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.