhinus mrigala)
g) Name a fish with ganoid scale.
Ans→ Bowfin fish (Amia calva); Paddlefish
h) How homocercal tail differs from diphycercal tail?
Ans→ Homocercal tail is symmetrical, with the upper and lower lobes of the tail fin being roughly equal in size, commonly found in most bony fish (e.g., tuna).
A diphycercal tail is shaped like a tapered fin, where the vertebral column extends into the tail, and the lobes are symmetrical but the tail is pointed, typically found in some primitive fish like the coelacanth.
i) Give example of a fish with three dorsal fins.
Ans→ Antenna Codlet (Physiculus dalwigki)
j) Write the scientific names of two ornamental fishes.
Ans→ Betta fish – Betta splendens
Guppy – Poecilia reticulata
k) Which parasite is known as carp lice?
Ans→ Argulus
l) Name the enzyme responsible for bioluminescence.
Ans→ Luciferase
m) Give two examples of amphidromous fish.
Ans→ Gobies (Gobies sp.); Striped Mullet (Mugil cephalus); Galaxias (Galaxias maculatus)
n) Name two fishing harbours located in West Bengal.
Ans→ Two fishing harbours in West Bengal are – Frasergunj Fishing Harbour & Digha Fishing Harbour.
o) What are Weberian ossicles?
Ans→ Weberian ossicles are small bones of some fishes connecting the air bladder with the inner ear to enhance hearing and aid in balance.
2) a) Write two differences between physoclistous and physostomous swim bladder.
Ans→
| Physoclistous Swim Bladder | Physostomous Swim Bladder | |
| 1) Connection to Gut | No connection to the digestive tract. | Connected to the digestive tract via a pneumatic duct. |
| 2) Gas Regulation | Gas exchange occurs through blood vessels (rete mirabile). | Gas regulation occurs by gulping or releasing air through the mouth. |
b) Write the role of Na-K-ATPase pump during electric discharge in electric rays.
Ans→ The Na-K-ATPase pump in electric rays helps in establishing ion concentration gradient across the cell membrane of electrocytes. The Na-K-ATPase pump actively transports any ions out of the electric organ sales and k ions into the cells that create an electrochemical gradient difference that causes electric discharge.
c) State the drawbacks of using ice for fish preservation.
Ans→ 1) Temperature fluctuation: Ice melts overtime, leading to temperature fluctuation that can affect the consistency of fish storage conditions.
2) Drip loss: As ice melts, it can result in drip loss causing the fish to lose moisture which may affect its texture and quality.
3) Freezer Burn: Prolonged use of ice in freezers can contribute to freezer burn, negatively impacting the flavour and texture of fish.
d) What are the causes for microbial spoilage after canning of fish?
Ans→ Microbial spoilage of canned fish occurs due to:
- Improper Sterilization: Insufficient heat treatment during canning may not kill all microbes, especially heat-resistant spores like Clostridium botulinum.
- Post-Process Contamination: Leaks in the can or poor sealing allow microbes to enter.
- Contaminated Raw Material: Using fish with high microbial loads can lead to spoilage if sterilization is inadequate.
- Storage Conditions: Improper storage (e.g., high temperature) can promote microbial growth if the seal is compromised.
e) Fishes are R-strategists- Explain.
Ans→ Fishes are R-strategists because they produce a large number of offspring with minimal parental care, prioritizing high reproductive rates over individual survival. This strategy helps them exploit unstable or variable environments.
f) Name two transgenic fishes.
Ans→ GloFish (Danio rerio): Genetically modified zebrafish that glow due to the insertion of fluorescent protein genes.
AquAdvantage Salmon (Salmo salar): Genetically modified Atlantic salmon with enhanced growth rates.
g) Write two applications of remote sensing in fisheries.
Ans→Fish Stock Assessment: Remote sensing helps identify fishing zones by detecting chlorophyll concentrations, sea surface temperatures, and plankton distribution, which indicate fish abundance.
Habitat Mapping: It is used to map and monitor aquatic habitats like coral reefs, mangroves, and seagrass beds to support sustainable fisheries management.
h) Write two applications of chitin.
Ans→
- (i) Medical sutures: Chitin from the exoskeleton of crustaceans is used in the production of absorbable surgical features.
- (ii) Cosmetics: Chitin is utilised in the cosmetic industry for its moisturising properties.
- (iii) Wastewater treatment: Chitin and its derivatives are introduced in the wastewater treatment process as they effectively bind with heavy metals, facilitating removal of pollutants.
Fish and Fisheries 2021
1) a) What is the main function of pectoral fin?
Ans→ Pectoral fin allows abrupt changes in side to side direction and Brake to decrease speed.
b) What is clasper?
Ans→ Claspers are specialised reproductive organs found in male cartilaginous fishes (Shark, Rays and Skates) used to transfer sperm to the female during mating.
c) What are the advantages of composite fishing (any two)?
Ans→ (i) Increased productivity. (ii) Disease management. (iii) Increased yield of fish.
d) What is the importance of fisheries law and regulations?
Ans→ (i) To preserve the fish population.
(ii) To prevent them from getting extinct.
e) Give an example of fish which shows bioluminescence.
Ans→ Angler Fish, Hatchetfish
f) Give an example of fish with rhomboid scale.
Ans→ Bowfin fish (Amia calva)
g) What are the causes of sex reversal in fishes?
Ans→ Change in temperature, hormonal disruption, genetic factors, social influences and stress can cause sex reversal in fishes.
h) What is the meaning of fish processing?
Ans→ Fish processing refers to the various methods and techniques used to transform raw fish into marketable products for human consumption.
i) Give an example of Bacterial fish diseases.
Ans→ Dropsy, Columnaris
j) What is the cage culture?
Ans→ Cage Culture is an aquaculture production system in which fishes are raised in cages submerged in water bodies such as lakes, rivers and seas.
Examples: Tilapia, Catfish, Carp etc.
k) What are the essential nutrients needed to formulate fish diet?
Ans→ Protein, Carbohydrate Omega-3 fatty acid, vitamins minerals such as Calcium and Phosphorus essential nutrients in fish diet.
l) What is extensive method of fish farming?
Ans→ Extensive fish farming usually refers to fish farming conducted in medium to large sized natural water bodies like ponds, lakes etc for high yield production.
m) What is the main function of gill?
Ans→ The main function of gills In fish is to extract Oxygen from water and release CO2, facilitating the process of respiration.
n) Expand TMAO.
Ans→ Trimethylamine N-oxide (CH3)NO
o) What are Indian Major Carps (IMC)?
Ans→ Catla (Catla Catla); Rohu (Labeo rohita); Mrigal (Cirrhinus mrigala)
2.) a) Write down two important functions of the swim bladder.
Ans→ (i) Buoyancy Control: Maintains the fish’s position in the water column.
(ii) Sound Production and Reception: Aids in communication and detecting vibrations.
b) Define homocercal tail.
Ans→ A homocercal tail is a symmetrical fish tail where the upper and lower lobes are equal in size, aiding in efficient forward movement.
c) Briefly write the effect of thermocline on marine fisheries of India.
Ans→ The thermocline, a layer of rapid temperature change in the ocean, affects marine fisheries in India by influencing fish distribution and behaviour. It creates distinct zones, limiting nutrient mixing and confining fish to specific depths, impacting catch potential.
d) Give an example of bottom feeder and surface feeder freshwater fish.
Ans→ Bottom Feeder: Catfish
Surface Feeder: Guppy
e) What is an accessory respiratory organ and its significance in fishes?
Ans→ Accessory respiratory organs in fishes are specialized structures that allow them to breathe air directly from the atmosphere when oxygen levels in water are low.
Significance: These organs help fishes survive in oxygen-depleted environments, such as stagnant or polluted waters, by enabling aerial respiration.
f) Write three key identifying characters of fishes.
Ans→ (i) Aquatic Habitat: Lives in water (freshwater or marine).
(ii) Respiration: Breathes through gills.
(iii) Body Structure: Has fins and scales for movement and protection.
g) What are the functions of electric organ?
Ans→ Electric organ in fish produce an electric field that helps in navigation, communication, self-defence and for predation.
h) Define brood stock management.
Ans→ Brood stock management involves the careful selection, maintenance and breeding of mature fish used as breeding stock in aquaculture.
Fish and Fisheries 2022
1) a) What do you mean by Pokkali-fish culture?
Ans→ Pokkali-fish culture Is a traditional rice-fish cultivation system simultaneously found only in the coastal areas of Kerala.
b) Write the scientific name of any one estuarine fish.
Ans→ Hilsa ilisha (Hilsa fish)
c) What is cage culture?
Ans→ Cage culture is an aquaculture cultivation system in which fishes are cultured in submerged cages in water bodies such as lakes, rivers and seas.
d) What are the advantages of semi-intensive fish farming?
Ans→ Semi-intensive fish farming has the following advantages:
- Balanced Resource Use: Combines natural food with supplemental feeding, reducing costs compared to intensive systems.
- Higher Productivity: Achieves better yields than extensive farming by enhancing natural productivity.
- Sustainability: Maintains ecological balance with controlled stocking and feeding practices.
e) What is the function of bioluminescence in fishes?
Ans→ (i) It is used to communicate with others.
(ii) They use their light to attract prey in deep sea.
f) What is the common parasitic disease of fish?
Ans→ White spot disease (Protozoan parasite – Ichthyophthirius multifiliis)
g) What is the importance of osmoregulation in fishes?
Ans→ (i) Maintain salt and water balance.
(ii) To keep a constant osmotic pressure in the body.
h) What is broodstock management?
Ans→ Broodstock management involves the careful selection, maintenance and breeding of mature fish used as breeding stock in aquaculture.
i) Give an example of bacterial disease in aquarium fish.
Ans→ Dropsy, Aeromonas, Septicemia.
j) What is meant by Inland Fisheries?
Ans→ Inland fisheries refers to the culture and harvesting of fishes in freshwater environments such as pond, lakes, rivers.
k) What is the difference between extensive and intensive culture methods?
Ans→
| Extensive Culture Method | Intensive Culture Method | |
| Productivity | Low productivity per unit area. | High productivity per unit area. |
| Feeding | Relies on natural food in the water | Supplemental or artificial feeding provided |
| Management | Minimal management and monitoring. | Requires constant monitoring and management |
l) Why are fishing ears important?
Ans→ Fishing gears are important because they determine the efficiency, selectivity, and sustainability of fish capture, helping to minimize bycatch and ensure sustainable fishing practices.
m) What is the function of electric organ in fish?
Ans→ Electric organ in fish produce an electric field that helps in navigation, communication, self-defence and for predation.
n) What is a fish by-product?
Ans→ Fish by-products refers to the extra body part of the fish such as skin, bone, scale which are utilised for products like fish meal, fish oil and others.
o) What is induced breeding?
Ans→ Induced breeding is a technique in fish culture where the natural breeding process of fish is stimulated by hormones.
2) a) What is meant by transgenic fish?
Ans→ Transgenic fish are genetically modified fish that have DNA from another species inserted into their genome to enhance certain traits.
Example: GloFish
b) What is pen culture in fish farming?
Ans→ Pen culture in fish farming involves confining fish within the underwater pens or enclosures allowing for controlled cultivation and management in natural water bodies.
c) How do environmental factors influence the growth of the fish?
Ans→(i) Temperature: Fish growth is influenced by water temperature; it affects metabolic rate digestion and overall activity.
(ii) Oxygen level: Adequate O2 is vital for fish growth. Low O2 levels can limit metabolism and reduce growth rates.
(iii) Water quality: Factors like pH, ammonia and nitrates levels impact fish health and growth.
d) How is cryopreservation useful in fishery?
Ans→ Cryopreservation in fishery preserves fees sperm or eggs at ultra low temperature which is useful in-
(i) Genetic conservation
(ii) Selective breeding program
(iii) Facilitates the transportation and trade
(iv) Contributing disease management in aquaculture.
e) What is compound fish feed?
Ans→ Compound fish feed is a nutritionally balanced and complete feed for fish, typically containing a mix of proteins, carbohydrates, vitamins and minerals to support optimal growth and health in aquaculture.
f) Write the application of ‘GIS’ in fishery’.
Ans→(i) Site selection: GIS helps to identify suitable locations for fish farms by analysing various environmental factors.
(ii) Fish habitat mapping : GIS is used to map and monitor fish habitats assisting conservation efforts.
(iii) Fish migration patterns: Tracking fish migration using GIS helps in understanding seasonal movements.
(iv) Market access planning: GIS assists in optimising transportation routes for fish products minimising cost and improving market access.
g) State the importance of EEZ (Exclusive Economic Zone) for the perspective of any country’s economy.
Ans→ 1) EEZ provides countries with exclusive rights to exploit and manage the resources within Maritime boundaries.
2) EEZ sustains local fishing communities, ensures food security and contributes to export.
3) Countries with extensive coastline in their EEZs often benefit from tourism.
4) EEZs offers opportunities for scientific research in Marine biology, Oceanography and environment studies.
h) What causes sex reversal in fish?
Ans→ 1) Changes in environment factors such as temperature fluctuations or exposure to pollutants can influence sex reversal.
2) Disruption of the endocrine system or exposure of synthetic hormones or chemicals can interfere with the normal sex determination and result in sex reversal in fish.
3) Genetic mutation for abnormalities may causes sex reversal in fish.