The role of Common Dolphins during the Sardine Run

mega pods – hundreds if not thousands!

When we are out at sea and spot a wall of white water moving towards us….we know that a mega pod of Common Dolphins is heading our way.  An amazing sight to see as they  leap out of the water and dive back down creating ripples of waves in their wake. They dramatically stampede in and out of the water at a high speed because there is less resistance in air than in water and this enables them to move as fast as possible.  These sightings are an indication that there are sardines as they are a primary predator and actively participate in the sardine run to take advantage of the abundance of food.

Common Dolphin mega pod during the 2023 Sardine Run in Port St. Johns. Hundreds of dolphins breaking through the ocean and hot on the tails of the Sardines.

Bait balls!

The dolphins play a valuable role in rounding up the sardines and sighting them often gives us an indication that the sardines are nearby. They separate a small pocket of sardines and circle around them to herd the sardines into a tight swirling mass called a bait ball. When a group of dolphins successfully form bait balls, they go into a feeding frenzy, taking turns darting through the densely packed schools of fish, using their speed and agility to catch individual sardines.

Diving with the dolphins is a huge part of experiencing the sardine run; they zoom around the divers with a distinct chatter of whistling and clicking sounds and suddenly they’re darting towards the sardines, next thing you see are the gannets plummeting into the water right beside you! The sardine run attracts many marine predators, such as sharks, seabirds, whales and big game fish species. We have often seen the dolphins swimming alongside these predators as all the marine animals are choosing to only go after the sardines.

How to spot a Common Dolphin?

They have a streamlined body with a slender build, allowing them to be fast and agile swimmers. The dolphin has a prominent curved dorsal fin, which is located on their backs and helps them maintain balance while swimming. They have a distinct color pattern with a light gray cape on their back and a cream-colored or white belly. Their sides have an hourglass pattern with a dark line running from the eye to the flipper.

Common dolphins are highly social and intelligent marine mammals that are well-known for their playful behavior and acrobatic displays such as leaping out of the water (breaching), performing flips and twists and riding the bow waves created by boats (bow-riding).

Incredible footage of Common Dolphins and Gannets on a bait ball during the 2023 Sardine Run season in Port St. Johns.