Navigating the winds - Challenges of the Vann Swet to coral reef restoration

The South-East trade winds, known as "Vann Swet" in Creole, which sweep across our islands from June to September bring about many changes. Weather and sea conditions get rough. Excursions to the ocean are reduced. Boat crossings get bumpy.

Weather and sea conditions get rough during this time

For Nature Seychelles’ Reef Rescuers carrying out the coral reef restoration project in the Cousin Island Special Reserve MPA, Vann Swet comes with a slew of challenges that can have a significant impact that tests the resilience and determination of those working tirelessly to restore corals.

These include reduced access to the project’s sites because of fewer diving days, poor diving conditions, and an influx of algae and debris requiring more effort in nursery upkeep.

Charlotte Dale, the project’s Science & Technical Field Officer explains.

“Navigating to Cousin Island becomes particularly challenging during this season. Rough seas and unpredictable weather conditions can make boat journeys dangerous. This poses logistical challenges as the safety of the team has to have priority; therefore, the transportation of personnel, equipment, and supplies becomes uncertain.”

During this period, strong winds prevail and the resulting rough sea affects the prevalent sandy bottom. This increases sand presence in the water column and reduces visibility. Wave action and surge also increase in project locations directly exposed to the wind.

“Almost all key project sites are exposed during the Vann Swet as they are located on the South and South-west side of Cousin Island. The only exception is the nursery site, though despite calmer waters, once we arrive the journey across the channel to reach the destination is generally difficult and limited,” Charlotte says.

As a result, nurseries are sometimes left unattended for a prolonged period of time until the winds die down.

Unfortunately, the decrease in water temperature and other environmental factors create ideal conditions for plankton and algae proliferation. Corals in nurseries can be affected, resulting in a reduction in their survival rates. This also means that the team has to put in extra effort to keep nurseries clean.

The team has to put in extra effort to keep coral nurseries clean

All this can disrupt project timelines, increase costs, and reduce the team's ability to meet targets.

To face these challenges the Reef Rescuers team plans activities to balance in-water and on-land targets.

Experiments are also ongoing to reduce algae overgrowth during prolonged periods of inaccessibility due to the monsoon.

Nature Seychelles is also set to roll out Africa’s first on-land restorative coral facility on Praslin to expand coral farming activities and increase restoration success.

Coral reefs are important ecosystems

Coral reefs are not only biodiversity hotspots but also provide livelihoods for many communities and protect coastlines from erosion and storm surges. The project seeks to restore the fringing coral reef within the Cousin Island MPA, which has been affected by climate-changed induced coral bleaching.

The current phase is part of a regional project in Seychelles and Mauritius, which is supported by the Adaptation Fund through the UNDP and the Government of Seychelles.