So what of the seahorse

We are standing on the deck of HMS President, Maritime Reserve Unit, on the invitation of Tom's Uncle Howard and Aunty Val. The occasion is a happy one – a 50th wedding anniversary – and we are outside in order to pose for a group photograph. As we look westward from our spot on St Katherine's Dock, admiring the view of Tower Bridge and beyond, Tom's mum Liz tells us the news that seahorses have been found in the Thames. The idea that these murky waters harbour such a magical, affectionate visitor seems fittingly romantic considering the premise on which we are gathered here.

Indeed the potentially monogamous seahorse (for at least the duration of a breeding season even for the low fidelity species) could be an inspiration to us all. Add co-parenting and male gestation and I'd say the seahorse is definitely a keeper. From their pre-dawn dance, in which a male and female seahorse wheel around in unison gripping the same strand of seagrass with their tails, to the true courtship dance that can last for as long as eight hours and allows the male to open his pouch for the female to deposit her eggs, and finally the fertilisation, gestation and birth – some seahorses give birth to an incredible 1,200 fry in one go – the couple stay together and support each other. Throughout gestation, which can last between two to four weeks, a female seahorse will visit her pregnant partner daily for morning greetings, interacting for about six minutes. Sweet, loving courtship, regular space and the male swells up while the female stays slim during reproduction. The perfect relationship!

The seahorse of which Liz speaks was discovered at Greenwich; a rare short-snouted 5cm-long juvenile seahorse to be exact, suggesting a breeding colony may be present in the river. Short-snouted seahorses have previously been found in several spots on the south coast – at Dagenham, Tilbury and Southend according to monitoring by London Zoo between 2006 and 2008 – but this is the furthest upriver the species has been discovered to date. And according to Emma Barton at the Environment Agency: 'This is a really good sign that seahorse populations are not only increasing but spreading to locations where they haven't been seen before.' The Environment Agency also confirmed that the seahorse was alive when captured and was released unharmed.

So what of our new friend the short-snouted seahorse? Well, this is an endangered species that normally lives around the Canary Islands and Italy. Hippocampus hippocampus, as the species is also known – hippocampus from the Ancient Greek hippos meaning horse and kappos meaning sea monster – is also usually found in shallow muddy waters, estuaries or seagrass beds; conservationists believe that their presence in the Thames is a good sign that the water quality of the river is improving and becoming a sustainable bio-diverse habitat for aquatic life. So our little short nosed creature is also the bearer of good news.

Thankfully these seahorses are now also protected under the Wildlife and Countryside Act 1981 and thus, conservationists are also more relaxed about telling the world they are here. Aquarists at the London Zoo are also studying their life history and behaviour so their wild habitats can be protected. And this, hopefully, means these amazing equine fish will hopefully be here to stay.

Watch Kate Humble observing British seahorses beneath the waters of Studland Bay in Dorset