A Northern Ireland minister has said he feels a sense of shame at the environmental crisis affecting Lough Neagh.
Agriculture, Environment and Rural Affairs Minister Andrew Muir said there are "no quick fixes" to the issues affecting the lake and that real and sustained improvements there will take decades.
Lough Neagh is the biggest freshwater lake, by surface area, in Ireland and the UK.
It supplies 40% of Northern Ireland’s drinking water, and sustains a major eel-fishing industry.
Noxious blooms covered large parts of the lake last summer, and affected other waterways and beaches.
Nitrogen and phosphorus from agricultural fertiliser running off fields were believed to be a major contributory factor.
The spread of the invasive zebra mussel species is also understood to have played a role, as they have made the water clearer, allowing more sunlight to penetrate, stimulating additional algal photosynthesis.
Climate change is another factor cited, with the highest water temperature at Lough Neagh recorded last June.
Mr Muir told Members of the Legislative Assembly (MLAs) that he had visited Lough Neagh in his first week in office.
He said in the past two decades the balance between growing the economy in Northern Ireland and safeguarding the environment had not been struck correctly.
A starting point for dealing with the issues at Lough Neagh, Mr Muir added, will be an Environmental Improvement Plan (EIP) being drawn up by his department.
"The blue-green algae issue, most notably seen in Lough Neagh, but also at various other water bodies in Northern Ireland, cannot be seen in isolation from the natural environment more generally.
"We cannot tackle its problems in isolation either.
"The Environmental Improvement Plan (EIP), which is the plan for significantly improving our natural environment, will contain actions setting the direction of travel for the coming decades relevant to improving water quality, including at Lough Neagh.
"Once it has received executive agreement I will bring a further and more specific paper on Lough Neagh with a more detailed action plan to a subsequent executive meeting."
Mr Muir said additional investment will also be required to tackle algae blooms and water quality issues.
"I cannot fix this alone. It is clear there is a need for collective action across government, the private and public sectors and also local communities.
"I am determined to continue my pledge to engage with partners and stakeholders to ensure we work together to improve water quality across Northern Ireland, including in Lough Neagh.
"Unfortunately, despite the actions we will take in the immediate future, which are important, there is no quick fix and a recurrence of the blue-green algae blooms is likely this year.
"If anything, I would detail to the committee they have reappeared already.
"Real and sustained improvement will take decades. Due to the nature of the algae blooms, actions in the first year may not have the immediate impact expected by the wider community.
"However, the identified actions, if funded in year one, will see a longer term benefit to Lough Neagh, and in turn other water bodies across Northern Ireland, much sooner than would be the case without the early intervention needed," Mr Muir said.
Answering a question from Alliance Party MLA John Blair about how the EIP could benefit the lake, the minister said: "I feel a sense of shame that Lough Neagh has been allowed to get into the situation it has.
"What is different this year compared to last year is we have ministers in place, we have an executive in place, we have an assembly committee in place."
He added: "We all know there are contributing factors - we have the agricultural run-off, we have wastewater infrastructure which needs massive investment, we have septic tanks; we also have the arrival of zebra mussels, we have climate change.
"We can’t have a situation where what we are doing is hoping and praying the weather is going to be better this summer so the problem isn’t as bad.
"If we are genuinely, sincerely wanting to address Lough Neagh it is going to require a really concerted effort across government and society to do that, and it is going to require funding."
