What does Pelagic Mean?

Pelagic. It’s a word we use all the time to talk about fish, but what does it mean? Pelagic is an adjective that is used to describe the open ocean. Fish that are considered pelagic can be broken down into the following zones:  

Epipelagic- This includes the inshore and offshore species which we primarily focus on here on the R/V Pilar, such as tuna and swordfish but it is also home to species like salmon, whale sharks, flying fish, and of course the smaller species like anchovies. The Epipelagic zone ranges from just below the surface down to about 650 feet, and due to its shallower location, it tends to be much warmer than the other zones.  

Mesopelagic-Sometimes called the twilight zone this zone is distinct as there are acute differences in salinity and temperature. The depth of this zone ranges from 650 to 2,267 feet, is around 60 degrees and is home to light producing species like the lantern fish. Additionally, you can find giant squid, blobfish, barrel eye fish, and opahs. 

Bathypelagic- From 2,297 feet to 6,562 feet deep this zone is around 50 degrees and is home to many unique looking species like anglerfish, viperfish, gulper eels, and telescope fish. While these odd looking species can be unnerving to look at, keep in mind they are typically fairly small and no larger than 10 inches in length. Want to learn more about these pelagic species, make sure to follow Monterey Bay Aquarium Institute. 

Abyssopelagic- The temperature in this zone drops to just below 40 degrees Fahrenheit and is 6,562 feet or deeper. Species found in this zone are either ambush predators who conserve energy waiting for prey to come their way like the cusk eel or they are muscular swimming species like the Orange Roughy. This zone is just above the sea floor and surrounding features like seamounts. 

Benthic- Any time you hear the word “benthic”, think bottom. The benthic zone in some of the shallower waters inshore could be home species like stingrays and eels or it could be the bottom zone in deeper darker waters. In the deeper benthic zones, species will have adaptations to make up for limited vision and have ways to conserve energy to make up for living in an area with limited food resources.