WALVIS BAY - The executive director of fisheries, Annely Haiphene, has urged coastal residents to be cautious and rather refrain from consuming fish that had washed ashore.

Schools of fish and jelly fish had washed out on Sunday at the Lagoon and the Salt Pans. As a result, some residents flocked to these areas and collected buckets of fish. The phenomenon continued yesterday as well when several residents were still collecting the fish in the lagoon area.

Many dead or dying mullets were observed in the Walvis Bay lagoon area.

According to Haiphene, satellite images show algal blooms along the central Namibian coast and water temperatures around 25°C, which are usual for this time of the year, because of weakened south-westerly winds and consequently no active upwelling taking place.

“This leads to warming of the water as well as the intrusion of warmer oceanic water into the coastal areas, which are favourable for algal blooms (phytoplankton). Algal blooms can be toxic, but even non-toxic species strip the water column of oxygen when decaying, and can lead to low oxygen events that are sometimes exacerbated by sulphur eruptions,” she explained.

The oxygen conditions are presumed to have trapped the fish in the lagoon and along the coast, causing them to die and wash out when the water level drops during low tide.

Haiphene said the ministry is conducting water analysis to identify the phytoplankton species present in the Walvis Bay lagoon and harbour areas, and to determine whether they are toxic or not. 

“In the meantime, we caution against consuming the washed-out mullets, until the cause of death is established,” she appealed.