Honours / Discipline Specific Elective (DSE)

 
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FISH & FISHERY
Unit 1: Introduction and Classification 

Feeding habit, habitat and manner of reproduction. Classification of fish (upto Subclasses) (Romar, 1959)

Q. What is the difference between actinopterygii and Sarcopterygii?

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Unit 2: Morphology and Physiology 

Types of fins and their modifications; Locomotion in fish; Hydrodynamics; Types of Scales, Use of scales in Classification and determination of age of fish; Gills and gas exchange; Swim Bladder: Types and role in Respiration, buoyancy; Electric organ, Bioluminescence

Q. What are the major functions of an electric organ?
(i)species having powerful electric organs use them both for offence and defence. The prey is paralysed as a result of the discharge and is then eaten. The primary function of the electric organs in all species may be to provide protection gainst attck from a predator. The electric catfish Malapterus sp and the Narcine sp probably use their capability to discharge a strong current mainly for defence.
(i)Species having weak electric organs like Mormyrids use the electric organs for detecting objects or enemy in the surrounding water by electrolocation. The fish creates an electric field surrounding its body and the fish becomes aware if the field is broken by any object. This is possible with the help of electrosensory system of the fish.

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Unit 3: Fisheries 

Inland Fisheries; Marine Fisheries; Fishing crafts and Gears; Depletion of fisheries resources; Application of remote sensing and GIS in fisheries; Fisheries law and regulations

Q.What is role of bacterial photophores?
I
n a number of species such as Photoblepharon, Malacocephalus  laevis, light is produced by symbiotic bacteria. These photophores consists of simple sacs or tubules that contain symbiotic bacteria. In some species (Malacocephalus), the luminescent organ opens by a duct on the ventral surface of the fish, a little ahead of the anus and is richly supplied by blood capillaries  (For further information follow our contact section)

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Unit 4: Aquaculture 

Extensive, semi-intensive and intensive culture of fish; Pen and cage culture; Polyculture; Composite fish culture; Brood stock management; Induced breeding of fish; Management of finfish hatcheries; Preparation and maintenance of fish aquarium; Preparation of compound diets for fish; Role of water quality in aquaculture; Fish diseases: Bacterial, viral and parasitic; Preservation and processing of harvested fish, Fishery by-products 

Q. What are the major factors influencing fish production along the West and East Coast?
(i)Salinity- Some species of fish are euryhaline and can tolerate wide range of salinity, but most species have a limited salinity tolerance (stenohaline). Changes in salinity affect osmoregulation of fish and buoyancy of the eggs. Along the west coast of India, salinity of water of the Arabian sea varies from 34-37/ 1000 and is higher than 30-34/ 1000 range in Bay of Bengal along the east coast.
(ii)pH- The pH of sea water along the west coast is favourable for the development of fish and varies from 8.0-8.3. The temperature of surface water ranges between 23-29°C in the Arabian Sea. In Bay of Bengal, the temperature is more uniform being 27-29°C. (iii)Plankton, (iv)Thermocline and upwelling, (v)Mud banks etc.
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Q.What is the purpose of using synahorin in induced breeding of fish?
In the Indian major carps, hCG or Synahorin (a mixture of chorionic gonadotropin and mammalian pituitary extract) induce successful spawning and is effective when injected in combination with carp pituitary extract (Chaudhuri, 1976). Comparable results have been obtained in the grass carp (Lin, 1965; Chen, Chow and Sin, 1969). However, Bhowmick (1979) has recently reported on the use of crude hCG prepared in the laboratory for inducing spawning in Labeo rohita. In the grey mullet, hCG (Kuo, Shehadeh and Nash, 1973) or SG-G100 (Shehadeh, Kuo and Milisen, 1973; Kuo, Nash and Shehadeh, 1974a) alone or pituitary homogenates from grey mullet or Pacific salmon along with Synahorin (Liao, 1969, 1975; Shehadeh and Ellis, 1970), or SG-G100 along with hCG or even deoxycorticosterone (Kuo and Nash, 1975) are effective in inducing spawning. 

 

Unit 5: Fish in research 

Transgenic fish, Zebra fish as a model organism in research

Q. What are the essential steps involved in the methodology of transgenic fish production?
(i)Acquiring the gene: 
The first step is the acquisition of an appropriate gene sequence along with regulatory flanking sequences from a gene library. The flanking sequences should include promoter sequence and enhancer sequences.
(ii)Cloning of the gene:
The acquired gene sequence or construct is cloned into a plasmid or phase vector and grown up in a suitable bacterial strain. This is followed by harvesting of the gene from the microbial cells and if desired, isolating it from the vector by the use of suitable restriction endonuclease enzymes.
(iii)Injecting the gene, (iv)Handling injected eggs, (v)Demonstration of gene expression, (vi)Germ-line incorporation of the gene etc.

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