Large-scale hydropower impacts and adaptation strategies on rural communities in the Amazonian floodplain of the Madeira River.

Understanding social and environmental impacts and household adaptation strategies in the face of expansions in energy infrastructure projects is essential to inform mitigation and interventions programs that promote well-being. Here we conducted surveys in seven communities distributed across varying degrees of proximity to a hydropower dam complex in the Brazilian Amazon along about 250 km of the floodplain of the Madeira River. Based on interviews with 154 fishers from these communities, we examine how fishers perceived changes in fisheries yields, changes in the composition of fish species, and whether and how adaptation strategies had evolved 8-9 years after the dams' construction. Most respondents (91%) indicated declines in yields after the dams for both upstream and downstream zones. Multivariate analyses revealed statistically significant differences in the composition of species yields in pre-and post-dam periods for all communities and in both upstream and downstream zones (p < 0.001). The composition of yields diversified after the dams, with an apparent decline in yields of species of greatest market value (e.g., catfishes Brachyplatystoma spp., Pseudoplatystoma spp., and jatuarana Brycon spp.), and increases in yields of a set of other smaller bodied and faster growing species (e.g., 'branquinhas' Psectrogaster spp., Potamohinna spp., and sardines Triportheus spp.). Both downstream and upstream fishers indicated that fishing profits decreased since the dams' construction (76.8% and 67.9%, respectively). To cope with these changes, the majority of both upstream and downstream fishers (>70%) stated they have had to devote more time to fishing after the dams were built. The time fishers spend traveling to fishing locations also increased for upstream communities (77.1%), but not for downstream communities. Thirty-four percent of the interviewees changed the gear they use to fish after the dams construction, with twice as many mentioning uses of non-selective gear, such as gillnets, and declining use of traditional fishing gears such as castnets and a trap ("covi"). Fish consumption overall decreased: fish was consumed 'everyday' before the dams, but 1-2 times per week or rarely after the dams were built. Although the species that declined were those of high economic value, 53% of fishers stated fish prices have increased overall after the dams. These results shed light on the potential challenges faced by fishers and which adaptation strategies they have evolved to maintain livelihoods since the construction of the dams.

Maturation of female common snook Centropomus undecimalis: implications for managing protandrous fishes.

The assumption for hermaphroditic fish species that mature individuals of the terminal sex arise directly from mature individuals of the primary sex has led to the use of sex ratios as a proxy for age at maturity (A50 ). The timing of transition and deficient energy reserves, however, can result in a delay between transition and spawning. To test the assumption of female maturity and investigate the relationship between maturation and energy reserves, common snook, Centropomus undecimalis, a protandrous hermaphrodite, were collected from rivers, estuaries, inlets and offshore habitats on the east coast of Florida during 2010-2015. Immature females were observed every month, with lowest proportions during the peak spawning months of July and August. When calculated based on sex ratio, A50 (8.1 years) overestimated the age at which 50% of the female population was, in fact, mature (4.1-4.9 years). Best-fit models indicate that mesenteric fat index (IF ) and hepato-somatic index (IH ) were significantly affected by gonad phase, month and size and weakly by habitat. In post hoc analysis, immature female IF did not differ significantly from developing and regenerating females, but immature female IH was significantly lower than that for all mature phases except animals in the regressing phase. Although immature females may have sufficient energy in terms of fat, it appears that energy is not allocated to reproductive processes, as evidenced by lower IH . Nonetheless, approximately 95% of females were spawning-capable during peak spawning months, suggesting that the energy threshold at which immature females reach maturity is met by most females each spawning cycle.

The invisibility of fisheries in the process of hydropower development across the Amazon.

We analyze the invisibility of fisheries and inadequacy of fishers' participation in the process of hydropower development in the Amazon, focusing on gaps between legally mandated and actual outcomes. Using Ostrom's institutional design principles for assessing common-pool resource management, we selected five case studies from Brazilian Amazonian watersheds to conduct an exploratory comparative case-study analysis. We identify similar problems across basins, including deficiencies in the dam licensing process; critical data gaps; inadequate stakeholder participation; violation of human rights; neglect of fishers' knowledge; lack of organization and representation by fishers' groups; and lack of governmental structure and capacity to manage dam construction activities or support fishers after dam construction. Fishers have generally been marginalized or excluded from decision-making regarding planning, construction, mitigation, compensation, and monitoring of the social-ecological impacts of hydroelectric dams. Addressing these deficiencies will require concerted investments and efforts by dam developers, government agencies and civil society, and the promotion of inter-sectorial dialogue and cross-scale participatory planning and decision-making that includes fishers and their associations.