Golden Algae Bloom--Fish Kill is ON

[skeet]

Dove at Possum Kingdom Lake on Thursday, first thing I noticed were flocks of birds all around the lake, walked out on the pier and notice quite a few dead and dieing fish and then you notice a slightly different coloration to the water. The shop owner came out and said she had heard a couple of days prior that it was starting. I am not experienced with regard biology and such but it does appear that it is happening again.

 

[archman]

Probably related to the weird warm spells we're having.

 

[Hank49]

Dove at Possum Kingdom Lake on Thursday, first thing I noticed were flocks of birds all around the lake, walked out on the pier and notice quite a few dead and dieing fish and then you notice a slightly different coloration to the water. The shop owner came out and said she had heard a couple of days prior that it was starting. I am not experienced with regard biology and such but it does appear that it is happening again.

Anyone have a dissolved oxygen meter? Like Archman said, weather changes can cause "turnovers" in lakes where nutrient rich, oxygen poor bottom water comes to the surface. Check it at dawn for the lowest point of the day. But it may be already past the low point and on its way back up.

 

[archman]

Anyone have a dissolved oxygen meter?

Ha ha.

Actually my lab has a very nice one, but Possum Kingdom's a bit out of my driving range. Anyway, you don't need a D.O. meter, just a thermometer and historical records. If it's an algal bloom, you can scoop up a sample, stick it in a container and ship it off to the nearest phycologist for I.D.. Parks & Wildlife has a few regional experts, and there's a bunch at my level with nominal expertise. If it's a toxin-producing species, stay clear of the water. Does the air around the water smell sorta acrid? That's a bad sign.

Actually, with all those dead fish around and birds pooping the place up, nobody should be in the water anyway. You're at higher risk for getting bacterial and viral infections.

Unless the lake had an ice cover, and that ice cover has melted, "standard" limnetic turnover processes are unlikely. Other avenues to explore are:
1. surface water temperature: warmer than normal for this time of year? Any diver with a console or computer should have a thermometer to get a reading. If temperatures are higher, check the next options. You don't need any of them to get a bloom, but they certainly help.

1A. unusually high numbers of overwintering birds? They're poopin' in the water, and that's jacking up your phytoplankton densities.
1B. some clown dumped fertilizer in the lake.
1C. sewage line break or storm drain overflow.
1D. dredging-type operation.

With a non-iced over lake this time of year, most Texas lakes have enough wind mixing to keep things stirred up at the surface. Warm spells that heat up the upper layers will bring a lot of critters out of dormancy, and eat all the nutrients lying around. There's the making for an algal bloom.

 

[skeet]

Archman, whats the difference between this Golden algae stuff and a regular bloom. This lake was a great fish producer untill it hit for the first time back in 2001, twice. Must have wiped out 80% of the fish,a rough guess.

 

[Scubatooth]

skeet thanks for the update, well that sucks for the marine creatures and for divers as there would be less to see, and will muck up the vis. also will cause some issues with gear as last summer my gear had to be destunk every couple of days.

Keep the information coming

Tooth

 

[archman]

Archman, whats the difference between this Golden algae stuff and a regular bloom. This lake was a great fish producer untill it hit for the first time back in 2001, twice. Must have wiped out 80% of the fish,a rough guess.

Eek, there's a veritable heap of algal species that can cause nasty blooms. Just lumping in major categories, there's dinophytes, diatoms, cyanophytes, pelagiophyceans... there's more but my memory is fading. Bloom colour is a very loose diagnostic, and not to be relied upon.

Algal/bacterial blooms can be the non-toxic sort that simply kills via sucking all the oxygen out of the water column, or the toxic sort. Oh and there's a third type, the mechanical abraders, where spines and other sharp protuberances get caught up in fish gills and other delicate membranes.

Frequently if a bloom is dense enough to actually discolor the water, densities are high enough to kill/maim. This is in reference to monotype (single species) blooms mind you, not "generic" discoloration where a varied population of plankton, in concert with suspended particulates and stains, modifies the water turbidity.

In a big lake like Possom Kingdom, an 80% fishkill is quite a disaster. That's more indicative of a toxic bloom. However, Hank's comments about oxygen-poor bottom water cannot be ruled out. In order to suffocate a fish, dissolved oxygen values would need to drop below 2mg/liter. That's pretty dang low.

Nice thing about toxic blooms; they tend to peak and crash fairly quickly. They have their own problems, a combination of depleting their local nutrients/oxygen, and pico & nano-plankton parasites and viruses that take advantage of high cell densities (think the Plague). Many species encyst within sediments, lying dormant until conditions are ripe and something kicks them up into the water column. They can remain encysted for years. This makes prediction of blooms problematic.

There are toxicology tests that the state and federal agencies have for fishkills. Many algae can be traced by the type of toxin (i.e. domoic acid, brevitoxin). If Possum Kingdom is stocked by the state for recreational fishermen, it's likely TPWD has already collected samples and run such tests. You may wish to check with the local office.

 

[skeet]

Thanks Archman, you made me remember that TP&W has a website and thanks for the information.

 

[skeet]

I found this at TP&W website, http://www.tpwd.state.tx.us/hab/ga/

 

[texdiveguy]

I found this at TP&W website, http://www.tpwd.state.tx.us/hab/ga/

That is an interesting site,,,,dang blooms.