The Solent's best kept secrets

© Linda Priestley

Here is Hampshire & Isle of Wight Wildlife Trust’s guide to the most fascinating secrets of the Solent

It is a common misconception that the Solent is mostly devoid of life, and that there isn’t much going on beneath the green-grey surface of our local seas. This couldn’t be further from the truth.

1. The Solent used to be a river - Ten thousand years ago, at the end of the last ice age, the river Solent carved its way eastwards along the south coast — the rivers Avon, Test and Itchen were mere tributaries. But as the ice receded, rising sea levels and sinking land slowly flooded the river valleys along the south coast, giving rise to today’s coastline.

2. Seahorses swim around our shores - Seahorses are usually associated with far off shores and distant coral reefs, but they also live right here in our local seas. In fact, two species of seahorse, the long-snouted seahorse and short-snouted seahorse have both been sighted off the Isle of Wight coast.

3. Cuttlefish are colour-changing clever-clogs - The cuttlefish of the Solent have camouflage skills that are so highly developed that if a checkerboard were placed beneath one, it would assume the same pattern. So you may be surprised to learn that they are, in fact, colour blind. They are able to camouflage using their enhanced perception of contrast and by detecting the polarisation of the light waves entering their eyes. 

4. Mantis shrimps are impressive predators - These remarkable burrowing crustaceans have perhaps the most complex colour vision in the animal kingdom and are ferocious predators, able to strike their prey at lightning speed. The Solent is a hotspot for a breeding population of these impressive, but elusive hunters.

5. There are meadows under the waves - The Solent’s shallow waters and intertidal mudflats host some of the most extensive seagrass meadows in the country. They provide shelter and food for hundreds of species. Just one hectare of seagrass can support 80,000 fish and 100,000 invertebrates such as seabass, spider crabs and seahorses. Not only that, seagrasses act as carbon sinks, removing CO2 from the atmosphere faster than tropical rainforests!

Seahorse in seagrass

© Julie Hatcher

6. Harbour seals are the Solent’s supreme scuba divers - The Solent has a small resident population of around 45 harbour seals. You may have guessed from their whiskery faces and puppy-dog eyes that seals share a common ancestor with dogs. When diving, their heart rate slows to 4-15 beats per minute.

7. Oysters make the best water filters - The Solent is home to the European flat oyster, and used to support the largest native oyster fishery in Europe. Oysters feed on suspended organic particles and plankton, which they suck up and filter through their gills. They are capable of filtering 200 litres of water a day.

8. Lobsters are sea royalty - Lobsters are the monarchs of the ocean — their blood is literally blue! They can live for 50 years and achieve up to 9kg in weight. They hide in rocky crevices in the Solent.

9. Our seas have a sense of porpoise - Bottlenose dolphins and harbour porpoises occasionally pass through our local seas. These intelligent marine mammals travel in groups and communicate through a complex system of squeaks and whistles. Last summer a bottlenose dolphin was spotted following the Gosport ferry!

10. The Solent is even home to sharks! - The thresher shark is perhaps one of the Solent’s most magnificent visitors. Named after their enormous, curving tail fin — a deadly weapon used to herd, stun and kill their prey — these sharks are instantly recognisable. One of the largest ever caught was landed just to the east of the Isle of Wight.