Buccal Pumping vs Ram Ventilation: Two Sides to Gills
- RRHS ScienceNHS
- Jan 8
- 2 min read
By: Malhar Debnat-
You might think all fish breathe the same way, because they’re all fish. Believe it or not there are two ways fish use their gills to breathe, and it’s the reason some fish die when they can't move! This also partially contributes to why some fish are white meat or red meat, but with only ram ventilation a fish is dead meat if it can’t move! Many fish and other sea animals however use both kinds of breathing.
Ram ventilation is exactly what is exactly what sounds like, the fish has to ram through the water in order to breathe. As it moves through the sea, the fish passes water over its gills. The blood in the capillaries of the gills take in the dissolved oxygen in the water. All fish get oxygen through the capillaries, but ram ventilation is a passive process that has to happen through constant effort, as it requires the fish to be moving through the water. Some species of sharks, tuna, and billfishes(marlins, sailfish, and swordfish) are all obligate ram ventilators, which means they can only breath if they are moving. That’s why in aquariums if a tuna bumps into a wall while swimming, it just dies if it can’t start moving again fast, as its body cannot handle the lack of oxygen and so the tuna suffocates to death. This also plays into the fact that most of these animals' meat is red in color, as it’s filled with myoglobin due to all the oxygen the fish need to store.
Buccal pumping is done through the buccal cavity, the part of your mouth between the teeth and the cheeks. For buccal pumping the fish opens its buccal cavity by lowering its mouth. This makes more water flow in to flow over the gills for the capillaries to take in the oxygen in the water, and then exhaling. It's relatively similar to our breathing! This allows fish to stay still and wait for food, or just not have to move around a bunch to stay alive, but it’s more energy draining. While many fish that use buccal pumping can also be red meat, there are many more white meat fish as they don’t have to move around to survive.
Most fish use both, but the optimization through the harshness of the seas can be a blessing and a curse for many species of fish, mainly the obligate ram ventilators. Some fish choose a third method that can be mixed with the other two, and breathe through their skin like amphibians. This is called cutaneous respiration. The life of a fish is very difficult, and it’s a race to survive. It’s interesting to learn about these different methods and strategies for the harsh life of the wild waters.
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