The ‘seaweed’ that has been turning up in Gibraltar waters over the past two years is a brown alga, commonly known as Forkweed (Dictyota dichotoma), which has increased tremendously in its distribution throughout the Bay.

The alga has been turning up on shores around the north of the Bay, including Western Beach and the Playa de Poniente in la Linea. It has also appeared growing and expanding in areas such as off Camp Bay, Seven Sisters, etc., where it is possibly beginning to interfere with other marine life.

As part of its continued marine surveillance programme, the Department of the Environment and Climate Change (DECC) has been monitoring the increasing presence of the brown alga throughout Gibraltar’s waters. Although this species has been present in the Strait and the wider Mediterranean region for some time, scientists from the DECC are now investigating the reasons why this species is quickly invading Gibraltar’s underwater environment and washing up in large quantities on our shorelines. Initial observations suggest that the growth of Forkweed could be attributed to changes in regional currents and nutrients, and the possibility of climate change being a contributing factor cannot be discarded. The DECC will continue to monitor the growth of this species in British Gibraltar Territorial Waters in order to try and understand the phenomenon better.