The family duo studying the winter secrets of Weymouth's seahorses

Fourteen-year-old Chloe Brown and her dad Chris have an unusual pastime together - they record the secret lives of seahorses off the Dorset Coast.

The duo, who are volunteer divers for the Seahorse Trust, are hoping to track the fish off Weymouth Bay through the winter to record their behaviour.

Mr Brown said: "This is the first year that I intend to dive throughout the year to confirm whether the seahorses stay in the same territory year round."

After passing her Professional Association of Diving Instructors (PADI) open water diver qualification, Chloe decided to team up with her dad - who is on the Weymouth-based charity's licence to survey.

She said: "It is going to involve some very cold diving but we want to know, will these seahorses that we have tracked for four months stay shallow in the winter, or will they go deeper."

Mr Brown, who has looked after and bred seahorses at aquariums for more than 20 years, said: "There is so much still unknown about their secret lives.

"It is really important that we learn more about their population dynamics and how they use these incredible seagrass habitats."

Armed with a slate and pencil, torch, compass to navigate, measuring wheel and camera the pair carry out their surveys by swimming slowly, parallel to each other over the seagrass hoping to spot some fluttering fins or a tail wrapped around some seagrass.

It's a delicate procedure, lasting up to 90 minutes involving hovering in the water or resting on the seafloor often "with just fingers and knees or tips of fins supporting us", Chloe said.

"They are very hard to spot and usually blend into their surroundings.

"Sometimes you can clearly see their silhouette, but sometimes if they are hiding with their head down, you just won't find them," she added.

Chloe said: "I can identify the different individual seahorses based on their markings... they all have unique spots on their face and body.

"When we find a seahorse I stay back and watch it while my dad photographs both sides of it for identification.

"As he moves away, I go closer and take some pictures and see if I can identify them while underwater."

They often see one of two seahorses during a dive who they hope will help with the winter project.

"A male we have named 'Snailhead' - because he had a snail on the top of his crown the first time we saw him and a female who we think is his partner - 'Snailless'!

"Their territories seem to overlap but we have never seen them both on the same dive. Hopefully the surveys will tell us more about how big their territories are," Chloe said.

Once back on dry land their pair write a detailed report from every dive and send it to the Seahorse Trust. The reports are collated by the trust each year and submitted to The Marine Management Organisation (MMO).

The pair, who started weekly dives in September, expect to reveal the findings from their winter dives in the spring.

Source: The Seahorse Trust

Follow BBC South on Facebook, Twitter, or Instagram. Send your story ideas to [email protected]