Seahorses escape death this time round
Sanparks coordinated a citizen science project of collecting seahorses after the breaching (opening) of the Swartvlei river mouth in Sedgefield following last week’s rains.
The Swartvlei estuary, which is also home to the seahorse, was breached at about 05:00 on 27 November.
A few days later, dozens of local residents responded to assist Sanparks researchers with the study – which includes collecting dead seahorses and returning those that are alive to the estuary.
Just last year, Sanparks staff with volunteers collected 900 seahorses, of which 450 were alive and returned to their habitat.
This year though, they found 11 and only one survived, which is indicative of certain trends, according to Clement Arendse of Sanparks scientific services.
He stated that the Swartvlei estuary has large population fluctuations and periodic mass deaths of seahorses.
“If we find no seahorses it could tell us that the delay in the dropping of water level assisted the seahorses in having enough time to escape, or perhaps the population is a bit lower than last year,” said Arendse, who explained that when the water level drops the seahorses “suddenly get exposed” and hang onto the grass and vegetation – which sometimes results in death. “We do vegetation studies as well and this will also give us information on the seahorses,” he said.
Volunteers searched for seahorses along assigned sections of the Swartvlei banks and were requested to collect permits for the work and complete information cards to be placed with any dead seahorses found at their assigned section.
“We are trying to find out why the populations fluctuate and how seahorses respond to breaching events. The information gathered will also help determine if areas that flood when the mouth is closed are used by seahorses as habitat.
“Citizen scientists therefore play a key role in helping to reduce mortality of seahorses in the Swartvlei estuary and provide invaluable information on their distribution and habitat, aiding management of this iconic species.”
Dozens of local residents with Sanparks rangers and staff.
Sanparks officials conduct a demonstration of measuring water levels after breaching the river mouth.