8 June 2015
Scientists are trying to prove that the sardines that appear on the KwaZulu-Natal coastline are a different population group in the hope of pressuring the government to give them better protection.
There is a belief that time is running out, with research revealing that with each passing season the annual sardine run is becoming less predictable.
It is unclear why, but over-fishing of the commodity before it reaches the KwaZulu- Natal coastline is believed to be a contributing factor.
Last week, a pilot shoal landed in Margate, but recent rough seas may have dashed any hope of another shoal being spotted any time soon.
The shoal moves up the East Coast generally when water temperatures drop during winter, beginning its trek at the Agulhus banks, south-east of Port Elizabeth. The main batch heads up the West Coast while a smaller group, just 2% to 5% of the entire South African population, goes to KwaZulu-Natal.
KwaZulu-Natal Sharks Board operations head Mike Anderson-Reade admitted another poor season could be problematic following the lacklustre season of the last two years.
“Last year was the first time I did not handle a sardine in my career. If we have three bad cycles then we possibly have a reason to be concerned.
“It is important. It is nature’s bounty. Very little is for free yet these fish provide good protein. It is a special event,” said Anderson-Reade.
Dr Allan Connell, a South African Institute of Aquatic Biodiversity honorary research associate who has been collecting sardine eggs for 25 years at Park Rynie on the South Coast, said his data had revealed that the last 12 years had been less “predictable than the first 12 years”.
Connell takes samples weekly, sometimes daily, which includes 226 separate species of eggs and early larvae of fishes spawning pelagic eggs.
“The first half of my data in relation to sardines was stable and predictable, the second half not so.”
Study of ear bone
Connell said the researchers were trying to prove that sardines spawned on the KwaZulu-Natal coast returned every year for their approximate five-year life cycle. To do this they were peering into the otolith (ear bone) for their study. The study is currently focused on juveniles of about 10mm to 15 mm, with larger sardines expected to be part of a later study. “Our first study has shown that the chemistry of the otolith is different in the Natal Sardine to the West Coast Sardine.”
He said they were waiting to complete two more studies. “One batch in research is not conclusive enough to convince statisticians. But because the sardine runs have been wobbly, the chances are less that we will find juveniles.”
He said if their research was conclusive and proved that the KwaZulu-Natal sardine was a different population from that of the West Coast sardine, it could be used to tighten fishing controls.
“Without the science it will be difficult to convince the politicians of the need to better manage the sardines.”
Justin Mackrory, the chief executive of South Coast Tourism, said the annual sardine run, nicknamed ‘The Greatest Shoal on Earth’, helped to contribute to the about R500-million economic injection into the region during winter.
The Department of Agriculture, Forestry and Fisheries was approached for comment but was unable to provide a response at the time of going to press.