Differential gene expression analysis in the scallop Argopecten purpuratus exposed to altered pH and temperature conditions in an upwelling-influenced farming area

Increased carbon dioxide in the atmosphere and its absorption across the ocean surface will alter natural variations in pH and temperature levels, occurring in coastal upwelling ecosystems. The scallop Argopecten purpuratus, one of the most economically important species farmed in northern Chile, has been shown to be vulnerable to these environmental drivers. However, the regulatory responses at the gene-level of scallops to these climate stressors remain almost unknown. Consequently, we used an orthogonal experimental design and RNAseq approach to analyze the acute effects of variability in pH and temperature on gene expression in the muscle tissue of A. purpuratus. In respect to control conditions (pH ~ 8.0/ 14 °C), the influence of low pH (~ 7.7) and temperature (14 °C) induced the activation of several genes associated with apoptotic signaling pathways and protein localization to plasma membrane. Elevated temperature (18 °C) and pH (~8.0) conditions increased the expression of transcripts associated with the activation of muscle contraction, regulation, and sarcomere organization effects on muscle tissue. In scallops exposed to low pH and elevated temperature, the genes expressed were differentially associated with the oxidation-reduction process, signal translation, and positive regulation of GTPase activity. These results indicated that the differentially expressed genes under the experimental conditions tested are mainly related to the mitigation of cellular damage and homeostasis control. Our results add knowledge about the function of the adductor muscle in response to stressors in scallops. Furthermore, these results could help in the identification of molecular biomarkers of stress necessary to be integrated into the aquaculture programs for the mitigation of climate change.

Displacement, disempowerment and corruption: challenges at the interface of fisheries, management and conservation in the Bijagós Archipelago, Guinea-Bissau

Small-scale fishers working in the West African Bijagós Archipelago are predominantly regional in-migrants, often living in isolated fishing camps (or economic enclaves) where capture, processing and trading activities occur. This paper explores the factors driving the fishing camp formation, relations with non-camp communities and interactions with prominent authority groups. One camp, presented here in the context of an anthropological case study, lost access to Ancopado beach during the designation of Orango National Park. Following violent evictions, migrant fishers shifted their efforts into less-observed waters, introducing challenging power negotiations with indigenous Bijagós islanders and fisheries authorities. Fishing persists inside the marine protected area, indicative of non-compliance by small-scale fishers who continue to resist a weak resource management agenda. The implications of this situation are discussed in terms of human rights to fish.