Step-by-Step: Sharks on Cape Cod: How Scared Should You Really Be?

Our project puts into perspective the fear of sharks on Cape Cod. We took the popular belief that the waters of Cape Cod are dangerous because of sharks and used data on shark attacks and shark sightings to prove whether or not there was any actual merit to this fear.

When we were first assigned this project and put into groups, we had several ideas about what kind of topic we wanted to investigate, and from there, what kind of statement we wanted our news article to make. We actually began our project wanting to collect data on the usage of ‘False Identification’ for the purchasing of alcohol, but that got intense very fast and also had many factors playing into it, primarily the fact that there is no real way to track the amount of ‘fake I.D’s’ that exist, as people don’t admit to having them until they’re in trouble.

As a group we decided that we would investigate shark attacks in Cape Cod, Massachusetts, since it is a popular vacation spot on the East Coast. We began our project knowing very little about the actual shark situation on the Cape. We basically knew that there were warnings to be aware of your surroundings when swimming in the waters of the Cape, but we did not know how real the threat of being attacked by a shark actually was.

So, we began there.

We googled “shark attacks in the United States” to formulate a starting point for our project. The very first site that came up was “” This website is a database containing records of all of the fatal and non-fatal shark attacks that have occurred in the world dating back to 1900.

From the home page, we clicked on the link that said “incidents by country.” From there, we found the United States and clicked on that link.

We were brought to this page, which lists all of the states in the United States and also provides an overview of the attacks in the United States. We were interested in Massachusetts, so we followed that link.

The data found on this page became the basis for our project. We looked at all of the incidents in Massachusetts and then narrowed it down to all of the incidents just on Cape Cod alone.

We collected the data for shark attacks in Massachusetts, both fatal and non-fatal, as well as the data for shark attacks in Cape Cod. We then went back and collected the data for shark attacks in all of the coastal states in the United States. The purpose for this was so we could provide a comparison between shark attacks in Massachusetts and shark attacks in other coastal states. We then took down the overall number of shark attacks in the United States as a whole to provide a general overview of how many shark attacks happen in the entirety of the United States as compared to just in Cape Cod.

We took all of the coastal states and used the recorded number of shark attacks to calculate how likely you are to be attacked by a shark in each state per year. We calculated this number out of one million people. We compared these likelihoods to the likelihood that you will be attacked by a shark in Massachusetts as a whole.

From this point, we had a solid basis for our project. We continued to explore shark attacks on Cape Cod. Creating a solid list of data sources that we would be taking numbers from.

After looking at all of these sites, we realized that the actual number of shark attacks that have occurred on Cape Cod is remarkably low. We thought that just writing a piece on shark attacks on Cape Cod wouldn’t really be enough. We decided to broaden our project to include the number of shark sightings on Cape Cod as well.

We found that there were a lot of articles out there that said different things about the number of shark sightings on Cape Cod. We wondered why this was. After researching shark sightings more in depth, we realized that most articles just include eye witness accounts of seeing sharks in the waters of Cape Cod. These accounts are not exactly reliable and didn’t provide us with any solid information on the number of sharks in the waters off Cape Cod.

We did however, stumble across “” This website provided us with answers to our questions on shark sightings on Cape Cod. The Atlantic White Shark Conservancy supports white shark research and raises awareness of white sharks on Cape Cod. They have created a sharktivity map that dates back to 2015 and provides information on shark detections based on the number of sharks that they have tagged since then.

Basically, what we learned from this website was that there are a lot more sharks in the water then we think that there are. The number of shark attacks that have actually taken place on Cape Cod and in Massachusetts as a whole does not even begin to compare to the number of sightings there actually are.

We realized that there should be a lot more shark attacks on Cape Cod then there actually are, based on the number of recorded sightings. According to this website, there are even more sharks out there then they are able to detect at this moment. Technology has not yet allowed them to ensure that they have detected all of the sharks in the waters of Cape Cod.

From here, we began to interview people.

We reached out to Cynthia Wigren (executive director, affiliated with Atlantic White Shark Conservancy), Dr. Gregory Skomal (project leader of the Massachusetts Shark Research Program), Leslie Reynolds (chief ranger at the Cape Cod National Seashore), Julie Lasry (frequent Cape Cod vacationer from Montreal) and Stuart Smith (the harbourmaster in the town of Chatham, Massachusetts). Unfortunately, only Reynolds, Lasry and Smith got back to us.

After cleaning our data- meaning we corrected state names, misspellings in attack definitions and funny year numbers- we looked for any patterns we could find to support our statement. We found that there was an increasing amount of shark sightings per year in Cape Cod. While we were conducting our interviews, this of course was a question that we posed to our sources- why were shark sightings increasing so dramatically each year?

After speaking with the Harbormaster of Chatham Massachusetts, he told us that shark sightings were increasing primarily because the seal population is increasing. Monomoy Island is directly off the coast of Cape Cod and is known for its warm waters, often attracting seals, and therefore sharks.

Reynolds said something to us during our interview with her about how people on Cape Cod are more likely to die of a bicycle accident then a shark attack. That statement really got us thinking. How likely are you to die of a shark attack in general? We started googling this question and we came across this website:

What we found on this site was a list of things that are more likely to kill you then a shark attack and just how much more likely they were to kill you.

We had compiled all of the data that we needed to really tell our story at this point. We wrote up a rough draft and moved on to creating some rough sketches of visualizations.

This first visualization is a rough representation of some of the data that we found on things that are more likely to kill you then shark attacks. We used an increase font size on the numbers to show how much more likely you are to die.

The first visualization evolved to the graphic above. However, we were not satisfied with this draft.

We ended up with this more sophisticated graphic that still utilized the feature of increased font size to represent the danger associated with each activity.

For this second sketch, we wanted to show where the majority of sightings take place on Cape Cod. We used the sharktivity map provided by the Atlantic White Shark Conservancy as a reference. However, this map got a bit jumbled, so we decided to choose 2015 and just use the shark sightings from that year instead.

Using Carto, we created the map below. This map shows just the shark detections in Massachusetts in 2015. The hover over feature includes the number of detections and the number of sharks that were spotted in each of the blue areas.

For our third visualization we decided to look at the United States as a whole. We sketched up a map that showed the severity of shark attacks in each state. We used colors to represent the severity based on mild, mediocre and extreme.

However, we decided to change this map up a lot for the final draft. While we still wanted to incorporate a map of the shark attacks in the United States, we felt the severity meter was very confusing. We decided to create an interactive map on Carto that just documented the shark attacks that occurred in the United States and detailed the incident in the hover over feature.

We did have one more visual that we sketched out that showed the correlation between shark sightings and the seal population on Cape Cod. However, we felt this visual did not add to our story and omitted it.

Once we were able to finalize our visualizations and to edit the rough draft of our story, we were able to compile the whole project on Medium: