The UK and Ireland's largest lake, Lough Neagh, is showing signs of a worrying ecosystem collapse.

In recent years, Lough Neagh in Northern Ireland, the largest lake across both the UK and the island of Ireland would be encased in swarms of flies.

Clothing lines, car windshields, anything in their path would also be covered. Each year they arrive around spring time. Except last year, they didn't arrive at all and there are growing concerns for this year too.

While the flies disappearing may sound like a positive outcome for the regular fly nuisance, there are far-wider negative implications.

The coined "Lough Neagh Fly" is the name for the non-biting midges, crucial to the ecosystem as food for fish, wildfowl, frogs and other insects. They converge over the lake to find a mate and shortly after are gone.

The absence of the flies can have several knock-on impacts to its surroundings, including deterioration in the water quality of the lake, and the spread of other invasive species.

The freshwater lake provides Northern Ireland with over 40% of its drinking water. The water quality however, has been declining since the 1960s and is still worsening as result of algae.

Last summer there was a vast toxic algae bloom. Algae blooms deprive the waters and subsequent ecology of oxygen, with this expected to be even worse this coming summer.

The lake is also home to the largest wild eel fishery in Europe, though last year the usual six month fishing period could only last three weeks due to the absence of eels, and lacking size; a result of the lack of flies and blooming algae. The trout have also disappeared to the rivers.

The algae blooms are said to be a complex issue that is expected to take many years to improve. However the lake may not have the time to wait that long.