IT’S the mystery hum that is making life a misery for people living on both sides of Southampton Water.

Noise experts are still trying to solve the puzzle surrounding the origin of the low frequency drone, which has sparked dozens of complaints from families suffering sleepless nights.

Residents affected by the deafening din have blamed everything from heavy industry to tugboats operating out of Southampton Docks.

Now a new and altogether more bizarre theory has surfaced – amorous fish and their noisy love life.

Some observers say the sound is similar to the so-called West Seattle Hum, which plagued parts of the US city this time last year.

Popular theories surrounding the origins of the noise included a cement factory and tanker ships operating off the coast.

But marine biologists at the University of Washington suggested that the culprit could be Midshipman fish, believed to live in the nearby Duwamish waterway.

The male fish let out a distinctive drone to let females know they are searching for a mate.

The noise can go on for hours and often increases in volume as competing males attempt to out-hum each other.

And scientists say the sound can be amplified by bouncing off buildings and ships.

The National Oceanography Centre in Southampton was unable to shed any light on the mystery, saying the noise heard in Seattle appeared to be a US phenomenon.

But the Scottish Association for Marine Science claimed that fish could be responsible for the bizarre buzzing sound.

Dr Ben Wilson said: “It’s not beyond the realms of possibility. There are certainly ‘sonic fish’ in the north Atlantic and the approaches to the English Channel.” However, the Poole-based Marine Biological Association doubts that fish are to blame.

A spokesman said: “We can’t think of any fish native to the north eastern Atlantic which makes a noise that’s audible outside the water.

“It’s more likely to be a man-made sound, given the nature of the area.”

People affected by the noise include Linda Zammit, of Woolston, Southampton.

She said: “I thought I was going mad until I saw the article in the Daily Echo.

“I hear it every night unless it’s windy or raining. It doesn’t keep me awake but it stops me getting back to sleep if I do happen to wake up.”

Fellow sufferer Maria Dennett of Sholing, added: “We regularly experience a humming noise at night.

“A few times we put it down to a neighbour’s washing machine or dishwasher but it’s happening so frequently that we know it’s not the case.

“It’s a really low pitched sound that literally pulsates through the house.” New Forest District Council has now received more than 30 complaints about the irritating hum.

A spokesman said noise monitoring equipment had been installed in several properties in a bid to track down the origin of the sound.