The warm phase of El Niño Southern Oscillation (ENSO) is characterized in Peru by positive sea surface temperatures and negative sea level pressure anomalies. Biotic responses to this event range from changes in species composition, abundance and biomass, changes in reproductive success, larval dispersal and recruitment, as well as changes in food availability, competition and predation. This thesis characterizes fishermen livelihoods and how they responded to El Niño events in two sites in the North (Sechura) and South (Pisco) of Peru. Additionally, it explored how institutions enable or constrain fishermen livelihoods and responses to El Niño. While both sites have different histories of ENSO related impacts, they share the fact that the artisanal fishing sector plays an important role in the local economy. Livelihood assets exhibit mixed patterns with Pisco possessing a stronger livelihood platform
in terms of assets but lower incomes than in Sechura. This finding highlights the fact that income is not an accurate measure of resilient livelihoods and needs to be contextualized.
Seasonal migration is a livelihood option practiced by fishermen in both sites depending on seasonality, the de facto open access facilitating fishermen mobility. The thesis also identifies that fishermen are largely dependent on marine resources for their livelihoods, occupational pluralism being low at both sites. Diversification being considered a risk-reduction mechanism and a building block towards resilient livelihoods, the findings suggest that fishermen are vulnerable to external shocks due to their high reliance on fishing activities. Moreover, disturbances do not only include climate variability, but also market changes to which fishermen must adapt.