Professor Ken Whelan:

I am grateful to the Cathaoirleach, Deputies and Senators for inviting me to speak on behalf of the Atlantic Salmon Trust. Since the industrial revolution, which began in 18th century, man-made barriers have become a major feature of rivers across Europe and North America. Waterways provided a readily available source of power generation and transportation and were fundamental to the growth of many major industries since that time. As the committee has heard, barriers come in the form of dams, weirs, rock barriers, abstraction and discharge points. They can result in the fragmentation of waterways and cause severe disruption to fish passage and to the natural life cycle of many freshwater and estuarine fish species.

In the past, rivers were seen as water channels and there was a complete disregard of the fact that, in their natural state, they are living entities which support complex, interacting aquatic food webs.

The effects of such barriers on large migratory fish species such as Atlantic salmon, European eels and even sturgeon originally in Irish rivers were very obvious, but the more subtle and, at times, far more complex impacts on the physical flowing water environment were little understood.

Facing into the full impacts of climate change over the years to come, it may well be that the impacts of barriers on flow and river discharge patterns, sedimentation and water temperature will come to fore. Barriers cause a wide range of issues for migrating fish, including: blockages and delays to migration, leading to mortality or the disruption of life-cycle phenomena such as spawning time and juvenile migration, which we call phenology; mortality of migrants due to fish passage issues and increased predation at so-called pinch points; water temperature impacts, particularly during prolonged and intense droughts; difficulty in traversing large reservoirs and failure of the fish’s flow-based migration systems, which we call rheotaxis; unnatural changes in water discharge patterns and in the variation of the strength of flow; and changes in sediment transport patterns and the build-up of sediment loads in reservoirs and slow-flowing reaches of impounded river systems can also be a problem.

Over the past two decades there has been a growing awareness of the need to tackle the issues relating to barriers and fish migration. Recognising that in Europe an increasing number of aging dams were approaching the end of their economic and technical lifespan, which is typically about 70 to 100 years, the European Commission developed guidance to assist EU member states in identifying and prioritising barriers for removal. The removal or mitigation of such barriers presents a unique opportunity for rejuvenating rivers and restoring ecological free passage for migrating fish. These efforts align with the European biodiversity strategy, which aims to restore 25,000 km of free-flowing rivers in the EU by 2030. A similar programme of barrier removal and mitigation is actively ongoing in North America. In 2022, some 60 dams were removed across the United States, reconnecting more than 430 upstream river miles, or 690 km, in 20 states. This effort aims to break down river barriers and restore natural flow patterns. The stated goal is to eventually see dam removals in all 50 states.

To identify and quantify the extent of the barrier issues involved in Europe, a major research programme was funded in recent years. The EU's adaptive management of barriers in European rivers, AMBER, project focused on fish passage in European rivers. Through IFI, Ireland has been actively involved in assessing the barriers present across the country, as members heard earlier. A major barrier and fish passage conference, hosted by the AMBER project, was held in 2021. This conference covered topics such as fish migration routes, fish behaviour, downstream migration, socioeconomic considerations, tidal barriers, fishway solutions, policy improvements and monitoring technology. It also explored nature-based solutions, climate change and dam removal options. Community involvement is essential to finding solutions to fish barrier issues. A co-operative, multidisciplinary approach has been found to be very effective in both Europe and North America. There are many examples showing just how effective such an approach can be.

Dam removal has been successfully achieved in France and the US. On the Sélune River in Normandy, the 36 m Vezins Dam was breached in 2019, marking the beginning of the largest dam removal project in Europe. The removal of this dam is part of a long-term effort to ensure that the Sélune River regains the status of a naturally free-flowing waterway. In addition, the 16 m high La Roche-qui-boit Dam was successfully removed in June 2022. The overall Sélune project aims to benefit wildlife, including Atlantic salmon and eels, and enhance water quality along the river. The Sélune River flows into the famous Mont Saint-Michel Bay, a UNESCO World Heritage site and a major tourist attraction.

In the US, major dam removal projects have been successfully achieved though co-operative ventures on the Penobscot and Kennebeck rivers. The Penobscot river faced significant challenges, including a dwindling population of wild Atlantic salmon and a drastic decline in alewife, which is a type of river herring.

By 2009, wild Atlantic salmon were added to the endangered species list in the US. The river’s health was in crisis, with only two alewives counted at the Veazie Dam in 2010, while historically, the river held millions of individuals of this species. The Penobscot Nation and the other organizations formed the Penobscot River Restoration Trust. Through their efforts two major dams: the Veazie Dam and the Great Works Dam were removed. In recent years, as many as 590,000 alewives (also known as river herring) were recorded moving upstream in the Penobscot River. This represents a 45-fold increase from the 2013 estimates of annual upstream migration!

By 2009, wild Atlantic salmon was added to the endangered species list in the US. The river’s health was in crisis, with only two alewives counted at the Veazie Dam in 2010, though historically the river held millions of individuals of this species. The Penobscot Nation and other organisations formed the Penobscot River Restoration Trust. Through their efforts, two major dams: the Veazie Dam and the Great Works Dam, were removed. In recent years, as many as 590,000 alewives, which are also known as river herring, were recorded moving upstream in the Penobscot River. This represents a 45-fold increase from the 2013 estimates of annual upstream migration.

In Europe, the European Rivers Network, ERN, has been involved in the removal and the mitigation of a wide range of barriers. The ERN was actively involved for many years in concluding an agreement with the French Electricity company Électricité de France, EDF, for the mitigation of the Poutès Dam on the upper Allier system, a key salmon-spawning tributary of the Loire River in France. The Poutès Dam was constructed during the Second World War for electricity production, without authorisation. Since the late 1980s, environmental NGOs have been concerned about its impact on the environment, particularly the near extinction of the Loire strain of Atlantic salmon. Following many years of negotiation between NGOs, local representatives and EDF, a compromise solution emerged. The dam would be maintained, but significantly modified to allow for the free passage of both juvenile and adult migratory fish, particularly Atlantic salmon, over their key migration periods. Construction of the fundamentally redesigned dam was completed in 2022, but the great achievement of this design is that it allows EDF to utilise some 70% of the river's original capacity to generate electricity, while guaranteeing a completely free-flowing passage for migratory fish at key times in their life cycle.

Decided recently, in December 2023, the designation of the International Union for Conservation of Nature, IUCN, of the global status of Atlantic salmon as near threatened, and in the UK as endangered, is a reminder to us that time is not on our side in tackling the issues which are impacting our migratory fish species. According to the IUCN's red list of threatened species, the status of the Atlantic salmon has changed quite significantly. In terms of its global classification, previously the Atlantic salmon were categorised as of "least concern” on the IUCN red list. However, due to multiple threats during their long-distance migrations between freshwater and marine habitats, global Atlantic salmon populations have declined by 23% since 2006. As a result, their global status has now been reclassified by IUCN from of "least concern” to "near threatened".

The UK populations of Atlantic salmon have faced even greater challenges. Since 2006, British populations have declined by 30% to 50%. Projections indicate a further decline between the years 2010 and 2025. Consequently, the UK population of Atlantic salmon has been reclassified as "endangered".