More fog means more sounds of foghorns on the Detroit River.

If you've been along the Detroit River the last few days, you've likely heard the sound of a foghorn blasting out.

Those deep sounds are a language for those on the water, relaying important messages.

One horn usually means hello, three means a ship is passing a port, and five usually means something different.

"When you hear five, that usually means there's an irate ship captain," said Peter Berry, Harbour Master with the Windsor Port Authority, adding that six horns is two vessels passing each other each honking three times.

Five foghorns means another vessel may in the way of a large lake ship, according to Berry, and is often heard around the Ambassador Bridge where the Detroit River is at its narrowest.

Berry says that stretch also attracts a lot of small fishing boats as it's a "honey hole" for fish. It can also be very dangerous as large ships cannot easily manoeuvre around smaller vessels.

"It takes a kilometre for a ship to stop and that's at a slow speed. So it's hard," he said. "But the ships are actually blind coming round the turn of the Ambassador Bridge so they really need fishermen to stay out of that area any time of year."

Dangers on the water

Windsor-Essex and the surrounding area has been under a fog advisory.

Environment Canada has warned of near-zero visibility due to the heavy fog, expected to lift Wednesday afternoon.

Heavy fog could be seen throughout the day on Tuesday in Windsor, at times obscuring the Detroit skyline.

Berry says the warmer weather has attracted more fishers to the river, but points out the water temperature is extremely cold leaving people at risk of hypothermia if they fall in.

The cooler water temperatures meeting the warmer air temperatures is also dangerous for large vessel operators, however Berry says when they can't see outside their windows they rely on radar, GPS and other technologies to navigate the channels and rivers. However, small boats don't always show up on navigation.

"It's very important these lakers go through and sound their horns to give their warning," said Berry.

LISTEN | Hear more from Berry about lakers on the Detroit River:

Despite their use for safety, Berry says the foghorn sounds are special in their own way to many who have lived near the water.

"It's a rich sound, I love the sound of the foghorn. I grew up on the east coast and lighthouses had fog horns," he said.