Crossing through a short-beaked common dolphin feeding area in the northwest Atlantic Ocean

It was a cloudy summer day on the Atlantic Ocean with little wind able to pass through the fog, creating perfect conditions for calm, mirror-like seas. A dense layer of fog encompassed the horizon, surrounding our ship like a thick, circular curtain floating above, almost as if merging, with the surface of the sea and extending to the sky around us.

While doing yoga with a coworker on the back of the ship, overlooking the ocean, another coworker yelled down to us that there were dolphins by the bow. We hurried to put our shoes on to get to the bow to hopefully see the dolphins as we saw them coming towards us at the stern and moving in a manner that is common for this species- fast and agile, traveling quickly across the ocean by propelling themselves out of the water continuously with an appearance of great ease (porpoising). They carried so much speed directly at us that it appeared, due to momentum, they would have to continue onto the ship but at 15 feet (5 meters) from the side of the ship they dove under, and we never saw them again. They continued their journey around the big blue sea, free to travel if they desired and if there were resources there, finding food, and friends, and fulfilling their dolphin duties.

The short-beaked common dolphin (Delphinus delphis) can be found in many places in the ocean around the world- from warm, tropical waters to cool temperate waters, mostly offshore. They love to eat cephalopods like squid and schooling fish such as herring and can be found feeding mostly at nighttime when their prey ascends from the depths of the ocean to the surface. They typically dive around 100 ft (30 m) to find food but are capable of diving up to 1000 ft (305 m). This encounter occurred off the coast of Rhode Island, USA and I have also seen them in Monterey, California, USA.

They are extremely talented swimmers, holding the record for the fastest species of dolphin on the planet, and can reach speeds up to 37 mph (59 kph). They are very social, impressive animals that enjoy acrobatic behavior and interacting with ships, riding the swell created by the bow or the stern. It seems that they’re abundant worldwide in their ranges but do face threats from bycatch (accidentally being caught in commercial fishing nets and drowning by not being able to come up to breathe), and hunting for meat and oil in Russia, Japan, and nations bordering the Black Sea and the Mediterranean Sea. All information regarding their biology and behavior comes from NOAA Fisheries with the link included at the end of the article.

Bycatch for this species is common in the United States and the gillnet fishery, a practice targeting the swordfish, mako shark, and thresher shark in California, has the highest mortality rate for killing whales, dolphins, and porpoises including this species as it is a monofilament (essentially invisible) net that is suspended in the water column and catches and suffocates anything in its path. We can directly help this species by avoiding or limiting the consumption of seafood, especially from unsustainable sources, but if you do enjoy this kind of food, try to make sure it is sustainable, dolphin-safe, and low or free of contaminants. Not all labels are true if it says dolphin safe so make sure you also do your research. I know that Monterey Bay Aquarium has a project called Seafood Watch that puts out a good list of sustainable and healthy seafood as well as toxic to human health and unsustainable seafood (https://www.seafoodwatch.org/seafood-basics/sustainable-healthy-fish).

A beautiful feeling is when I first observe these dolphins from afar, then run down safely to the bow to see if they are bow-riding. Sometimes they are which brings a huge smile, while other times they dive right under the boat, never to be seen again. While watching them ride the swell from our bow, I can take a step into their world and see how they interact with our vessel, their behavior, and their relationships with each other. If there are babies present, which there have been many from the middle of July to now (the start of August) in the waters off of Rhode Island, the pod stays close together with the mother next to the baby for most of the time while surrounded by the rest of the pod. The mother or female figure gives a glimpse of freedom to the baby by allowing it to jump out of the water by itself while bow riding, subsequently swimming quickly to its mother’s side, appearing to merge like one upon looking from a bird’s eye view. The juveniles in the pod left the bow riding first by diving out of sight, followed by the mother and calf pairs, leaving only a few adults left bow riding and the babies along with the rest of the pod, never to be seen again.

Short-beaked common dolphins love riding the swell that the bow of our vessel creates as it slices through the ocean and creates a pressure wave for the dolphins to ride, essentially like surfing a super long wave. If dolphins are traveling in the same direction as the ship, possibly to find food or friends, hitching a ride to take a break (basically like the moving floor in some airports) is a temptation and obvious consideration for dolphins when they encounter ships. Their highly developed sonar-like abilities used primarily for navigation and feeding, small size (6 ft, 2 m), and muscular physiology allows them to adapt to boat and vessel noise and reap the benefits of the wave our boat brings, showing a commensalism relationship with boats that seems to bring happiness and ease to the dolphin's lives.

The short-beaked common dolphins display synchronous swimming and close contact with the mother-and-calf-pair and the pod protect the mother and calf pairs by putting them in the middle of the group, showing an evidently strong bond between the mother and calf. I have had the privilege of observing this species on multiple occasions this summer off the coast of Rhode Island and they are truly a charismatic, energetic, and curious species that inspire me to be free, live life fully, and be compassionate to all those that come my way.

Links

• Super Green List | Healthy and environmentally sustainable seafood | Seafood Watch

• Short-Beaked Common Dolphin | NOAA Fisheries