Cape Cod Sea Life


The Cape Cod sea life is diverse and plentiful. These waters are nutrient rich and are home to a huge number of species like the seal in the above photo.

In June, seals can be seen lounging in the sun just off the coasts of Chatham and Monomoy (where that photo was taken).

Most of the time, the type you will see on Cape Cod are Harbor seals. You can spot them in harbors (especially the commercial fishing harbors of Chatham and Provincetown), or hauled out onto the beaches in the off-season.

Sometimes, Grey seals are even spotted around Chatham and Nantucket - the southernmost breeding ground for these mammals.

Adult harbor seals have gray, brown or black spots, are around 5-6 feet long, and can weigh between 150 and 200 pounds. Grey seals are brown or silver with black splotches and are much larger than harbor seals, ranging from 7 to 8 feet long. The males can weigh 400 pounds, while the larger females can top 700 pounds.

An easy way to tell them apart is by the shape of their heads. The Grey seals have elongated heads, while the Harbor seals have a much rounder profile.

The seals eat a variety of Cape Cod sea life such fish, shrimp, squid and any crustaceans they can dig up along the sea bed.

While I visited Monomoy a few years ago, I saw huge numbers of Grey seals in the waves just off the beach. We walked for a long time and the seals were following us down the shoreline. When we stopped---they stopped. I guess they were as curious about us, as we were about them!

What are you looking at?

horseshoe crab

Another interesting creature in Cape Cod sea life is the horseshoe crab. Now, I've seen many, many, horseshoe crabs over the years but never so many at once--or so I thought...

It turns out, that all these "tiny crabs" were actually "castings." When a horseshoe crab grows, it sheds (molts) its outer skin (or shell) like a snake does.

When it is finished, the result is a casting that looks exactly like a tiny horseshoe crab. horseshoe crab casting When I first saw this, I thought some horrible accident or disease caused the death of all these little sea creatures.

Cape Cod sea life has another interesting member. The starfish.Starfish, which are neither a star nor a fish, are commonly called "Sea Stars" in other parts of the world, but in the states, they are called starfish.

There are over 1,800 known species of starfish, and they live in all of the world's oceans but they are relatively rare North of Massachusetts.

The best time to hunt for starfish is at low tide, in the crannies and crevices of tide pools, under or along the sides of rocks and even in empty shells.

Starfish are carnivores and will prey on mollusks (oysters, quahogs, and mussels) and crustaceans (barnacles, crabs, and shrimp).

An interesting fact about starfish: They are capable of asexual reproduction. This is achieved when an arm of the animal is removed, (with some of the central disc attached), and a new independent star fish is formed.


Before we realized that they were capable of this, fisherman whose haul of shellfish were greatly diminished by the predatory starfish, would remove them from their nets and chop the animals in half, returning them back to the sea.

Finally, fisherman started watching the Discovery Channel and stopped accidentally doubling the number of starfish.

Possibly the most dangerous of the starfish is called an Asterias. This starfish will twist its body backward and completely succumb the creature it's devouring.

It pushes its stomach through to the outside of its body and takes the other animal apart. It then injects the animal with a digestive juice that completely kills the animal.

These animals are known to live on the ocean floors, especially in rocky areas.

There are two forms of this creature that live in waters surrounding the United States. Asterias Forbesi are part of Cape Cod sea life and are bright orange, with voracious appetites.

The Asterias Vulgaris also live in the Cape Cod area. These animals are yellow in color.

A funny story about Cape Cod starfish: One year, we decided to let 2 of our friends join us on our trip to the Cape. My friend Lisa kept saying, "All I want to do is find starfish..."

I told her she would be disappointed because there are no starfish in Cape Cod. Once again, or so I thought...

Off she went on a walk down Coast Guard Beach and guess what? About a half hour later, she came back with a bunch of starfish that had washed up onto shore.

I was dumbfounded.
Never in all my trips to Cape Cod, have I ever seen one #@$!&* starfish!

Despite her protests, I made her put them back into the ocean--after a picture of course.

Along with hermit crabs, lobsters and many types of fish, there are so many cool things in the waters off Cape Cod.

My favourite items of Cape Cod sea life by far, are sand dollars.

sand dollars

If I had a real dollar for every sand dollar I have collected over the years in Maine, Cape Cod and in Florida, well I'd be rich!

By the time they are washed onto shore, they are no longer alive and have turned a whitish colour.

live sand dollar
If you see a brown sand dollar with a velvety covering, it is alive so make sure you return it to its home.

It is illegal (and unethical)to remove any live specimens from the beach!

Since the sand dollar lives in sandy locations, anyone who would like to collect their shells should comb beaches as the tide recedes. The very best time for collecting is after a heavy storm, as many of the shells that have died are dredged up by the increased wave action.

There is an old poem called "The Legend Of The Sand Dollar." which I love.

When it comes to Cape Cod sea life, you have to mention sharks right?

After all, wasn't "Jaws" filmed here?

Even though Jaws was partially filmed on Martha's Vineyard, you don't really need to worry too much about sharks.

When I surf in Florida, I see them all the time but on Cape Cod, they are a less common sight.

Oh, they are still there, you just don't see them as much because the water is a little murkier than down south!

dead shark
Still, most of the sharks you will ever see in Cape Cod are on whale watching expeditions (basking sharks) and young dead ones, washed up onto shore--like this one.

Up for a swim?

According to the International Shark Attack Files there hasn't been a fatality in Cape Cod from sharks since 1936, but for anyone that has seen the movie "Jaws", it doesn't matter. We all get a little paranoid when we enter the water.

Another part of Cape Cod sea life are birds. There are so many different species of birds here that it is truly a birder's paradise.

If you are into birdwatching and would like to know the best spots on Cape Cod to see birds (and which ones you'll see) then visit the Cape Cod Birding page.

Cape Cod whale

No list about Cape Cod sea life would be complete without mention of the gentle giants of the ocean---whales.

Many tourists come to Cape Cod just for the extraordinary whale watching tours that depart from Hyannis or Provincetown.

For more on this topic, check out the

Cape Cod Whale Watching page.

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