25 November, 2014 25 November, 2014

Red Tide, Take Two

The pictures speak for themselves but the coastline along PE, looking somewhat apocalyptic, does spark at least some inquiry. Not the funnest conditions for a quick dawnie before work that’s for sure. After looking at the photographs, our heads tweaked slightly to the side in bewilderment, we decided to get some first-hand information from PE local Kerry Wight, in hopes of finding out exactly what’s potting with this unusual environmental phenomenon.

“Eish, the red tide has returned,” wrote Kerry Wright of Millerslocal.

Images © Millerslocal and Algoa FM


Saturday morning dawned with a sea that looked like tomato soup. Another phytoplankton bloom had sprung up overnight. It was visible in thick concentrations from Avalanche down to King’s Beach, and despite the beautiful summer weather there weren’t too many takers willing to hazard a swim in the soup.

There had been reports of small concentrations of red tide from Plett through to Jbay and the Wildside of PE earlier in the week, but it only bloomed in the bay on Saturday.


The first question on everyone’s lips was whether it was the same critter that was responsible for the lengthy red tide at the start of this year. It has however been confirmed by SAEON that it is most likely a species called Noctiluca Miliaris. This is not the same guy as before – Lingulodinium Polyedrum – although some cells of this species were recorded in the water column.

That’s not to say LP won’t be back. Cells of the plankton form cysts on the sea floor can re-emerge when the environmental conditions are right. So those lil critters will stay in the bay permanently, lurking in the shadows until conditions to come out and jol again look perfect again. They may yet return in the heat of summer if conditions are right.


Noctiluca Miliaris, the species responsible for Saturday’s bloom, is not a new species to Algoa Bay, but hasn’t bloomed here on this scale before. It’s a marine-dwelling species of Dinoflagellate that can exhibit bio-luminescence when disturbed. It seems like only some strains of the species glow-in-the-dark though, so whether this guy will give rise to any night time plankton parties is anyone’s guess. Haven’t heard any reports of it yet.


Typical South African logic would say how to take two kak things and turn them into something lekker. Red tide is kak, load shedding is kak, but a load shed at night so we can see the light show glow on the beach out front – that’d be pretty cool…

So is it toxic? No-one seems sure yet, but it has been associated with fish and marine invertebrate mortality events in other parts of the world. Although this species does not produce a toxin itself, it has been found to accumulate toxic levels of ammonia which is then excreted into the surrounding waters, and it is this that could be acting as the killing agent in blooms. So spit the water out, don’t swallow.


Let’s hope we don’t have a long, red summer. But if conditions are like they were last year, it might well be.

The good news for now is that Saturday’s bloom dissipated overnight, and the sea in the bay has gone back to being blue. Let’s hope it stays that way.


1 Comment

  1. nick
    25 November, 2014 at 7:56 am · Reply

    ts drifted down the coast to Cape St Francis though . . .

Leave a reply

Your email address will not be published. Required fields are marked *