Historical ecology has described long-term changes in aquatic ecosystems, documenting population declines for marine and freshwater fish in excess of 90% (Rosenberg et al. 2005, Humphries and Winemiller 2009). One goal of historical ecology research has been to provide baselines for restoration, as documenting past abundance can both provide quantitative targets and motivate action among community members (McClenachan et al. 2012). In practice, however, restoration of animal populations to past abundances is often not possible due to larger ecosystem changes or inherent biological characteristics of the species itself (Yoshiyama et al. 1998, Marsh et al. 2005). In the eastern United States, industrial decline has facilitated large-scale river restoration, which has resulted in the rapid return of some species of anadromous fish populations, a phenomenon that is perhaps most pronounced in the state of Maine (Lichter et al. 2006). These successful restoration efforts provide an opportunity to assess the benefits of restoring historical ecosystem connectivity and animal populations. Although research on the benefits of ecological restoration has assessed increased biodiversity and ecosystem services (Benayas et al. 2009, de Groot et al. 2013), as well as direct economic benefits (Lewis et al. 2008), the social, nonmarket benefits of restoration are typically overlooked and thus have been consistently underestimated (Aronson et al. 2010, Petursdottir et al. 2013).
Documenting the social benefits of restored ecosystems falls within the realm of “new conservation,” defined in part through a focus on identifying and enhancing links among healthy ecosystems, economies, and social structures (Tallis et al. 2008, Kareiva and Marvier 2013, Levin 2014). Although the new conservation paradigm is not universally accepted as the best approach to protecting nature (e.g., Soulé 2013, Cafaro and Primack 2014, Miller et al. 2014), it provides a useful framework for analysis of restoration in highly altered landscapes. Its applied focus runs parallel to a rise in social–ecological systems (SES) research, which emphasizes the need to more fully describe the reciprocal relationships between humans and ecosystems (Gonzalez et al. 2008, Folke et al. 2010). An important tenet of both new conservation and SES work is that nature can be resilient, which has directed attention toward human-dominated landscapes such as urban and industrial areas. A second tenet of new conservation is that conservation efforts are most effective when they have a broad base of support. Therefore, it advocates finding common ground with groups typically outside the traditional folds of conservation, such as corporations and those involved with natural resource extraction. Likewise, SES research has highlighted links between ecological and social resilience (Folke et al. 2010), the ability of resource users to be stewards of natural resources (Friedlander et al. 2013), and commonalities between ecological fragmentation and social issues such as poverty and cultural disengagement (Cumming 2011).
In coastal regions, one robust SES in the past was small-scale, diversified fisheries (McClenachan and Kittinger 2013). Social benefits of small-scale, diversified fisheries include local empowerment over resource management, the ability for individual fishers to efficiently shift among target species, depending on seasonal abundance and availability, and increased individual profit through direct local sale of the seafood products. Ecological benefits include spreading effort across the ecosystem, thereby reducing pressure on any one fish stock, the ability to target locally abundant species, and decreased energy associated with transporting seafood to the consumer (McClenachan et al. 2014). In stark contrast, modern globalized fisheries systems have eroded both social and ecological integrity, with highly mobile fishing fleets resulting in serial depletion of fish populations (Berkes et al. 2006), contributing to widespread overfishing and economic marginalization of coastal communities (Thara Srinivasan et al. 2010).
Fisheries in coastal Maine have reflected these global patterns, characterized at present by extremely low diversity (Steneck et al. 2011) following serial depletion of high-value fisheries (Berkes et al. 2006). Changes over the last three decades have also resulted in a simplification of related SES: concentration of wealth (Bradley 2011), a reduction of diverse fishing rights (Alden 2011), and loss of ecologically important spatial diversity in fish populations (Ames and Lichter 2012). However, Maine also has a strong history of small-scale diversified fisheries and has shown recent momentum back toward these systems (Alden 2011, McClenachan et al. 2014, 2015). Likewise, recent restoration efforts in riverine systems have increased ecological connectivity and fish populations, while also creating opportunities for fisheries diversification. Such postindustrial restoration may not only allow a return of historical ecosystems and fish populations, but also a partial return to the types of preindustrial, small-scale fisheries systems that these rivers supported in the past. This fundamental shift may be both economically and socially important in areas currently characterized by depressed economies and lowered opportunity for community engagement. In this research, we investigate the suite of social benefits conferred by restoring historical fisheries and ecosystems using a case-study approach: alewives in Maine.
Alewives (Alosa pseudoharengus) are small, anadromous herrings ranging from Labrador to South Carolina that migrate upstream each spring to spawn in lakes. In Maine's rivers, alewives are harvested during the spring migration with small-scale gear, including weirs, cast nets, seines, and dip nets. Alewives have been an important source of food since the beginning of human settlement in New England, with 4000-year-old alewife bones identified from middens (Watts 2012). At the time of European settlement, alewives migrated through nearly every coastal watershed in Maine. Colonial fisheries developed in the 1600s, and by the end of the 19th century, annual alewife landings from Maine's river fisheries exceeded 3 million pounds (Smith 1896).
Alewife populations are closely tied to river development. From 1634 to 1850, industrial dam construction on Maine’s rivers reduced access to lake spawning habitat by over 95%, with subsequent population crashes (Hall et al. 2011). This industrial landscape dominated New England’s rivers until the early 20th century (Frank 2011). Restoration efforts to benefit alewives began in the 1940s (Rounsefell and Stringer 1945), and over the past two decades, large-scale dam removal and fish passage enhancement have occurred in Maine (Crane 2009, Maine Department of Marine Resources (MDMR) 2011). Local alewife populations have rebounded quickly in response. For example, the Fort Halifax dam in the Sebasticook River (Fig. 1) was removed in 2008; the first cohort of alewives to pass upstream exceeded 1.7 million fish, the largest run on the U.S. east coast in 2009 (MDMR 2009). Such increases are ecologically significant: alewives are the base of marine, freshwater, and terrestrial food webs, so alewife increases may contribute to increases in predator abundance (Lichter et al. 2006). Alewives also act as a prey buffer for endangered Atlantic salmon (Salmo salar), so their increase may facilitate the recovery of an endangered species (Saunders et al. 2006). The increase in alewife population appears to have simultaneously benefited people, as it has resulted in the growth of traditional river fisheries, in some cases reestablishing fisheries in towns lacking fisheries for more than two centuries. Here, we investigate those social benefits.