Monitoring the Penobscot River Restoration Project: Baseline Data to Inform Ecosystem Response

Dam removal is increasingly being used as a tool to restore aquatic habitats and recover imperiled species. However, many presumed effects of dam removal (i.e. fish community changes, water quality improvements) are largely un-documented. Given significant investments being made in dam removal, rigorous monitoring is needed to elucidate ecological impacts and allow for informed decision making when allocating restoration resources. The Penobscot River Restoration Project in Maine, USA, is an innovative restoration project aimed at restoring self-sustaining populations of diadromous fish through increased connectivity via dam removals and fish passage improvements, while maintaining hydropower output. Beginning prior to dam removal in 2009, independent researchers began documenting baseline conditions via a multi-disciplinary, coordinated monitoring framework. The framework has continued through project implementation, following a before-after study design. Monitoring focuses on geomorphology, water quality, fish community, fish passage, habitat use, shoreline revegetation and marine-freshwater nutrient transfers. As before-after comparative analyses continue to unfold, this presentation aims to provide the most current results of this monitoring effort, highlighting several patterns which have emerged to-date: 1) all native diadromous species of fish are present in the river, many successfully reproducing on their own; 2) diadromous species persist despite access to only a small percentage of their historic habitat, many now beginning to increase in number; 3) the former lowermost dam, represented a near complete barrier to migration for most species and is now traversed by many similarly to free-flowing sections; 4) large changes to flow, sediment regime, and habitat (except in the immediate vicinity of the former dam sites) were unexpected and did not occur; and 5) water quality did not appear to be limiting for most species. This effort provides an objective, credible basis for evaluating ecosystem response to dam removal and a knowledge base to support restoration approaches in other systems

The Living Planet Index (LPI) for migratory freshwater fish:Technical Report

Migratory freshwater fish (i.e. fish that use freshwater systems, either partly or exclusively) occur around the world and travel between critical habitats to complete their life cycle. They are disproportionately threatened compared to other fish groups but global trends in abun-dance, regional differences and drivers of patterns have not yet been comprehensively described. Using abundance information from the Living Planet Database, we found widespread declines between 1970 and 2016 in tropical and temperate areas and across all regions, all migration categories and all populations. Globally, migratory freshwater fish have declined by an average of 76%. Average declines have been more pronounced in Europe (-93%) and Latin America & Caribbean (-84%), and least in North America (-28%). The percentage of species represented was highest in the two temperate regions of Europe and North America (almost 50%). For the continents of Africa, Asia, Oceania, and South America, data was highly deficient, and we advise against making conclusions on the status of migratory freshwater SUMMARYfish in these areas. Potamodromous fish, have declined more than fish migrating between fresh and salt water on average (-83% vs -73%). Populations that are known to be affected by threats anywhere along their migration routes show an average decline of 94% while those not threatened at the population level have increased on av-erage. Habitat degradation, alteration, and loss accounted for around a half of threats to migratory fish, while over-exploitation accounted for around one-third. Protected, regulated and exploited populations decreased less than unmanaged ones, with the most often recorded actions being related to fisheries regulations, including fishing restrictions, no-take zones, fisheries closures, bycatch reductions and stocking (these were most com-mon in North America and Europe). Recorded reasons for observed increases tended to be mostly unknown or un-described, especially in tropical regions. This information is needed to assemble a more complete picture to assess how declines in migratory freshwater fishes could be reduced or reversed. Our findings confirm that migratory freshwater fish may be more threatened throughout their range than previously documented

Session C3: Balancing Power Production and Fisheries Restoration in the Penobscot River Watershed: Background, Updates, Recent Successes and Difficulties

Abstract: In 1820 the Penobscot (USA) Maine\u27s largest river was first completely dammed, effectively blocking passage of what was likely an annual run of well over 10 million fish including over 100,000 now-Federally Endangered Atlantic salmon. Populations of sea-run fish plummeted to a fraction (thousands to mere hundreds) of historic counts and marine fisheries which foraged on the searun adults and juveniles also declined precipitously. Through an innovative FERC relicensing process, a multiparty agreement was signed in 2004 by the hydropower company, a new NGO, The Penobscot River Restoration Trust (the Trust), as well as signatories from state and federal agencies. This agreement resolved decades of conflict over fisheries and hydropower in this most critical river for Atlantic salmon. Looking at a system of dams rather than one at a time, allowed a solution that increases power generation at six dams while increasing fish passage at five others. It led to the acquisition and decommissioning of three large mainstem dams and removal of the two lowest-most dams in 2012 and 2013. The development of a river-like bypass around an upstream dam is under construction. Once finished, mainstem dam improvements will increased access to over 1,000 miles (1609 km) of habitat upstream, meanwhile energy generation already has increased slightly above pre-project levels. At the same time a coalitions of restoration partners are restoring access to tributaries through dam removals, upgraded culverts at road stream-crossings and developing effective fishways to other tributary waters – especially with ponds for alewife spawning.Early results include e hundreds of thousands of new fish coming upstream and we are at the front of the projected population growth. This presentation summarizes creative problem solving balancing energy production with ecological values and reports on the stunning biological responses to restoration in the first of recovery

More than one million barriers fragment Europe’s rivers

Rivers support some of Earth’s richest biodiversity1 and provide essential ecosystem services to society2, but they are often fragmented by barriers to free flow3. In Europe, attempts to quantify river connectivity have been hampered by the absence of a harmonized barrier database. Here we show that there are at least 1.2 million instream barriers in 36 European countries (with a mean density of 0.74 barriers per kilometre), 68 per cent of which are structures less than two metres in height that are often overlooked. Standardized walkover surveys along 2,715 kilometres of stream length for 147 rivers indicate that existing records underestimate barrier numbers by about 61 per cent. The highest barrier densities occur in the heavily modified rivers of central Europe and the lowest barrier densities occur in the most remote, sparsely populated alpine areas. Across Europe, the main predictors of barrier density are agricultural pressure, density of river-road crossings, extent of surface water and elevation. Relatively unfragmented rivers are still found in the Balkans, the Baltic states and parts of Scandinavia and southern Europe, but these require urgent protection from proposed dam developments. Our findings could inform the implementation of the EU Biodiversity Strategy, which aims to reconnect 25,000 kilometres of Europe’s rivers by 2030, but achieving this will require a paradigm shift in river restoration that recognizes the widespread impacts caused by small barriers

More than one million barriers fragment Europe’s rivers

Rivers support some of Earth’s richest biodiversity and provide essential ecosystem services to society, but they are often fragmented by barriers to free flow. In Europe, attempts to quantify river connectivity have been hampered by the absence of a harmonized barrier database. Here we show that there are at least 1.2 million instream barriers in 36 European countries (with a mean density of 0.74 barriers per kilometre), 68 per cent of which are structures less than two metres in height that are often overlooked. Standardized walkover surveys along 2,715 kilometres of stream length for 147 rivers indicate that existing records underestimate barrier numbers by about 61 per cent. The highest barrier densities occur in the heavily modified rivers of central Europe and the lowest barrier densities occur in the most remote, sparsely populated alpine areas. Across Europe, the main predictors of barrier density are agricultural pressure, density of river-road crossings, extent of surface water and elevation. Relatively unfragmented rivers are still found in the Balkans, the Baltic states and parts of Scandinavia and southern Europe, but these require urgent protection from proposed dam developments. Our findings could inform the implementation of the EU Biodiversity Strategy, which aims to reconnect 25,000 kilometres of Europe’s rivers by 2030, but achieving this will require a paradigm shift in river restoration that recognizes the widespread impacts caused by small barriers