Bahia

Salvador stands at the entrance to Baía de Todos os Santos — the Bay of All Saints — one of the largest bays in the Americas by surface area, at roughly 1,100 square kilometres of sheltered water enclosed behind a narrow entrance between the Itapagipe Peninsula and the Ilha de Itaparica to the southwest. The bay's size and geometry produce the defining tidal fact of this coast: the bay amplifies the tidal range compared to the open Atlantic immediately outside. Semidiurnal tides with a mean spring range of 2.5 to 3.0 m make Salvador one of the more tide-influenced coastal cities in Brazil, where much of the Atlantic-facing northeast coast sees a smaller range. The bay's hydrodynamics are complex. The Itaparica island and the Tinharé-Boipeba archipelago to the south create tidal passages where currents run at speeds that matter to both commercial and artisanal navigation. The traditional sail-powered fishing craft of the bay — the saveiro, a broad-beamed working vessel with a lateen-style rig developed from Portuguese colonial-era boat-building — have been reading these tidal currents for centuries. The saveiro is now rare in working configuration, more often seen in the annual Regata dos Saveiros yacht race, but the tidal literacy embedded in the traditional fishing communities around the bay margins persists in the artisanal fishing villages on Itaparica's eastern shore. The bay margins support some of the most extensive mangrove systems in Bahia State. These forests are tidal-dependent in the most literal sense: the frequency and duration of tidal inundation determines species composition and productivity. The mangroves around the Paraguaçu River mouth, Cachoeira, and the northern bay fringe at Iguape are functionally significant fisheries nurseries for the species — snook, snapper, mullet — that artisanal fishers target in the bay's open water. The tidal cycle is the operating pulse of those nurseries. Salvador itself sits on a bluff above the bay entrance; the Elevador Lacerda, the art-deco urban lift connecting the upper and lower city, looks directly over the tidal water of the harbour basin. The tide is the context for everything that happens at water level below.