After the deaths of five people in the waters of the Cape and Islands within two weeks this month, public safety officials on the Cape and Islands are asking swimmers to exercise caution and practice water safety habits.

But there’s no single cause for the deaths, which experts say demonstrate some of the many dangers facing swimmers in the marine environment.

The victims included a 50-year-old father who died trying to reach a child struggling against the current in Pocasset; a 60-year-old man swimming to his boat off a newly lifeguarded beach in Dennis; and a 42-year-old Plymouth man who jumped or fell into water of Buzzards Bay off a bridge or dock.

In addition, a 76-year-old woman died July 9 after swimming to shore from a sailboat on Nantucket, and a 69-year-old Barnstable man died after being found floating off Coast Guard Beach in what a Cape Cod National Seashore ranger said was a “probable cardiac event.”

Since June 1, the Massachusetts State Police have responded to 16 drownings, state police spokesman David Procopio said.

“The State Police urge members of the public to familiarize themselves with water safety guidelines and boating safety requirements and to be aware of the danger of ocean and river currents,” Procopio wrote in an email. “We also urge parents or adult guardians to keep constant watch over children under their care near any body of water, pool or tub.”

Drownings of children in Massachusetts since June 1 have included a 6-year-old who died in a river, a child who drowned in a pool and another who drowned in a tub, Procopio said.

In Falmouth, a 7-year-old boy from Ireland, Jonah Maguire, nearly drowned at the Sea Crest Beach Hotel June 29 but was pulled to the surface and resuscitated.

Since then at least two more people on Cape Cod — a 17-year-old girl at Covell’s Beach in Centerville and a young woman at Maushop Village Beach in Mashpee — were resuscitated by bystanders and lifeguards after being found unresponsive in the water.

Lakeville resident John Lima died July 12 off 371 Circuit Ave. in Pocasset.

According to a preliminary report by the state police assigned to the Cape and Islands District Attorney’s office, witnesses saw Lima and his two children playing Frisbee in the water in the early evening.

One of the children went out to get a Frisbee and “had a hard time swimming in the current,” the report says. “Lima went out to help and was overwhelmed in the current and went under the water.”

The children grabbed Lima and held onto a nearby mooring buoy, yelling for help until a passerby who was in a small boat nearby motored them all to shore.

Neighbors performed chest compressions and rescue breaths on Lima until emergency rescue crews arrived but could not get a response.

Lima was in cardiac arrest when he was pulled from the water, according to Bourne Deputy Fire Chief Joseph Carrara.

The narrow waterway where Lima succumbed is lined with marshes and has a few dinghies on moorings.

“It wasn’t a dedicated swim beach,” said Timothy Mullen, natural resources director for the Upper Cape town of Bourne.

There can be a strong current when tides are changing, but Mullen estimated it was about 7 knots — not strong enough to have swept a swimmer into Buzzards Bay.

The current where 42-year-old Michael Ford of Plymouth died the afternoon of July 2 is too strong and dangerous to be considered safe for swimming at any time, Mullen said.

Ford was pulled from the water near 39 Buttermilk Way in Buzzards Bay, close to William Dalton Memorial Bridge connecting Bourne to Wareham, according to the preliminary state police report on the incident.

Ford’s girlfriend told investigators that Ford — whom she described as a very good swimmer — told her he was going bridge-diving that afternoon.

Witnesses at a Buzzards Bay restaurant told police they saw Ford “jump off the dock into the water” and struggle to return to shore.

“No one should be swimming there,” Mullen said. “They jump off the bridge, which they shouldn’t be doing. There’s a ton of boat traffic.”

The current moves quickly through the area at 12 to 15 knots, Mullen said.

If swimming in that section of Buzzards Bay by Taylors Point is risky business, the Dennis beach where Matthew Maderios, of Fall River, died July 5 could not have been safer, according to Dennis Beach and Recreation Director Dustin Pineau.

Realizing that the Horsefoot Path area near busy Mayflower Beach was becoming more popular with beachgoers, the town added a lifeguard and tower this summer, Pineau said.

The 22-year-old lifeguard, a trained EMT, was on duty when beachgoers spotted Maderios “having a difficult time swimming out to his anchored boat,” according to the state police report.

“He went down quick,” Pineau said. “They couldn’t have got there any quicker.”

On-duty, off-duty, and retired emergency rescue personnel tried to revive Maderios after he was brought to shore, Pineau said.

“We had so many public safety officials there,” Pineau said. “You can be an Olympic swimmer. But sometimes something happens in the water.”

Having five people die in the waters off the Cape and Islands isn’t a particularly high number over the course of a year.

Every year from 2012 to 2014 there were four unintentional drownings in Barnstable County, according to the state Department of Public Health. The Times has reported there were also four drownings on the Cape in 2016.

What was noticeable about the recent events was the short time period into which they were compressed.