AN ENVIRONMENTAL agency has revealed the cause of thousands of fish mortalities in a pond in Glasgow. 

Oatlands resident Lisa Gillen had spotted the dead fish in Richmond Park during one of her daily walks this month. 

She had first noticed “little white things” on the surface of the main pond’s water.

She was left shocked when she realised the white specks were actually the bodies of thousands of fish floating in the water.

Glasgow City Council had since warned visitors to the park not to touch the water, due to a suspected blue-green algae infestation. 

Now, the Scottish Environment Protection Agency (Sepa) has confirmed the infestant would be the cause behind the unusual event.


A spokesperson said: “When visiting the park, Sepa noted a significant algal bloom in the pond.

"Officers believe a combination of factors - including algal growth, low dissolved oxygen due to algal respiration during the night, and a mass spawning event – contributed to the deaths of the fish. 

“Algal blooms in ponds can be caused by nutrient enrichment.

"Sepa is aware that the local authority plans to erect signage around the pond to discourage the public from feeding bread to ducks and suggest alternatives, which will also be better for the pond.

“Sepa has engaged with the local authority throughout this incident and will continue to do so as required.”


Glasgow City Council previously said crews had cleared the dead fish and waste, and a plan would be put in place to deal with the algae infestation.

The local authority has also installed a warning notice at the pond reading: "High concentration of blue-green algae have been found in this water, which can cause serious health effects."

The council is warning people not to swim or paddle in the water, fish, and drink or touch the water and the scum around the pond.

It is also advising to keep children and pets away from the water and scum. 

If a person or animal is exposed to the water or scum, it is advising to wash with water immediately and seek medical advice.

HeraldScotland: Glasgow City Council has installed a warning notice regarding blue-green algae in Richmond Park's pond.Glasgow City Council has installed a warning notice regarding blue-green algae in Richmond Park's pond.

Ms Gillen, who has lived in the area for 33 years, swore she had “never seen anything like this”.

A video captured by the resident showed the fish amassed near a low bridge and surrounded by floating litter.

The 49-year-old said: “It was a bit of a shock.

“The pond has been in a bit of a state for a couple of years, but I’ve never seen something like this before and [I’ve] stayed in the area for 33 years.

“I was walking with my daughter and my dogs. We usually walk along the pond anyway because there’s usually a lot of swans.

“We just spotted wee little white things floating and upon closer inspection, I said to my daughter ‘they’re fish and they’re dead’.

“Then we walked up where the bridge is, and we just saw this kind of block and it was just all these dead fish. There was a lot of rubbish and just one little fish swimming about himself.

“I thought ‘I’ve never seen anything like this in my life’.”

Ms Gillen, who runs the Friends of Richmond Park group, had said the pond usually has no fish, and had previously only seen some tadpoles swimming in the water.

The woman, who volunteers to look after the park as part of the group, had said there was a long-standing issue with a pump in the pond.

She added the problem had been repeatedly highlighted in community meetings over the years, to no avail.

HeraldScotland: Images show the current state of the pond.Images show the current state of the pond.



“It’s been going on far too long,” she said.

“A burn that runs around the park also had chemical waste in it, so the park has been through a bit of a rough time.

“It’s a historical place and it’s got good wildlife, so we need to try to preserve it as much as we can."

What are blue-green algae?

According to the UK Centre for Ecology and Hydrology, blue-green algae or blooming algae naturally occur in lakes, ponds, canals, rivers and reservoirs around the world.

They are actually a type of bacteria, known as cyanobacteria, which can produce toxic chemicals that are very harmful to the health of people and animals. T

hey are particularly a health risk during warm summer months when their concentrations increase in the water to form blooms and scums on the surface.

This can look like green or turquoise wispy paint, green scum or clumps of green particles.

Often these surface scums accumulate along the shore where children or dogs play, or where livestock come to drink.

Are blue-green algae dangerous? What are the risks?

The UK Centre for Ecology and Hydrology says blue-green algae can produce potent toxins that can result in a range of health effects in people and animals.

Effects on people coming into contact with toxic scums include skin rashes, eye irritations, vomiting and diarrhoea, fever and pains in muscles and joints.

Blue-green algae have caused the deaths of dogs, horses, cattle, birds and fish across the UK.