Pelagic Fish Explained

If we were to ask you what tuna, mackerel, sardines, and anchovies all have in common—and you’re not allowed to mention their consumption by humans—then the most suitable response would be to say that all of these fish are known as pelagic fish.

         What is a pelagic fish, you ask? Read on to find out!

What Is a Pelagic Fish?

         Pelagic fish are types of fish that inhabit the pelagic zone of the world’s lakes, rivers, and oceans. The pelagic zone is defined as the open water column that’s not associated with the shore or the bottom; fish and organisms residing in this zone have no contact with either. According to the National Ocean Service, the pelagic zone “is the largest habitat on earth with a volume of 330 million cubic miles. Different species of pelagic fish are found throughout this zone. Numbers and distributions vary regionally and vertically, depending on availability of light, nutrients, dissolved oxygen, temperature, salinity, and pressure.”

Two Types of Pelagic Fish

         Pelagic fish are classified as either coastal or oceanic. Which subcategory these fish belong to depends on the depth of water they inhabit. Coastal pelagic fish usually swim in sunlit waters above the continental shelf; these waters can reach as deep as approximately 700 feet. Coastal pelagic fish examples include anchovies, sardines, and herring.

Oceanic pelagic fish make their homes in waters much deeper than 700 feet. They tend to swim in the upper ocean column and cover significant distances as they search for their next meal. Oceanic pelagic fish examples include tuna species (bluefin, yellowfin, and albacore among them), mahi-mahi, blue and white marlins, and swordfish. Believe it or not, some sharks are even considered pelagic fish! Blue sharks, oceanic whitetip sharks, and whale sharks are three oceanic pelagic fish examples.

According to American Oceans, “Pelagic fish are ecologically significant, accounting for approximately 20%-25% of the total annual global fisheries catch. As vital links in the food chain, they have direct impacts on the populations of other marine organisms, and their size and distribution can serve as useful indicators of the overall health of marine ecosystems.” Without pelagic fish, bodies of water around the world would not be nearly as healthy and well-balanced.

Three Defining Characteristics of Pelagic Fish

         Now that you can confidently answer the question, “What is a pelagic fish?”, it’s time to learn about three of their most defining characteristics.

         Most pelagic fish are fast, agile swimmers. Their sleek bodies help them navigate the pelagic zone with speed and precision.

         Mobility is also another notable characteristic of pelagic fish; they are always searching for food as they swim and migrate. Oftentimes they cover great distances, and this not only has to do with feeding but also their interest in finding suitable breeding and spawning grounds, favorable water temperatures, and optimal environmental conditions to sustain their thriving populations.

         Pelagic fish are also known for their schooling behavior. Have you ever watched a video of sardines and anchovies swimming? If so, you’ve likely marveled at the sheer number of them and how they appear to shimmer as they swim; moving together in tight formations, shimmering as they go, creates confusion and visual chaos for would-be predators—it’s essentially how they protect themselves as they swim in the pelagic zone. If you haven’t seen a video of sardines swimming, by the way, we recommend this one courtesy of BBC Earth.

Learn More About Pelagic Fish on a Harbor Breeze Cruise!

         At Harbor Breeze Cruises, we’re always interested in learning as much as we can about the fish, mammals, and other creatures that inhabit our oceans, especially because we’re in a position to share our knowledge and insights with those who join us for a whale-watching cruise. We offer affordable, family-friendly cruises year-round, and we’d be delighted if you decided to join us on an upcoming one; it’s a great way to spend time connecting with nature on the beautiful Pacific Ocean, and we recommend that you bring a camera so you can capture the marine wildlife that you’re bound to encounter from your comfortable seat on one of our luxurious, state-of-the-art catamarans. For more information or to book a tour, please give us a call at 562-983-6880.