Price and market structures in fisheries change rapidly, now 40% of seafood is traded internationally and are associated with overharvesting of marine species. We have developed a bio-economic fishery model to address the pressing need of managing the interplay of different markets. We first regard local, multi-level and global markets individually and then analyze the effect of transitioning between markets on the exploitation of species and the stability of income. We find that in gradually globalizing markets, transition management needs to account for non-linear price changes since earlier policies may not be suitable after globalization. We hypothesize that short-term policies to ban harvest in the interest of species recovery benefit a local market in which incentives prevent overharvesting. In global markets we expect that sustained initiatives are needed to prevent overharvesting. Individual fisheries using contextualized models representing local ecological and trade structures may benefit from assessing the price dynamics presented in this analysis.

Small-scale fisheries are ubiquitous and critically important around the world, but they are under serious threat from climatic changes and variability. Climate-driven redistribution of maximum fisheries catch potential is expected to be most severe across tropical regions where small-scale fisheries are widely governed through relationships between fishery users, i.e. fishers and traders. These informal cooperative and competitive relationships provide access, support, and incentives for fishing and affect benefit distribution in fisheries. Yet, their formal management is often informed by economic analyses that focus primarily on the actions of and impacts on individuals. We argue this leads to a disconnect between reality and its model representation, which may reduce the efficiency and efficacy of formal fisheries management 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 and competitive trade relations in an illustrative, empirical showcase in the Mexican Humboldt squid fishery.We find that (1) the social-ecological model substantially improves accuracy in predicting observed fishery variables compared to the simple bioeconomic model, (2) climate-driven changes in cooperative trade relationships affect fishers’ income and income inequality, and (3)  the current fishery development program, that is supported by the predictions of the simple bioeconomic model, may increase income inequality between fishers and traders. Our findings highlight the real and urgent need to re-think the current analytical boundaries of models in the context of small-scale fisheries and climate change worldwide to encompass social relationship dynamics.

Fisher-trader relationships (FTR) encompass a wide range of influential and informal relationships that are present in many small-scale fisheries (SSF) worldwide. FTRs' potential to establish and maintain informal rules (FTR rules) that affect the resilience of fishing practices has shifted them into focus for formal fisheries management. Linking formal management rules to the landscape of informal rules requires a better understanding of fishers and traders’ role in rule-making and types of informal rules related to fishing practices. Here, we map out the informal rules related to fishing practices in Indonesia, Spermonde and compare them to formal fisheries management measures. We further assess fishers and traders' role in shaping certain fishing practices from which we draw preliminary conclusions about how and when formal fisheries management should involve fishers and traders. We find that FTR rules in Spermonde relate to a diversity of fishing practices and correspond to formal fisheries management measures such as in- and output control, temporal and spatial management. The emergence of fishing practices are linked to multiple functions within the FTR and to the network of relations of fishers and traders with other groups. These external relations are primarily served by traders. Thus, we argue that a foundation for linking formal fisheries management and informal rules exists on the basis of their similarity. Understanding the multiple functions and networks of relations can help identify intervention points for building or breaking resilience of fishing practices in Spermonde and beyond.

Increases in the speed and scale of seafood trade in the global trade network along with the simultaneous decline of many marine fisheries globally raises serious concerns about the sustainability of such trade development. The continuity, number and grouping of trade connections has changed: seafood trade in the Anthropocene is short-lived and globally connected. In this new reality, (i) the formation of new trade connections can outpace that of regulatory action in fisheries and (ii) the state of a fishery can depend on its trade-related connectivity to other fisheries. Despite mounting empirical and theoretical evidence of the importance of trade networks in natural resource management, indicators of network speed and scale are rarely used to understand fisheries sustainability. Here, we assess whether the speed and scale of the seafood trade network is indicative of fishery status. Our data consolidates post-1995 global, bilateral trade data including >400,000 bilateral trade flows and stock status estimates for 746 stocks from 222 countries and is analyzed with both static and dynamic panel analysis methods. We find that low levels of grouping in the network correlates with low fishery status and despite increasing numbers of trade connections grouping has declined. Contrary to earlier findings, we demonstrate that long-term trade connections correlate with low fishery status. These results highlight the importance of the way trade develops i.e. in the continuity and grouping of trade connections as key indicators of fisheries sustainability. Thus, policies aimed at improving fisheries sustainability cannot focus on regulating local fisheries alone. For one, trade agreements could target the formation of new multilateral trade alliances. Parallel efforts of international trade organizations, national trade and fisheries ministries need to create incentives that long-term trade connections enable sustainable fisheries use.