Sea levels in parts of the north and west of Solomon Islands are running well below normal, the Solomon Islands Meteorological Service said on 16 October, in a pattern it links to past El Niño events.

The tide gauge at Tarekukure Wharf is reading approximately 0.30 metres (30cm) below predicted tide levels, the service said, while satellite data show sea levels well under average off Santa Isabel and in the New Georgia and Marovo regions.

El Niño sets in when the trade winds that drive warm surface water west weaken, the service said. Ocean water and sea levels then shift east towards the central and eastern Pacific Ocean, pulling sea levels in the western Pacific, Solomon Islands among it, down by around 10 to 40 centimetres, and by more in stronger events. El Niño is now well established and is expected to strengthen further by the end of the year, so the low levels should hold for months yet, the service said.

Marovo Lagoon and other reef-enclosed waters get less water over the reef barrier on each tide, the service said, so the lagoon and the open sea trade water more slowly and natural flushing drops off.

Satellite readings also show raised chlorophyll along parts of the coastline, a sign of more phytoplankton, the microscopic marine plants. Phytoplankton are a normal and important part of marine ecosystems, but the service said very high levels can point to nutrient-rich water and bring on algal blooms, and that oxygen is used up as large amounts of organic material break down.

Sea surface temperatures are near normal or slightly cooler than average, which the service said suggests a marine heatwave is not behind the changes seen in Marovo. It pointed instead to low sea levels, slower water movement and fewer nutrients coming in, alongside other natural processes.

Dissolved oxygen may fall for periods in sheltered or poorly flushed areas, the service said, stressing fish and other marine organisms and, in severe cases, killing fish in one spot, as in the incident in Marovo. With El Niño forecast to keep strengthening into early 2027, it urged communities and resource managers to watch for further impacts in lagoon systems, and said sea levels, water quality and marine ecosystems should keep being monitored.

Source: Statement issued on 16 October 2026 by the Solomon Islands Meteorological Service, published on the Solomon Islands Government portal on 20 October 2026. https://solomons.gov.sb/low-sea-levels-linked-to-el-nino-may-increase-environmental-risks-around-solomon-islands/