Kerala University of Fisheries and Ocean Studies (Kufos) is set to launch a genome editing mission to revolutionize aquaculture and boost pearl spot production.

• Purpose: To target the genetic makeup of the fish inhibiting faster rate of growth. It would also help enhance breeding and seed production of pearl spots.
• The DNA sequencing of pearl spots was expected to be available in the public domain soon.

About Pearl Spot Fish

• Scientific Name:  Etroplus suratensis and commonly known as “Karimeen” in Kerala.
• Native Species: Pearl spots are a high valued food fish endemic to peninsular India and Sri Lanka. 
• Recognition: The species was declared as the ‘State fish of Kerala’ in the year 2010. 
• Potential for aquaculture: 
  • The pearl spot has high market demand, hardy nature, non-predatory habits and ability to breed naturally in confined waters making it a suitable candidate for aquaculture.
• Features: 
  • Habitat: Pearlspot is a euryhaline fish, thriving well in brackish waters and has the ability to live both in fresh and saline waters.
  • Feeding habits: It is an omnivorous detritus feeder which feeds mainly on plankton, small worms, prawns and algae with Periphyton dominated with spirogyra being its favorite food. 
  • Breeding habits: It has an asynchronous type of ovary which indicates its continuous spawning habit. It breeds throughout the year with two peaks during the monsoons.
    • Breeding behavior involves pairing, courtship, chasing, nest making and parental care.
  • Physical Attributes: Pearl spots have an elevated laterally compressed body and a small cleft mouth.
    • Coulor: In the natural habitat, the fish is light green in color with eight vertical bands.
    • Scales: Most of the scales above the lateral line have a pearly white spot and some irregular black spots are seen on the abdominal scales.
  • Prone to diseases: The most common disease causing agents are bacteria including Pseudomonas, Alcaligenes, Flavobacteria, Moraxella, Vibrio and gram-positive Micrococci, Athrobacter and Bacillus spp.

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Pearl Spot Farming

• Culture: The pearl spot is suitable for culture in confined, fresh and brackish waters  in traditional ponds in Kerala at small scale which can be harvested in 9-12 months ( achieving a body weight of 300 to 400 grams). 
• It is cultured in the traditional manner, in the ‘Pokkali’ fields.
  • Annual Production: Kerala produces around 2,000 tonnes of pearl spots annually against the market demand for about 10,000 tonnes as per 2020 estimates.
• Seed production: Seed of pearl spot is available throughout the year along the east and south-west coasts of India with the peak season being during the months of May-July and November-February. 
  • Method of seed collection: In this method twigs or branches are kept submerged in the water a week before the  day of collection taking advantage of the tendency of the fish to congregate in large numbers for feeding on epiphytic growth.
• Spawning Surfaces: 
  • Natural Environment: The fish attaches its eggs to submerged substrata like stones, aquatic plants etc. 
  • Cultured Environment: In a prepared pond materials like palmyrah leaves tied in bunches to fixed poles, coconut leaf petioles, coconut husks, bricks, pieces of asbestos sheets etc.is being provided in the ponds.