Dolphins are found in the waters surrounding Cape Cod, a region with a rich marine environment. These mammals are a frequent sight for those exploring coastal and offshore areas of Massachusetts. Their presence contributes to the diverse ecosystem thriving in these productive Atlantic waters.
Dolphin Species in Cape Cod Waters
Several dolphin species inhabit the waters around Cape Cod, with the Atlantic white-sided dolphin and the short-beaked common dolphin most frequently observed. Atlantic white-sided dolphins are robust, 8 to 9 feet long and 360 to 505 pounds. They are identifiable by their distinctive color pattern: a dark gray back, lighter gray sides, a white underside, and a unique white patch below a yellow-tan streak on their flank. Short-beaked common dolphins, around 6 feet long and 170 pounds, also display complex coloration. Their bodies exhibit an hourglass pattern of dark gray, light gray, and yellow.
Bottlenose dolphins are also occasionally sighted, though less common close to shore. They are larger, distinguished by uniformly gray bodies and short, rounded snouts, differing from other species’ intricate patterns. Harbor porpoises, smaller and more elusive, can also be found closer to shore throughout Massachusetts coastal areas.
Prime Locations and Seasons for Sightings
Dolphin sightings around Cape Cod occur from late spring through early autumn. During these months, abundant prey draws dolphins closer to the surface and to areas accessible by tours. Offshore locations, particularly Stellwagen Bank, are prime viewing spots.
Stellwagen Bank, a federally protected marine sanctuary, serves as an important feeding ground for many marine mammals, including dolphins. Whale and dolphin watching tours frequently depart from ports like Provincetown Harbor and Barnstable Harbor, offering trips to this productive area. While dolphins can be seen in Cape Cod Bay, especially from July through December, offshore excursions often provide more consistent encounters.
Understanding Dolphin Behavior
Dolphins are drawn to Cape Cod waters primarily due to abundant food sources. Their diet often includes small schooling fish like herring, mackerel, smelt, and sand lance, as well as squid and shrimp. These prey species are plentiful in the nutrient-rich waters of the continental shelf and slope. Dolphins, particularly Atlantic white-sided dolphins, are known to be cooperative feeders, working together to herd fish.
Dolphin movements are influenced by the seasonal availability of their prey. They may move closer to shore or further offshore depending on where their food sources are concentrated. Cape Cod’s geography, with its sloped sandbars, shallow waters, and significant tidal fluctuations, can lead to strandings when dolphins follow prey into areas that become traps at low tide. This makes Cape Cod a frequent location for dolphin strandings, especially in the southeast corner of Cape Cod Bay.
Ethical Dolphin Watching
Observing dolphins in their natural habitat should be done responsibly to ensure the animals’ safety and well-being. Maintaining a respectful distance is a primary guideline; vessels should remain at least 50 yards away from dolphins. This distance helps prevent disturbance to their natural behaviors.
Limiting observation time to 30 minutes or less helps minimize potential stress on the animals. It is important to avoid sudden changes in speed or direction when near dolphins and to never pursue, encircle, or trap them between watercraft or the shore. Feeding wild dolphins is strictly prohibited, as it can alter their natural behaviors, make them dependent on humans, and expose them to health risks. If dolphins approach a vessel, engines should be put in neutral until the animals have safely moved away.