For more than a decade, water management solutions firm Aquatic Harvesting has conducted environmental assessments and provided ecological monitoring, erosion prevention, and water-based project management services aimed at improving Ireland’s rivers, lakes, wetlands, and canals.
While out on the water completing such tasks as removing invasive plant species, Aquatic Harvesting team members began to notice that many Irish riverbeds were uniform and compacted, making it difficult for female salmon to clear gravel beds and lay eggs.
In response, Aquatic Harvesting has devised a machine to make the country’s rivers more amenable to breeding wild salmon, which could help revive sharply declining populations of the fish in Ireland.
“We did a lot of research and development,” Aquatic Harvesting CEO David Graham told SeafoodSource. “Using our machine floating on the water surface, we lift the riverbed with a mechanical bucket and let the water wash the stones. Therefore, the stones are more accessible for a female fish.”
Graham explained that the research and development entailed looking back to the 1940s and ‘50s in Ireland, when fish populations were at record highs. He said that at the time, teams of people used hand tools to loosen riverbeds for salmon breeding.
“There were 14 or 15 lads on low wages who would work for months at a time on a stretch of river, shaking up the riverbed. The survival rates of salmon then were much higher than now,” Graham said, describing the inspiration behind his firm’s new machine. “Today however, health and safety regulations wouldn’t allow workers to operate at a similar level, and people today don’t want to do that kind of work. Our machine will do the job much quicker than manual labor could.”
As part of the machine’s eventual rollout onto Ireland’s rivers, Aquatic Harvesting is working with Inland Fisheries, the Irish authoritative body that oversees inland freshwater waterways Atlantic salmon use to access breeding grounds. Inland Fisheries, which will trial the machine before its use on the country’s rivers, has reported that the number of wild salmon returning to Ireland to breed has progressively declined from well over 1 million for much of the 1970s to under 200,000 in recent years. Current catch totals are less than half the levels seen in the 2000s.
The decline has prompted concern within the Irish government, with Minister of State at the Irish Department of Agriculture, Food, Fisheries, and the Marine Timmy Dooley recently calling for public consultation on how best to achieve population recovery.
“The continued decline in stocks is of great concern to me,” he said. “I have asked Inland Fisheries Ireland for their views on the existing salmon management regime and to consider what options may be available to address the ongoing decline in stocks, up to and including a moratorium on the harvesting of salmon.”
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