Native oysters have made a surprise return to the shores of Belfast Lough after more than 100 years.
The discovery has both delighted and puzzled scientists and researchers who say they they haven’t worked out yet how they got there.
Because without the assistance of a reintroduction programme Ostrea edulis, the European flat oyster, has set up home in Belfast Lough where it once was found in massive numbers.
Now they believe with a little help, the Belfast Oyster could become an industry once more.
Oysters were last recorded in the Belfast area during the late 1800s but as food for the poor, they were fished to oblivion within years.
Today the oyster is listed as threatened and/or declining by the Ospar conservation scheme and is the focus of numerous biodiversity projects around Europe.
Northern Ireland’s David Smyth, a marine environmental ecologist, has a keen interest in habitat restoration and enhancement through bio-engineering of the native oyster.
The former Queen’s University student, now a science officer at Bangor University, Wales was alerted to the recurrence of the species by a friend who had taken a loughside walk and later sent him a WhatsApp photo of an oyster he’d found.
David said: “I nearly fell off my chair.”
And in May and June of this year he conducted a systematic survey and discovered 41 live oysters scattered around the coast.
He said: “It’s a boost to biodiversity in the lough, since oysters filter seawater and their shells provide a habitat for many other sea creatures including tiny worms, snails, algae and anemones.”
And his publication in the Regional Studies in Marine Science journal, revealed that some of the oysters, based on estimates of their age, could have been living in the lough for a decade.
He said: “The big question is, how did they get there?”
One theory suggested by the researchers is that sediment moved to Belfast Lough from the Irish Sea contained young oysters, which then went on to establish a small population in the area.
Belfast is an increasingly busy port and it is also possible that the regular washing effect caused by ships’ wakes has reduced the amount of sediment along the lough shore to levels suitable for oyster reproduction.
David added: “The oysters, still scarce in the lough, would probably require intervention from conservationists if they are to thrive. Because of this, and the possibility that the shellfish may contain pollutants, I would cautioned against members of the public gathering and eating them.
"In principle, however, the lough could one day be home to a future oyster fishery right near Northern Ireland’s capital.”
The return of oysters has been welcomed as “encouraging” by Lynn Gilmore of the Seafish Northern Ireland Advisory Committee, an industry group.
