The Agulhas current

The Agulhas Current is a powerful western boundary current in the Indian Ocean, flowing southward along the eastern coast of southern Africa. Originating near the Mozambique Channel, it is one of the strongest ocean currents in the world, transporting warm, saline water from the tropical Indian Ocean toward the southern tip of Africa. In the context of Mozambique, which boasts over 2,500 kilometers of coastline, the Agulhas Current plays a pivotal role in shaping the coastal climate, marine ecosystems, and socioeconomic activities. This article explores the current's effects on Mozambique's coast, highlighting its influence on climate, marine biodiversity, fisheries, and coastal vulnerabilities.

Climate Moderation

The Agulhas Current significantly influences Mozambique's coastal climate by transporting warm water along the shoreline, contributing to the region's tropical and subtropical characteristics. Cities like Maputo, Beira, Quelimane, and Pemba experience moderated temperatures due to the current's warm waters, which maintain relatively stable conditions year-round. For instance, coastal daytime temperatures rarely drop below 20°C (68°F), even in the cooler dry season (April to September), and often reach 30°C (86°F) or higher during the wet season (October to March). This warmth enhances humidity, particularly in northern and central coastal regions, where levels frequently exceed 75–85% during the wet season. The current's heat also strengthens monsoon systems, driving heavy rainfall to coastal areas, especially in provinces like Nampula and Zambezia, which receive 1,300–1,600 mm annually.

Marine Biodiversity and Ecosystems

The Agulhas Current is a lifeline for Mozambique's rich marine ecosystems, supporting diverse habitats such as coral reefs, mangroves, and seagrass beds. The warm, nutrient-rich waters foster high biodiversity, particularly in the coastal waters of Inhambane, where coral reefs thrive, and in Cabo Delgado, home to the Quirimbas Archipelago. These ecosystems are critical for species like dugongs, sea turtles, and numerous fish, many of which rely on the current's warmth for reproduction and survival. However, the current's strong flow can also lead to nutrient upwelling in certain areas, such as near Pemba, enhancing plankton growth and supporting complex food webs. This biodiversity underpins Mozambique's status as a global hotspot for marine life, attracting ecotourism to coastal regions.

Fisheries and Economic Impacts

Mozambique's coastal communities, particularly in provinces like Sofala and Nampula, depend heavily on fisheries sustained by the Agulhas Current. The current's warm waters support abundant fish stocks, including mackerel, sardines, and prawns, which are vital to both artisanal and commercial fishing industries. In Beira, a major port city, the fishing sector benefits from the current's role in maintaining productive fishing grounds, contributing significantly to local livelihoods and food security. The current also facilitates the migration of commercially important species, ensuring seasonal availability for fishers. However, overfishing and climate-driven changes in the current's strength or temperature could threaten these resources, posing risks to coastal economies.

Coastal Vulnerabilities and Extreme Weather

While the Agulhas Current supports Mozambique's coastal environment, it also exacerbates vulnerabilities to extreme weather events. The warm waters fuel the formation and intensification of tropical cyclones, which frequently strike the coast between January and March. Cities like Quelimane and Pemba are particularly susceptible, with cyclones like Idai (2019) and Kenneth (2019) causing devastating floods and infrastructure damage. The current's heat provides energy for these storms, increasing their intensity and rainfall potential, which can overwhelm drainage systems in low-lying areas. Additionally, the current contributes to coastal erosion in regions like Xai-Xai, where strong wave action driven by the current's flow erodes beaches and threatens infrastructure, necessitating adaptive measures like breakwaters.