Bernardino Sergio Malauene

The South‐West Indian Ocean (SWIO) displays marked spatial variations in physical forcings, driving in turn distinct seasonal biogeochemical regimes. Mesoscale eddies in the Mozambique Channel drive large‐scale redistribution of nutrients and plankton, while eastern Madagascar waters are highly oligotrophic. However, the spatial organization and diversity of biogeochemical seasonal cycles across the SWIO remain insufficiently characterized on the basin scale. This study examines the seasonal and interannual variability of surface chlorophyll‐a (Chl‐a), used as a proxy for primary production. A phenoregion approach is employed, involving the grouping of areas exhibiting similar Chl‐a phenology, that is, bloom timing (austral winter and/or summer) and the number of blooms per year (0, 1, or 2). 22‐year of weekly satellite‐derived Chl‐a from the OC‐CCI data set was used to generate normalized climatological seasonal cycles, which were subsequently clustered using a k‐means algorithm. This approach identifies six distinct Chl‐a phenoregions across the SWIO. Winter blooms dominate the basin and are likely associated with mixed‐layer deepening and enhanced vertical nutrient supply, leading to temporally stable phenoregions. In contrast, summer blooms are restricted to coastal regions and south‐eastern Madagascar, coinciding with enhanced terrestrial nutrient inputs during the wet season. In the Mozambique Channel, Chl‐a exhibits limited seasonal variability, likely reflecting strong eddy‐driven exchanges between coastal and offshore waters. Interannual analysis reveals stable phenoregion cores with consistent seasonality, while their boundaries exhibit variability, highlighting contrasts between persistent and highly intermittent biogeochemical regimes. The results obtained provide a basin‐scale framework for linking physical dynamics to ecosystem variability in the SWIO.

Sustainable fishery management requires a thorough knowledge of lifetime connectivity for exploited species to accurately define stocks and implement conservation and regulation measures at appropriate scales. This knowledge is especially critical in coastal regions in the Mozambique Channel, where communities rely on marine resources.In Mozambique more than two-thirds of the rapidly growing population (33 million) live near the coast; penaeid shrimps are a vital component of the local food supply, livelihood and the country’s blue economy. However, shrimp catches have declined dramatically over the last two decades. This decline is attributed to increased artisanal fishing in estuarine nursery areas, removing juveniles before they can grow and recruit into the adult populations offshore, where the industrial fishery operates.To understand larval connectivity and recruitment in the Sofala Bank region, we have employed a coupled biophysical model that accounts for adverse oceanographic conditions. Our research revealed that offshore eddies activity has an important role on coastal connectivity, and can have opposite effects depending on their locations, resulting in either larval recruitment, loss, or trapping.These results improve our understanding of local marine functional connectivity patterns and show the necessity to study connectivity at a local scale to assist in developing targeted management strategies for adaptation and resilience, ensuring the sustainability of both commercial and artisanal fisheries.

Fisheries are recognized as important in Mozambique, yet they are increasingly threatened by over-exploitation and climate change. We collate and synthesize the available literature and data on marine fisheries in Mozambique; assess the status of the main fishery species/stocks; give an overview of current management of the fishery, and discuss planning for fisheries resilience in the face of climate change predictions. In Mozambique there is a heavy reliance on marine fisheries. From a food security and local economy perspective, the critical sector is the artisanal fisheries which comprises over 90% of the total landings and provides food and livelihood for millions of people, particularly in the coastal zone. Regarding economic value and earning foreign currency, the most valuable industrial / semi-industrial fisheries are the shallow-water shrimp, the deep-water crustacean and the rocky bottom demersal. Current stock assessment for these sectors indicates that the core stock species are fully- or over-exploited. Limited data are available for the artisanal fishery, but it is likely that the same status applies to this sector. Globally, well-managed fisheries have been among the most resilient to climate change—overall, fisheries best practices confer ecological resilience by providing a portfolio of options to fishers and a buffer against losing target stock. Ideally, best practices include scientifically-informed catch limits, accountability measures, regional flexibility in policy practices, protection of essential fish habitat (Marine Protected Areas), and effective monitoring, control and surveillance. Mozambique has a relatively well-managed industrial/semi-industrial fishery. However, the artisanal fishery, due to its spatial scattering, multi-gear and multi-species nature, presents a huge challenge. Facing the future with climate change will require increased attention to reduce stressors to the social–ecological systems in which fisheries exist and persist. Specific recommendations in this context are presented.

The shallow-water shrimp fishery is an important social and economic sector in Mozambique. However, catches of shrimps have been declining over the last decades, presumably due to poor recruitment. Climate change has been proposed as a potential cause of increased mesoscale eddy activity over the Mozambique Channel, which may have played a role in poor shrimp recruitment. Indeed, stronger eddies could transport matter, including increased numbers of shrimp larvae, from the coast to unfavourable offshore areas. In this study we used a biophysical model to investigate the influence of eddies on the dispersal of larvae of two commercial shrimp species (Penaeus indicus and Metapenaeus monoceros) from their spawning areas on the Sofala Bank. We found some 5 large events of offshore or southward transport loss (>10% loss) from the Sofala Bank caused by eddies, occurring sporadically. The northern and central Sofala Bank areas were the most affected by larvae lost offshore. Simulations revealed that temperature-induced larval mortality, associated with cold-core cyclonic eddies, could also play a role in larval loss of up to 40%, which is greater than the larval transport loss associated with the eddy circulation. However, when they survived, larvae transported offshore could travel long distances (600–1600 km in 15 days), potentially promoting connectivity with other stocks in the region.

Mozambique is amongst the most vulnerable of Western Indian Ocean (WIO] countries to the impacts of climate change on its marine fisheries. We used rapid assessment methods to evaluate sensitivity, exposure and vulnerability of fisheries species to climate change, appropriate for data-deficient, developing countries in the region. Species were selected based on their importance in industrial and artisanal fisheries’ landings, further prioritized by local experts. Species’ attributes likely to be sensitive to climate change were identified and scored, utilizing life history or biological characteristics. Sea Surface Temperature (SST] was the most prominent climate exposure factor and for which we could confidently predict likely future change. Most species had low or medium overall sensitivity to climate change, with only eight considered highly sensitive. Climate exposure (SST] scores were high off northern Mozambique, while the central and southern regions were generally of medium exposure. Ten species received a High vulnerability score, 14 were Medium, and 16 had a Low vulnerability score. The highly vulnerable species were all fishes, apart from one crustacean; 4 of the 9 were strongly estuarine-associated; the most vulnerable species was the parrotfish Scarus ghobban. This is the first attempt to use a rapid, semi-quantitative, specialist- and trait-based vulnerability assessment of the anticipated effect of climate change on marine fisheries species in the WIO. Challenges experienced were data paucity, limited resources, the large study area, and the complex oceanography of the region. However, a simple methodology was developed, derived from efforts elsewhere, and which can be used to undertake similar assessments for other WIO countries. Raised awareness of climate change among small-scale fishing communities is a necessity, combined with adaptation by promoting fisheries co-management. Also required is support from government to ensure that people can be flexible to change.

The highly diverse goatfish genus Upeneus (Mullidae) requires enhanced attention regarding the possible occurrence of undescribed species in insufficiently explored regions. This study focuses on the South-Western Indian Ocean region (SWIO), and on the so-called japonicus-group, a taxonomic species group of Upeneus. Based on in-situ observations and collections in Sodwana Bay, KwaZulu-Natal, South Africa, the Floros goatfish, U. floros n. sp., is described. Detailed comparative studies of colour patterns and morphological characters of all other 13 japonicus-group species were undertaken as well as COI barcoding. The new species occurs in the coastal area between Angoche, N Mozambique and KwaZulu-Natal and partly overlaps in distribution with two similar species, U. guttatus, widely distributed in the Indo-W Pacific, and U. saiab, assumed to be endemic in a small area off Angoche. Two additional japonicus-group species occurring in the SWIO, U. seychellensis from the Seychelles Bank and U. pori from the Mediterranean Sea (as Lessepsian migrant), Northern Red Sea and Madagascar, were also compared. Because specimens as well as in-situ photographs of U. floros have been erroneously identified as either U. guttatus or U. pori during previous studies, updated taxonomic accounts and diagnoses are provided for these species taking size-related and population differences into account. For U. pori, of which a single preserved specimen from SW Madagascar was known so far, a new record from NE Madagascar is reported based on three specimens and a fresh-colour photo. Upeneus floros can be distinguished from U. guttatus and U. pori by a combination of three characters: head length, first dorsal-fin height and number of gill rakers. Upeneus guttatus can be distinguished from the other two species by disproportionally higher anterior dorsal-fin spines vs. a proportional decrease of dorsal-fin spines in height, barbels mostly yellow vs. white or creamy-white, and slightly fewer pectoral-fin rays. COI barcoding detected a clear distinction between U. guttatus and U. floros and U. pori, respectively, but no significant divergence between the two latter species. COI barcoding also failed to differentiate several other Upeneus species which are clearly distinguished morphologically. Possible interrelationships between species distribution patterns and physical oceanography are discussed. An identification key for the 22 WIO Upeneus species is provided.