Now in its 32nd year, the annual beach and roadside verge clean-up takes place every spring, organised by Shetland Amenity Trust, and over 20 per cent of the isles population get involved.
In previous years, volunteers have collected over 60 tonnes of litter that has been washed up on Shetland beaches or thrown from car windows.
Despite seeing a similar number of volunteers as in previous years and putting in a similar number of hours, the weight of rubbish collected this year has fallen markedly to just over 48 tonnes.
Amenity trust head of engagement Sandy Middleton said: “We are not sure exactly why the weight of rubbish collected this year has reduced, particularly as the number of volunteers and hours put in has not reduced.
“We think there may be a number of contributing factors. Many of the groups reported that they spent much of their time this year collecting micro-plastics and small bits of fishing nets which is really time consuming.
“These items weigh far less than the big bulky items but in some ways are far more important for us to collect as they are the ones that cause greatest risk to our wildlife.
“We also had less big storms this year directly before the clean-up so there may have been less large items on the beaches. We are also seeing more and more people doing mini beach cleans year round which may have helped.”
This year over 4,500 volunteers participated in the clean-up with 240 groups covering over 1,075 kilometres.
Each group cleaned up an average of nearly three miles of coastline and roadside verges amounting to 13,500 volunteer hours. That is estimated to be worth the equivalent of over £120,000 in paid work.
Ms Middleton added: “People in Shetland are immensely proud of their incredible natural environment and rightly so. This is why we continue to see so many people turn out every year to help care for it.
“We couldn’t run the event without them and we are extremely grateful to our partners the Shetland Islands Council and sponsors Enquest, Shetland Charitable Trust, and Tesco Bags of Help who all help to make it happen.”