Conservation of Cephalopods

• 24 Dec 2024

Source: TH 

Why in News? 

Recently, California and Washington have approved bans on octopus farming. Hawaii is considering similar action against raising octopus, a member of Cephalopods, demand for food. 

What are Cephalopods? 

• About: Cephalopods are a class of ocean-dwelling intelligent invertebrates that includes cuttlefish, squid and octopus. 
  • Cephalopods are a broad class of molluscs. Mollusca are soft-bodied invertebrates, often enclosed partly or fully in a calcium carbonate shell. 
  • Early cephalopods had protective shells, but many lost them, and evolved traits like high intelligence, flexible arms, and camouflage. 
• Diversity: Cephalopods are a diverse class with three superorders: 
  • Octopodiforms (octopuses and related species) 
  • Decapodiforms (squid, cuttlefish, and related species) 
  • Nautiloids (nautiluses and related species) 
• Anatomy: The term cephalopod means "head foot," referring to the connection between their head and arms. 
  • Cephalopods have two eyes and at least eight arms. E.g., octopuses are eight-armed while squids are ten-armed. 
  • Nautiluses are the only cephalopods with an external shell. 
• Eyes and Vision: Most cephalopods are likely colorblind and exhibit visual camouflage.   
  • They can open and close tiny sacs just below their skin that contain coloured pigments and reflectors, revealing specific colours. 
• Movement: Cephalopods mainly use jet propulsion, expelling water from their mantle cavity to propel themselves. 
  • Octopuses walk with their arms, while squid and cuttlefish use fins for movement.  
• Circulatory System: Cephalopods have three hearts: two pump deoxygenated blood, and one pumps oxygenated blood. 
  • Their blood is blue due to copper-based hemocyanin, which is less efficient than iron-based hemoglobin but highly effective in cold, low-oxygen environments. 
• Brain: Over half of the neurons in common octopus (Octopus vulgaris) are not in the brain at all, but distributed in “mini-brains,” or ganglia, in the arms.  
  • Most neurons in the central brain focus on vision, leaving less than a quarter for learning and memory. 

 

UPSC Civil Services Examination Previous Year Question (PYQ) 

Prelims 

Q. With reference to the evolution of living organisms, which one of the following sequences is correct?(2009)

(a) Octopus – Dolphin – Shark 

(b) Pangolin – Tortoise – Hawk 

(c) Salamander – Python – Kangaroo 

(d) Frog – Crab – Prawn 

Ans: (c)