The increase in mussel production is part of industry body Scotland Food and Drink’s ambition to double food production in Scotland by 2030.
So researchers in Scotland have been studying how mussel larvae move to give farmers who raise mussels and other shellfish important information about where and how to grow them.
Discovery: It’s all about the current.
The Institute of Aquaculture at the University of Stirling used genetic testing of mussels in trial sites along the west coast of Scotland, combined with mathematical modeling to understand where mussels grow well.
Research in this area has so far been limited, according to Ph.D. Ana Corrachan-Freille. “Mussel farming was a black box,”he said. “The larvae swim in the water, we let the cables into the sea, and the larvae appear there. When stocks fall, we don’t know why. When the quality drops, we don’t know why.”
The team found that the mussel larvae move in the current from south to north. “We found that a cloud of larvae can travel from the Scottish border near Stranraer to Islay in 30 days. [about 80 miles] for example. Then they attach themselves to a substrate – something solid in the water, which can be ropes – and grow for a year and a half until they start to reproduce. The next generation of larvae is carried by the current from Islay to the Outer Hebrides in 30 days – a lot further because the current is faster there.’
She added: “Knowing where mussels come from and where they go tells us a lot about the best and worst places to farm.”
The researchers worked with the Scottish Marine Science Association as well as mussel farms in various locations on the west coast through the Fishmongers’ Company, Scottish Sea Farms Ltd and the Scottish Seafood Producers’ Association. They found, for example, that larvae from Loch Isle Farm leave the loch but no new larvae arrive, so while the Loch Isle population is self-sustaining, it also contributes to populations elsewhere such as Loch Linne.
The head of Corrochano-Fraile, computational biologist Dr. Michael Beckert, said: “We were amazed at how fast the larvae moved in such a short period of time, and how fragile and vulnerable they were.
“The research shows that if we somehow blocked the flow between Scotland and Northern Ireland or slowed it down, we would lose larvae. Likewise, if we were to pollute the sea there, or somewhere like Lough Lynne, where a lot of fresh larvae wash up, it would have a huge impact. Breeding quality mussels, like anything else, requires as much genetic diversity as possible, so you don’t want to lose fresh genes by messing with the flow or polluting the environment.
“We will need to better understand the effects of climate change, but if the current moved much faster, for example, the larvae could sweep past the Outer Hebrides without stopping at all!”
Forty percent of the UK’s mussels are produced in Scotland, with half grown along the west coast and the rest around Shetland. Growing mussels has little impact on the environment, as they do not require food, grow on ropes and, being bivalves, even clean the water around them.
“This means they are vulnerable to contamination,”Dr. Beckert explained. “They will absorb, for example, heavy metals. If we give them garbage to eat, they keep it. But if these fast-moving waters are clean, so are the mussels.
“It is possible to produce a lot of mussels with very low costs – environmental and economic. The most expensive thing is their harvesting and processing.”
Dr. Beckart added: “This level of detailed oceanographic information is also relevant to other valuable bivalves such as scallops and oysters, and being on a scale of meters rather than kilometers, is even useful for the salmon industry.”
paper,Predictive biophysical models of larval distribution of bivalve molluscs in Scotland, published in Frontiers in Marine Science.
https://www.foodnavigator.com/Article/2022/09/23/scottish-researchers-track-currents-to-new-insights-into-shellfish-farming?utm_source=RSS_Feed&utm_medium=RSS&utm_campaign=RSS Scottish researchers are tracking new knowledge about shellfish farming