Social relationship dynamics mediate climate impacts on income inequality: evidence from the Mexican Humboldt squid fishery

Abstract

Small-scale fisheries are critically important for livelihoods around the world, particularly in tropical regions. However, climate variability and anthropogenic climate change may seriously impact small-scale fisheries by altering the abundance and distribution of target species. Social relationships between fishery users, such as fish traders, can determine how each individual responds and is affected by changes in fisheries. These informal cooperative and competitive relationships provide access, support, and incentives for fishing and affect the distribution of benefits. Yet, individuals’ actions and impacts on individuals are often the primary focus of the economic analyses informing small-scale fisheries’ formal management. This focus dismisses relevant social relationships. We argue that this leads to a disconnect between reality and its model representation used in formal management, which may reduce formal fisheries management’s efficiency and efficacy and potentially trigger adverse consequences. Here, we examine this argument by comparing the predictions of a simple bioeconomic fishery model with those of a social-ecological model that incorporates the dynamics of cooperative relationships between fish traders. We illustrate model outcomes using an empirical case study in the Mexican Humboldt squid fishery. We find that (1) the social-ecological model with relationship dynamics substantially improves accuracy in predicting observed fishery variables to the simple bioeconomic model. (2) Income inequality outcomes are associated with changes in cooperative trade relationships. When environmental temperature is included in the model as a driver of species production dynamics, we find that climate-driven temperature variability drives a decline in catch that, in turn, reduce fishers’ income. We observe an offset of this loss in income by including cooperative relationships between fish traders (oligopoly) in the model. These relationships break down following species distribution changes and result in an increase in prices fishers receive. Finally, (3) our social-ecological model simulations show that the current fishery development program, which seeks to increase fishers’ income through an increase in domestic market demand, is supported by predictions from the simple bioeconomic model, may increase income inequality between fishers and traders. Our findings highlight the real and urgent need to re-think fisheries management models in the context of small-scale fisheries and climate change worldwide to encompass social relationship dynamics.

Climate change impacts increase economic inequality: evidence from a systematic literature review

“…Indeed, this conservative approach might have led us to underreport the evidence of the regressive effect of climate change on economic inequality because of our decision not to categorise studies that did not make explicit statements on those effects. In the final list of papers, only two studies conclude that climate change decreases inequality, both of which focus on very specific local circumstances [36,37], and four papers identify the rich, either households [32,33], counties [34], or countries [35], as being more impacted by climate change, again mostly in very specific settings. The main exceptions are found to be a few studies where rich agents incur higher losses due to the higher size or value of owned physical assets.…”

“…Among the 52 papers which provide a conclusion on the impact of climate change on economic inequality, 35 papers find an increase in inequality due to climate change. Only two papers show a decrease in inequality due to climate change, both of which focus on very specific local circumstances: floods in Pakistan [36], which is however associated with a decrease in income in the affected regions, and inequality of prices between fishers and traders in Mexico [37]. A majority of studies thus concludes that climate change either increases economic inequalities, or has more impact on the poor, or both (69% of the corpus, 83% of the papers which conclude on either dimension).…”

Fisheries connectivity measures of adaptive capacity in small-scale fisheries

“…During anomalously warm years, squid catch volume declines but value increases as the resource becomes scarcer (Elsler et al, 2021). For most fishers, this means catching proportionally less squid and diversifying to other species.…”

“…Importantly, social processes can also influence how fishers respond to resource scarcity. For instance, in areas of high cooperation between fish buyers, fishers may receive less value for their squid catch as buyers collude to fix prices (Elsler et al, 2021). Depending on existing cooperative or competitive relationships with buyers, fishers may respond differently to squid shortages by ei-ther focusing on scarce but valuable squid or diversifying effort into other fisheries.…”

Strong collective action enables valuable and sustainable fisheries for cooperatives

“…Traders' and exporters' high margins, i.e. the profit from buying and selling not counting transaction and shipping costs, can deprive local communities of the benefits of international trade (Wamukota et al 2014, Purcell et al 2017, Elsler et al 2021. In addition, evidence shows that international trade can drive local depletion of fish populations (Crona et al 2016, Eisenbarth 2022, particularly those of high-priced species, by creating financial incentives that lead to overfishing (Elsler et al 2019).…”