Blooming Algae

[Slider]

I would rather not be the bringer of this news as I know there are a heap of guys out there that won't receive it well. But our now annual scourge of anaulus australis has arrived en mass to Teewah Beach and I expect Fraser.

I wasn't impressed to see yesterday morning that the surf which had been crystal clear on Friday, had turned brown overnight. I can only assume that the front that brought a dribble of rain Friday night was the catalyst for the bloom.

The algae is of a microscopic type which isn't as bad as the hincksia which plagued us from 2001 to 2006, but it's not much better. Fish will come into the brown surf while the algae is alive, but seemingly reluctantly. But as the algae dies off, the water becomes eutrophied (deoxygenated) and the fish don't want to know about it at all.

There is no toxicity associated with this algae and it is safe to swim in, but it just doesn't look very inviting.

In the past, this algae once it arrives, doesn't go anywhere until a good solid south easterly blow, a low pressure system or cyclone comes along to kill it off. But I'm not sure that we'll have much other than northerlies for the next few months which would only exacerbate the situation.

Sorry guys.

Lindsay

[chisel]

So this stuff doesn't stick to lines and clog up runners too much?

[Slider]

Not at all Chisel. You can't actually see any individual particle of algae, but as the density of the billions of individual particles increases, the affect is to turn the surf zone green, then brown. This bloom was very rapid from blue to brown in less than 24hrs. It doesn't 'wash in' from elsewhere - it grows/blooms in the surf zone where temperature is ideal and through summer can extend offshore for several hundred metres. At the moment it is just the surf zone with a very definate change of colour where it is clean beyond that and a line of foamy green 'stuff' on the tide line.
However!!
When outbreaks of anaulus australis have occurred - every spring through summer for the last 9 yrs - snot weed has been quite bad. Last year I looked into any correlations and discovered that the 'salp' which is what snot weed is, feeds on algae. And when blooms occur, then the salps reproduce astronomically with the food resource. This may help reduce the time span for each bloom, but we end up with an alternating cycle of algae and snot weed.
Also of great concern is that this bloom didn't require a flood or particularly high temps to trigger it. The blooms that I can recall have all resulted (we think) from nutrient outfall with high spring rainfall in this region and/or with a sequence of days with temps over 30 degrees in late spring to early summer. Water temps here are still only around 21 degrees and previous blooms triggered by temperature have generally been when water temps were more like 24 degrees.

All cheery stuff when the surf is normally only clean between say March/April and September, and is netted between May and August.

[cuzzamundi]

Thanks Slider, some great info. I've noticed in Hervey Bay over the years that the snot weed is more prevalent in some areas than others....same as the dreaded hinksia! Generally the mouths of major rivers have been a huge problem in the past few years, yet a few km away from there, and the hinksia is less of an issue. I've also found that southeasters seem to bring the weed back in certain areas...why is that? Yet in others, the northerlies makes it worse. Does it affect fishing say a few km's out from the stretches it's at? Very interesting about the lack of oxygen in the water when it comes...I never thought of that, and it makes perfect sense. Thanks again for the great info as I've been wondering about this dreaded s@it for years!

CUzza

[Just_chips]

Not really what I wanted to hear only a couple of weeks from heading up to Fraser myself, but I can't say that I am surprised as with all this warmer weather/northerlies I was expecting it.

Hopefully I can find a gutter or two that isn't too badly affected.

Kev

[adrian johnson]

thanks for that info slider,we were heading up to teewah this week-end,might have to change our plans,cheers adrian

[Slider]

Am told the same algae bloomed on eastern beach of Moreton at the same time.

Water here is a fair bit cleaner today but still algaed.

[Slider]

Cuzza, it has been a bit of a mystery for us also on the movement of the hincksia. It seems certain that fresh water outfall - particularly from streams entering the sandy straights and hervey bay triggers hincksia blooms. Also hot weather causes it to bloom. But that's not to say that it can't grow in south easters it seems, and particularly in mid summer to early autumn. And hincksia, being a weed, takes a lot longer than anaulus australis to break down and will move where the currents take it until it has broken down.
As to affecting fishing offshore from hincksia - I doubt it. The eutrophication of the water would only be where the hincksia/algae is present - and dying.

I wouldn't expect any hincksia outbreaks this year due to the good wet seasons we've had the last 2 years and repeated large seas. But if we slip into el nino again ...

[Slider]

Algae is bad today - very brown in the surf zone.

[bam424]

Was thinking of heading up Teewah this week, has anyone got any info on the algae . Bruce

[bowds13]

hey bam was up there on the weekend the algea wasnt to bad but the fishing was pretty slow all weekend!

cheers

[adrian johnson]

hey bam was also up there on the week-end,like bowds13 said no algae no fish we got 2 whiting between 6 of us,cheers

[mowerman]

I was down at Pottsville on the weekend.

Yep, surf was full of algae.



Rod

[death_ship]

the water offshore from caloundra had plenty brown snotty stuff on top on friday, is this stuff an algal bloom?

[Slider]

Algae has been ... not so bad for the last few days, but still there. Was turning very brown in patches today though. Have seen a few dart caught from cleaner areas. Warmer conditions coming up the next few days are a worry.

Death ship, that would be trichodesmium which is an algae that occurs naturally in barrier reef waters. Blooms are said to be getting larger and moving further south. Haven't heard of any actual adverse affects from this algae.