ABSTRACT
Coastal bivalves constitute valuable small-scale fisheries (SSFs), which are being threatened by several external drivers. One driver, climate, has been invoked as a putative factor causing mass mortalities during the last decades. However, there is a poor understanding about how these social-ecological systems respond to mass mortalities. The yellow clam (Mesodesma mactroides) is harvested in the sandy beaches of Brazil, Argentina and Uruguay and has been decimated throughout its geographic range by mass mortalities. By applying the integrated assessment framework I-ADApT, we assessed the responses of natural, social and governing systems of the yellow clam SSF to mass mortalities in Uruguay. The natural system was not resilient to the detrimental impacts of mass mortalities, even under a full fishery closure from 1994 to 2008. The social and governance systems were unaware of the occurrence of mass mortalities in the short term, and no contingency plans were in place, causing loss of income and unemployment. Fishers responded by diversifying their livelihoods in other sectors of the economy. During the fishery closure, the national government developed high-level policy goals, including an Ecosystem Approach to Fisheries (EAF) and co-management as the formal governance mode (EAF/co-management), which is applied today. EAF/co-management was implemented in the yellow clam fishery at Barra del Chuy, taking into account fishery traditions and the long-term relationship between fishers and government scientists. The fishery was reopened 14 years after mass mortalities, when the resource showed signs of recovery. Although clam abundance never reached pre-mortality levels, bioeconomic indicators showed a positive response to EAF/co-management implementation, and new markets were created. The government is using the results of this study to replicate this initiative to other SSFs. However, as external drivers remain potential threats to the system, information on early warnings of tipping points are needed to help manage this SSF.
