• Olfactory Organs:
  Carp possess nostrils (nares) with flaps of skin that guide water into the olfactory system. 
• Olfactory Receptor Neurons:
  These neurons are located in the nasal cavity and contain receptors that detect odorant molecules. 
• Olfactory Bulb:
  This is the first relay station in the brain where olfactory information is processed. 
• Olfactory Tract:
  Axons from the olfactory bulb form the olfactory tract, which carries signals to the olfactory cortex. 
• Olfactory Cortex:
  This area of the brain processes olfactory information and plays a role in behaviors like feeding, reproduction, and social interactions. 

Carp rely on their sense of smell for various activities: 

• Foraging:
  They use their olfactory system to locate food sources in the water.
• Social Interactions:
  Olfaction plays a role in social behavior, including recognizing other carp and potential mates.
• Predator Avoidance:
  Carp can detect the presence of predators through their sense of smell, allowing them to take evasive action.
• Navigation:
  Olfaction is also believed to be important for homing and migration in some fish species. In essence, the carp's olfactory system is a vital sensory system that plays a crucial role in their survival and behavior. 

• Food Finding:

  Carp rely on their sense of smell to locate food sources, including amino acids, esters, aldehydes, and fatty acids commonly found in baits. 

   
• Predator Avoidance:

  The olfactory system helps carp detect the presence of predators and potentially avoid them. 

   
• Mate Attraction:

  Carp use pheromones, detected by their olfactory system, to attract potential mates, particularly during spawning. 

   
• Navigation:

  Olfaction plays a role in guiding carp during migration. 

   

• The carp's olfactory system exhibits plasticity, meaning it can adapt and change based on experience. 
   
• For example, long-term potentiation (LTP), a form of synaptic plasticity, has been observed in the carp olfactory bulb and is believed to be involved in olfactory memory formation. 
   
• The system can also be affected by environmental factors, such as increased CO2 levels, which can impair olfactory sensitivity. 

The olfactory system in carp, like other vertebrates, is responsible for the sense of smell. Carp have nostrils or nares located on their head, which channel water into a sensitive olfactory bulb system. The system includes olfactory receptor neurons in the nasal cavity, the olfactory bulb, and the olfactory cortex, which process olfactory information and contribute to behaviors like feeding and social interaction.