If you’re one of the millions of tourists flocking to the Canary Islands this summer, be careful when swimming in the sea.

While the turquoise waters around the Spanish archipelago’s seven main islands are a big part of their attraction, parts are currently tinged with a greenish-brown algae that swimmers have been warned to avoid.

[Read more: Swimming: 5 fascinating holidays with a difference]

The algae is a type of bacteria called trichodesmium erythraeum, also known as sea sawdust, which can produce a toxin that can irritate the skin. For that reason, the Canaries’ authorities say bathers should try to avoid coming into contact with the algae in the water, or if bits have been deposited on the sand.

The bloom is thought to be linked to global warming, and some reports suggest that in Tenerife tourists who’ve bathed in the sea have come out scratching themselves after accidentally touching the algae.

The travel association ABTA says: “ABTA is aware there have been reports of algae in Tenerife in recent weeks. We recommend holidaymakers follow the advice of any local authorities and always avoid swimming at any beach that is flying a red flag.” It says holidaymakers with concerns about the algae should speak to their hotel or resort rep.

But still, don’t let that put you off. There are still plenty of reasons to jet off to these sunshine islands, including:

1. The unusual climate – the Canary Islands enjoy an ‘eternal spring’, with long sunny days with temperatures ranging between 19C and 25C throughout the year.

2. The sea in the Canary Islands maintains a year-round temperature of around 20C.

[Read more: Best beach spots: 8 tips to find the perfect place to enjoy a day by the sea]

3. Gran Canaria is said to have some of the best beaches in Europe.

4. The islands are a haven for extreme sports, so you can run, pedal, jump, fly and climb your way around the wild landscapes.

5. The Canaries are volcanic, and this means there’s a wide range of climbing surfaces and conditions, with routes for all types and levels of climber.

6. 40% of the Canaries are environmentally protected in reserves boasting volcanoes, thousand-year-old forests, idyllic beaches, sand dunes, dramatic cliffs, natural swimming pools and waterfalls.

7. There are four spectacular national parks, in Lanzarote, La Palma, Tenerife and La Gomera.

8. Because of the islands’ volcanic heritage, there’s a choice of white, red, yellow or volcanic black sand.

9. If you dive in the waters around the islands you might be lucky enough to see an endangered Loggerhead Turtle.

10. The diverse food available on the islands is a mixture of native Guanche, Spanish, African and Latin American, and includes fried bananas, stews and spicy mojo sauces.

Have you been to the Canary Islands before? What did you think? Tell us about it in the comments below