Bringing Wild Salmon Back to the Rivers

29 May 2012
BOXMEER, The Netherlands

MSD Animal Health has teamed up with Marine Harvest and local aquaculture suppliers to help conservation groups in the UK and Norway restock populations of wild salmon

Following decades of declining wild salmon populations, a new multi-year trial aimed at restocking rivers is producing positive results. Working with the River Lochy Association in Lochaber, Scotland, and Vassalage (Vosso Guild) in Norway, Marine Harvest, the world's leading seafood company and largest producer of farmed salmon, began producing and introducing smolts — young salmon capable of migrating directly to the sea — into these formerly salmon-rich rivers.

By introducing smolts into the rivers, Marine Harvest works to increase the number of salmon returning to the rivers without increasing competition for food with the fish bred and reared in the river itself. In both the River Lochy and River Vosso, Marine Harvest utilizes eggs from the indigenous salmon species found in the rivers to produce these smolts.

Since the repopulation projects started in 2008, data show an increase in spawning salmon and number of eggs laid for fertilization. Larger Vossolak salmon are also being caught more frequently by anglers in both rivers heralding the return of improved sport fishing.

Protecting young salmon

Working together, Marine Harvest and MSD Animal Health are creating a unique bridge between the wild and farmed industries in aquaculture. MSD Animal Health contributes to the repopulation efforts by supplying SLICE® (emamectin benzoate), the industry’s leading product for controlling sea lice, naturally occurring parasites that live in the ocean and threaten the health and welfare of salmon.

“If left uncontrolled, sea lice can cause high mortality. They can also stress fish and make them more susceptible to bacterial and viral infections,” says Richard Endris, PhD, aquaculture research program manager for MSD Animal Health.

Due to the success of the restocking efforts, smolt production at River Lochy Association’s hatchery near Glenfinnan has been expanded to produce up to 100,000 per year. In Norway, more than 200,000 Vossolak, wild Atlantic salmon, have been released from Vassalage hatcheries. Reports from 2011 show an increase in the number of medium-sized salmon returning to River Vosso with large salmon expected in 2012. In both countries, the young fish are being fed medicated feed containing SLICE to protect them from the devastating effects of sea lice.

“This restocking project is a great example of how both interests — wild and farmed — can not only exist but thrive side by side as we move forward,” Ben Hadfield, Marine Harvest Scotland Production Manager, said in a recent press report.

“It’s great to be able to help,” added MSD Animal Health’s Bjarte Lygren, a member of the Aquatic Animal Health Business team in Norway. “There are several lice remedies, but SLICE is the only one with long-term effects capable of protecting the salmon from lice on its way out to the ocean.”

Technical expertise

Over the past decade, MSD Animal Health has garnered considerable technical expertise in the control of sea lice from working with salmon farms worldwide to manage the costly parasite. The company’s highly successful SLICE Sustainability Project is helping salmon farms develop integrated, long-term strategies for control.

“Through working with Marine Harvest and external stakeholders we have been able to provide a highly effective solution which benefits all participants and the environment,” adds Keith Morris, senior key account manager for MSD Animal Health in the UK, who believes that this innovative approach demonstrates the true potential from meaningful collaboration.

“Sea lice are a major challenge for both farmed and indigenous salmon populations. As result of sharing our technical and practical knowledge we have been able to collaborate with local conservation groups and create a program that significantly limits the impact of the lice burden and importantly supports the establishment and protection of local breeding programs.”