This story was supported by the Pulitzer Center

LIFE IN LOUGH Hyne, Ireland’s only statutory marine reserve, is under threat.

Once described as “a gigantic marine aquarium” by the renowned Irish naturalist Robert Llyod Praeger, this lough in Co Cork is facing a barrage of stressors.

The Journal Investigates can reveal that the recent influx of thousands of Mauve stinger jellyfish into the protected area is just the latest of many threats facing this delicate ecosystem.

Pollution, fishing, poaching and heavy recreational use are ongoing and could be having detrimental impacts on the lough’s wildlife. Meanwhile, experts say that the current management is not fit for purpose.

Until recently, the lough’s shallow basins were dominated by the purple sea urchin, Paracentrotus lividus, which numbered thousands of individuals in the 1990s. Now, just over 100 remain.

Within the past few decades, other species common to the lough’s subtidal zone have also vanished, among them conical sea snails, called top shells, and spiny starfish.

Dense blooms of thick, noxious algae – a likely sign of eutrophication, which impairs conditions for marine life – now blanket the lough’s shallow seafloor in warmer months.

This likely stems from agricultural run-off along the south-west coast of Ireland, with polluted water entering the lough from the wider Atlantic Ocean.

Life is also thinning out deeper down.

Typically, sponges form dense gardens of up to 100 varied, colourful species along the lough’s sheer cliffs. But since 2010, half have disappeared. The largest individuals, comparable to old trees in a forest, have been hardest hit. While two sites have shown signs of regrowth, other sites have not recovered.

Some experts say there is “zero management” of the site by the competent authority, National Parks and Wildlife Service (NPWS), and that it urgently needs a management plan to improve conditions for wildlife.

Mark Costello, a global expert in marine protected areas (MPAs) at Nord University in Norway, whose PhD research was conducted at Lough Hyne, says: 

They’ve completely just let it lapse – the management of it.

NPWS denies the site is mismanaged, while acknowledging that such views have been expressed by some sources.

Declan O’Donnell, District Conservation Officer, covering the Cork region for NPWS, says that there has been a loss of marine life from the lough’s shallows, but that “the cause is unclear”.

As far as NPWS is concerned, the biggest risk to wildlife is likely polluted waters entering the lough from the open sea, which they see as an issue outside of their control.

“It’s a worldwide issue – the elevated nitrogen levels in inshore waters,” says O’Donnell.

Life in the lough is under even more pressure in recent weeks, with the arrival of thousands of Mauve stinger jellyfish adding yet another threat to the many species already in decline.

Scientists observing the jellyfish say the swarm is removing vast quantities of plankton from the ecosystem, the fate of which is hanging in the balance. 

Just over 100 purple sea urchins remain in Lough Hyne's shallow basins. Gray Williams Gray Williams

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‘Little awareness on how to treat the lough’

Lough Hyne Marine Reserve in County Cork became the first marine site designated for protection in Ireland, and in Europe, in 1981. The site was selected for its abundant and diverse marine life and because of its global importance as a site of scientific research.

Since 1923, biologists have studied the lough’s marine life in detail.

Measuring just one square kilometre, the lough is connected to the wider Atlantic Ocean through a narrow channel called ‘the rapids’, through which water ebbs and flows.

It has a deep trough that reaches 52 metres, and two shallow basins, each just over 20 metres deep.

The lough’s diverse habitats – tidal marshes, rocky shores, seagrass meadows, and steep vertical cliffs – support a variety of species rare in Irish waters, including a red-mouthed goby fish usually found in the Mediterranean, bright orange and yellow sponges, and a peach-coloured ‘cup’ coral found nowhere else in Ireland.

Three-quarters of marine algal species recorded in Ireland are also present here.

Lough Hyne Marine Reserve is Ireland’s only strict or ‘no-take’ marine protected area (MPA), meaning that, in theory, fishing and other extractive activities should be prohibited. In practice, while permits are required to remove plants or animals from the lough, some types of fishing are exempt from this rule.

Recreational and commercial fishing – potting for prawns – persist on the lough. It is legal to fish for mackerel, mullet and a variety of other species in the lough, for instance, though anglers should practise ‘catch-and-release’. Meanwhile, a local family retains a historic licence for prawn-potting, which happens on a seasonal basis.

Poaching of urchins and other shellfish such as lobsters, is an ongoing problem, according to Cynthia Trowbridge, an American ecologist based at the University of Oregon, who has been studying Lough Hyne since 2001. She says:

As soon as most of the tourists go, the poachers come.

Trowbridge admitted that, at times, she has avoided reporting poachers for fear of retaliation. “We don’t want to be the target. As scientists, we’re over at the lab often, and there’s only one way in and one way out – on a boat”.

Much of the signage at Lough Hyne is obscured by bushes and lacks clear information for visitors. It’s possible that many do not realise they are visiting a protected area, nor that it is illegal to harvest shellfish from Lough Hyne.

One of the signs at Lough Hyne when The Journal Investigates visited earlier this year. Olive Heffernan Olive Heffernan

“People are definitely taking things out of the lough that they shouldn’t,” says resident Steven Grant, who, in 2021 co-founded Lough Hyne Matters, a group of citizens concerned with the lough’s future.

Since 2014, there’s been a dramatic increase in visitors using the lough for water sports, including sea swimming and kayaking. On warm summer days, the lough draws large crowds, yet public waste bins and toilets are absent from the site.

Scientists and locals say the uptick in numbers has had unpleasant outcomes: people tramping the seabed and harming marine life, dumping their rubbish on the foreshore, urinating in the carpark and worse still.

“I’ve had faeces in my driveway,” says Grant. “There’s currently very little awareness here of how to treat the lough and how to interact with it,” he says.

Foul waters and lack of data

Despite its protected status, there’s no national programme to monitor wildlife or water quality at Lough Hyne Marine Reserve.

In recent decades, however, independent scientists have monitored the shoreline of the lough annually, and more recently, others have surveyed its deeper waters.

Though wildlife still thrives in large portions of the lough, the emerging picture is of an ecosystem undergoing rapid change, with many species dying off.

Eutrophication – caused by an excess of nitrates – is suspected as a contributor to the disappearance of urchins and other species in the lough’s shallows.

“The major effect of eutrophication is in the shallow subtidal area, where during the summer, specifically, we get this horrible green gunge forming,” says Rob McAllen, professor of marine biology at nearby University College Cork (UCC).

McAllen, among other experts, has noticed the disappearance of purple urchins from the lough’s shallow regions since 2010.

Co Cork is one of the largest dairy-farming regions in Ireland. Because of Ireland’s nitrates derogation, dairy farmers here are allowed to have more livestock and spread more slurry as well as chemical nitrogen than is recommended under the EU Nitrates Directive, a law aimed at limiting water pollution from agricultural sources.

One outcome of this policy has been a decline in water quality along the southwest coast since 2010, coinciding with the visible growth of algae in Lough Hyne.

Urchins on the lough's basin, with algae visible nearby. Cynthia Trowbridge Cynthia Trowbridge

In deeper waters, other factors may be at play, says McAllen of UCC.

From his research with James Bell – a marine biologist based in New Zealand – McAllen is convinced that sponge die-offs occurred during one or two discrete events between 2010 and 2015, with the major cause being changes in the oxygen content and temperature of the water.

The EPA, which has responsibility for monitoring national water quality, does not monitor Lough Hyne, however, and so it is impossible to pinpoint the cause or the timing of any of these losses.

EPA samples water quality data at 45 of the 110 coastal sites under its jurisdiction and extrapolates sampled data across unsampled sites. Water quality data from the Western Celtic Sea are, typically, assigned to Lough Hyne.

The EPA says that “the purpose of the monitoring programme is to assign ecological status to waterbodies… and not to conduct an assessment of biodiversity in protected areas.”

Excessive nitrogen levels highlighted

There are some exceptions. As part of a national research programme called STRIVE, the EPA funded McAllen’s research team to monitor water quality in Lough Hyne from 2007-2013.

They found that nitrogen levels in Lough Hyne in 2008 to 2009 were up to four times higher than those in 1992 to 1993.

The EPA also monitored the wider southwest coast during this period and found evidence of excess nitrogen.

“Recent reports have highlighted issues with excessive nitrogen levels in waters along the southern seaboard. The most recent assessment of the Western Celtic Sea, to which Lough Hyne is connected, shows it is at high status for nutrient condition,” says a spokesperson for the EPA.

From 2018 to 2021, the EPA attempted to monitor water quality in Lough Hyne using a buoy, but according to scientists who work at the lough the device was regularly removed for use elsewhere and experienced multiple technical failures during its deployment. They say that no reliable data were collected.

In response, an EPA spokesperson says that it “deployed a buoy to monitor nutrients in Lough Hyne on foot of a request from NPWS”.

“The EPA gathered a good dataset from the buoy in Lough Hyne and technical issues did not affect this data.” They add that “no evidence of elevated nutrients” was found in the lough during this time.

Samples from the same period analysed by scientists, including McAllen, concluded there was eutrophication in the lough.

While nutrient-rich water, loaded with nitrates, is likely entering the lough from the wider ocean, there’s a question as to whether run-off from farms surrounding the lough is also contributing.

Colin Little (centre) surveying Lough Hyne with volunteer scientists. Penny Stirling Penny Stirling

McAllen says that the water quality data collected from 2007 to 2013 discounts that possibility.

But others are unconvinced. Trowbridge says that water quality data from within Lough Hyne is too sparse to be conclusive and says she has seen visual evidence of run-off coming into the reserve.

Whatever the source, Trowbridge says that high levels of nitrates in the water fuels the growth of noxious algae, which now covers boulders and rocks in the lough’s shallow waters.

This impedes the movements of adult sea urchins, making it hard for them to reproduce. It also makes it difficult for juvenile urchins to settle and survive.

Algal blooms can also lead to a build-up of hydrogen sulphide, a toxic gas that smells of rotten eggs.

At times, in recent years, hydrogen sulphide levels have been outside the range considered safe for humans, says Trowbridge.

Visitors ‘wrecking the place’

It’s not just land use that has changed since Lough Hyne was designated as a protected site. Over the past decade, the lough has seen a dramatic increase in visitors, mostly using it as a water sports destination.

Lough Hyne Marine Reserve is included on the Wild Atlantic Way, which – according to residents – has brought day trippers in large numbers.

Last year, Fáilte Ireland listed Lough Hyne as the fourth best swimming spot in the country, noting that its sheltered waters are around one degree warmer than those of the wider Atlantic Ocean.

Residents say this encouraged yet more visitors.

Residents say that inclusion of the lough on the Wild Atlantic Way brought large numbers of tourists. Olive Heffernan Olive Heffernan

“In terms of the changes… It’s just the sheer number of visitors and its popularity as a swimming place,” says Declan O’Donnell, the District Conservation Officer for NPWS, who also said that windsurfing and kayaking have “exploded”.

The change in use of Lough Hyne concerns scientists, such as Penny Stirling, who says it is out of sync with its status as a marine reserve. She says: 

If you let too many people in anywhere, it wrecks the place.

Both Stirling and Little say that the lough needs some restrictions on use and numbers, with a warden routinely on duty.

O’Donnell says that NPWS wants to continue to welcome visitors to Ireland’s national parks. They don’t consider activities such as windsurfing and swimming as harmful to Lough Hyne.

No management plan in place

When Lough Hyne was established as Europe’s first marine reserve in 1981, the intention was that it should be “managed in such a way as to ensure the conservation of the marine ecosystem which it constitutes”.

The regulations specified that permits were required for research, diving, the use of powerboats and the removal of wildlife. Until around 2005, a park warden, who lived on site, patrolled the lough daily, checking compliance with the rules.

The current NPWS ranger now only visits the lough occasionally. Their area covers 1,000 square kilometres of land and sea, compared to one single square kilometre patrolled by the site’s first warden.

In 1998, Lough Hyne and its surrounds, including an area of forested woodland called Knockomagh Hill, became ‘a Special Area of Conservation’ (SAC) under the EU Habitats Directive. In 2021, the government agreed to new protections for the site requiring more activities, including “organised recreational activities”, such as kayaking, to have permits.

Permits are required for most activities on or around Lough Hyne. Olive Heffernan Olive Heffernan

Although the site has conservation objectives in place since 2014, it has no management plan to limit numbers of visitors or the overall extent of activities.

“The absence of a formal document such as a Management Plan does not imply that the site is not being properly managed” says a spokesperson for NPWS.

To comply with the EU Habitats Directive, a legally binding charter, the authorities responsible for a protected area must, however, meet several obligations. One of these is a requirement to evaluate any potential harm from planned activities.

This process is called ‘appropriate assessment’ and allows regulators to gauge the possibility of harm from activities within designated sites.

Since 2021, NPWS has conducted an appropriate assessment of commercial kayaking at lough, but not of other activities. It also hasn’t assessed the larger impact of alleged crowding.

“There’s a duty to understand the entirety of the pressures… [on a protected area],” says John Condon, a legal expert on protected areas with international environmental law charity ClientEarth.

“They should have monitoring data,” says MPA expert Costello, “so that if they allow an activity [to] take place, they [can] say afterwards that it had no effect on the nature conservation status of the reserve.”

The EU Habitats Directive specifically requires authorities to assess all planned activities in the context of existing pressures.

NPWS says that they believe that any activities which might pose a “significant threat” are regulated and managed to the degree that negative impacts on the Lough are unlikely.

While few would argue that Lough Hyne needs to outlaw recreation or visitors, the authorities have a duty to ensure that all activities occur at a level that is safe for wildlife. Researchers, including McAllen, are interested in monitoring these activities and their impacts.

A spokesperson for NPWS says that they hope to part-fund such research, with the Irish Research Council, and that the findings will inform future considerations on how they manage the lough.

NPWS says that, in the meantime, existing permits – for fishing and commercial recreation – have associated conditions designed to eliminate or minimise any potential negative impacts.

A sea anemone, one of the many creatures living in the lough’s diverse habitats. James Bell James Bell

There is also a wider obligation, within the Habitats Directive, however, to avoid the deterioration of habitats and the disturbance of species for which a site was designated. For a site in decline, the authorities are required to make remedial efforts.

According to Cordon, that duty exists even in the face of external pressures, such as pollution. Speaking about Lough Hyne, he says:

There’s a serious question around the deterioration of that MPA and whether appropriate steps have been taken.

In response, NPWS says “we look forward to the general reduction in nitrogen levels in the open ocean”, which they anticipate will ensue from implementation of international policies such as the Nitrates Directive, and from upgrades to local wastewater treatment plants, both outside of their remit.

But with no monitoring of water quality in the lough, the authorities aren’t currently assessing whether the situation is improving or deteriorating, let alone what is causing the loss of marine life.

Opportunities to improve marine conservation

Unfortunately, the situation at Lough Hyne Marine Reserve is not unusual in Ireland. Of Ireland’s protected sites, 254 are wholly or partially marine.

Of these, Lough Hyne is the only reserve to outlaw bottom trawling, a notoriously destructive fishing practice.

Since 2015, 4,000 square kilometres of Irish seabed ‘protected’ under the Habitats Directive has been fished by bottom trawlers, according to a recent analysis.

More generally, Ireland lacks meaningful rules to protect life in its designated marine sites, according to an analysis by Seas at Risk and Oceana, published in April.

Very few Irish MPAs have management plans. In this regard, Lough Hyne Marine Reserve is not alone.

New legislation may force government bodies such as NPWS to change course.

In August 2024, the EU adopted a nature restoration law, which applies to all member states. In Ireland, it should strengthen conservation of its national parks.

Government bodies including NPWS now have a legal obligation to actively counter biodiversity loss and to report their progress.

The announcement came with a €3.15bn climate and nature fund.

In February 2024, Ireland received additional funding of €15.14 million from Europe to expand and enforce its network of marine protected areas. In October, the Irish government pledged €25 million towards protecting and restoring marine biodiversity in Ireland.

Together, these funds should enable NPWS to effectively implement, monitor and protect its marine parks.

For the moment, however, NPWS has no plans to change tack at Lough Hyne, and the fate of this reserve remains uncertain.

“It might take a long time for the urchins to return”, says Little. “But things would improve with a management plan.”

Reporter: Olive Heffernan • Editor: Maria Delaney • Main Image Design: Lorcan O’Reilly • Social Media: Sadbh Cox • Video Edit: Nicky Ryan

This story was supported by the Pulitzer Center