Spatiotemporal spatfall dynamics and prevailing estuarine conditions for optimal oyster (Crassostrea tulipa) spat availability in selected Gulf of Guinea brackish systems

Uncertainties associated with wild harvests of seed and adult oysters due to unknown oceanographic oscillations are a major challenge in oyster fisheries and aquaculture development. In contribution to addressing this challenge, we proffer clarity on the spatiotemporal variations in spatfall (number of spat/m2) of the mangrove oyster Crassostrea tulipa (Lamarck, 1819) in four estuaries along the Gulf of Guinea coast. By monthly deployment of artificial substrates affixed to bamboo racks over 12 months, we find significant differences in spatfall among and within the brackish systems, and across months and seasons. Spatfall regimes were unique in each ecosystem albeit with an overall preponderance of dry season availability of spat. Locations with reef oysters had superior spatfall to mangrove root-adapted-oyster areas. Narkwa, a relatively small lagoon with reef oysters had the highest annual mean spatfall, which was 1.3, 2.5, and 9.8 folds the spatfall in Densu Delta, Benya Lagoon and Whin Estuary, respectively. Spatfall varied significantly by depth as the more frequently exposed top collectors harvested much less spat than submerged collectors. There was a year-round availability of spat, confirming continuous spawning in C. tulipa. Spatfall variability was significantly driven by fluctuations in prevailing dissolved oxygen and salinity. Prevailing dissolved oxygen and salinity levels in the estuaries for optimal spat settlement were 1.68 – 3.40 mg L-1 and 11.00 – 29.33 ppt (parts per thousand), respectively. The findings of this study are recommended as empirical reference points for sustainable seed procurement for aquaculture production and management of C. tulipa fishery in the region of the study

Marine fisheries management in the Eastern Central Atlantic Ocean

Marine fishing is crucial to the socio-economy of West Africa fishery. However, the sector has many challenges, which have increased the call for an integrated approach that provides links among human needs, activities, changes in the state of the environment, and the resultant effect on ecosystem services for sustainable management in fulfilment of the Conservation on Biological Diversity and the Sustainable Development Goals. This study uses a socio-ecological framework (Drivers (D), Activities (A), Pressure (P), State (S), Impact (I) on welfare (W), and Response (R) as a Measure (M); DAPSI(W)R(M)) to assess the marine fishery sector of Ghana. Data were systematically sampled and analysed from vessel logbooks, fish manifests, observer reports, and relevant publications. Results show that Drivers, including livelihoods and revenue, food, and social status, contribute to industrial tuna and trawl fishing, and marine artisanal fishing activities. Where illegal fishing methods such as small meshsize nets (less than 25 mm), lights, poisonous substances, among others, are used. These activities have contributed to the pressures of selective fishing of juvenile and adult pelagic and demersal fish species. This has contributed to (changes in the State) the decline and vulnerability of Sardinella spp., and Engraulis encrasicolus, among others. The Impact on welfare includes Ghana becoming a net importer of marine species with increasing idleness of fishers due to reduced catch. Several management measures, including the Fisheries Act 625 of 2002 and Fisheries (Amendment) Regulations L.I. 2217 of 2015, and quotas in the tuna sector, among others, have been instituted to curb the effect of anthropogenic activities. Management measures, including influencing consumer behaviour for a sustainable fishery, enforcement, and data-driven management, have been recommended, in response to the targets of the Sustainable Development Goals, the United Nations Decade of Ocean and the Convention on Biological Diversity.info:eu-repo/semantics/publishedVersio

WTO must ban harmful fisheries subsidies

Sustainably managed wild fisheries support food and nutritional security, livelihoods, and cultures (1). Harmful fisheries subsidies—government payments that incentivize overcapacity and lead to overfishing—undermine these benefits yet are increasing globally (2). World Trade Organization (WTO) members have a unique opportunity at their ministerial meeting in November to reach an agreement that eliminates harmful subsidies (3). We—a group of scientists spanning 46 countries and 6 continents—urge the WTO to make this commitment..