Biobío Coast

The Biobío coast occupies central Chile's Pacific edge, roughly between the Maule Region to the north and the Araucanía to the south. The tidal regime is mixed semidiurnal; spring range at Talcahuano, the naval port immediately north of Concepción, is approximately 1.5–2.0 m above Chart Datum — modest by the standards of the Los Lagos Region to the south but with sufficient range to create productive intertidal zones along the rocky points and inside the sheltered reaches of Biobío Bay. This coastline carries a significant geological and historical memory. The Mw 8.8 Chile earthquake of 27 February 2010 ruptured the subduction zone offshore; the tsunami that followed reached Dichato with run-up heights of 4–6 m above mean sea level, largely destroying the town. The rebuilt Dichato is a modern village with a modest beach and a hard-earned awareness of tsunami risk. SHOA operates the Pacific-wide tsunami warning centre from Valparaíso; the regional emergency protocols require timed evacuation drills at coastal communities including Dichato and the Arauco Peninsula settlements. The Bay of Arauco to the south of Concepción focuses incoming Pacific swell around the Arauco Peninsula, producing consistent surf conditions at several exposed points. Shore-fishing along this coast targets congrio (cusk eel, Genypterus chilensis), corvina (Cilus gilberti), and lenguado (flounder) — species that respond to the incoming tide concentrating bait on the rocky points. Concepción Bay (Bahía de Concepción) is a broad semi-enclosed bay; the city of Concepción sits 10 km inland on the Biobío River, with Talcahuano as its port. SHOA publishes Chilean tide tables; Open-Meteo Marine powers predictions here: accuracy ±45 min / ±0.2–0.3 m.