Think You Spotted a Great White? Here’s What You Probably Saw
It’s easy to mistake several marine creatures commonly found in Casco Bay for the famously frightening sharks that visit our waters far less frequently
While you may have heard about sightings of great white sharks in Maine, the likelihood of seeing one inside Casco Bay is very slim. In fact, none of Portland Paddle’s guides have ever seen one in the bay. Due to boat traffic to and from the harbors and relatively shallow waters, Great Whites tend to keep their distance — especially in the waters around Portland harbor.
There are many other marine creatures, however, that are easy to mistake for a Great White. If you think you may have spotted one cruising in our cool waters, take another look! It’s much more likely that it’s one of the following creatures.
Though ocean sunfish are large (4-8’ long) with a tall dorsel fin, these fish are not to be confused with sharks. Ocean sunfish pose no threat to humans, but should still be reported if seen because they are increasingly rare to see! One of the tell-tell ways to distinguish a sunfish from a shark is by its movement. The sunfish tends to swim on its side with its fin moving in and out of the water, whereas a shark fin slices smoothly through the water. Sunfish are seen in Casco Bay and are a very unique fish to spot!
Though intimidating looking, the basking shark is only a threat to plankton, its main food source. In fact, the basking shark only has nubs for teeth and feeds much like a whale does. Basking sharks are the largest sharks that would venture into Casco Bay, a 20 foot basking shark was spotted by lobstermen last summer near Portland Harbor! This is much larger than even the biggest great whites. Though basking sharks can be difficult to distinguish from a great white, there are subtle differences. The basking sharks have a more rounded dorsel fin with motled coloring where a great white has a straight fin with two-toned colors.
Atlantic White-Sided Dolphin
These beautiful, playful creatures are sometimes seen among the waves in the outer reaches of Casco Bay. They can grow to 9 feet long and and weigh 400-500 pounds! Though it has a dorsel fin like a shark, dolphins have a smaller, more rounded fin, where shark fins are more triangular. Dolphins are commonly misidentified as sharks. These dolphins travel in small groups, so if you see one, keep your eyes peeled for more!
The harbor porpoise is the cetecean we most often spot in Casco Bay. Though much smaller than a great white, and more closely resembling a dolphin, the harbor porpoise still has a dorsel fin that could be mistaken for a shark to the untrained eye. Measuring up to 6 feet and traveling in small pods, the harbor porpoise is an exciting animal to see in Casco Bay. You’ll often hear the puff of their blows before you see them.
Of these marine creatures, the most commonly confused for great white sharks are the ocean sunfish and the basking shark, due to their size. Though rare, great whites have been reported off the coast of Maine, but they rarely venture into the areas of Casco Bay that are most popular for kayaking. The likelihood of a great white attacking a kayak in Casco Bay is even lower — in fact, it has never happened. Moreover, the kayaks we use for most of our tours are as big if not bigger than most great whites, so they are unlikely to mistake us as prey — especially when we are in a group. There are very serious risks to consider when paddling in Casco Bay, including the risk of hypothermia in cold water and the dangers of boat traffic. We encourage anyone who is paddling without a guide to focus more on those very immediate and present risks. And also don’t forget to keep your eyes peeled for all of the majestic and exciting marine creatures found in these waters!