Do Fish Have Noses
The answer to this question is yes, fish do have nostrils. However, they are not used in the same way that humans use theirs. Fish use their nostrils to smell food and potential predators. They also use them to determine water quality. If the water is polluted, the fish will be able to smell it and will likely avoid that area.
Do Fish Smell Underwater
Surprisingly, fish actually have an extremely sensitive sense of smell. Since some fish have only two nostrils, some water filters through their nasal passage on the way to the nasal cavity. Inside the nasal cavity are the olfactory epithelium, which contains the sensory cells that respond to water odor. Most fish species have very sensitive olfactory receptors.
Fish have small openings near their mouths called nares, but they are called nostrils by a fancier name. These holes, however, do not lead to the extremity of a mammal’s nose. Instead, they lead to a sinus cavity that’s lined with sinuses.
Through two holes on each nare, there are intake tubes and discharge tubes. They are separated by two flaps. Some freshwater fish are unable to move water and wastewater via cilia that are fairly sharp.
Others use muscular movements to pump water through their pores and fin muscles. Many smaller fish, such as mackerel, can swim and only use muscles to pump water in with their pore canals and system.
The water that is pumped into the nare goes into the sensory chamber in which there is a rosette. Sensors noted in the rosette grant hundreds of thousands of small nooks on the racking component of each square millimeter of fish. For smelling detection, the racking accesses the bare tissue that stocks tiny cells.
The sense of smell is incredibly important to fish. It helps them find food, avoid predators, and find mates. Fish have a highly developed olfactory system that allows them to detect even the faintest smells in the water.
The olfactory system is made up of the nose, which contains the olfactory organs, and the brain, which processes the information from those organs.
The olfactory organs are tiny structures located on either side of the fish’s nose. They contain millions of sensory cells called cilia. These cells come into contact with odor molecules in the water and relay that information to the brain. The brain then interprets that information and decides what action to take based on it.
The sense of smell is so important to fish that they can actually smell things in water that we can’t even see.
Chemical Sense
Interestingly, not all fish use their sense of smell in the same way. Some species rely primarily on their sense of smell for finding food, while others use it more for avoiding predators or finding mates. Still others use it for both purposes equally.
References
- Wakisaka, N., Miyasaka, N., Koide, T., Masuda, M., Hiraki-Kajiyama, T., & Yoshihara, Y. (2017). An adenosine receptor for olfaction in fish. Current Biology, 27(10), 1437-1447
