Pond Boss Forums AQUATIC VEGETATION Controlling unwanted plants New Pond Algae Problems

This is my personal commentary about some statements in this thread which
I think should be explained in a little more detail.

1. Bluegillkiller says: �� but it�s a never ending battle and with the little vegetation your pond has you will always have algea.� BillCody (BC) - This I think is a good statement. Some form or specie of algae either filamentous or planktonic will always exist in all ponds and water bodies even under toxic conditions. Algae is the basis of the aquatic food web and forms of it are everywhere and it has many ways of being introduced to your pond. It usually has dormancy stages that allow it of regrow when conditions for its growth improve. Filamentous algae when over abundant is often considered a nuisance. The good part about it is, while growing it is absorbing lots of dissolved substances from the water, thus purifying the water. Dying and decomposing it is polluting your water by putting or recycling all the stored or bound nutrients back into the pond ecosystem.

2. Sandman says: �I fear that if I spray now, too much algae will die and deplete the oxygen.� BC - Partly true. Too much dying algae or any organic material that is rapidly decomposing will consume lots of dissolved oxygen from the water. The better plan when �killing� abundant algae is to not treat all the algae at one time. Treat a smaller percentage (20%-30%) of the algae at intervals of 7-10 days at each application when the algae are abundant and covering larger areas.

3. Sandman asks �I'm still left to wonder why I have an algae problem. There is NO runoff at all coming into my new pond. � and Esshup responds: �By pumping water from the other pond, you added nutrients. Without submerged plants in the pond to utilize the nutrients, the FA started growing�. BC - Basically true. A large portion of the nutrients in a new pond can also came from the fresh exposed dirt especially if that dirt is fertile which usually contains enough nutrients to grow lots of terrestrial plants/weeds or aquatic plants, often those plants are FA absorbing nutrients from the fresh nutrient laden bottom sediment. Often in a new pond without submerged plants the first plants to grow are phytoplankton (algae) or filamentous algae. There are several common pond plants that are primary invaders in a newly built pond. Which one grows and how much is determined by the nutrient N:P ratio, who gets seeded first, are usually the ones that are dormant in the sediment, or first to get introduced. Plant species can get seeded into a new pond can come from the water from the fish hatchery or bird manure! Usually phytoplankton and filamentous algae both grow but one type grows more abundantly based on conditions. Some people introduce or seed plankton into a new pond so it is likely the first to bloom.

Esshup �If you leave the FA there, it will continue to grow/die/re-grow. By stocking Tilapia, they will eat the FA, and when they are removed at the end of the year (either by you or by scavengers) some of the nutrients in the pond will be removed�. BC - Basically true. A lot of the contained nutrients in the pond are recycled. However some will become bound in the sediments or bound into the living biomass of the pond ecosystem. Others become dissolved to be used by the various types of aquatic plants � primary production.

Esshup: �Doing an alum treatment in the pond will also help by binding up phosphorus, which the FA loves. See the "alum kicks clays butt" thread in the muddy water section�. BC - Basically true. Some species of FA thrive more on higher nitrogen than some of the other FA. It depends on the species of filamentous and what nutrient concentration it is best adapted to utilize.

Esshup: �Hitting it with an algacide will work, but you'll probably be on a (roughly) 6 week treatment cycle, depending on the nutrient load in the pond�. BC - Partly true. Sometimes algal treatments will keep algae growths reduced for longer than 6 weeks. It depends on the amount of available dissolved nutrients and the N:P ratio that are available after algal treatment. Sometimes after an algal treatment, the nutrient concentration shifts or changes and without the previous abundant FA colonizers / growers a plankton bloom will form, become abundant and keep FA and submerged weeds reduced - shading. Several noticeable or visible different conditions can occur in a pond after a herbicide treatment.

Esshup: �The growth cycle of the FA is as follows:
It grows on the pond bottom where sunlight can reach, and occasionally it grows suspended in the water column. Once it grows thick enough, any gasses that are generated in the pond are trapped in the mat. Once enough gasses are trapped, that part of the FA mat breaks free from the bottom and floats to the surface, where it gets more sunlight, and continues to grow/die/re-grow.� BC - Partly true. FA at least the green Chlorophyta FA group very rarely if ever grow truly plankonically (suspended). When green filamentous algae exists in the water column it is a tycoplankter or accidental plankter and does not actively reproduce while a plankter or floating. The floating green mats become thick, shade the underlying holdfast cells, those die and the mat floats due to entrapped gasses. Some bluegreen (Cyanobacteria) filamentous species are truly planktonic species. Truly planktonic filamentous Chlorphyta algae, especially the more common species are very rare, I know of none that are truly planktonic almost all are accidental plankters, dislodged from the underwater surfaces.

4. Sandman: �Tell me honestly, do they effectively reduce algae up in these northern climes? Do they cause any problems when they all die off at once in the fall?�
Rainman:� stocked properly and at the right rates/sizes, the algae reduction/elimination is nothing short of amazing!!! Plus there are a myriad of other benefits that are achieved from adding tilapia with dramatically improved water quality, improved health, size and numbers of all your other pond fish...Reduced muck...� BC - Words describing tilapia such as �amazing� and �myriad� of benefits� are adjectives and subjective opinions. However, personal reports from pond owners in northern Ohio and many other areas have been very positive regarding how tilapia can consume algae, pondowners that use them properly at the correct numbers are believers and repeat customers. One pond management company that sold blue tilapia for the first time had a 90%+ repurchase rate of returning customers; this is a proven and documented fact.

5. Esshup: � Also, I found out last year that if there is a submerged or emergent weed clump, the Tilapia will not force their way thru the weeds to get at the FA.� BC - Probably true. Submerged weeds could act as a fence or barrier to the encroachment of tilapia. The type or specie of weed may also be a factor with this behavior. Blue tilapia have been observed eating Chara, a type of submerged branched vegetation (true algae). Thus it is feasible that tilapia could eat a pathway through the more delicate and thin types of submerged weeds.

6. Sandman: � I'm not sure whether to get the tilapia alone, the alum alone, both tilapia and alum, or just study this more and wait until next year�. BC - Sometimes a combination of tools will be the best approach to deal with a pond problem. The pond manager has to weigh all factors when deciding which tool or combination of tools to use for each particular problem.

7. PondPro: �One word. Clipper.
This is a newer product to the aquatic pest management industry and I can attest from personal experience that this product works amazing on algae.�
BC � this is from the manufacturer (Valent) of Clipper: �Clipper selectively controls a number of invasive and nuisance aquatic plants, including submersed plants such as hydrilla, Eurasian watermilfoil, curlyleaf pondweed and cabomba as well as floating plants such as duckweed, giant salvinia, water lettuce and watermeal.� The product label suggests that Clipper be used primarily on floating types of filamentous algae. �Floating Filamentous Algae: When applied at rates of 6 to 12 ounces per acre as a surface spray, Clipper Herbicide provides control of floating filamentous algae, including Pithophora and Cladophora. Follow application instructions for surface foliar applications.� BC - All filamentous green algae begins growth primarily on the bottom or attached to underwater surfaces. Clipper is suggested to be used on floating filamentous algae and not label recommended for dealing with the attached submerged growth forms of FA on the bottom or underwater. These underwater growths are the main incubation areas of filamentous green algae. When the surface mats are killed often large underwater FA growths are still present that can later break loose, float and be problematic. The instructions of the label of Clipper also caution users to not apply Clipper in water with pH higher than 8-8.5 which leads to inactivation of Clipper.

8. PondPro continued:� Regarding Tilipia for a means of control... That's hell of a lot of money to spend on fish that will NOT control the algae as previously stated. Besides, that is a hell of a lot of fish excrement in the water that will only add to the nutrient load and further algae problems�. BC - Many different pond situations occur in dealing with filamentous algae and use of tilapia for algae control. Not all tilapia are the same subspecies. Reportedly some subspecies or hybrid tilapia are different and have different �tastes� and appetites for filamentous algae. Some such as the blue tilapia stay active eating algae is slightly cooler water compared to other tilapia. Number of predators in the pond can affect how many of the young algae eating tilapia survive to eat algae. There are lots of variables of why tilapia and chemicals may or may not work to control FA. Yes - the fish that eat algae do produce manure. But also a lot of the algae that is eaten is converted to fish biomass and this is especially true in the new young of year (YOY) tilapia. This can amount to a significant amount of bound nutrients that were in the consumed as FA. These bound nutrients in small tilapia can be further moved upward into predator biomass which is a more long term nutrient binding of nutrients that were once in FA. True, dead decomposing tilapia as with many of the other natural mortality of old fish decompose in the pond and are recycled back into the pond ecosystem. Nutrient pathways in the pond food web can be complex.

9. Bocomo says: �The experts said that tilapia WILL control the algae if adults are stocked at the correct density�. BC � Not only experts but numerous pond owners have confirmed by repurchasing and testifying that tilapia especially blue tilapia work well for them in various types of pond settings that have many types of filamentous algae problems.

10. Rainman says: �Tilapia utilize virtually all nutrient they consume at a rate of 1.2:1...that "excretement, is nearly devoid of nutrient. Unlike other fish waste�. BC - All manure has nutrient content. No doubt that some types of manure contain more nutrient value than others. I have seen whole kernel corn in manure of some animals � inefficient digestion. �nearly devoid of nutrient� is subjective and could be partially true compared to the nutrient content of manure from other species of animals. Chicken manure for instance is very high in ammonia �nitrogen. Some bird manures are very high in phosphorus. Tilapia are low on the food chain and digestion could be more efficient compared to inefficient digesters. This assumes the tilapia can convert plants into fish biomass at the rate of 1.2 :1.

11. Rainman says: �Tilapia reduce the net available nutrient load in waters they are stocked in, by moving the nutrient up the food chain, not increasing it....�. BC- Partly true. Since tilapia do not directly consume available dissolved nutrients, tilapia convert the bound nutrients and move a portion of the consumed biomass into fish biomass putting some of the bound nutrients into a �higher part� or level of the food chain. When tilapia consume algae the soluble nutrients in their manure are available for other primary producers such as phytoplankton, periphyton, rooted plants and FA. Additional nutrients are released from decomposing tilapia manure as is that of other fish and all dead organics in a pond.

12. Rainman says: �Tilapia are fast becoming a viable and far safer alternative to algaecides in many market areas�. BC � partially true especially for people that prefer a natural non-chemical control of plant problems.

13. Rainman says: �Any chemical can kill a plant, yet there is no reduction in nutrient, merely a recycling of it through decay....plus the hope and a prayer that some plant other than algae takes up the recycled nutrient�. BC - Primarily true. Herbicides can kill plants if used on susceptible plants. Dead organics including those washed or blown into the pond do usually decompose and release soluble and bound nutrients back into the pond ecosystem. Dissolved nutrients are used by plants as primary producers and some bacteria to thrive in the aquatic habitat.

14. Cecil Baird1 says: �If so why is it (tilapia manure) sold as plant fertilizer?� �..it just seems hard to swallow that their excretement is "nearly devoid of nutrient." BC - Many types of manures and organic materials are composted and sold as soil improvements for plant growth. Nearly devoid of nutrient is probably a relative statement compared to manure of other types of animals that have high nutrient content in their concentrated manure such as chickens - birds. As mentioned earlier, some types of manure are more nutrient rich than other types � depending on the animal and what it has eaten. It all depends.

15. Sprkplug says: �.. . when the Tilapia die off due to colder temps, wouldn't their decomposition add nutrients right back into the pond? I know it's often touted as an advantage to predatory fish, as in the Tilapia become easier for them to catch when they get sluggish in colder water, but what about a scenario wherein no such adequate predators are present? (just LMB in the 12" range) ....I can see where the smaller Tilapia might be eaten, but not the adults.�
�Wouldn't that shift the burden of removal right back onto the pondowner, as in more manual labor removing dead or dying fish? And what about the ones that sink to the bottom? It seems like fertilizer to me?� BC � basically true conclusions. Decomposition of dead tilapia and other fish do ultimately release � recycle nutrients back into the pond. Soluble nutrients grow plants. Dying struggling lethargic tilapia are very vulnerable to predators. Consumption of herbaceous tilapia moves a measurable amount of nutrients especially important the phosphorus (in protein) into predator biomass further keeping nutrients bound and unavailable to plants. Removal of dead fish is beneficial to removing bound nutrients from the pond ecosystem.

16. esshup says: �In my pond, the Tilapia that are too large for the fish to eat are usually either eaten by turtles, or dragged out of the pond by raccoons or other mammals and eaten. I've never seen more than 5 tilapia dead in my pond a few days after they died off�. BC � Most if not all tilapia that I�ve witnessed of them living in a cage - when they die they sink. When gas forms inside the fish they float. When the fish sink, sometimes scavengers get on the limp fish or dead fish which may be why many adult dead tilapia are not seen on the surface.