Wooing Under Water: The More the Merrier

As February is the month of romance, we're turning our attention to some amorous activities under the waves. As it turns out, sometimes three's company...

Once again it's the time of year when we celebrate our loved ones through good food, bad films, and colourful floral arrangements. Valentine's Day may be one of the key events in the human romantic calendar, but our marine wildlife puts just as much effort into wooing potential partners. Here are a few local marine species that either enjoy a lot of company or don't let it get in the way of a good time.

Love train

Sea hares are hermaphrodites, which proves a great advantage when it comes to courtship. During the mating season they meet up and form a sort of conga line, with each acting as male to one adjacent partner and female to the other - at the same time! The result is pink, spaghetti-like strands containing millions of eggs, which the hares attach to underwater plants for safekeeping.

Sea hare © Paul Naylor

Sea hare © Paul Naylor

All change

Although one of several wrasse species found in UK waters, the ballan wrasse is easily distinguishable by its large size, stocky build, and intricate patterning. All ballan wrasse begin life as females and stay that way until reaching sexual maturity, at which point around half of them become males so they can breed.

These males definitely like to keep their options open - they form harems of females and mate with whichever ones take their fancy. But if the male of the harem dies then the largest female gets a promotion: she just changes into a male and picks up right where he left off!

Heady heights

Slipper limpets also change their sex in response to their partners. They position themselves in stacks where the lower animals are female and the higher ones are male. If newcomers settle on an existing stack they stay male, but if they settle alone they become females and start trying to attract company.

Once they're settled, the limpets will stay put for the rest of their lives. When it's time to mate, the males simply send extensions down the stack to fertilise the females' eggs. In order to preserve this balance, when the bottom female in the stack dies the first male above her becomes female as a replacement.

Acorn barnacles © Paul Naylor

Acorn barnacles © Paul Naylor

Lonely hearts

Just like slipper limpets, acorn barnacles have to find love from a stationary position. But they prefer being next-door neighbours to living the high life in stacks, which means their dating scene can be a little crowded. To get round this, they have incredibly long penises that can extend to eight times the length of their bodies!

These appendages are covered in bristles that sense chemical signals from barnacles acting as females - they're hermaphrodites and can take either role when mating. So with a bit of effort and detective work, these barnacles can find a mate from the comfort of their own homes.

Marine wildlife wonders

Our local waters are filled with fascinating species like seahorses and cuttlefish, as well as important habitats like beds of maerl and seagrass. We're working to protect this vibrant underwater world, and need your help to do it. You can get involved in celebrating and safeguarding our seas through our project Secrets of the Solent, or through our broader Wilder Solent activities.