Cape City – No lifeless or dying sardines have been reported to the Division of Forestry, Fisheries and the Atmosphere since Thursday, 6 August, suggesting that the current mortality occasion alongside the Western Cape coast has run its course.
West Coast canneries proceed to simply accept wholesome sardines caught north of St Helena Bay, whereas some factories in affected areas have elected to await the division’s outcomes earlier than resuming operations.
The trigger has not but been confirmed.
A large-ranging investigation involving the division, analysis establishments, specialist laboratories, the fishing trade and different collaborating scientists is constant.
Samples of lifeless sardines have been obtained from Saldanha Bay, Hout Bay, Betty’s Bay, Gansbaai and the Cape Canyon space.
Apparently wholesome sardines from Elands Bay and Lambert’s Bay have additionally been collected for comparability.
South African Institute for Aquatic Biodiversity (SAIAB) and Rhodes College are endeavor illness testing, whereas SAIAB and a specialist industrial laboratory are screening samples for marine biotoxins.
The division’s scientists are analyzing water samples, abdomen contents and gills for proof of dangerous algae.
Fundamental organic examinations, together with measurements of dimension, weight, situation and maturity, and macroscopic examination of the gills, have additionally been undertaken.
A dangerous algal bloom brought on by Alexandrium catenella was current in Saldanha Bay when the mortality started.
This dangerous alga has beforehand been related to sardine mortalities in South Africa and stays one of many doable causes below investigation.
Nonetheless, it has not been detected within the water samples or sardine abdomen contents examined so far, and preliminary analyses haven’t recognized a harmful-algal trigger.
Oceanographic info provided by SAEON and the CSIR signifies enhanced upwelling, unusually chilly nearshore water and low oxygen in St Helena Bay earlier than the occasion.
A southward-moving coastal present may even have transported affected fish from the West Coast in the direction of Cape Level and farther east.
These observations present helpful context however don’t set up the trigger.
No wider results on the marine ecosystem have been reported so far.
Sardines are however an vital meals supply for seabirds, seals and predatory fish, and the division will proceed to observe any doable results on the sardine inhabitants and its predators.
As a precaution, whereas testing continues, members of the general public shouldn’t acquire or eat lifeless fish discovered on seashores.
The division thanks the fishing trade, particular person fishers and vessel crews, CapMarine, BirdLife South Africa, SAIAB, Rhodes College, SAEON, the CSIR, Cape Nature, different collaborating scientists and specialist laboratories, and members of the general public who provided studies, pictures, movies and samples.
The response demonstrates the robust hyperlinks between authorities, analysis establishments, specialist laboratories and the fishing trade, enabling a number of parallel traces of investigation to proceed quickly.
The division stated additional updates will probably be supplied as soon as illness testing and preliminary biotoxin outcomes can be found, most probably early subsequent week.
These specialised analyses take time as a result of samples should endure a number of phases of preparation, testing and verification earlier than the outcomes will be interpreted reliably.
